Estimating Mass Parameters of Doubly Synchronous Binary Asteroids

NASA Astrophysics Data System (ADS)

Davis, Alex; Scheeres, Daniel J.

2017-10-01

The non-spherical mass distributions of binary asteroid systems lead to coupled mutual gravitational forces and torques. Observations of the coupled attitude and orbital dynamics can be leveraged to provide information about the mass parameters of the binary system. The full 3-dimensional motion has 9 degrees of freedom, and coupled dynamics require the use of numerical investigation only. In the current study we simplify the system to a planar ellipsoid-ellipsoid binary system in a doubly synchronous orbit. Three modes are identified for the system, which has 4 degrees of freedom, with one degree of freedom corresponding to an ignorable coordinate. The three modes correspond to the three major librational modes of the system when it is in a doubly synchronous orbit. The linearized periods of each mode are a function of the mass parameters of the two asteroids, enabling measurement of these parameters based on observations of the librational motion. Here we implement estimation techniques to evaluate the capabilities of this mass measurement method. We apply this methodology to the Trojan binary asteroid system 617 Patroclus and Menoetius (1906 VY), the final flyby target of the recently announced LUCY Discovery mission. This system is of interest because a stellar occultation campaign of the Patroclus and Menoetius system has suggested that the asteroids are similarly sized oblate ellipsoids moving in a doubly-synchronous orbit, making the system an ideal test for this investigation. A number of missed observations during the campaign also suggested the possibility of a crater on the southern limb of Menoetius, the presence of which could be evaluated by our mass estimation method. This presentation will review the methodology and potential accuracy of our approach in addition to evaluating how the dynamical coupling can be used to help understand light curve and stellar occultation observations for librating binary systems.

Forming the wide asynchronous binary asteroid population

NASA Astrophysics Data System (ADS)

Jacobson, S.; Scheeres, D.; McMahon, J.

2014-07-01

We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semi-major axes relative to most near-Earth-asteroid and main-belt-asteroid systems as shown in the attached table. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational-fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide-asynchronous-binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

Capture orbits around asteroids by hitting zero-velocity curves

NASA Astrophysics Data System (ADS)

Wang, Wei; Yang, Hongwei; Zhang, Wei; Ma, Guangfu

2017-12-01

The problem of capturing a spacecraft from a heliocentric orbit into a high parking orbit around binary asteroids is investigated in the current study. To reduce the braking Δ V, a new capture strategy takes advantage of the three-body gravity of the binary asteroid to lower the inertial energy before applying the Δ V. The framework of the circular restricted three-body problem (CR3BP) is employed for the binary asteroid system. The proposed capture strategy is based on the mechanism by which inertial energy can be decreased sharply near zero-velocity curves (ZVCs). The strategy has two steps, namely, hitting the target ZVC and raising the periapsis by a small Δ V at the apoapsis. By hitting the target ZVC, the positive inertial energy decreases and becomes negative. Using a small Δ V, the spacecraft inserts into a bounded orbit around the asteroid. In addition, a rotating mass dipole model is employed for elongated asteroids, which leads to dynamics similar to that of the CR3BP. With this approach, the proposed capture strategy can be applied to elongated asteroids. Numerical simulations validate that the proposed capture strategy is applicable for the binary asteroid 90 Antiope and the elongated asteroid 216 Kleopatra.

Investigating the binary nature of active asteroid 288P/300163

NASA Astrophysics Data System (ADS)

Agarwal, Jessica

2016-10-01

We propose to study the suspected binary nature of active asteroid 288P/300163. We aim to confirm or disprove the existence of a binary nucleus, and - if confirmed - to measure the mutual orbital period and orbit orientation of the compoents, and their sizes. We request 5 orbits of WFC3 imaging, spaced at intervals of 8-12 days. 288P belongs to the recently discovered group of active asteroids, and is particularly remarkable as HST images obtained during its last close approach to Earth in 2011 are consistent with a barely resolved binary system. If confirmed, 288P would be the first known active binary asteroid. For the first time, we would see two important consequences of rotational break-up in a single object: binary formation and dust ejection, highlighting the importance of the YORP-effect in re-shaping the asteroid belt. Confirming 288P as a binary would be a key step towards understanding the evolutionary processes underlying asteroid activity. In order to resolve the two components we need 288P at a geocentric distance comparable to or less than we had in 2011 December (1.85 AU). This condition will be fulfilled for the first time since 2011, between mid-July and mid-November of 2016. The next opportunity to carry out such observations will be in 2021.

Anisotropic distribution of orbit poles of binary asteroids

NASA Astrophysics Data System (ADS)

Pravec, P.; Scheirich, P.; Vokrouhlický, D.; Harris, A. W.; Kusnirak, P.; Hornoch, K.; Pray, D. P.; Higgins, D.; Galád, A.; Világi, J.; Gajdos, S.; Kornos, L.; Oey, J.; Husárik, M.; Cooney, W. R.; Gross, J.; Terrell, D.; Durkee, R.; Pollock, J.; Reichart, D.; Ivarsen, K.; Haislip, J.; Lacluyze, A.; Krugly, Y. N.; Gaftonyuk, N.; Dyvig, R.; Reddy, V.; Stephens, R. D.; Chiorny, V.; Vaduvescu, O.; Longa, P.; Tudorica, A.; Warner, B. D.; Masi, G.; Brinsfield, J.; Gonçalves, R.; Brown, P.; Krzeminski, Z.; Gerashchenko, O.; Marchis, F.

2011-10-01

Our photometric observations of 18 mainbelt binary systems in more than one apparition revealed a strikingly high number of 15 having positively re-observed mutual events in the return apparitions. Our simulations of the survey showed that the data strongly suggest that poles of mutual orbits between components of binary asteroids are not distributed randomly: The null hypothesis of the isotropic distribution of orbit poles is rejected at a confidence level greater than 99.99%. Binary orbit poles concentrate at high ecliptic latitudes, within 30° of the poles of the ecliptic. We propose that the binary orbit poles oriented preferentially up/down-right are due to formation of small binary systems by rotational fission of critically spinning parent bodies with poles near the YORP asymptotic states with obliquities near 0 and 180°. An alternative process of elimination of binaries with poles closer to the ecliptic by the Kozai dynamics of gravitational perturbations from the sun does not explain the observed orbit pole concentration as in the close asteroid binary systems the J2 perturbation due to the primary dominates the solar-tide effect.

Lifetime of a spacecraft around a synchronous system of asteroids using a dipole model

NASA Astrophysics Data System (ADS)

dos Santos, Leonardo Barbosa Torres; de Almeida Prado, Antonio F. Bertachini; Sanchez, Diogo Merguizo

2017-11-01

Space missions allow us to expand our knowledge about the origin of the solar system. It is believed that asteroids and comets preserve the physical characteristics from the time that the solar system was created. For this reason, there was an increase of missions to asteroids in the past few years. To send spacecraft to asteroids or comets is challenging, since these objects have their own characteristics in several aspects, such as size, shape, physical properties, etc., which are often only discovered after the approach and even after the landing of the spacecraft. These missions must be developed with sufficient flexibility to adjust to these parameters, which are better determined only when the spacecraft reaches the system. Therefore, conducting a dynamic investigation of a spacecraft around a multiple asteroid system offers an extremely rich environment. Extracting accurate information through analytical approaches is quite challenging and requires a significant number of restrictive assumptions. For this reason, a numerical approach to the dynamics of a spacecraft in the vicinity of a binary asteroid system is offered in this paper. In the present work, the equations of the Restricted Synchronous Four-Body Problem (RSFBP) are used to model a binary asteroid system. The main objective of this work is to construct grids of initial conditions, which relates semi-major axis and eccentricity, in order to quantify the lifetime of a spacecraft when released close to the less massive body of the binary system (modeled as a rotating mass dipole). We performed an analysis of the lifetime of the spacecraft considering several mass ratios of a binary system of asteroids and investigating the behavior of a spacecraft in the vicinity of this system. We analyze direct and retrograde orbits. This study investigated orbits that survive for at least 500 orbital periods of the system (which is approximately one year), then not colliding or escaping from the system during this time. In this work, we take into account the gravitational forces of the binary asteroid system and the solar radiation pressure (SRP). We found several regions where the direct and retrograde orbits of a spacecraft survive throughout the integration time (one year) when the solar radiation pressure is taken into account. Numerical evidence shows that retrograde orbits have a larger region initial conditions that generate orbits that survive for one year, compared to direct orbits.

Dynamical and Physical Properties of 65803 Didymos, the AIDA Mission Target

NASA Astrophysics Data System (ADS)

Campo Bagatin, A.; Richardson, D. C.; Tsiganis, K.; Cheng, A. F.; Michel, P.

2017-09-01

The near-Earth asteroid (NEA) 65803 Didymos is a binary system and is the target of the proposed Asteroid Impact & Deflection Assessment (AIDA) mission, which combines an orbiter (Asteroid Impact Mission, AIM, or the reduced-scope AIM Deflection Demonstration, AIM-D2) [1, 2] and a kinetic impactor experiment (Double Asteroid Redirection Test, DART) planned to impact the secondary of the Didymos binary system in October, 2022 [3]. The Dynamical and Physical Properties of Didymos Working Group supports the AIDA mission by addressing questions related to understanding the dynamical state of the system and inferring the physical properties of the components

The Asteroid Impact Mission - Deflection Demonstration (AIM - D2)

NASA Astrophysics Data System (ADS)

Küppers, M.; Michel, P.; Carnelli, I.

2017-09-01

The Asteroid Impact Mission (AIM) is ESA's contribution to the international Asteroid Impact Deflection Assessment (AIDA) cooperation, targeting the demonstration of deflection of a hazardous near-earth asteroid. AIM will also be the first in-depth investigation of a binary asteroid and make measurements that are relevant for the preparation of asteroid resource utilisation. AIM is foreseen to rendezvous with the binary near-Earth asteroid (65803) Didymos and to observe the system before, during, and after the impact of NASA's Double Asteroid Redirection Test (DART) spacecraft. Here we describe the observations to be done by the simplified version Asteroid Impact Mission - Deflection Demonstration (AIM-D2) and show that most of the original AIM objectives can still be achieved.

THE PUZZLING MUTUAL ORBIT OF THE BINARY TROJAN ASTEROID (624) HEKTOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marchis, F.; Cuk, M.; Durech, J.

Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on W. M. Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the orbits of other large multiple asteroid systems studied so far. From lightcurve observations recorded since 1957, we showed that because the large Req = 125 km primary may be made of two joint lobes, the moon could be ejecta of the low-velocity encounter, which formedmore » the system. The inferred density of Hektor's system is comparable to the L5 Trojan doublet (617) Patroclus but due to their difference in physical properties and in reflectance spectra, both captured Trojan asteroids could have a different composition and origin.« less

Dust motions in quasi-statically charged binary asteroid systems

NASA Astrophysics Data System (ADS)

Maruskin, Jared M.; Bellerose, Julie; Wong, Macken; Mitchell, Lara; Richardson, David; Mathews, Douglas; Nguyen, Tri; Ganeshalingam, Usha; Ma, Gina

2013-03-01

In this paper, we discuss dust motion and investigate possible mass transfer of charged particles in a binary asteroid system, in which the asteroids are electrically charged due to solar radiation. The surface potential of the asteroids is assumed to be a piecewise function, with positive potential on the sunlit half and negative potential on the shadow half. We derive the nonautonomous equations of motion for charged particles and an analytic representation for their lofting conditions. Particle trajectories and temporary relative equilibria are examined in relation to their moving forbidden regions, a concept we define and discuss. Finally, we use a Monte Carlo simulation for a case study on mass transfer and loss rates between the asteroids.

Population trends of binary near-Earth asteroids based on radar and lightcurves observations

NASA Astrophysics Data System (ADS)

Brozovic, Marina; Benner, Lance A. M.; Naidu, Shantanu P.; Taylor, Patrick A.; Busch, Michael W.; Margot, Jean-Luc; Nolan, Michael C.; Howell, Ellen S.; Springmann, Alessondra; Giorgini, Jon D.; Shepard, Michael K.; Magri, Christopher; Richardson, James E.; Rivera-Valentin, Edgard G.; Rodriguez-Ford, Linda A.; Zambrano Marin, Luisa Fernanda

2016-10-01

The Arecibo and Goldstone planetary radars are invaluable instruments for the discovery and characterization of binary and triple asteroids in the near-Earth asteroid (NEA) population. To date, 41 out of 56 known binaries and triples (~73% of the objects) have been discovered by radar and 49 of these multiple systems have been detected by radar. Their absolute magnitudes range from 12.4 for (1866) Sisyphus to 22.6 for 2015 TD144 and have a mean and rms dispersion of 18.1+-2.0. There is a pronounced decrease in the abundance of binaries for absolute magnitudes H>20. One of the smallest binaries, 1994 CJ1, with an absolute magnitude H=21.4, is also the most accessible binary for a spacecraft rendezvous. Among 365 NEAs with H<22 (corresponding to diameters larger than ~ 140 m) detected by radar since 1999, ~13% have at least one companion. Two triple systems are known, (15391) 2001 SN263 and (136617) 1994 CC, but this is probably an underestimate due to low signal to noise ratios (SNRs) for many of the binary radar detections. Taxonomic classes have been reported for 41 out of 56 currently known multiple systems and some trends are starting to emerge: at least 50% of multiple asteroid systems are S, Sq, Q, or Sk, and at least 20% are optically dark (C, B, P, or U). Thirteen V-class NEAs have been observed by radar and six of them are binaries. Curiously, a comparable number of E-class objects have been detected by radar, but none is known to be a binary.

Natural and Artificial Satellite Dynamics and Evolution around Near-Earth Asteroids with Solar Radiation Pressure

NASA Astrophysics Data System (ADS)

Rieger, Samantha M.

Natural and artificial satellites are subject to perturbations when orbiting near-Earth asteroids. These perturbations include non-uniform gravity from the asteroid, third-body disturbances from the Sun, and solar radiation pressure. For small natural (1 cm-15 m) and artificial satellites, solar radiation pressure is the primary perturbation that will cause their orbits to go unstable. For the asteroid Bennu, the future target of the spacecraft OSIRIS-REx, the possibility of natural satellites having stable orbits around the asteroid and characterize these stable regions is investigated. It has been found that the main orbital phenomena responsible for the stability or instability of these possible natural satellites are Sun-synchronous orbits, the modified Laplace plane, and the Kozai resonance. These findings are applied to other asteroids as well as to artificial satellites. The re-emission of solar radiation pressure through BYORP is also investigated for binary asteroid systems. Specifically, the BYORP force is combined with the Laplace plane such that BYORP expands the orbit of the binary system along the Laplace surface where the secondary increases in inclination. For obliquities from 68.875° - 111.125° the binary will eventually extend into the Laplace instability region, where the eccentricity of the orbit will increase. A subset of the instability region leads to eccentricities high enough that the secondary will impact the primary. This result inspired the development of a hypothesis of a contact-binary binary cycle described briefly in the following. YORP will increase the spin rate of a contact binary while also driving the spin-pole to an obliquity of 90°. Eventually, the contact binary will fission. The binary will subsequently become double-synchronous, thus allowing the BYORP acceleration to have secular effects on the orbit. The orbit will then expand along the Laplace surface to the Laplace plane instability region eventually leading to an impact and the start of a new cycle with the YORP process.

A Newborn Asteroid Family of Likely Rotational Origin Harboring a Doubly-Synchronous Binary

NASA Astrophysics Data System (ADS)

Drahus, Michal; Waniak, Waclaw

2016-10-01

From the total number of about twenty active asteroids identified to date, one of the most intriguing is P/2012 F5. The 2-km sized object has a short rotation period of 3.24 hr - the shortest known among main-belt active asteroids and comets - and is trailed by several fragments recently separated from the main nucleus (Drahus et al. 2015, ApJL 802, L8). Our extensive observations with Hubble in late 2015 and early 2016 have revealed that the fragments are real and stable "baby asteroids", still cocooned in their birth dust trail. Consequently, P/2012 F5 is the first known asteroid family forming in the present-day epoch. Given the rapid spin of the main nucleus, the system is also the best candidate for the first "rotational" asteroid family originating from rotational fission (as opposed to the long-known "collisional" families), extending the recently identified class of asteroid pairs (Pravec et al. 2010, Nature 466, 1085). Furthermore, the HST data allowed us to measure a light curve of the brightest fragment of P/2012 F5, several magnitudes fainter than the main nucleus. The light curve has all the characteristics of a close binary with significantly elongated, roughly equal sized components, having equal rotation and orbital periods of about 9 hr. The existence of a doubly-synchronous binary in an ultra-young asteroid family is seemingly inconsistent with the established "slow" binary formation path, in which YORP torques first lead to rotational fission and then tides lead to synchronization (Jacobson & Scheeres 2011, Icarus 214, 161). Instead, we believe that the object fissioned while orbiting the main nucleus and drawing its angular momentum, and was subsequently ejected from the system as a finished doubly-synchronous binary. This scenario is consistent with computer simulations in that the timescales for secondary fission and ejection from the system are indeed very short (Jacobson & Scheeres 2011, Icarus 214, 161). But the empirical evidence that fissioned secondaries can escape as doubly-synchronous binaries came as a surprise, so we seem to have accidentally identified a new, "rapid" formation path of such systems, not yet accounted for by the prevailing theory.

Determination of the Period of Binary Asteroid Systems

NASA Astrophysics Data System (ADS)

Lust, Nathaniel B.; Britt, D. T.

2008-09-01

In the study of asteroids, binary pairs offer a unique window of study. By observing these systems and determining the period of the secondary, it is possible to determine system mass (e.g. Pravec and Hahn 1997; Ryan et al., 2004). With mass and volume, properties such as bulk density and porosity can be derived. At the University of Central Florida we have begun a binary asteroid hunt, in conjunction with the Prague consortium, in order to identify new binary candidates and to better constrain data on known pairs. All of the observations are collected on campus using a 0.5meter f/8.1 Ritchey-Chretien telescope with a SBIG STL-6303E detector. For our first test target we observed the known binary asteroid 107 Camila over a period of six days for approximately six to eight hours a night. The data is then processed using an open source python algorithm developed by Nate Lust. The data is read in, reduced, and compared to a standard star. Once the light curve was generated we make use of the CLEAN algorithm, originally developed by Hogbom (1974), to extract meaningful periods from the light curve.

LONG-TERM STABLE EQUILIBRIA FOR SYNCHRONOUS BINARY ASTEROIDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobson, Seth A.; Scheeres, Daniel J.

Synchronous binary asteroids may exist in a long-term stable equilibrium, where the opposing torques from mutual body tides and the binary YORP (BYORP) effect cancel. Interior of this equilibrium, mutual body tides are stronger than the BYORP effect and the mutual orbit semimajor axis expands to the equilibrium; outside of the equilibrium, the BYORP effect dominates the evolution and the system semimajor axis will contract to the equilibrium. If the observed population of small (0.1-10 km diameter) synchronous binaries are in static configurations that are no longer evolving, then this would be confirmed by a null result in the observationalmore » tests for the BYORP effect. The confirmed existence of this equilibrium combined with a shape model of the secondary of the system enables the direct study of asteroid geophysics through the tidal theory. The observed synchronous asteroid population cannot exist in this equilibrium if described by the canonical 'monolithic' geophysical model. The 'rubble pile' geophysical model proposed by Goldreich and Sari is sufficient, however it predicts a tidal Love number directly proportional to the radius of the asteroid, while the best fit to the data predicts a tidal Love number inversely proportional to the radius. This deviation from the canonical and Goldreich and Sari models motivates future study of asteroid geophysics. Ongoing BYORP detection campaigns will determine whether these systems are in an equilibrium, and future determination of secondary shapes will allow direct determination of asteroid geophysical parameters.« less

Matching asteroid population characteristics with a model constructed from the YORP-induced rotational fission hypothesis

NASA Astrophysics Data System (ADS)

Jacobson, Seth A.; Marzari, Francesco; Rossi, Alessandro; Scheeres, Daniel J.

2016-10-01

From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis is consistent with the observed population statistics of small asteroids in the main belt including binaries and contact binaries. These conclusions rest on the asteroid rotation model of Marzari et al. ([2011]Icarus, 214, 622-631), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis, described in detail within, and the binary evolution model of Jacobson et al. ([2011a] Icarus, 214, 161-178) and Jacobson et al. ([2011b] The Astrophysical Journal Letters, 736, L19). Our complete asteroid population evolution model is highly constrained by these and other previous works, and therefore it has only two significant free parameters: the ratio of low to high mass ratio binaries formed after rotational fission events and the mean strength of the binary YORP (BYORP) effect. We successfully reproduce characteristic statistics of the small asteroid population: the binary fraction, the fast binary fraction, steady-state mass ratio fraction and the contact binary fraction. We find that in order for the model to best match observations, rotational fission produces high mass ratio (> 0.2) binary components with four to eight times the frequency as low mass ratio (<0.2) components, where the mass ratio is the mass of the secondary component divided by the mass of the primary component. This is consistent with post-rotational fission binary system mass ratio being drawn from either a flat or a positive and shallow distribution, since the high mass ratio bin is four times the size of the low mass ratio bin; this is in contrast to the observed steady-state binary mass ratio, which has a negative and steep distribution. This can be understood in the context of the BYORP-tidal equilibrium hypothesis, which predicts that low mass ratio binaries survive for a significantly longer period of time than high mass ratio systems. We also find that the mean of the log-normal BYORP coefficient distribution μB ≳10-2 , which is consistent with estimates from shape modeling (McMahon and Scheeres, 2012a).

Equilibrium points and associated periodic orbits in the gravity of binary asteroid systems: (66391) 1999 KW4 as an example

NASA Astrophysics Data System (ADS)

Shi, Yu; Wang, Yue; Xu, Shijie

2018-04-01

The motion of a massless particle in the gravity of a binary asteroid system, referred as the restricted full three-body problem (RF3BP), is fundamental, not only for the evolution of the binary system, but also for the design of relevant space missions. In this paper, equilibrium points and associated periodic orbit families in the gravity of a binary system are investigated, with the binary (66391) 1999 KW4 as an example. The polyhedron shape model is used to describe irregular shapes and corresponding gravity fields of the primary and secondary of (66391) 1999 KW4, which is more accurate than the ellipsoid shape model in previous studies and provides a high-fidelity representation of the gravitational environment. Both of the synchronous and non-synchronous states of the binary system are considered. For the synchronous binary system, the equilibrium points and their stability are determined, and periodic orbit families emanating from each equilibrium point are generated by using the shooting (multiple shooting) method and the homotopy method, where the homotopy function connects the circular restricted three-body problem and RF3BP. In the non-synchronous binary system, trajectories of equivalent equilibrium points are calculated, and the associated periodic orbits are obtained by using the homotopy method, where the homotopy function connects the synchronous and non-synchronous systems. Although only the binary (66391) 1999 KW4 is considered, our methods will also be well applicable to other binary systems with polyhedron shape data. Our results on equilibrium points and associated periodic orbits provide general insights into the dynamical environment and orbital behaviors in proximity of small binary asteroids and enable the trajectory design and mission operations in future binary system explorations.

Analysis of GSC 2475-1587 and GSC 841-277: Two Eclipsing Binary Stars Found During Asteroid Lightcurve Observations

NASA Astrophysics Data System (ADS)

Stephens, R. D.; Warner, B. D.

2006-05-01

When observing asteroids we select from two to five comparison stars for differential photometry, taking the average value of the comparisons for the single value to be subtracted from the value for the asteroid. As a check, the raw data of each comparison star are plotted as is the difference between any single comparison and the average of the remaining stars in the set. On more than one occasion, we have found that at least one of the comparisons was variable. In two instances, we took time away from our asteroid lightcurve work to determine the period of the two binaries and attempted to model the system using David Bradstreet's Binary Maker 3. Unfortunately, neither binary showed a total eclipse. Therefore, our results are not conclusive and present only one of many possibilities.

Speckle interferometry applied to asteroids and other solar system objects

NASA Technical Reports Server (NTRS)

Drummond, J. D.; Hege, E. K.

1985-01-01

The application of speckle interferometry to asteroids and other solar system objects is discussed. The assumption of a triaxial ellipsoid rotating about its shortest axis is the standard model. Binary asteroids, 433 Eros, 532 Herculina, 511 Davida, and Pallas are discussed.

Science case for the Asteroid Impact Mission (AIM): A component of the Asteroid Impact & Deflection Assessment (AIDA) mission

NASA Astrophysics Data System (ADS)

Michel, Patrick; Cheng, A.; Küppers, M.; Pravec, P.; Blum, J.; Delbo, M.; Green, S. F.; Rosenblatt, P.; Tsiganis, K.; Vincent, J. B.; Biele, J.; Ciarletti, V.; Hérique, A.; Ulamec, S.; Carnelli, I.; Galvez, A.; Benner, L.; Naidu, S. P.; Barnouin, O. S.; Richardson, D. C.; Rivkin, A.; Scheirich, P.; Moskovitz, N.; Thirouin, A.; Schwartz, S. R.; Campo Bagatin, A.; Yu, Y.

2016-06-01

The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to test the kinetic impactor technique to deflect an asteroid. The European Asteroid Impact Mission (AIM) is set to rendezvous with the asteroid system to fully characterize the smaller of the two binary components a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near-Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Having direct information on the surface and internal properties of small asteroids will allow us to understand how the various processes they undergo work and transform these small bodies as well as, for this particular case, how a binary system forms. Making these measurements from up close and comparing them with ground-based data from telescopes will also allow us to calibrate remote observations and improve our data interpretation of other systems. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. AIDA will thus offer a great opportunity to test and refine our understanding and models at the actual scale of an asteroid, and to check whether the current extrapolations of material strength from laboratory-scale targets to the scale of AIDA's target are valid. Moreover, it will offer a first check of the validity of the kinetic impactor concept to deflect a small body and lead to improved efficiency for future kinetic impactor designs. This paper focuses on the science return of AIM, the current knowledge of its target from ground-based observations, and the instrumentation planned to get the necessary data.

First known terrestrial impact of a binary asteroid from a main belt breakup event.

PubMed

Ormö, Jens; Sturkell, Erik; Alwmark, Carl; Melosh, Jay

2014-10-23

Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt, which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. We here provide evidence that Lockne and its nearby companion, the 0.7-km diameter, contemporaneous, Målingen crater, formed by the impact of a binary, presumably 'rubble pile' asteroid. This newly discovered crater doublet provides a unique reference for impacts by combined, and poorly consolidated projectiles, as well as for the development of binary asteroids.

AIDA: The Asteroid Impact & Deflection Assessment Mission

NASA Astrophysics Data System (ADS)

Galvez, A.; Carnelli, I.; Michel, P.; Cheng, A. F.; Reed, C.; Ulamec, S.; Biele, J.; Abell, P.; Landis, R.

2013-09-01

The Asteroid Impact and Deflection Assessment (AIDA) mission, a joint effort of ESA, JHU/APL, NASA, OCA, and DLR, is the first demonstration of asteroid deflection and assessment via kinetic impact. AIDA consists of two independent but mutually supporting mission elements, one of which is the asteroid kinetic impactor and the other is the characterization spacecraft. These two missions are, respectively, JHU/APL's Double Asteroid Redirection Test (DART) and the European Space Agency's Asteroid Investigation Mission (AIM) missions. As in the separate DART and AIM studies, the target of this mission is the binary asteroid [65803] Didymos in October, 2022. For a successful joint mission, one spacecraft, DART, would impact the secondary of the Didymos system while AIM would observe and measure any change in the relative orbit. AIM will be the first probe to characterise a binary asteroid, especially from the dynamical point of view, but also considering its interior and subsurface composition. The mission concept focuses on the monitoring aspects i.e., the capability to determine in-situ the key physical properties of a binary asteroid playing a role in the system's dynamic behavior. DART will be the first ever space mission to deflect the trajectory of an asteroid in a measurable way.- It is expected that the deflection can be measured as a change in the relative orbit period with a precision better than 10%. The joint AIDA mission will return vital data to determine the momentum transfer efficiency of the kinetic impact [1,2].

First known Terrestrial Impact of a Binary Asteroid from a Main Belt Breakup Event

PubMed Central

Ormö, Jens; Sturkell, Erik; Alwmark, Carl; Melosh, Jay

2014-01-01

Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt, which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. We here provide evidence that Lockne and its nearby companion, the 0.7-km diameter, contemporaneous, Målingen crater, formed by the impact of a binary, presumably ‘rubble pile’ asteroid. This newly discovered crater doublet provides a unique reference for impacts by combined, and poorly consolidated projectiles, as well as for the development of binary asteroids. PMID:25340551

Formation of the Wide Asynchronous Binary Asteroid Population

NASA Astrophysics Data System (ADS)

Jacobson, Seth A.; Scheeres, Daniel J.; McMahon, Jay

2014-01-01

We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor axes relative to most near-Earth and main belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

A binary main-belt comet.

PubMed

Agarwal, Jessica; Jewitt, David; Mutchler, Max; Weaver, Harold; Larson, Stephen

2017-09-20

Asteroids are primitive Solar System bodies that evolve both collisionally and through disruptions arising from rapid rotation. These processes can lead to the formation of binary asteroids and to the release of dust, both directly and, in some cases, through uncovering frozen volatiles. In a subset of the asteroids called main-belt comets, the sublimation of excavated volatiles causes transient comet-like activity. Torques exerted by sublimation measurably influence the spin rates of active comets and might lead to the splitting of bilobate comet nuclei. The kilometre-sized main-belt asteroid 288P (300163) showed activity for several months around its perihelion 2011 (ref. 11), suspected to be sustained by the sublimation of water ice and supported by rapid rotation, while at least one component rotates slowly with a period of 16 hours (ref. 14). The object 288P is part of a young family of at least 11 asteroids that formed from a precursor about 10 kilometres in diameter during a shattering collision 7.5 million years ago. Here we report that 288P is a binary main-belt comet. It is different from the known asteroid binaries in its combination of wide separation, near-equal component size, high eccentricity and comet-like activity. The observations also provide strong support for sublimation as the driver of activity in 288P and show that sublimation torques may play an important part in binary orbit evolution.

AIDA: the Asteroid Impact & Deflection Assessment mission

NASA Astrophysics Data System (ADS)

Vincent, Jean-Baptiste

2016-07-01

The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to assess the possibility of deflecting an asteroid trajectory by using a kinetic impactor. The European Asteroid Impact Mission (AIM) is under Phase A/B1 study at ESA from March 2015 until summer 2016. AIM is set to rendez-vous with the asteroid system a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft to fully characterize the smaller of the two binary components. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions: AIM will release a set of CubeSats in deep space and a lander on the surface of the smaller asteroid and for the first time, deep-space inter-satellite linking will be demonstrated between the main spacecraft, the CubeSats, and the lander, and data will also be transmitted from interplanetary space to Earth by a laser communication system. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Small asteroids are believed to result from collisions and other processes (e.g., spinup, shaking) that made them what they are now. Having direct information on their surface and internal properties will allow us to understand how these processes work and transform these small bodies as well as, for this particular case, how a binary system forms. So far, our understanding of the collisional process and the validation of numerical simulations of the impact process rely on impact experiments at laboratory scales. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. By comparing our in situ measurements with ground-based data from telescopes, we can calibrate better the remote observations and improve our data interpretation of other systems. Therefore, AIDA offers a unique opportunity to test and refine our understanding and models at the actual scale of an asteroid. This will allow feeding small-body collisional evolution models with more realistic parameters to draw a more reliable story of the Solar System formation and evolution. Moreover, it will offer a first check of the validity of the kinetic impactor concept to deflect a small body trajectory and lead to improved efficiency for future kinetic impactor designs.

Binary asteroid orbit evolution due to primary shape deformation

NASA Astrophysics Data System (ADS)

Hirabayashi, Masatoshi; Jacobson, Seth A.; Davis, Alex

2017-10-01

About a sixth of all small asteroid systems are binary [Margot et al., Science, 2002]. Many binary asteroids consist of an elongated synchronous secondary body orbiting a fast-rotating spheroidal primary body with ridges on its equator. The primary in such systems has experienced a long-term spin-up due to the YORP effect [Vokrouhlick'y et al., Asteroid IV, 2015]. This spin-up process can make the primary reach its spin barrier inducing shape deformation processes that ease the structural condition for failure inside the primary [e.g., Holsapple, Icarus, 2010]. Earlier works have shown that structural heterogeneities in the primary such as the shape and density distribution induce asymmetric deformation [Sánchez and Scheeres, Icarus, 2016]. Here, we investigate how asymmetric shape deformation in the primary affects the mutual motion of a binary system. We use a dynamics model for an irregularly shaped binary system that accounts for possible deformation of the primary [Hirabayashi et al., LPSC, 2017]. In this model, we consider asymmetric deformation that occurs based on structural failure in the primary and thus it modifies the location of the center of mass of the system. Using 1999 KW4 as an example, we study a hypothetical case in which the primary is initially identical to the current shape [Ostro et al., Science, 2006] with an aspect ratio (AR) of 0.83 and then suddenly changes its shape to an AR of 0.76. The results show that the asymmetric deformation process and the shift of the center of mass excite the eccentricity of the mutual orbit. Considering that the original mutual orbit has an eccentricity of 0.0004, after the primary shape change the eccentricity reaches values up to 0.15. Also, since the gravity field is modified after deformation, the secondary’s spin is desynchronized from the mutual orbit. Since synchronicity is a requirement for the binary YORP (BYORP) effect, which modifies the semi-major axis of binary asteroids, a primary shape change temporarily pauses the BYORP effect, in effect lengthening the effective BYORP timescale.

Three-body affairs in the outer solar system

NASA Astrophysics Data System (ADS)

Funato, Yoko; Makino, Junichiro; Hut, Piet; Kokubo, Eiichiro; Kinoshita, Daisuke

Recent observations have revealed an unexpectedly high binary fraction among the Trans-Neptunian Objects (TNOs) that populate the Kuiper Belt. The TNO binaries are strikingly different from asteroid binaries in four respects: their frequency is an order of magnitude larger, the mass ratio of their components is closer to unity, and their orbits are wider and highly eccentric. Two explanations have been proposed for their formation, one assuming large numbers of massive bodies, and one assuming large numbers of light bodies. We argue that both assumptions are unwarranted, and we show how TNO binaries can be produced from a modest number of intermediate-mass bodies of the type predicted by the gravitational instability theory for the formation of planetesimals. We start with a TNO binary population similar to the asteroid binary population, but subsequently modified by three-body exchange reactions, a process that is far more efficient in the Kuiper belt, because of the much smaller tidal perturbations by the Sun. Our mechanism can naturally account for all four characteristics that distinguish TNO binaries from main-belt asteroid binaries.

Origin of Martian Moons from Binary Asteroid Dissociation

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Lyons, Valerie J. (Technical Monitor)

2001-01-01

The origin of the Martian moons Deimos and Phobos is controversial. A common hypothesis for their origin is that they are captured asteroids, but the moons show no signs of having been heated by passage through a (hypothetical) thick martian atmosphere, and the mechanism by which an asteroid in solar orbit could shed sufficient orbital energy to be captured into Mars orbit has not been previously elucidated. Since the discovery by the space probe Galileo that the asteroid Ida has a moon 'Dactyl', a significant number of asteroids have been discovered to have smaller asteroids in orbit about them. The existence of asteroid moons provides a mechanism for the capture of the Martian moons (and the small moons of the outer planets). When a binary asteroid makes a close approach to a planet, tidal forces can strip the moon from the asteroid. Depending on the phasing, either or both can then be captured. Clearly, the same process can be used to explain the origin of any of the small moons in the solar system.

Binary asteroid population. 2. Anisotropic distribution of orbit poles of small, inner main-belt binaries

NASA Astrophysics Data System (ADS)

Pravec, P.; Scheirich, P.; Vokrouhlický, D.; Harris, A. W.; Kušnirák, P.; Hornoch, K.; Pray, D. P.; Higgins, D.; Galád, A.; Világi, J.; Gajdoš, Š.; Kornoš, L.; Oey, J.; Husárik, M.; Cooney, W. R.; Gross, J.; Terrell, D.; Durkee, R.; Pollock, J.; Reichart, D. E.; Ivarsen, K.; Haislip, J.; LaCluyze, A.; Krugly, Yu. N.; Gaftonyuk, N.; Stephens, R. D.; Dyvig, R.; Reddy, V.; Chiorny, V.; Vaduvescu, O.; Longa-Peña, P.; Tudorica, A.; Warner, B. D.; Masi, G.; Brinsfield, J.; Gonçalves, R.; Brown, P.; Krzeminski, Z.; Gerashchenko, O.; Shevchenko, V.; Molotov, I.; Marchis, F.

2012-03-01

Our photometric observations of 18 main-belt binary systems in more than one apparition revealed a strikingly high number of 15 having positively re-observed mutual events in the return apparitions. Our simulations of the survey showed that it cannot be due to an observational selection effect and that the data strongly suggest that poles of mutual orbits between components of binary asteroids in the primary size range 3-8 km are not distributed randomly: The null hypothesis of an isotropic distribution of the orbit poles is rejected at a confidence level greater than 99.99%. Binary orbit poles concentrate at high ecliptic latitudes, within 30° of the poles of the ecliptic. We propose that the binary orbit poles oriented preferentially up/down-right are due to either of the two processes: (i) the YORP tilt of spin axes of their parent bodies toward the asymptotic states near obliquities 0° and 180° (pre-formation mechanism) or (ii) the YORP tilt of spin axes of the primary components of already formed binary systems toward the asymptotic states near obliquities 0° and 180° (post-formation mechanism). The alternative process of elimination of binaries with poles closer to the ecliptic by dynamical instability, such as the Kozai effect due to gravitational perturbations from the Sun, does not explain the observed orbit pole concentration. This is because for close binary asteroid systems, the gravitational effects of primary’s irregular shape dominate the solar-tide effect.

Artificial equilibrium points in binary asteroid systems with continuous low-thrust

NASA Astrophysics Data System (ADS)

Bu, Shichao; Li, Shuang; Yang, Hongwei

2017-08-01

The positions and dynamical characteristics of artificial equilibrium points (AEPs) in the vicinity of a binary asteroid with continuous low-thrust are studied. The restricted ellipsoid-ellipsoid model of binary system is employed for the binary asteroid system. The positions of AEPs are obtained by this model. It is found that the set of the point L1 or L2 forms a shape of an ellipsoid while the set of the point L3 forms a shape like a "banana". The effect of the continuous low-thrust on the feasible region of motion is analyzed by zero velocity curves. Because of using the low-thrust, the unreachable region can become reachable. The linearized equations of motion are derived for stability's analysis. Based on the characteristic equation of the linearized equations, the stability conditions are derived. The stable regions of AEPs are investigated by a parametric analysis. The effect of the mass ratio and ellipsoid parameters on stable region is also discussed. The results show that the influence of the mass ratio on the stable regions is more significant than the parameters of ellipsoid.

A contact binary asteroid evolutionary cycle driven by BYORP & the classical Laplace plane

NASA Astrophysics Data System (ADS)

Rieger, Samantha; Scheeres, Daniel J.

2017-10-01

Several contact binaries have been observed to have high obliquities distributed around 90°. With this information, we explore the possibility of these high obliquities being a key characteristic that causes an evolutionary cycle of contact binary formation and separation.The contact binary cycle begins with a single asteroid that is spinning up due to the YORP effect. For the binary cycle we assume YORP will drive the obliquity to 90°. Eventually, the asteroid will reach a critical spin frequency that will cause the asteroid to fission into a binary. We assume that the mass-ratio, q, of the system is greater than 0.2. With a high q, the secondary will not escape/impact the primary but will evolve through tides into a stable circular double-synchronous orbit. The binary being synchronous will cause the forces from BYORP to have secular effects on the system. For this cycle, BYORP will need to expand the secondary away from the primary.As the system expands, we have found that the secondary will follow the classical Laplace plane. Therefore, the secondary’s orbit will increase in inclination with respect to the equator as the secondary’s orbit expands. The Laplace plane is a stable orbit to perturbations from J2 & Sun tides except for an instability region that exists for primaries with obliquities above 68.875° & a secondary orbital radius of 13.5-19.5 primary radii. Once BYORP expands the secondary into this instability region, the eccentricity of the secondary’s orbit will increase until the orbit intersects with the primary & causes an impact. This impact will create a contact binary with a new obliquity that will randomly range from 23°-150°. The cycle will begin again with YORP driving the contact binary to an obliquity of 90°.Our contribution will discuss the proposed contact binary cycle in more detail, including the mechanics of the system that drives the events given above. We will include investigations into how losing synchronous lock will disrupt the eccentricity growth in the Laplace plane instability region. We will also discuss the time scales of each event to help predict which part of the cycle we will most likely to be observing when discovering new contact binaries & binary systems.

The Asteroid Impact Mission (AIM): Studying the geophysics of small binaries, measuring asteroid deflection and studying impact physics

NASA Astrophysics Data System (ADS)

Kueppers, Michael; Michel, Patrick; AIM Team

2016-10-01

Binary asteroids and their formation mechanisms are of particular interest for understanding the evolution of the small bodies in the solar system. Also, hazards to Earth from impact of near-Earth asteroids and their mitigation have drawn considerable interest over the last decades.Those subjects are both addressed by ESA's Asteroid Impact mission, which is part of the Asteroid Impact & Deflection Assessment (AIDA) currently under study in collaboration between NASA and ESA. NASA's DART mission will impact a projectile into the minor component of the binary near-Earth asteroid (65803) Didymos in 2022. The basic idea is to demonstrate the effect of the impact on the orbital period of the secondary around the primary. ESA's AIM will monitor the Didymos system for several months around the DART impact time.AIM will be launched in aurumn 2020. It is foreseen to arrive at Didymos in April 2022. The mission takes advantage of a close approach of Didymos to Earth. The next opportunity would arise in 2040 only.AIM will stay near Didymos for approximately 6 months. Most of the time it will be placed on the illuminated side of the system, at distances of approximately 35 km and 10 km. AIM is expected to move away from Didymos for some time around the DART impact.The reference payload for AIM includes two visual imagers, a hyperspectral camera, a lidar, a thermal infrared imager, a monostatic high frequency radar, and a bistatic low frequency radar. In addition, AIM will deploy a small lander on the secondary asteroid, and two cubesats that will be used for additional, more risky investigations close to or on the surface of the asteroid.Major contributions from AIM are expected in the study of the geophysics of small asteroids (including for the first time, radar measurements of an interior structure), the formation of binary asteroids, the momentum enhancement factor from the DART impact (through measuring the mass and the change of orbit of the seondary), and impact physics through observing the outcome of an impact with well known impact conditions. In addition, AIM will test new technologies (Cubesats in interplanetary space, Intersatellite links, optical telecommunication in deep space, infrared navigation).

Trojan Asteroid Lightcurves: Probing Internal Structure and the Origins

NASA Astrophysics Data System (ADS)

Ryan, E. L.

2017-12-01

Studies of the small bodies of the solar system reveal important clues about the condensation and formation of planetesimal bodies, and ultimately planets in planetary systems. Dynamics of small bodies have been utilized to model giant planet migration within our solar system, colors have been used to explore compositional gradients within the protoplanetary disk, & studies of the size-frequency distribution of main belt asteroids may reveal compositional dependences on planetesimal strength limiting models of planetary growth from collisional aggregration. Studies of the optical lightcurves of asteroids also yield important information on shape and potential binarity of asteroidal bodies. The K2 mission has allowed for the unprecedented collection of Trojan asteroid lightcurves on a 30 minute cadence for baselines of 10 days, in both the L4 and L5 Trojan clouds. Preliminary results from the K2 mission suggest that Trojan asteroids have bulk densities of 1 g/cc and a binary fraction ≤ 33 percent (Ryan et al., 2017, Astronomical Journal, 153, 116), however Trojan lightcurve data is actively being collected via the continued K2 mission. We will present updated results of bulk density and binary fraction of the Trojan asteroids and compare these results to other small body populations, including Hilda asteroids, transNeptunian objects and comet nuclei to test dynamical models of the origins of these populations.

New observations and new models of spin-orbit coupling in binary asteroids

NASA Astrophysics Data System (ADS)

Margot, Jean-Luc; Naidu, Shantanu

2015-08-01

The YORP-induced rotational fission hypothesis is the leading candidate for explaining the formation of binaries, triples, and pairs among small (<20 km) asteroids (e.g., Margot et al, Asteroids IV, subm., 2015). Various evolutionary paths following rotational fission have been suggested, but many important questions remain about the evolutionary mechanisms and timescales. We test hypotheses about the evolution of binary asteroids by obtaining precise descriptions of the orbits and components of binary systems with radar and by examining the system dynamics with detailed numerical simulations. Predictions for component spin states and orbital precession rates can then be compared to observables in our data sets or in other data sets to elucidate the states of various systems and their likely evolutionary paths.Accurate simulations require knowledge of the masses, shapes, and spin states of individual binary components. Because radar observations can provide exquisite data sets spanning days with spatial resolutions at the decameter level, we can invert for the component shapes and measure spin states. We can also solve for the mutual orbit by fitting the observed separations between components. In addition, the superb (10e-7--10e-8) fractional uncertainties in range allow us to measure the reflex motions directly, allowing masses of individual components to be determined.We use recently published observations of the binary 2000 DP107 (Naidu et al. AJ, subm., 2015) and that of other systems to simulate the dynamics of components in well-characterized binary systems (Naidu and Margot, AJ 149, 80, 2015). We model the coupled spin and orbital motions of two rigid, ellipsoidal bodies under the influence of their mutual gravitational potential. We use surface of section plots to map the possible spin configurations of the satellites. For asynchronous satellites, the analysis reveals large regions of phase space where the spin state of the satellite is chaotic. The presence of chaotic regions may substantially increase spin synchronization timescales, delay BYORP-type evolution, extend the lifetime of binaries, and explain the observed fraction of asynchronous binaries.

Multiple Asteroid Systems: Dimensions and Thermal Properties from Spitzer Space Telescope and Ground-based Observations

NASA Technical Reports Server (NTRS)

Marchis, F.; Enriquez, J. E.; Emery, J. P.; Mueller, M.; Baek, M.; Pollock, J.; Assafin, M.; Matins, R. Vieira; Berthier, J.; Vachier, F.;

Compositional Investigation of Binary Near-Earth Asteroid 66063 (1998 RO1): A Potentially Undifferentiated Assemblage

NASA Technical Reports Server (NTRS)

Abell, P. A.; Gaffey, M. J.; Landis, R. R.; Jarvis, K. S.

2005-01-01

It is now thought that approximately 16% of all asteroids among the near-Earth population may be binary objects. Several independent lines of evidence, such as the presence of doublet craters on the Earth and Moon [1, 2], complex lightcurves of near-Earth objects exhibiting mutual events [3], and radar images of near-Earth asteroids revealing distinct primary and secondary objects, have supported this conclusion [4]. To date at least 23 near-Earth objects have been discovered as binary systems with expectations that many more have yet to be identified or recognized. Little is known about the physical characteristics of binary objects except that they seem to have fairly rapid rotation rates, generally have primaries in the approx. 1 km diameter range with smaller secondaries on the order of a few hundred meters, and apart from a few exceptions, are in synchronous orbits [4, 5]. Previously only two of these binary near-Earth asteroids (1998 ST27 and 2003 YT1) have been characterized in terms of detailed mineralogical investigations [6, 7]. Such investigations are required to fully understand the formation mechanisms of these binary objects and their possible source regions. In addition, detailed knowledge of these objects may play an important role for planning future spacecraft missions and for the development of impact mitigation strategies. The work presented here represents a continued effort to characterize this particular sub-group of the near- Earth asteroid population.

Tidal stress and failure in the moon of binary asteroid systems: Application to asteroid (65803) Didymos

NASA Astrophysics Data System (ADS)

Sophal Pou, Laurent; Garcia, Raphael F.; Mimoun, David; Murdoch, Naomi; Karatekin, Ozgur

2017-04-01

Rocky remnants left over from the early formation of the Solar System, asteroids are a target of choice for planetary science since much about the history of planetary formation and small body evolution processes can be learnt by studying them. Here we consider the case of the binary asteroid (65803) Didymos, the target of several mission proposals e.g., AIM [1] and DART [2]. A mission to Didymos would be a great opportunity for in-situ geophysical investigation, providing information on the surface and interior of asteroids. Such studies would improve our knowledge of binary asteroid formation and subsequent evolution of asteroids, thus of the history of the Solar System. As Didymos is a binary asteroid [3] with the main 800-meter diameter asteroid named Didymain and a 150-meter sized moon named Didymoon, both are subject to tidal stress. Recent investigations suggest that Didymoon is tidally locked and moves in a retrograde motion around Didymain along an elliptic orbit with a 0.03 eccentricity at most. In the case of an eccentric orbit, the tidal stress varies periodically and may be strong enough to cause tidal quakes on Didymoon at some points of the orbit. For this study, we modelled Didymoon as a spherical, layered body with different internal structures: a homogeneous model, and two models with a 1-meter and 10-meter regolith layer on top of a stronger internal core. Simulations show that, for a cohesionless body with an internal friction angle of 30°, tidal stress is strong enough to cause failure at the surface of Didymoon. A maximal stress is reached around the poles and for a mean anomaly of 90°. These results would mean that if tidal quakes occur on Didymoon, then they are likely to happen at these locations. An extension of these results to an ellipsoidal model of Didymoon is also presented for comparison with the spherical case and for application to other bodies. [1]: P. Michel et al., Science case for the asteroid impact mission (aim): A component of the asteroid impact and deflection assessment (aida) mission, Advances in Space Research 57 (12) (2016) 2529 - 2547. doi:http://dx.doi.org/10.1016/j.asr.2016.03.031. [2]: A. F. Cheng et al., Asteroid Impact & Deflection Assessment mission: Kinetic impactor, Planetary and Space Science 121 (2016) 27-35. doi:10.1016/j.pss.2015.12.004. [3]:"AIM-A Team", ASTEROID IMPACT MISSION: DIDYMOS REFERENCE MODEL v10, ESA document reference: AD3-AIMA.

Dynamical Evolution and Momentum Transfer for Binary Asteroid Systems

NASA Astrophysics Data System (ADS)

Bellerose, Julie

Over the past decade, robotic missions have been sent to small bodies, providing a basic understanding of their environment. Some of these small systems are found to be in pairs, orbiting each other, which are thought to represent about 16% of the near-Earth asteroid population. It is fair to assume that a mission will target a binary asteroid system in the near future as they can enable scientific insight into both the geology and dynamics of asteroids. In previous work, the dynamical evolution of binary systems was investigated for an ellipsoidsphere model. From the dynamics of two celestial bodies, equilibrium configurations and their stability were analyzed. For a given value of angular momentum, it was shown that there are in general two relative equilibrium configurations which are opposite in stability. When perturbations are introduced, we found that the equilibrium states are the minimum energy points of nearby periodic families. General dynamics from unstable to stable configurations were investigated for binaries in close proximity. Accounting for the dynamics of binaries, the dynamics of particles in this gravitational field were also studied. The location of the analogue Lagrangian points and energy associated with them were characterized. The L1 region is a key element for transfers between the bodies. It was shown that L1 can be situated between or inside the bodies depending on the free parameters of the system modifying the transfer possibilities since L1 has a hyperbolic manifold associated with it. In the current work, we look at the L1 region for binary system where the bodies are in relative equilibrium, close to each other. We find that L1 transits from outside to inside the ellipsoid when the mass ratio is larger than 0.6. For binary systems in close proximity with L1 being inside the ellipsoidal body, simulations show that particles on the surface tend to move away from the ellipsoid, toward the spherical primary. We can relate this to the Roche limit of binaries which affect the distribution of mass between the bodies. Other parameters such as the spin rate of a larger spherical primary may also influence particle distribution. Hence, we can map and characterize the mass distribution and momentum exchange that may occur within a closely formed binary systems.

The Double Asteroid Redirection Test (DART)

NASA Astrophysics Data System (ADS)

Rivkin, A.; Cheng, A. F.; Stickle, A. M.; Richardson, D. C.; Barnouin, O. S.; Thomas, C.; Fahnestock, E.

2017-12-01

The Double Asteroid Redirection Test (DART) will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. DART is currently in Preliminary Design Phase ("Phase B"), and is part of the Asteroid Impact and Deflection Assessment (AIDA), a joint ESA-NASA cooperative project. The AIDA target is the near-Earth binary asteroid 65803 Didymos, an S-class system that will make a close approach to Earth in fall 2022. The DART spacecraft is designed to impact the Didymos secondary at 6 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts. The DART impact on the Didymos secondary will change the orbital period of the binary by several minutes, which can be measured by Earth-based optical and radar observations. The baseline DART mission launches in late 2020 to impact the Didymos secondary in 2022 near the time of its close pass of Earth, which enables an array of ground- and space-based observatories to participate in gathering data. The AIDA project will provide the first measurements of momentum transfer efficiency from hyper-velocity kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are characterized or constrained. The DART kinetic impact is predicted to make a crater of 6 to 17 meters diameter, depending on target physical properties, but will also release a large volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes.

Autonomous vision-based navigation for proximity operations around binary asteroids

NASA Astrophysics Data System (ADS)

Gil-Fernandez, Jesus; Ortega-Hernando, Guillermo

2018-02-01

Future missions to small bodies demand higher level of autonomy in the Guidance, Navigation and Control system for higher scientific return and lower operational costs. Different navigation strategies have been assessed for ESA's asteroid impact mission (AIM). The main objective of AIM is the detailed characterization of binary asteroid Didymos. The trajectories for the proximity operations shall be intrinsically safe, i.e., no collision in presence of failures (e.g., spacecraft entering safe mode), perturbations (e.g., non-spherical gravity field), and errors (e.g., maneuver execution error). Hyperbolic arcs with sufficient hyperbolic excess velocity are designed to fulfil the safety, scientific, and operational requirements. The trajectory relative to the asteroid is determined using visual camera images. The ground-based trajectory prediction error at some points is comparable to the camera Field Of View (FOV). Therefore, some images do not contain the entire asteroid. Autonomous navigation can update the state of the spacecraft relative to the asteroid at higher frequency. The objective of the autonomous navigation is to improve the on-board knowledge compared to the ground prediction. The algorithms shall fit in off-the-shelf, space-qualified avionics. This note presents suitable image processing and relative-state filter algorithms for autonomous navigation in proximity operations around binary asteroids.

Autonomous vision-based navigation for proximity operations around binary asteroids

NASA Astrophysics Data System (ADS)

Gil-Fernandez, Jesus; Ortega-Hernando, Guillermo

2018-06-01

Future missions to small bodies demand higher level of autonomy in the Guidance, Navigation and Control system for higher scientific return and lower operational costs. Different navigation strategies have been assessed for ESA's asteroid impact mission (AIM). The main objective of AIM is the detailed characterization of binary asteroid Didymos. The trajectories for the proximity operations shall be intrinsically safe, i.e., no collision in presence of failures (e.g., spacecraft entering safe mode), perturbations (e.g., non-spherical gravity field), and errors (e.g., maneuver execution error). Hyperbolic arcs with sufficient hyperbolic excess velocity are designed to fulfil the safety, scientific, and operational requirements. The trajectory relative to the asteroid is determined using visual camera images. The ground-based trajectory prediction error at some points is comparable to the camera Field Of View (FOV). Therefore, some images do not contain the entire asteroid. Autonomous navigation can update the state of the spacecraft relative to the asteroid at higher frequency. The objective of the autonomous navigation is to improve the on-board knowledge compared to the ground prediction. The algorithms shall fit in off-the-shelf, space-qualified avionics. This note presents suitable image processing and relative-state filter algorithms for autonomous navigation in proximity operations around binary asteroids.

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2017 April thru June

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2017-10-01

Lightcurves for 16 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2017 April thru June. Many of the asteroids were “strays” in the field of planned targets, demonstrating a good reason for data mining images. Analysis shows that the Hungaria asteroid (45878) 2000 WX29 may be binary.

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2016 December thru 2017 March

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2017-07-01

Lightcurves for 18 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2016 December thru 2017 March. Many of the asteroids were “strays” in the field of planned targets, demonstrating a good reason for data mining images. Analysis shows that the Hungaria asteroid (45878) 2000 WX29 may be binary.

Binary Asteroids and Human Exploration Considerations

NASA Technical Reports Server (NTRS)

Abell, P. A.

2013-01-01

In 2009 the Augustine Commission identified near-Earth asteroids (NEAs) as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. Subsequently, the U.S. presidential administration directed NASA on April 15, 2010 to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010. Current NASA plans to explore NEAs do not include binary systems. However, with a few in situ robotic precursor missions to binary NEAs, and increased confidence in human mission capabilities, the scientific and hazard mitigation benefits, along with the programmatic and operational benefits of a human venture beyond the Earth-Moon system, make a mission to a binary NEA using NASA's proposed exploration systems a compelling endeavor.

Disaggregation of small, cohesive rubble pile asteroids due to YORP

NASA Astrophysics Data System (ADS)

Scheeres, D. J.

2018-04-01

The implication of small amounts of cohesion within relatively small rubble pile asteroids is investigated with regard to their evolution under the persistent presence of the YORP effect. We find that below a characteristic size, which is a function of cohesive strength, density and other properties, rubble pile asteroids can enter a "disaggregation phase" in which they are subject to repeated fissions after which the formation of a stabilizing binary system is not possible. Once this threshold is passed rubble pile asteroids may be disaggregated into their constituent components within a finite time span. These constituent components will have their own spin limits - albeit potentially at a much higher spin rate due to the greater strength of a monolithic body. The implications of this prediction are discussed and include modification of size distributions, prevalence of monolithic bodies among meteoroids and the lifetime of small rubble pile bodies in the solar system. The theory is then used to place constraints on the strength of binary asteroids characterized as a function of their type.

Asteroid Impact Mission (aim) & Deflection Assessment: AN Opportunity to Understand Impact Dynamics and Modelling

NASA Astrophysics Data System (ADS)

Galvez, A.; Carnelli, I.; Fontaine, M.; Corral Van Damme, C.

2012-09-01

ESA's Future Preparation and Strategic Studies Office has carried out the Asteroid Impact Mission (AIM) study with the objective of defining an affordable and fully independent mission element that ESA could contribute to an Asteroid Impact Deflection Assessment campaign (AIDA), a joint effort of ESA, JHU/APL, NASA, OCA and DLR. The mission design foresees two independent spacecraft, one impactor (DART) and one rendezvous probe (AIM). The target of this mission is the binary asteroid system (65803) Didymos (1996 GT): one spacecraft, DART, would impact the secondary of the Didymos binary system while AIM would observe and measure any the change in the relative orbit. For this joint project, the timing of the experiment is set (maximum proximity of the target to Earth allowing for ground-based characterisation of the experiment) but the spacecraft are still able to pursue their missions fully independently. This paper describes in particular the AIM rendezvous mission concept.

The asteroid impact mission: testing laser communication in deep-space

NASA Astrophysics Data System (ADS)

Carnelli, I.; Mellab, K.; Heese, C.; Sodnik, Z.; Pesquita, V.; Gutierrez, B.

2017-09-01

In October 2022 the binary asteroid system 65803 Didymos will have an exceptionally close approach with the Earth flying by within only 0.088 AU. ESA is planning to leverage on this close encounter to launch a small mission of opportunity called Asteroid Impact Mission (AIM) to explore and demonstrate new technologies for future science and exploration missions while addressing planetary defence and performing asteroid scientific investigations.

(3749) BALAM: A VERY YOUNG MULTIPLE ASTEROID SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vokrouhlicky, David, E-mail: vokrouhl@cesnet.c

2009-11-20

Binaries and multiple systems among small bodies in the solar system have received wide attention over the past decade. This is because their observations provide a wealth of data otherwise inaccessible for single objects. We use numerical integration to prove that the multiple asteroid system (3749) Balam is very young, in contrast to its previously assumed age of 0.5-1 Gyr related to the formation of the Flora family. This work is enabled by a fortuitous discovery of a paired component to (3749) Balam. We first show that the proximity of the (3749) Balam and 2009 BR60 orbits is not amore » statistical fluke of otherwise quasi-uniform distribution. Numerical integrations then strengthen the case and allow us to prove that 2009 BR60 separated from the Balam system less than a million years ago. This is the first time the age of a binary asteroid can be estimated with such accuracy.« less

Design concepts and options for the Thermal Infrared Imager (TIRI) as part of ESA's Asteroid Impact Mission.

NASA Astrophysics Data System (ADS)

Bowles, Neil; Calcutt, Simon; Licandro, Javier; Reyes, Marcos; Delbo, Marco; Donaldson Hanna, Kerri; Arnold, Jessica; Howe, Chris

2016-04-01

ESA's Asteroid Impact Mission (AIM) is being studied as part of the joint ESA/NASA AIDA mission for launch in 2020. AIDA's primary mission is to investigate the effect of a kinetic impactor on the secondary component of the binary asteroid 65803 Didymos in late 2022. AIM will characterise the Didymos system and monitor the response of the binary system to the impact. A multi-spectral, thermal-infrared imaging instrument (TIRI) will be an essential component of AIM's remote sensing payload, as it will provide key information on the nature of the surfaces (e.g. presence or absence of materials, degree of compaction, and rock abundance of the regolith) of both components in the Didymos system. The temperature maps provided by TIRI will be important for navigation and spacecraft health and safety for proximity/lander operations. By measuring the asteroids' diurnal thermal responses (thermal inertia) and their surface compositions via spectral signatures, TIRI will provide information on the origin and evolution of the binary system. In this presentation we will discuss possible instrument design for TIRI, exploring options that include imaging spectroscopy to broadband imaging. By using thermal models and compositional analogues of the Didymos system we will show how the performance of each design option compares to the wider scientific goals of the AIDA/AIM mission.

Spin Rate Distribution of Small Asteroids Shaped by YORP Effect

NASA Astrophysics Data System (ADS)

Pravec, Petr

2008-09-01

We studied a distribution of spin rates of main belt/Mars crossing (MB/MC) asteroids with diameters 3-15 km using data obtained within the Photometric Survey of Asynchronous Binary Asteroids (Pravec et al. 2008). We found that the spin distribution of the small asteroids is uniform in the range from f = 1 to 9.5 d-1, and there is an excess of slow rotators with f < 1 d-1. The observed distribution appears to be controlled by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. The magnitude of the excess of slow rotators is related to the residence time of slowed down asteroids in the excess and the rate of spin rate change outside the excess. We estimated a median YORP spin rate change of 0.022 d-1/Myr for asteroids in our sample (i.e., a median time in which the spin rate changes by 1 d-1 is 45 Myr), thus the residence time of slowed down asteroids in the excess is 110 Myr. The spin rate distribution of near-Earth asteroids (NEAs) with sizes in the range 0.2-3 km ( 5-times smaller in median diameter than the MB/MC asteroids sample) shows a similar excess of slow rotators, but there is also a concentration of NEAs at fast spin rates with f = 9-10 d-1. The concentration at fast spin rates is correlated with a narrower distribution of spin rates of primaries of binary systems among NEAs; the difference may be due to the apparently more evolved population of binaries among MB/MC asteroids. Reference: Pravec, P., and 30 colleagues, 2008. Spin rate distribution of small asteroids. Icarus, in press. DOI: http://dx.doi.org/10.1016/j.icarus.2008.05.012

Vesta Cratered Landscape: Double Crater and Craters with Bright Ejecta

NASA Image and Video Library

2011-11-23

This image from NASA Dawn spacecraft is dominated by a double crater which may have been formed by the simultaneous impact of a binary asteroid. Binary asteroids are asteroids that orbit their mutual center of mass.

Near-Earth asteroid satellite spins under spin-orbit coupling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naidu, Shantanu P.; Margot, Jean-Luc

We develop a fourth-order numerical integrator to simulate the coupled spin and orbital motions of two rigid bodies having arbitrary mass distributions under the influence of their mutual gravitational potential. We simulate the dynamics of components in well-characterized binary and triple near-Earth asteroid systems and use surface of section plots to map the possible spin configurations of the satellites. For asynchronous satellites, the analysis reveals large regions of phase space where the spin state of the satellite is chaotic. For synchronous satellites, we show that libration amplitudes can reach detectable values even for moderately elongated shapes. The presence of chaoticmore » regions in the phase space has important consequences for the evolution of binary asteroids. It may substantially increase spin synchronization timescales, explain the observed fraction of asychronous binaries, delay BYORP-type evolution, and extend the lifetime of binaries. The variations in spin rate due to large librations also affect the analysis and interpretation of light curve and radar observations.« less

Tidal and Dynamical Evolution of Binary Asteroids

NASA Astrophysics Data System (ADS)

Jacobson, Seth A.; Scheeres, D. J.

2009-05-01

We derive a realistic model for the evolution of a tidally perturbed binary, using classical theory, to examine the system just after a spin-up fission event. The spin rate of an asteroid can be increased by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect -- thermal re-radiation from an asymmetric body, which induces torques that can rotationally accelerate the body. If the asteroid is modeled as a "rubble pile", a collection of gravitationally bound gravel with no tensile strength, increasing the spin rate will lead to a fission process that would resemble that of a viscous fluidic body [Holsapple 2007]. However, high-resolution imagery of an asteroid's constituents indicates that there is a significant distribution of size scales. A specific example is the asteroid Itokawa, which appears to be two such rubble piles in contact with each other [Fujiwara 2006]. The shape of these bodies will be irregular (modeled as tri-axial ellipsoids with a gravitational potential expanded up to second order). Their motions will raise tides on the opposing body. These tides will dissipate energy, potentially providing enough energy loss for the system to settle into a stable orbit. Fissioned binary systems are always initially unstable [Scheeres 2009, 2008]. We expect tidal dissipation rates to vary widely during the initial evolution of the system, due to this instability. The model applies instantaneous tidal torques to determine energy loss. Our preliminary results indicate that tidal energy dissipation could relax the system to a state of relative equilibrium on order 100,000 years, creating systems similar to those observed. Holsapple, K. A., Icarus, 187, 2007. Fujiwara, A., Science, 312, 2006. Scheeres, D., CMDA, 2009 (Accepted Jan 10, 2009). Scheeres, D., AAS, DDA meeting #39, #9.01, 2008.

Binary YORP Effect and Evolution of Binary Asteroids

NASA Astrophysics Data System (ADS)

Steinberg, Elad; Sari, Re'em

2011-02-01

The rotation states of kilometer-sized near-Earth asteroids are known to be affected by the Yarkevsky O'Keefe-Radzievskii-Paddack (YORP) effect. In a related effect, binary YORP (BYORP), the orbital properties of a binary asteroid evolve under a radiation effect mostly acting on a tidally locked secondary. The BYORP effect can alter the orbital elements over ~104-105 years for a Dp = 2 km primary with a Ds = 0.4 km secondary at 1 AU. It can either separate the binary components or cause them to collide. In this paper, we devise a simple approach to calculate the YORP effect on asteroids and the BYORP effect on binaries including J 2 effects due to primary oblateness and the Sun. We apply this to asteroids with known shapes as well as a set of randomly generated bodies with various degrees of smoothness. We find a strong correlation between the strengths of an asteroid's YORP and BYORP effects. Therefore, statistical knowledge of one could be used to estimate the effect of the other. We show that the action of BYORP preferentially shrinks rather than expands the binary orbit and that YORP preferentially slows down asteroids. This conclusion holds for the two extremes of thermal conductivities studied in this work and the assumption that the asteroid reaches a stable point, but may break down for moderate thermal conductivity. The YORP and BYORP effects are shown to be smaller than could be naively expected due to near cancellation of the effects at small scales. Taking this near cancellation into account, a simple order-of-magnitude estimate of the YORP and BYORP effects as a function of the sizes and smoothness of the bodies is calculated. Finally, we provide a simple proof showing that there is no secular effect due to absorption of radiation in BYORP.

Doublet craters and the tidal disruption of binary asteroids

NASA Technical Reports Server (NTRS)

Melosh, H. J.; Stansberry, J. A.

1991-01-01

An evaluation is conducted of the possibility that the tidal disruption of a population of contact binary asteroids can account for terrestrial-impact 'doublet' craters. Detailed orbital integrations indicate that while such asteroids are often disrupted by tidal forces outside the Roche limit, the magnitude of the resulting separations is too small to account for the observed doublet craters. It is hypothesized that an initial population of km-scale earth-crossing objects encompassing 10-20 percent binaries must be responsible for doublet impacts, as may be verified by future observations of earth-approaching asteroids.

Revealing Secrets of Triple Asteroid Systems with SPHERE

NASA Astrophysics Data System (ADS)

Yang, Bin; Wahhaj, Zahed; Beauvalet, Laurene; Marchis, Franck; Dumas, Christophe; Marsset, Michaël

2015-11-01

A multiple-asteroid system provides otherwise unattainable information about the intrinsic properties of the system itself as well as its formation and evolution. Comparative spectroscopy and imaging of two large multiple main-belt asteroids: (93) Minerva and (130) Elektra were performed using the newly commissioned Spectro-Polarimetric High-contrast Exoplanet Research instrument (SPHERE) on ESO's 8.2-m VLT. A new moon (S/2014 (130) 1), of the known binary asteroid (130) Elektra, was discovered based on the SPHERE observations, making (130) Elektra the sixth triple system detected in the asteroid belt. We will present the component-resolved near infrared spectra, from 0.9 to 1.6 micron, of the Minerva and the Elektra triple systems. We will also present the orbital solution and the dynamical simulations on the two moons of (130) Elektra.

Shapes, rotation, and pole solutions of the selected Hilda and Trojan asteroids

NASA Astrophysics Data System (ADS)

Gritsevich, Maria; Sonnett, Sarah; Torppa, Johanna; Mainzer, Amy; Muinonen, Karri; Penttilä, Antti; Grav, Thomas; Masiero, Joseph; Bauer, James; Kramer, Emily

2017-04-01

Binary asteroid systems contain key information about the dynamical and chemical environments in which they formed. For example, determining the formation environments of Trojan and Hilda asteroids (in 1:1 and 3:2 mean-motion resonance with Jupiter, respectively) will provide critical constraints on how small bodies and the planets that drive their migration must have moved throughout Solar System history, see e.g. [1-3]. Therefore, identifying and characterizing binary asteroids within the Trojan and Hilda populations could offer a powerful means of discerning between Solar System evolution models. Dozens of possibly close or contact binary Trojans and Hildas were identified within the data obtained by NEOWISE [4]. Densely sampled light curves of these candidate binaries have been obtained in order to resolve rotational light curve features that are indicative of binarity (e.g., [5-7]). We present analysis of the shapes, rotation, and pole solutions of some of the follow-up targets observed with optical ground-based telescopes. For modelling the asteroid photometric properties, we use parameters describing the shape, surface light scattering properties and spin state of the asteroid. Scattering properties of the asteroid surface are modeled using a two parameter H-G12 magnitude system. Determination of the initial best-fit parameters is carried out by first using a triaxial ellipsoid shape model, and scanning over the period values and spin axis orientations, while fitting the other parameters, after which all parameters were fitted, taking the initial values for spin properties from the spin scanning. In addition to the best-fit parameters, we also provide the distribution of the possible solution, which should cover the inaccuracies of the solution, caused by the observing errors and model. The distribution of solutions is generated by Markov-Chain Monte Carlo sampling the spin and shape model parameters, using both an ellipsoid shape model and a convex model, Gaussian curvature of which is defined as a spherical harmonics series [8]. References: [1] Marzari F. and Scholl H. (1998), A&A, 339, 278. [2] Morbidelli A. et al. (2005), Nature, 435, 462. [3] Nesvorny D. et al. (2013), ApJ, 768, 45. [4] Sonnett S. et al. (2015), ApJ, 799, 191. [5] Behrend R. et al. (2006), A&A, 446, 1177. [6] Lacerda P. and Jewitt D. C. (2007), AJ, 133, 1393. [7] Oey J. (2016), MPB, 43, 45. [8] Muinonen et al., ACM 2017.

Characteristics of Known Triple Asteroid Systems in the Main Belt

NASA Astrophysics Data System (ADS)

Marchis, Franck; Berthier, J.; Burns, K. J.; Descamps, P.; Durech, J.; Emery, J. P.; Enriquez, J. E.; Lainey, V.; Reiss, A. E.; Vachier, F.

2010-10-01

Since the discovery of "Sylvia Remus II” [1], around the binary asteroid (87) Sylvia [2] using the VLT/NACO instrument, the number of known triple systems increased significantly. Using the same instrument, a second moonlet was discovered around the binary (45) Eugenia [3] in 2007 [4]. Using an improved W.M. Keck II AO system, [5] announced the discovery of two 3 & 5-km moons orbiting the M-type asteroid (216) Kleopatra and more recently, [6] revealed the presence of two tiny 4-km moons around the C-type (93) Minerva. 3749 Balam is a different triple asteroid system whose existence was suggested by combining lightcurves and AO observations [7]. The properties of these triple systems have been derived individually and published recently [1, 8,9,10]. We will review and contrast their characteristics, including the orbital parameters of the satellite orbits, the size and shape of the primary and the satellites, their taxonomic classes, their bulk densities, and their ages. The goal of this study is to uncover clues concerning the formation and evolution of these mini-planetary systems. The National Science Foundation supported this research under award number AAG-0807468. 1. Marchis et al. Nature 2005 2. Brown et al., IAU 7588, 2001 3. Merline et al. Nature 401, 1999 4. Marchis et al. IAU 1073, 2007 5. Marchis et al. IAU 8980, 2008 6. Marchis et al., IAU 9069, 2009 7. Marchis et al., IAU 8928, 2008 8. Marchis et al., A Dynamical Solution of the Triple Asteroid System (45) Eugenia , Icarus in press, 2010 9. Descamps et al, Triplicity and Physical Characteristics of Asteroid 216 Kleopatra Icarus, in revision, 2010 10. Marchis et al., Triplicity and Physical Characteristics of the main-belt Asteroid (93) Minerva, Icarus submitted 2010

The Double Asteroid Redirection Test in the AIDA Mission

NASA Astrophysics Data System (ADS)

Cheng, Andrew; Reed, Cheryl; Rivkin, Andrew

2016-07-01

The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts based on measured physical properties of the asteroid surface and sub-surface, and including long-term dynamics of impact ejecta. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observations. The DART impact on the Didymos secondary will change the orbital period of the binary which can be measured by supporting Earth-based optical and radar observations. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September,2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close approach to Earth. The AIM spacecraft will be launched in Dec. 2020 and arrive at Didymos in spring, 2022, several months before the DART impact. AIM will characterize the Didymos binary system by means of remote sensing and in-situ instruments both before and after the DART impact. The asteroid deflection will be measured to higher accuracy, and additional results of the DART impact, like the impact crater, will be studied in detail by the AIM mission. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency from hyper-velocity kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. The DART impact on the Didymos secondary is predicted to cause a 4.4 minute change in the binary orbit period, assuming unit momentum transfer efficiency. The predicted transfer efficiency would be in the range 1.1 to 1.3 for a porous target material based on a variety of numerical and analytical methods, but may be much larger if the target is non-porous. The DART kinetic impact is predicted to make a crater of 6 to 17 meters diameter, depending on target physical properties, but will also release a large volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes.

Lunar and Planetary Science XXXV: Origin of Planetary Systems

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Origin of Planetary Systems" included the following reports: (12753) Povenmire - Standard Comparison Small Main Belt Asteroid?; Gravitational Frequencies of Extra-Solar Planets; 'Jumping Jupiters' in Binary Star Systems; Hermes, Asteroid 2002 SY50 and the Northern Cetids - No Link Found!; What Kind of Accretion Model is Required for the Solar System; and Use of an Orbital Phase Curve of Extrasolar Planet for Specification of its Mass.

HST/FGS High Angular Resolution Observations of Binary Asteroids

NASA Astrophysics Data System (ADS)

Hestroffer, Daniel; Tanga, P.; Cellino, A.; Kaasalainen, M.; Torppa, J.; Marchis, F.; Richardson, D. C.; Elankumaran, P.; Berthier, J.; Colas, F.; Lounis, S.

2006-09-01

Binary or multiple asteroids are important bodies that provide insight into the physical properties of asteroids in general. The knowledge of the components orbit in a binary provides the total mass with high accuracy and generally permits a rough bulk-density estimate [1,2]. We have observed 10 selected binary or multiple asteroids (22 Kalliope, 45 Eugenia, 87 Sylvia, 90 Antiope, 107 Camilla, 121 Hermione, 283 Emma, 379 Huenna, 617 Patroclus, 762 Pulcova) with the HST/FGS interferometer in order to obtain high resolution data on the size and shape of their primaries (HST proposal ID 10614). All these systems except the Jupiter Trojan 617 Patroclus are located in the main-belt of asteroids. Combining these HST/FGS data to topographic models obtained from lightcurve inversion [3,4] yields the volume and hence the bulk density of these bodies with unprecedented accuracy [5]. This work will allow us to obtain important information on their internal structure, and insight into the possible gravitational re-accumulation process after a catastrophic disruptive collision [e.g. 6,7,8].In particular, one can see whether or not the surfaces of theses bodies closely follow an effective equipotential surface, and under what circumstances such a correspondence is or is not attained . We will present the preliminary results for the data reduction and the size and bulk density determination. [1] Merline et al. (2003). In: Asteroids III, pp 289. [2] Marchis et al. (2005) ACM 2005, Buzios, Brazil. [3] Kaasalainen et al. (2002) Icarus 159, 359. [4] Torppa et al. (2003) Icarus 164, 346. [5] Hestroffer et al. (2003) ACM 2002, ESA-SP 500, 493. [6] Michel et al. (2004) P&SS 52, 1109. [7] Durda et al. (2004) Icarus 167, 342. [8] Paolicchi et al. (1993) Cel. Mech., 57, 49.

The binary Kuiper-belt object 1998 WW31.

PubMed

Veillet, Christian; Parker, Joel Wm; Griffin, Ian; Marsden, Brian; Doressoundiram, Alain; Buie, Marc; Tholen, David J; Connelley, Michael; Holman, Matthew J

2002-04-18

The recent discovery of a binary asteroid during a spacecraft fly-by generated keen interest, because the orbital parameters of binaries can provide measures of the masses, and mutual eclipses could allow us to determine individual sizes and bulk densities. Several binary near-Earth, main-belt and Trojan asteroids have subsequently been discovered. The Kuiper belt-the region of space extending from Neptune (at 30 astronomical units) to well over 100 AU and believed to be the source of new short-period comets-has become a fascinating new window onto the formation of our Solar System since the first member object, not counting Pluto, was discovered in 1992 (ref. 13). Here we report that the Kuiper-belt object 1998 WW31 is binary with a highly eccentric orbit (eccentricity e approximately 0.8) and a long period (about 570 days), very different from the Pluto/Charon system, which was hitherto the only previously known binary in the Kuiper belt. Assuming a density in the range of 1 to 2 g cm-3, the albedo of the binary components is between 0.05 and 0.08, close to the value of 0.04 generally assumed for Kuiper-belt objects.

YORP and collisional shaping of the sub-populations, rotation rate and size-frequency distributions in the main-belt

NASA Astrophysics Data System (ADS)

Rossi, A.; Marzari, F.; Scheeres, D.; Jacobson, S.; Davis, D.

In the last several years a comprehensive asteroid-population-evolution model was developed incorporating both the YORP effect and collisional evolution \\citep{rossi_2009}, \\citep{marz_2011}, \\citep{jac_mnras}. From the results of this model we were able to match the observed main belt rotation rate distribution and to give a first plausible explanation of the observed excess of slow rotators, through a random walk-like evolution of the spin, induced by repeated collisions with small projectiles. Moreover, adding to the model the rotational fission hypothesis (i.e. when the rotation rate exceeds a critical value, erosion and binary formation occur; \\citealt{sch_2007}) and binary-asteroid evolution \\citep{jac_sch}, we first showed that the YORP-induced rotational-fission hypothesis has strong repercussions for the small size end of the main-belt asteroid size-frequency distribution. We also concluded that this hypothesis is consistent with observed asteroid-population statistics and with the observed sub-populations of binary asteroids, asteroid pairs and contact binaries. An overview of the results obtained, the modelling uncertainties and the ongoing work will be given.

Planetary geology: Impact processes on asteroids

NASA Technical Reports Server (NTRS)

Chapman, C. R.; Davis, D. R.; Greenberg, R.; Weidenschilling, S. J.

1982-01-01

The fundamental geological and geophysical properties of asteroids were studied by theoretical and simulation studies of their collisional evolution. Numerical simulations incorporating realistic physical models were developed to study the collisional evolution of hypothetical asteroid populations over the age of the solar system. Ideas and models are constrained by the observed distributions of sizes, shapes, and spin rates in the asteroid belt, by properties of Hirayama families, and by experimental studies of cratering and collisional phenomena. It is suggested that many asteroids are gravitationally-bound "rubble piles.' Those that rotate rapidly may have nonspherical quasi-equilibrium shapes, such as ellipsoids or binaries. Through comparison of models with astronomical data, physical properties of these asteroids (including bulk density) are determined, and physical processes that have operated in the solar system in primordial and subsequent epochs are studied.

The Double Asteroid Redirection Test in the AIDA Project

NASA Astrophysics Data System (ADS)

Cheng, Andrew; Rivkin, Andrew; Michel, Patrick

2016-04-01

The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, that includes the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid, by targeting an object larger than ~100 m and large enough to qualify as a Potentially Hazardous Asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the period change of the binary orbit; (3) understand the hyper-velocity collision effects on an asteroid, including the long-term dynamics of impact ejecta; and validate models for momentum transfer in asteroid impacts, based on measured physical properties of the asteroid surface and sub-surface. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary. Supporting Earth-based optical and radar observations and numerical simulation studies are an integral part of the DART mission. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September, 2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close approach to Earth. The AIM spacecraft will be launched in Dec. 2020 and arrive at Didymos in spring, 2022, several months before the DART impact. AIM will characterize the Didymos binary system by means of remote sensing and in-situ instruments both before and after the DART impact. The asteroid deflection will be measured to higher accuracy, and additional results of the DART impact, like the impact crater, will be studied in great detail by the AIM mission. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency β from hyper-velocity kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. The DART impact on the Didymos secondary is predicted to cause a ~4.4 minute change in the binary orbit period, assuming β=1, and is expected to be observable within a few days. The predicted β would be in the range 1.1 to 1.3 for a porous target material based on a variety of numerical and analytical methods, but may be much larger if the target is non-porous. The DART kinetic impact is predicted to make a crater of ~6 to ~17 meters diameter, depending on target physical properties, but will also release a large volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes.

Creep stability of the proposed AIDA mission target 65803 Didymos: I. Discrete cohesionless granular physics model

NASA Astrophysics Data System (ADS)

Zhang, Yun; Richardson, Derek C.; Barnouin, Olivier S.; Maurel, Clara; Michel, Patrick; Schwartz, Stephen R.; Ballouz, Ronald-Louis; Benner, Lance A. M.; Naidu, Shantanu P.; Li, Junfeng

2017-09-01

As the target of the proposed Asteroid Impact & Deflection Assessment (AIDA) mission, the near-Earth binary asteroid 65803 Didymos represents a special class of binary asteroids, those whose primaries are at risk of rotational disruption. To gain a better understanding of these binary systems and to support the AIDA mission, this paper investigates the creep stability of the Didymos primary by representing it as a cohesionless self-gravitating granular aggregate subject to rotational acceleration. To achieve this goal, a soft-sphere discrete element model (SSDEM) capable of simulating granular systems in quasi-static states is implemented and a quasi-static spin-up procedure is carried out. We devise three critical spin limits for the simulated aggregates to indicate their critical states triggered by reshaping and surface shedding, internal structural deformation, and shear failure, respectively. The failure condition and mode, and shear strength of an aggregate can all be inferred from the three critical spin limits. The effects of arrangement and size distribution of constituent particles, bulk density, spin-up path, and interparticle friction are numerically explored. The results show that the shear strength of a spinning self-gravitating aggregate depends strongly on both its internal configuration and material parameters, while its failure mode and mechanism are mainly affected by its internal configuration. Additionally, this study provides some constraints on the possible physical properties of the Didymos primary based on observational data and proposes a plausible formation mechanism for this binary system. With a bulk density consistent with observational uncertainty and close to the maximum density allowed for the asteroid, the Didymos primary in certain configurations can remain geo-statically stable without requiring cohesion.

The Asteroid Impact and Deflection Assessment Mission and its Potential Contributions to Human Exploration of Asteroids

NASA Technical Reports Server (NTRS)

Abell, Paul A.; Rivkin, Andy S.

2014-01-01

The joint ESA and NASA Asteroid Impact and Deflection Assessment (AIDA) mission will directly address aspects of NASA's Asteroid Initiative and will contribute to future human exploration. The NASA Asteroid Initiative is comprised of two major components: the Grand Challenge and the Asteroid Mission. The first component, the Grand Challenge, focuses on protecting Earth's population from asteroid impacts by detecting potentially hazardous objects with enough warning time to either prevent them from impacting the planet, or to implement civil defense procedures. The Asteroid Mission, involves sending astronauts to study and sample a near-Earth asteroid (NEA) prior to conducting exploration missions of the Martian system, which includes Phobos and Deimos. AIDA's primary objective is to demonstrate a kinetic impact deflection and characterize the binary NEA Didymos. The science and technical data obtained from AIDA will aid in the planning of future human exploration missions to NEAs and other small bodies. The dual robotic missions of AIDA, ESA's Asteroid Impact Monitor (AIM) and NASA's Double Asteroid Redirection Test (DART), will provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific examinations of the binary target Didymos both prior to and after the kinetic impact demonstration. The knowledge gained from this mission will help identify asteroidal physical properties in order to maximize operational efficiency and reduce mission risk for future small body missions. The AIDA data will help fill crucial strategic knowledge gaps concerning asteroid physical characteristics that are relevant for human exploration considerations at similar small body destinations.

Dynamical model of binary asteroid systems through patched three-body problems

NASA Astrophysics Data System (ADS)

Ferrari, Fabio; Lavagna, Michèle; Howell, Kathleen C.

2016-08-01

The paper presents a strategy for trajectory design in the proximity of a binary asteroid pair. A novel patched approach has been used to design trajectories in the binary system, which is modeled by means of two different three-body systems. The model introduces some degrees of freedom with respect to a classical two-body approach and it is intended to model to higher accuracy the peculiar dynamical properties of such irregular and low gravity field bodies, while keeping the advantages of having a full analytical formulation and low computational cost required. The neighborhood of the asteroid couple is split into two regions of influence where two different three-body problems describe the dynamics of the spacecraft. These regions have been identified by introducing the concept of surface of equivalence (SOE), a three-dimensional surface that serves as boundary between the regions of influence of each dynamical model. A case of study is presented, in terms of potential scenario that may benefit of such an approach in solving its mission analysis. Cost-effective solutions to land a vehicle on the surface of a low gravity body are selected by generating Poincaré maps on the SOE, seeking intersections between stable and unstable manifolds of the two patched three-body systems.

The Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS)

NASA Astrophysics Data System (ADS)

Rivkin, A.; Cohen, B. A.; Barnouin, O. S.; Chabot, N. L.; Ernst, C. M.; Klima, R. L.; Helbert, J.; Sternovsky, Z.

2015-12-01

The asteroids preserve information from the earliest times in solar system history, with compositions in the population reflecting the material in the solar nebula and experiencing a wide range of temperatures. Today they experience ongoing processes, some of which are shared with larger bodies but some of which are unique to their size regime. They are critical to humanity's future as potential threats, resource sites, and targets for human visitation. However, over twenty years since the first spacecraft encounters with asteroids, they remain poorly understood. The mission we propose here, the Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS), explores the diversity of asteroids to understand our solar system's past history, its present processes, and future opportunities and hazards. MANTIS addresses many of NASA's highest priorities as laid out in its 2014 Science Plan and provides additional benefit to the Planetary Defense and Human Exploration communities via a low-risk, cost-effective tour of the near-Earth and inner asteroid belt. MANTIS visits the materials that witnessed solar system formation and its earliest history, addressing the NASA goal of exploring and observing the objects in the solar system to understand how they formed and evolve. MANTIS measures OH, water, and organic materials via several complementary techniques, visiting and sampling objects known to have hydrated minerals and addressing the NASA goal of improving our understanding of the origin and evolution of life on Earth. MANTIS studies the geology and geophysics of nine diverse asteroids, with compositions ranging from water-rich to metallic, representatives of both binary and non-binary asteroids, and sizes covering over two orders of magnitude, providing unique information about the chemical and physical processes shaping the asteroids, addressing the NASA goal of advancing the understanding of how the chemical and physical processes in our solar system operate, interact, and evolve. Finally, the set of measurements carried out by MANTIS at near-Earth and main-belt asteroids will by definition characterize objects in the solar system that pose threats to Earth or offer resources for human exploration, a final goal in the NASA Science Plan.

Shape Shifting Satellites in Binary Near-Earth Asteroids: Do Meteoroid Impacts Play a Role in BYORP Orbital Evolution?

NASA Technical Reports Server (NTRS)

Rubincam, David Parry

2012-01-01

Less than catastrophic meteoroid impacts over 10(exp 5) years may change the shape of small rubble-pile satellites in binary NEAs, lengthening the average BYORP (binary Yarkovsky-Radzievskii-Paddack) rate of orbital evolution. An estimate of shape-shifting meteoroid fluxes give numbers close enough to causing random walks in the semimajor axis of binary systems to warrant further investigation

ASPECT spectral imaging satellite proposal to AIDA/AIM CubeSat payload

NASA Astrophysics Data System (ADS)

Kohout, Tomas; Näsilä, Antti; Tikka, Tuomas; Penttilä, Antti; Muinonen, Karri; Kestilä, Antti; Granvik, Mikael; Kallio, Esa

2016-04-01

ASPECT (Asteroid Spectral Imaging Mission) is a part of AIDA/AIM project and aims to study the composition of the Didymos binary asteroid and the effects of space weathering and shock metamorphism in order to gain understanding of the formation and evolution of the Solar System. The joint ESA/NASA AIDA (Asteroid Impact & Deflection Assessment) mission to binary asteroid Didymos consists of AIM (Asteroid Impact Mission, ESA) and DART (Double Asteroid Redirection Test, NASA). DART is targeted to impact Didymos secondary component (Didymoon) and serve as a kinetic impactor to demonstrate deflection of potentially hazardous asteroids. AIM will serve as an observational spacecraft to evaluate the effects of the impact and resulting changes in the Didymos dynamic parameters. The AIM mission will also carry two CubeSat miniaturized satellites, released in Didymoon proximity. This arrangement opens up a possibility for secondary scientific experiments. ASPECT is one of the proposed CubeSat payloads. Whereas Didymos is a space-weathered binary asteroid, the DART impactor is expected to produce a crater and excavate fresh material from the secondary component (Didymoon). Spectral comparison of the mature surface to the freshly exposed material will allow to directly deter-mine space weathering effects. It will be also possible to study spectral shock effects within the impact crater. ASPECT will also demonstrate for the first time the joint spacecraft - CubeSat operations in asteroid proximity and miniature spectral imager operation in deep-space environment. Science objectives: 1. Study of the surface composition of the Didymos system. 2. Photometric observations (and modeling) under varying phase angle and distance. 3. Study of space weathering effects on asteroids (comparison of mature / freshly exposed material). 4. Study of shock effects (spectral properties of crater interior). 5. Observations during the DART impact. Engineering objectives: 1. Demonstration of CubeSat semi-autonomous operations in deep space environment. 2. Navigation in the vicinity of a binary asteroid. 3. Demonstration of a satellite survival during impact. 4. Demonstration of joint spacecraft - CubeSat operations. ASPECT is a 3U CubeSat (size of 3 units, Fig. 1) equipped with a spectral imager from 500 nm to 1600 nm (spatial resolution < 2 m, spectral resolution 10 - 30 nm; VIS channel 512 x 512 pixels, NIR channel 256 x 256 pixels), and a non-imaging spectrometer from 1600 - 2500 nm. The design is based on the Aalto-1 CubeSat Spectral Imager heritage. ASPECT will also demonstrate the capabilities of a CubeSat and a miniature spectral imager for the first time in deep-space environment. Acknowledgements: This work is done under Sys-Nova: R&D Studies Competition for Innovation contract with ESA.

Seeing Double Old and New: Observations and Lightcurve Analysis at the Palmer Divide Observatory of Six Binary Asteroids

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2013-04-01

Results of the analysis of lightcurves of six binary asteroids obtained at the Palmer Divide Observatory are reported. Of the six, three were previously known to be binary: 9069 Hovland, (26471) 2000 AS152, and 1994 XD. The remaining three are new confirmed or probable binary discoveries made at PDO: 2047 Smetana, (5646) 1990 TR, and (52316) 1992 BD.

Simulation of the dusty plasma environment of 65803 Didymos for the Asteroid Impact Mission (AIM)

NASA Astrophysics Data System (ADS)

Cipriani, Fabrice; Rodgers, David; Hilgers, Alain; Hess, Sebastien; Carnelli, Ian

2016-10-01

The Asteroid Impact and Deflection Assessment mission (AIDA) is a joint European-US technology demonstrator mission including the DART asteroid impactor (NASA/JHU/APL) and the AIM asteroid rendezvous platform (ESA/DLR/OCA) set to reach Near Earth binary Object 65803 Didymos in October 2022. Besides technology demonstration in the deep space communications domain and the realization of a kinetic impact on the moonlet to study deflection parameters, this asteroid rendezvous mission is an opportunity to carry out in-situ observations of the close environment of a binary system, addressing some fundamental science questions. The MASCOT-2 lander will be released from the AIM platform and operate at the surface of the moonlet of 65803 Didymos, complemented by the ability of the Cubesat Opportunity Payloads (COPINS) to sample the close environment of the binary.In this context, we have developed an model describing the plasma and charged dust components of the near surface environment of the moonlet (170m in diameter), targeted by the MASCOT-2 lander and of the DART impactor. We performed numerical simulations in order to estimate the electrostatic surface potentials at various locations of the surface, resulting from its interaction with the solar wind plasma and solar photons. In addition, we describe charging levels, density profiles, and velocity distribution of regolith grains lifted out from the surface up to about 70m above the surface.

Spin rate distribution of small asteroids

NASA Astrophysics Data System (ADS)

Pravec, P.; Harris, A. W.; Vokrouhlický, D.; Warner, B. D.; Kušnirák, P.; Hornoch, K.; Pray, D. P.; Higgins, D.; Oey, J.; Galád, A.; Gajdoš, Š.; Kornoš, L.; Világi, J.; Husárik, M.; Krugly, Yu. N.; Shevchenko, V.; Chiorny, V.; Gaftonyuk, N.; Cooney, W. R.; Gross, J.; Terrell, D.; Stephens, R. D.; Dyvig, R.; Reddy, V.; Ries, J. G.; Colas, F.; Lecacheux, J.; Durkee, R.; Masi, G.; Koff, R. A.; Goncalves, R.

2008-10-01

The spin rate distribution of main belt/Mars crossing (MB/MC) asteroids with diameters 3-15 km is uniform in the range from f=1 to 9.5 d -1, and there is an excess of slow rotators with f<1 d -1. The observed distribution appears to be controlled by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. The magnitude of the excess of slow rotators is related to the residence time of slowed down asteroids in the excess and the rate of spin rate change outside the excess. We estimated a median YORP spin rate change of ≈0.022 d/Myr for asteroids in our sample (i.e., a median time in which the spin rate changes by 1 d -1 is ≈45 Myr), thus the residence time of slowed down asteroids in the excess is ≈110 Myr. The spin rate distribution of near-Earth asteroids (NEAs) with sizes in the range 0.2-3 km (˜5 times smaller in median diameter than the MB/MC asteroids sample) shows a similar excess of slow rotators, but there is also a concentration of NEAs at fast spin rates with f=9-10 d. The concentration at fast spin rates is correlated with a narrower distribution of spin rates of primaries of binary systems among NEAs; the difference may be due to the apparently more evolved population of binaries among MB/MC asteroids.

AIDA: Asteroid Impact & Deflection Assessment

NASA Astrophysics Data System (ADS)

Cheng, Andrew; Michel, Patrick; Ulamec, Stephan; Reed, Cheryl; Galvez, Andres; Carnelli, Ian

On Feb. 15, 2013, an exceptionally close approach to Earth by the small asteroid 2012 DA14 was eagerly awaited by observers, but another small asteroid impacted Earth over Chelyabinsk, Russia the same day without warning, releasing several hundred kilotons TNT of energy and injuring over 1500 people. These dramatic events remind us of the needs to discover hazardous asteroids and to learn how to mitigate them. The AIDA mission is the first demonstration of a mitigation technique to protect the Earth from a potential asteroid impact, by performing a spacecraft kinetic impact on an asteroid to deflect it from its trajectory. We will provide an update on the status of parallel AIDA mission studies supported by ESA and NASA. AIDA is an international collaboration consisting of two independent but mutually supporting missions, one of which is the asteroid kinetic impactor, and the other is the characterization spacecraft which will orbit the asteroid system to monitor the deflection experiment and measure the results. These two missions are the NASA Double Asteroid Redirection Test (DART), which is the kinetic impactor, and the European Space Agency's Asteroid Impact Monitoring (AIM) mission, which is the characterization spacecraft. The target of the AIDA mission will be a binary asteroid, in which DART will target the secondary, smaller member in order to deflect the binary orbit. The resulting period change can be measured to within 10% by ground-based observations. The asteroid deflection will be measured to higher accuracy, and additional results of the DART impact, like the impact crater, will be studied in great detail by the AIM mission. AIDA will return vital data to determine the momentum transfer efficiency of the kinetic impact and key physical properties of the target asteroid. The two mission components of AIDA, DART and AIM, are each independently valuable, but when combined they provide a greatly increased knowledge return. The AIDA mission will combine US and European space experience and expertise to address an international problem, the asteroid impact hazard. AIDA will also be a valuable precursor to human spaceflight to an asteroid, as it would return unique information on an asteroid's strength and internal structure and would be particularly relevant to a human mission for asteroid mitigation. AIDA will furthermore return fundamental new science data on impact cratering, surface properties and interior structure. AIDA will target the binary Near-Earth asteroid Didymos with two independently launched spacecraft, with the deflection experiment to occur in October, 2022.

Asteroid Properties from Photometric Observations: Constraining Non-Gravitational Processes in Asteroids

NASA Astrophysics Data System (ADS)

Pravec, P.

2013-05-01

From October 2012 we run our NEOSource project on the Danish 1.54-m telescope on La Silla. The primary aim of the project is to study non-gravitational processes in asteroids near the Earth and in their source regions in the main asteroidal belt. In my talk, I will give a brief overview of our current knowledge of the asteroidal non- gravitational processes and how we study them with photometric observations. I will talk especially about binary and paired asteroids that appear to be formed by rotational fission, about detecting the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) and BYORP (binary YORP) effects of anisotropic thermal emission from asteroids that change their spins and satellite orbits, and about non-principal axis rotators (the so called "tumblers") among the smallest, super-critically rotating asteroids with sizes < 100 meters.

A Unified Model for Repeating and Non-repeating Fast Radio Bursts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagchi, Manjari, E-mail: manjari@imsc.res.in

The model that fast radio bursts (FRBs) are caused by plunges of asteroids onto neutron stars can explain both repeating and non-repeating bursts. If a neutron star passes through an asteroid belt around another star, there would be a series of bursts caused by a series of asteroid impacts. Moreover, the neutron star would cross the same belt repetitively if it were in a binary with the star hosting the asteroid belt, leading to a repeated series of bursts. I explore the properties of neutron star binaries that could lead to the only known repeating FRB so far (FRB121102). Inmore » this model, the next two epochs of bursts are expected around 2017 February 27 and 2017 December 18. On the other hand, if the asteroid belt is located around the neutron star itself, then a chance fall of an asteroid from that belt onto the neutron star would lead to a non-repeating burst. Even a neutron star grazing an asteroid belt can lead to a non-repeating burst caused by just one asteroid plunge during the grazing. This is possible even when the neutron star is in a binary with the asteroid-hosting star, if the belt and the neutron star orbit are non-coplanar.« less

AIDA DART asteroid deflection test: Planetary defense and science objectives

NASA Astrophysics Data System (ADS)

Cheng, Andrew F.; Rivkin, Andrew S.; Michel, Patrick; Atchison, Justin; Barnouin, Olivier; Benner, Lance; Chabot, Nancy L.; Ernst, Carolyn; Fahnestock, Eugene G.; Kueppers, Michael; Pravec, Petr; Rainey, Emma; Richardson, Derek C.; Stickle, Angela M.; Thomas, Cristina

2018-08-01

The Asteroid Impact & Deflection Assessment (AIDA) mission is an international cooperation between NASA and ESA. NASA plans to provide the Double Asteroid Redirection Test (DART) mission which will perform a kinetic impactor experiment to demonstrate asteroid impact hazard mitigation. ESA proposes to provide the Hera mission which will rendezvous with the target to monitor the deflection, perform detailed characterizations, and measure the DART impact outcomes and momentum transfer efficiency. The primary goals of AIDA are (i) to demonstrate the kinetic impact technique on a potentially hazardous near-Earth asteroid and (ii) to measure and characterize the deflection caused by the impact. The AIDA target will be the binary asteroid (65803) Didymos, which is of spectral type Sq, with the deflection experiment to occur in October, 2022. The DART impact on the secondary member of the binary at ∼6 km/s changes the orbital speed and the binary orbit period, which can be measured by Earth-based observatories with telescope apertures as small as 1 m. The DART impact will in addition alter the orbital and rotational states of the Didymos binary, leading to excitation of eccentricity and libration that, if measured by Hera, can constrain internal structure of the target asteroid. Measurements of the DART crater diameter and morphology can constrain target properties like cohesion and porosity based on numerical simulations of the DART impact.

The full two-body-problem: Simulation, analysis, and application to the dynamics, characteristics, and evolution of binary asteroid systems

NASA Astrophysics Data System (ADS)

Fahnestock, Eugene Gregory

The Full Two-Body-Problem (F2BP) describes the dynamics of two unconstrained rigid bodies in close proximity, having arbitrary spatial distribution of mass, charge, or similar field quantity, and interacting through a mutual potential dependent on that distribution. While the F2BP has applications in areas as wide ranging as molecular dynamics to satellite formation flying, this dissertation focuses on its application to natural bodies in space with nontrivial mass distribution interacting through mutual gravitational potential, i.e. binary asteroids. This dissertation first describes further development and implementation of methods for accurate and efficient F2BP propagation based upon a flexible method for computing the mutual potential between bodies modeled as homogenous polyhedra. Next application of these numerical tools to the study of binary asteroid (66391) 1999 KW4 is summarized. This system typifies the largest class of NEO binaries, which includes nearly half of them, characterized by a roughly oblate spheroid primary rotating rapidly and roughly triaxial ellipsoid secondary in on-average synchronous rotation. Thus KW4's dynamics generalize to any member of that class. Analytical formulae are developed which separately describe the effects of primary oblateness and secondary triaxial ellipsoid shape on frequencies of system motions revealed through the F2BP simulation. These formulae are useful for estimating inertia elements and highest-level internal mass distributions of bodies in any similar system, simply from standoff observation of these motion frequencies. Finally precise dynamical simulation and analysis of the motion of test particles within the time-varying gravity field of the F2BP system is detailed. This Restricted Full-detail Three-Body-Problem encompasses exploration of three types of particle motion within a binary asteroid: (1) Orbital motion such as that for a spacecraft flying within the system about the primary, secondary, or system barycenter at large distance; (2) Motion of ejecta particles originating from the body surfaces with substantial initial surface-relative velocity; (3) Motion of particles originating from the primary surface near the equator, with no initial surface-relative velocity, but when primary spin rate is raised past the "disruption spin rate" for which material on the surface will be spun off.

Ejecta evolutions and fates from the AIDA impact on the secondary of the binary asteroid Didymos: a NEOShield-2 project contribution

NASA Astrophysics Data System (ADS)

Michel, P.; Yu, Y.

2017-09-01

We simulated the evolutions and fates of ejecta produced by the impact of a projectile of the secondary of the binary asteroid Didymos, in the framework of the AIDA space mission project. Our results show how these evolutions and fates depend on the impact location on the secondary and ejection speeds of the ejecta. This information can be used to defined safe positions for an observing spacecraft and to better understand the outcome of an impact in the environment of a binary asteroid.

Lightcurve Analysis of the NEA Binary Asteroid 5381 Sekhmet

NASA Astrophysics Data System (ADS)

Warner, Brian D.; Harris, Alan W.

2014-10-01

Radar observations in 2003 (Nolan et al., 2003) showed that the near-Earth asteroid (NEA) 5381 Sekhmet was a binary. CCD photometry observations made from the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) during the 2014 apparition confirmed the discovery and found the first precise values for the primary rotation period, P1 = 2.8233 ± 0.0001 h, and the orbital period of the satellite, P_ORB = 12.379 ± 0.004 h. The estimated effective size ratio of the two bodies is Ds/Dp ≥ 0.25 ± 0.02, which is in good agreement with the sizes estimated by radar.

Orbital evolution of small binary asteroids

NASA Astrophysics Data System (ADS)

Ćuk, Matija; Nesvorný, David

2010-06-01

About 15% of both near-Earth and main-belt asteroids with diameters below 10 km are now known to be binary. These small asteroid binaries are relatively uniform and typically contain a fast-spinning, flattened primary and a synchronously rotating, elongated secondary that is 20-40% as large (in diameter) as the primary. The principal formation mechanism for these binaries is now thought to be YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect induced spin-up of the primary followed by mass loss and accretion of the secondary from the released material. It has previously been suggested (Ćuk, M. [2007]. Astrophys. J. 659, L57-L60) that the present population of small binary asteroids is in a steady state between production through YORP and destruction through binary YORP (BYORP), which should increase or decrease secondary's orbit, depending on the satellite's shape. However, BYORP-driven evolution has not been directly modeled until now. Here we construct a simple numerical model of the binary's orbital as well the secondary's rotational dynamics which includes BYORP and selected terms representing main solar perturbations. We find that many secondaries should be vulnerable to chaotic rotation even for relatively low-eccentricity mutual orbits. We also find that the precession of the mutual orbit for typical small binary asteroids might be dominated by the perturbations from the prolate and librating secondary, rather than the oblate primary. When we evolve the mutual orbit by BYORP we find that the indirect effects on the binary's eccentricity (through the coupling between the orbit and the secondary's spin) dominate over direct ones caused by the BYORP acceleration. In particular, outward evolution causes eccentricity to increase and eventually triggers chaotic rotation of the secondary. We conclude that the most likely outcome will be reestablishing of the synchronous lock with a "flipped" secondary which would then evolve back in. For inward evolution we find an initial decrease of eccentricity and secondary's librations, to be followed by later increase. We think that it is likely that various forms of dissipation we did not model may damp the secondary's librations close to the primary, allowing for further inward evolution and a possible merger. We conclude that a merger or a tidal disruption of the secondary are the most likely outcomes of the BYORP evolution. Dissociation into heliocentric pairs by BYORP alone should be very difficult, and satellite loss might be restricted to the minority of systems containing more than one satellite at the time.

The Binary Asteroid in-situ Explorer (BASiX) Mission

NASA Astrophysics Data System (ADS)

Dissly, Richard; Scheeres, D. J.; Nilsen, E.; Roark, S.; Frazier, W.; Bank, T.; Rosing, D.; Jordan, E.; BASiX Science Team

2010-10-01

The Binary Asteroid in-situ Explorer (BASiX) Mission represents the next phase of asteroid exploration, carrying out geophysical experiments by active engagement with an asteroid in a controlled and repeatable manner. BASiX will address new and timely scientific goals that address unresolved issues at the heart of our understanding of these bodies and which serve as barriers to their future exploration. A primary objective of the BASiX Mission is to determine the fundamental mechanical and strength properties of an asteroid through the creation of craters on the asteroid surface using calibrated charges. BASiX also takes advantage of these experiments to further understand the weathering and seismic properties of an asteroid. By carrying out these experiments at a binary Near Earth Asteroid (NEA), BASiX also advances our understanding of these ubiquitous bodies in the small asteroid population. BASiX is an efficient and simple mission concept that can deliver revolutionary science with its threshold mission and adds substantial enhancements with its baseline mission. BASiX assembles an international team of top small body scientists and astronomers and is led by PI Dan Scheeres (University of Colorado). BASiX is managed by JPL, which is also where mission and science operations will be based. The BASiX Spacecraft is built by Ball Aerospace & Technologies Corp. Instruments are built by JPL and Ball with additional contributed instruments from CNES.

Stochastic YORP On Real Asteroid Shapes

NASA Astrophysics Data System (ADS)

McMahon, Jay W.

2015-05-01

Since its theoretical foundation and subsequent observational verification, the YORP effect has been understood to be a fundamental process that controls the evolution of small asteroids in the inner solar system. In particular, the coupling of the YORP and Yarkovsky effects are hypothesized to be largely responsible for the transport of asteroids from the main belt to the inner solar system populations. Furthermore, the YORP effect is thought to lead to rotational fission of small asteroids, which leads to the creation of multiple asteroid systems, contact binary asteroids, and asteroid pairs. However recent studies have called into question the ability of YORP to produce these results. In particular, the high sensitivity of the YORP coefficients to variations in the shape of an asteroid, combined with the possibility of a changing shape due to YORP accelerated spin rates can combine to create a stochastic YORP coefficient which can arrest or change the evolution of a small asteroid's spin state. In this talk, initial results are presented from new simulations which comprehensively model the stochastic YORP process. Shape change is governed by the surface slopes on radar based asteroid shape models, where the highest slope regions change first. The investigation of the modification of YORP coefficients and subsequent spin state evolution as a result of this dynamically influenced shape change is presented and discussed.

Speckle interferometry applied to asteroids and other solar system objects

NASA Technical Reports Server (NTRS)

Drummond, J. D.; Hege, E. K.

1986-01-01

Speckle interferometry is a high angular resolution technique that allows study of resolved asteroids. By following the changing size, shape, and orientation of minor planets, and with a few general assumptions (e.g., geometric scattering, triaxial ellipsoid figures, no albedo features), it is possible to directly measure an asteroid's true dimensions and the direction of its spin axis in one or two nights. A particular subset of triaxial ellipsoid figures are equilibrium shapes, and would imply that some asteroids are thoroughly fractured. Such shapes if they exist among the asteroids would allow a determination of bulk density since there is a unique relation among spin period, size, shape, and density. The discovery of even a single rubble pile, (just as the finding of even one binary asteroid by speckle interferometric techniques) would drastically alter the notion of asteroids as small solid planets. The Pluto/Charon system was studied to aid in improving the orbital elements necessary to predict the eclipse/occultation season currently in progress. Four asteroids were reduced to their size, shape, and pole direction: 433 Eros, 532 Herculina, 511 Davida, and 2 Pallas.

The partial fission of fast spinning asteroids

NASA Astrophysics Data System (ADS)

Tardivel, Simon; Sanchez, Paul; Scheeres, Daniel J.

2016-10-01

The spin rates of asteroids systematically change over time due the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. Above a certain spin rate that depends on the body's density, regions of an asteroid can enter in tension, with components held to the body by cohesive forces. When the body fails, deformation or fission can occur. Catastrophic fission leading to complete disruption has been directly observed in active asteroid P/2013 R3. Partial fission, the loss of only part of the body, has been proposed as a mechanism for the formation of binaries and is explored here.The equatorial cavities of (341843) 2008 EV5 and of (185851) 2000 DP107 (a binary system) are consistent with a localized partial fission of the body (LPSC 2016 #1036). The examination of the gravity field of these bodies reveals that a mass placed within these cavities could be shed. In this mechanism, the outward pull of inertial forces creates an average stress at the cavity interface of ≈1 Pa for 2008 EV5 and ≈3 Pa for 2000 DP107 at spin periods of ≈3.15 h for the assumed densities of 1.3 g/cm3.This work continues the study of this partial, localized fission. Specifically, it addresses the issue of the low cohesion necessary to the mechanism. These cohesion values are typically lower than global strength values inferred on other asteroids (10 - 200 Pa), meaning that partial fission may occur prior to larger-scale deformations. Yet, several processes can explain the discrepancy, as they can naturally segregate particles by size. For instance, landslides or granular convection (Brazil nut effect) could bring larger boulders to the equator of the body, while finer particles are left at higher latitudes or sink to the center. Conversely, failure of the interior could bring boulders to the surface. The peculiar profile shape of these asteroids, shared by many binaries (e.g. 1999 KW4, 1996 FG3) may also be a clue of this heterogeneity, as this "spin top" shape is obtained in simulations with a weak shell and a strong core.Using observations and simulations, we consider these processes and the role that this partial fission mechanism could play in the formation of binary asteroids and the creation of equatorial divots on asteroids.

Discovery of the triple asteroidal system 87 Sylvia.

PubMed

Marchis, Franck; Descamps, Pascal; Hestroffer, Daniel; Berthier, Jérome

2005-08-11

After decades of speculation, the existence of binary asteroids has been observationally confirmed, with examples in all minor planet populations. However, no triple systems have hitherto been discovered. Here we report the unambiguous detection of a triple asteroidal system in the main belt, composed of a 280-km primary (87 Sylvia) and two small moonlets orbiting at 710 and 1,360 km. We estimate their orbital elements and use them to refine the shape of the primary body. Both orbits are equatorial, circular and prograde, suggesting a common origin. Using the orbital information to estimate its mass and density, 87 Sylvia appears to have a rubble-pile structure with a porosity of 25-60 per cent. The system was most probably formed through the disruptive collision of a parent asteroid, with the new primary resulting from accretion of fragments, while the moonlets are formed from the debris, as has been predicted previously.

Period Determination of Binary Asteroid Targets Observed at Hunters Hill Observatory: May-September 2009

NASA Astrophysics Data System (ADS)

Higgins, David; Oey, Julian; Pravec, Petr

2011-01-01

Lightcurves for seven confirmed or possible binary asteroids were obtained at the Hunters Hill Observatory (HHO) and Leura Observatory from 2009 May through 2010 September: 1453 Fennia, 2501 Lohja, 3076 Garbor, 4029 Bridges, 5325 Silver, 6244 Okamoto, and (6265) 1985 TW3.

Searching for Solar System Wide Binaries with Pan-STARRS-1

NASA Astrophysics Data System (ADS)

Holman, Matthew J.; Protopapas, P.; Tholen, D. J.

2007-10-01

Roughly 60% of the observing time of the Pan-STARRS-1 (PS1) telescope will be dedicated to a "3pi steradian" survey with an observing cadence that is designed for the detection of near-Earth asteroids and slow-moving solar system bodies. Over this course of its 3.5 year cience mission, this unprecedented survey will discover nearly every asteroid, Trojan, Centaur, long-period comet, short-period comet, and trans-neptunian object (TNO) brighter than magnitude R=23. This census will be used to address a large number of questions regarding the physical and dynamical properties of the various small body populations of the solar system. Roughly 1-2% of TNOs are wide binaries with companions at separations greater than 1 arcsec and brightness differences less than 2 magnitudes (Kern & Elliot 2006; Noll et al 2007). These can be readily detected by PS1; we will carry out such a search with PS1 data. To do so, we will modify the Pan-STARRS Moving Object Processing System (MOPS) such that it will associate the components of resolved or marginally resolved binaries, link such pairs of detections obtained at different epochs, and the estimate the relative orbit of the binary. We will also determine the efficiency with which such binaries are detected as a function of the binary's relative orbit and the relative magnitudes of the components. Based on an estimated 7000 TNOs that PS1 will discover, we anticipate finding 70-140 wide binaries. The PS1 data, 60 epochs over three years, is naturally suited to determining the orbits of these objects. Our search will accurately determine the binary fraction for a variety of subclasses of TNOs.

A fast method for finding bound systems in numerical simulations: Results from the formation of asteroid binaries

NASA Astrophysics Data System (ADS)

Leinhardt, Zoë M.; Richardson, Derek C.

2005-08-01

We present a new code ( companion) that identifies bound systems of particles in O(NlogN) time. Simple binaries consisting of pairs of mutually bound particles and complex hierarchies consisting of collections of mutually bound particles are identifiable with this code. In comparison, brute force binary search methods scale as O(N) while full hierarchy searches can be as expensive as O(N), making analysis highly inefficient for multiple data sets with N≳10. A simple test case is provided to illustrate the method. Timing tests demonstrating O(NlogN) scaling with the new code on real data are presented. We apply our method to data from asteroid satellite simulations [Durda et al., 2004. Icarus 167, 382-396; Erratum: Icarus 170, 242; reprinted article: Icarus 170, 243-257] and note interesting multi-particle configurations. The code is available at http://www.astro.umd.edu/zoe/companion/ and is distributed under the terms and conditions of the GNU Public License.

Geodynamic stability of the primary in the binary asteroid system 65803 Didymos

NASA Astrophysics Data System (ADS)

Barnouin, Olivier S.; Maurel, Clara; Richardson, Derek C.; Ballouz, Ronald-Louis; Schwartz, Stephen; Michel, Patrick

2015-11-01

The moon of the near-Earth binary asteroid 65803 Didymos is the target of the Asteroid Impact and Deflection Assessment (AIDA) mission. This mission is a joint concept between NASA and ESA to investigate the effectiveness of a kinetic impactor in deflecting an asteroid. The mission is composed of two components: the NASA-led Double Asteroid Redirect Test (DART) that will impact the Didymos moon, and the ESA-led Asteroid Impact Monitoring (AIM) mission that will characterize the Didymos system. In order to provide AIDA constraints on the physical character of the both objects in this binary system, we undertook preliminary numerical investigations to evaluate the stability of the shape of the primary using its rapid 2.26 h rotation. We modeled the primary as a rubble pile. Each model consisted of thousands of uniform rigid spheres collapsed together under their own gravity to form a spherical pile that was then carved to match the current radar-derived shape model of the primary, as well as other comparable shapes (e.g. asteroid 1999 KW4, spheres) that were scaled to match best estimates of the size of Didymos. Each model was given a starting rotation period of 6 h with the spin axis aligned to the pole. At each timestep the spin rate was increased by a small amount so that after about 1 million timesteps the spin would match the observed rotation of 2.26 h. We tested a range of bulk densities spanning the current observational uncertainty (mean 2.4 g/cc) using "gravel"-like material parameters that provide significant resistance to sliding and rolling. We find that at the upper range of the density uncertainty it is possible for Didymos to hold its shape and not lose mass at its nominal rotation period, without the need for cohesive forces. At lower densities or with smoother particles, significant shape change occurs and mass loss is possible. We conclude that based on the radar shape available at the time of this writing, Didymos is marginally stable as a rubble pile with bulk density close to 3 g/cc. Revisions to the radar shape in process may allow for stability at lower bulk densities without cohesion. These results suggest that the moon of Didymos may also not be heavily influenced by cohesion.

A mission concept for a Grand Tour of Multiple Asteroid Systems

NASA Astrophysics Data System (ADS)

Marchis, F.; Dankanich, J.; Tricarico, P.; Bellerose, J.

2009-12-01

In 1993, the Galileo spacecraft imaged the first companion of asteroid, Dactyl orbiting 243 Ida, a main-belt asteroid. Since then, discoveries have been accumulated thanks to the development of high angular resolution imaging on ground-based telescopes (adaptive optics), radar observations and accurate photometric light curve measurements. To date, 180 companions of small solar system bodies (SSSBs) are known in various populations, including 100 in the asteroid main belt, 33 Near Earth Asteroids, 4 Jupiter-Trojan asteroids and 44 in the Kuiper Belt. Multiple Asteroids have been shown to be complex worlds in their own with a wide range of morphologies, dynamical histories, and structural evolution. To the exception of 243 Ida, no spacecraft has visited any of them. Investigating binary asteroid systems can verify and validate current theories on their formation and on the influence of the sun in their formation (YORP effect) and evolution (space weathering). In particular, assessing the origin of the secondary satellite, if it is of common origin or capture, can provide clue of their formation. To a larger extend, the determination of their nature, scenario formation and evolution are key to understand how planet formation occurred but also to understand i) the population and compositional structure of the SSSB today ii) how the dynamics and collisions modify this structure over time iii) what the physical properties of asteroids are (density, porosity) iv) how the surface modification processes affect our ability to determine this structure (e.g. space weathering). In addition, being able to study these properties on closeby asteroids will give a relative scale accounting for the sizes, shape, rotation periods and cratering rate of these small and young bodies. In the framework of the NASA Discovery program, we propose a mission consisting of a Grand Tour of several multiple asteroid systems, including the flyby of a near earth binary asteroid and the rendezvous with several multiple asteroid systems located in the main belt. This mission concept uses the NASA's evolutionary Xenon Thruster (NEXT), the second generation of electric propulsion with 3 times more input power than the previous generation (NSTAR) of the Dawn mission. The mission objectives for each rendezvous asteroid are i) the characterization of the surface geology by direct imaging in visible and thermal infrared spectroscopy, ii) the characterization of the shape and gravity coupling visible observations with LIDAR ranging data, iii) the determination of the thermophysical properties of the surface, and iv) the identification of the surface composition by visible and near-infrared spectroscopy. The trajectory, science package and mission operations of the mission will be described. This work is supported by the National Science Foundation 05-608, "Astronomy and Astrophysics Research Grants (AAG)" No AST-0807468

Stability of binaries. Part 1: Rigid binaries

NASA Astrophysics Data System (ADS)

Sharma, Ishan

2015-09-01

We consider the stability of binary asteroids whose members are possibly granular aggregates held together by self-gravity alone. A binary is said to be stable whenever each member is orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability test for rotating granular aggregates introduced by Sharma (Sharma, I. [2012]. J. Fluid Mech., 708, 71-99; Sharma, I. [2013]. Icarus, 223, 367-382; Sharma, I. [2014]. Icarus, 229, 278-294) to the case of binary systems comprised of rubble members. In part I, we specialize to the case of a binary with rigid members subjected to full three-dimensional perturbations. Finally, we employ the stability test to critically appraise shape models of four suspected binary systems, viz., 216 Kleopatra, 25143 Itokawa, 624 Hektor and 90 Antiope.

Primary Surface Particle Motion as a Mechanism for YORP-Driven Binary Asteroid Evolution

NASA Astrophysics Data System (ADS)

Fahnestock, Eugene G.; Scheeres, D. J.

2008-09-01

Within the largest class of binary asteroid systems -- asynchronous binaries typified by 1999 KW4 -- we hypothesize continued YORP spin-up of the rapidly rotating primary leads to recurring episodic lofting motion of primary equator regolith. We theorize this is a mechanism for transporting YORP-injected angular momentum from primary spin into the mutual orbit. This both enables binary primaries to continue to spin at near surface fission rates and produces continued orbit expansion on time scales several times faster than expansion predicted by tidal dissipation alone. This is distinct from the Binary Yorp (BYORP) phenomenon, not studied in this work but to be added to it later. We evaluate our hypotheses using a combination of techniques for an example binary system. First high-fidelity dynamic simulation of surface-originating particles in the full-detail gravity field of the binary components, themselves propagated according to the full two body problem, gives particle final disposition (return impact, transfer impact, escape). Trajectory end states found for regolith lofted at different initial primary spin rates and relative poses are collected into probability matrices, allowing probabilistic propagation of surface particles for long durations at low computational cost. We track changes to mass, inertia dyad, rotation state, and centroid position and velocity for each component in response to this mapped particle motion. This allows tracking of primary, secondary, and mutual orbit angular momenta over time, clearly demonstrating the angular momentum transfer mechanism and validating our hypotheses. We present current orbit expansion rates and estimated orbit size doubling times consistent with this mechanism, for a few binary systems. We also discuss ramifications of this type of rapid binary evolution towards separation, including the frequency with which "divorced binaries" on similar heliocentric orbits are produced, formation of triple systems such as 2001 SN263, and separation timescale dependence on heliocentric distance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinberg, Elad; Sari, Re'em, E-mail: elad.steinberg@mail.huji.ac.il

The rotation states of kilometer-sized near-Earth asteroids are known to be affected by the Yarkevsky O'Keefe-Radzievskii-Paddack (YORP) effect. In a related effect, binary YORP (BYORP), the orbital properties of a binary asteroid evolve under a radiation effect mostly acting on a tidally locked secondary. The BYORP effect can alter the orbital elements over {approx}10{sup 4}-10{sup 5} years for a D{sub p} = 2 km primary with a D{sub s} = 0.4 km secondary at 1 AU. It can either separate the binary components or cause them to collide. In this paper, we devise a simple approach to calculate the YORPmore » effect on asteroids and the BYORP effect on binaries including J{sub 2} effects due to primary oblateness and the Sun. We apply this to asteroids with known shapes as well as a set of randomly generated bodies with various degrees of smoothness. We find a strong correlation between the strengths of an asteroid's YORP and BYORP effects. Therefore, statistical knowledge of one could be used to estimate the effect of the other. We show that the action of BYORP preferentially shrinks rather than expands the binary orbit and that YORP preferentially slows down asteroids. This conclusion holds for the two extremes of thermal conductivities studied in this work and the assumption that the asteroid reaches a stable point, but may break down for moderate thermal conductivity. The YORP and BYORP effects are shown to be smaller than could be naively expected due to near cancellation of the effects at small scales. Taking this near cancellation into account, a simple order-of-magnitude estimate of the YORP and BYORP effects as a function of the sizes and smoothness of the bodies is calculated. Finally, we provide a simple proof showing that there is no secular effect due to absorption of radiation in BYORP.« less

The Discovery of Binary Asteroid 5674 Wolff at Isaac Aznar Observatory

NASA Astrophysics Data System (ADS)

Aznar Macias, Amadeo; Pravec, Petr; Oey, Julian; Groom, Roger

2016-07-01

We report on the discovery that minor planet 5674 Wolff is a fully-synchronous binary system with an orbital period of 93.7 ± 0.2 h. The combined primary+secondary rotation amplitude is 0.52 ± 0.02 mag. A lower limit on the secondary-to-primary mean diameter ratio is D2/D1 = 0.80.

Concept of Operations for Deploying a Lander on the Secondary Body of Binary Asteroid 1996 FG3

NASA Astrophysics Data System (ADS)

Tardivel, Simon; Michel, P.; Scheeres, D.

2012-10-01

The European Space Agency is currently performing an assessment study of the MarcoPolo-R space mission, in the framework of the M3 class competition of its Cosmic Vision Program. MarcoPolo-R is a sample return mission to a primitive asteroid, whose baseline target is the binary asteroid 1996FG3. The baseline mission, including the sample, is focused on the primary of the binary system. To date, little has yet been considered for the investigation of the secondary, apart from remote observations from the spacecraft. However, MarcoPolo-R may carry an optional lander, and if such a lander could be accommodated it may be relevant to use it for a more detailed investigation of the secondary. This poster presents a strategy for deploying a lander using an unpowered trajectory towards the secondary. This ballistic deployment allows for the design of a light lander with minimum platform overhead and maximum payload. The deployment operations are shown to be very simple and require minimum preparation. The main spacecraft is set on an orbit that reaches a specific point near the binary system L2 Lagrange Point facing the far side of the secondary, about 220 meters from the secondary surface, with a relative speed of about 10cm/s. The lander is then jettisoned using a spring-release mechanism that sets it on an impact trajectory that robustly intersects with the secondary surface. On impact, the lander only needs to dissipate a small amount of kinetic energy in order to ensure that it is energetically and dynamically trapped on the surface. Considering errors on spacecraft GNC and on the spring-release mechanism, and very large uncertainties on the gravity field of the asteroids, the strategy presented here yields a successful landing in more than 99.9% of cases, while ensuring the absolute safety of the spacecraft before, during and after deployment operations.

Alien Sunset Artist Concept

NASA Image and Video Library

2007-03-29

Observations from NASA Spitzer Space Telescope have revealed that mature planetary systems -- dusty disks of asteroids, comets and possibly planets -- are more frequent around close-knit twin, or binary, stars than single stars like our sun.

A Re-examination of the Lightcurves for Seven Hungaria Asteroids

NASA Astrophysics Data System (ADS)

Warner, Brian D.; Stephens, Robert, D.; Harris, Alan W.; Pravec, Petr

2009-10-01

During the course of a study of long period asteroids (f < 1/d) within the Hungaria asteroid population, the lightcurves for seven asteroids were re-examined using updated software and techniques. Several were found to have significantly different periods from those previously reported by two of the authors (Warner and Stephens). The most significant change was 2074 Shoemaker, which was initially reported to have a period of 57 h but now appears to be a binary asteroid with a primary period of 2.5328 ± 0.0004 h and a possible orbital period of 55.52 ± 0.01 h. The other asteroids that were re-examined were 1919 Clemence, 3043 San Diego, 3353 Jarvis, 4142 Dersu-Uzala, (20232) 1997 YK, and (101549) 1998 YY2. The reexamination showed once again the importance of placing data on at least an internal system to achieve accurate night-to-night calibrations.

The Asteroid Redirect Mission (ARM): Exploration of a Former Binary NEA?

NASA Technical Reports Server (NTRS)

Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

2016-01-01

The National Aeronautics and Space Administration (NASA) is developing the Asteroid Redirect Mission (ARM) as a capability demonstration for future human exploration, including use of high-power solar electric propulsion, which allows for the efficient movement of large masses through deep space. The ARM will also demonstrate the capability to conduct proximity operations with natural space objects and crewed operations beyond the security of quick Earth return. The Asteroid Redirect Robotic Mission (ARRM), currently in formulation, will visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, conduct a demonstration of a slow push planetary defense technique, and redirect the multi-ton boulder into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts aboard an Orion spacecraft will dock with the robotic vehicle to explore the boulder and return samples to Earth. The ARM is part of NASA's plan to advance technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. The ARM and subsequent availability of the asteroidal material in cis-lunar space, provide significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, and in-situ resource utilization (ISRU). The current reference target for the ARM is NEA (341843) 2008 EV5, which may have been the primary body of a former binary system (Busch et al., 2011; Tardivel et al., 2016). The ARRM will perform several close proximity operations to investigate the NEA and map its surface. A detailed investigation of this object may allow a better understanding of binary NEA physical characteristics and the possible outcomes for their evolution. An overview of the ARM robotic and crewed segments, including mission operations, and a discussion of potential opportunities for participation with the ARM will be provided in this presentation.

Two New Binaries and Continuing Observations of Hungaria Group Asteroids

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2015-04-01

Analysis of CCD photometry for five asteroids lead to the discovery of two new binary objects. (190208) 2006 AQ, is a rare “wide binary” example with a primary period of 182 h and secondary period of 2.62002 h. 2014 WZ120 is a near-Earth asteroid with a primary period of 3.361 h and orbital period of 13.665 h. The estimated effective diameter ratio for the pair is Ds/Dp >= 0.32. The other three asteroids, 1103 Sequoia, 2083 Smither, and 3880 Kaiserman, all members of the Hungaria group, show varying signs of a secondary period but no mutual events that would confirm the existence of a satellite.

Radar Observations of Binary Asteroid 2000 DP107

NASA Technical Reports Server (NTRS)

Margot, J. L.; Nolan, M. C.; Benner, L. A. M.; Ostro, S. J.; Jurgens, R. F.; Giorgini, J. D.; Slade, M. A.; Campbell, D. B.

2001-01-01

We present the discovery and characterization of DP107 with the Goldstone and Arecibo radars, including a detailed sequence of images showing the system's orbital motion. Additional information is contained in the original extended abstract.

Asteroid Impact & Deflection Assessment mission: Kinetic impactor

NASA Astrophysics Data System (ADS)

Cheng, A. F.; Michel, P.; Jutzi, M.; Rivkin, A. S.; Stickle, A.; Barnouin, O.; Ernst, C.; Atchison, J.; Pravec, P.; Richardson, D. C.; AIDA Team

2016-02-01

The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor to deflect an asteroid. AIDA is an international cooperation, consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the ESA Asteroid Impact Mission (AIM) rendezvous mission. The primary goals of AIDA are (i) to test our ability to perform a spacecraft impact on a potentially hazardous near-Earth asteroid and (ii) to measure and characterize the deflection caused by the impact. The AIDA target will be the binary near-Earth asteroid (65803) Didymos, with the deflection experiment to occur in late September, 2022. The DART impact on the secondary member of the binary at 7 km/s is expected to alter the binary orbit period by about 4 minutes, assuming a simple transfer of momentum to the target, and this period change will be measured by Earth-based observatories. The AIM spacecraft will characterize the asteroid target and monitor results of the impact in situ at Didymos. The DART mission is a full-scale kinetic impact to deflect a 150 m diameter asteroid, with known impactor conditions and with target physical properties characterized by the AIM mission. Predictions for the momentum transfer efficiency of kinetic impacts are given for several possible target types of different porosities, using Housen and Holsapple (2011) crater scaling model for impact ejecta mass and velocity distributions. Results are compared to numerical simulation results using the Smoothed Particle Hydrodynamics code of Jutzi and Michel (2014) with good agreement. The model also predicts that the ejecta from the DART impact may make Didymos into an active asteroid, forming an ejecta coma that may be observable from Earth-based telescopes. The measurements from AIDA of the momentum transfer from the DART impact, the crater size and morphology, and the evolution of an ejecta coma will substantially advance understanding of impact processes on asteroids.

Arecibo Radar Observations of Near-Earth Asteroids

NASA Astrophysics Data System (ADS)

Rivera-Valentin, Edgard G.; Taylor, Patrick A.; Virkki, Anne; Saran Bhiravarasu, Sriram; Venditti, Flaviane; Zambrano-Marin, Luisa Fernanda; Aponte-Hernandez, Betzaida

2017-10-01

The Arecibo S-Band (2.38 GHz, 12.6 cm; 1 MW) planetary radar system at the 305-m William E. Gordon Telescope in Arecibo, Puerto Rico is the most active, most powerful, and most sensitive planetary radar facility in the world. As such, Arecibo is vital for post-discovery characterization and orbital refinement of near-Earth asteroids. Since August 2016, the program has observed 100 near-Earth asteroids (NEAs), of which 38 are classified as potentially hazardous to Earth and 31 are compliant with the NASA Near-Earth Object Human Space Flight Accessible Targets Study (NHATS). Arecibo observations are critical for identifying NEAs that may be on a collision course with Earth in addition to providing detailed physical characterization of the objects themselves in terms of size, shape, spin, and surface properties, which are valuable for assessing impact mitigation strategies. Here, we will present a sampling of the asteroid zoo observed by Arecibo, including press-noted asteroids 2014 JO25 and the (163693) Atira binary system.

Roles of Shape and Internal Structure in Rotational Disruption of Asteroids

NASA Astrophysics Data System (ADS)

Hirabayashi, Masatoshi; Scheeres, Daniel Jay

2015-08-01

An active research area over the last decade has been to explore configuration changes of rubble pile asteroids due to rotationally induced disruption, initially driven by the remarkable fact that there is a spin period threshold of 2 hr for asteroids larger than a few hundred meters in size. Several different disruption modes due to rapid rotation can be identified, as surface shedding, fission and failure of the internal structure. Relevant to these discussions are many observations of asteroid shapes that have revealed a diversity of forms such as oblate spheroids with equatorial ridges, strongly elongated shapes and contact binaries, to say nothing of multi-body systems. With consideration that rotationally induced deformation is one of the primary drivers of asteroid evolution, we have been developing two techniques for investigating the structure of asteroids, while accounting for their internal mechanical properties through plastic theory. The first technique developed is an analytical model based on limit analysis, which provides rigorous bounds on the asteroid mechanical properties for their shapes to remain stable. The second technique applies finite element model analysis that accounts for plastic deformation. Combining these models, we have explored the correlation between unique shape features and failure modes. First, we have been able to show that contact binary asteroids preferentially fail at their narrow necks at a relatively slow spin period, due to stress concentration. Second, applying these techniques to the breakup event of active asteroid P/2013 R3, we have been able to develop explicit constraints on the cohesion within rubble pile asteroids. Third, by probing the effect of inhomogeneous material properties, we have been able to develop conditions for whether an oblate body will fail internally or through surface shedding. These different failure modes can be tested by measuring the density distribution within a rubble pile body through determination of its gravity field. This talk will explore these different modes of failure and motivate divergent theories of failure that depend on properties of rubble piles.

Asteroid Impact Mission: relevance to asteroid mining

NASA Astrophysics Data System (ADS)

Michel, P.; Kueppers, M.; Carnelli, I.

2017-09-01

The Asteroid Impact Mission (AIM) is the European (ESA) component of the AIDA mission in collaboration with NASA. The objectives of AIDA are: (1) to perform a test of asteroid deflection using a kinetic impactor with the USA (NASA) component DART, and (2) with AIM, to investigate the binary near-Earth asteroid Didymos, in particular its secondary and target of DART, with data of high value for mining purposes.

The Asteroid Impact Mission

NASA Astrophysics Data System (ADS)

Carnelli, Ian; Galvez, Andres; Mellab, Karim

2016-04-01

The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and radar facilities. For the first time, an impact experiment at asteroid scale will be performed with accurate knowledge of the precise impact conditions and also the impact outcome, together with information on the physical properties of the target, ultimately validating at appropriate scales our knowledge of the process and impact simulations. AIM's important technology demonstration component includes a deep-space optical communication terminal and inter-satellite network with two CubeSats deployed in the vicinity of the Didymos system and a lander on the surface of the secondary. To achieve a low-cost objective AIM's technology and scientific payload are being combined to support both close-proximity navigation and scientific investigations. AIM will demonstrate the capability to achieve a small spacecraft design with a very large technological and scientific mission return.

Near-Earth Asteroid 2005 CR37: Radar Images and Photometry of a Candidate Contact Binary

NASA Technical Reports Server (NTRS)

Benner, Lance A. M.; Nolan, Michael C.; Ostro, Steven J.; Giorgini, Jon D.; Pray, Donald P.; Harris, Alan W.; Magri, Christopher; Margot, Jean-Luc

2006-01-01

Arecibo (2380 MHz, 13 cm) radar observations of 2005 CR37 provide detailed images of a candidate contact binary: a 1.8-km-long, extremely bifurcated object. Although the asteroid's two lobes are round, there are regions of modest topographic relief, such as an elevated, 200-m-wide facet, that suggest that the lobes are geologically more complex than either coherent fragments or homogeneous rubble piles. Since January 1999, about 9% of NEAs larger than approx.200 m imaged by radar can be described as candidate contact binaries.

Dynamics of ejecta from the binary asteroid Didymos, the target of the AIDA mission

NASA Astrophysics Data System (ADS)

Michel, Patrick; Yu, Yang; Schwartz, Stephen; Naidu, Shantanu; Benner, Lance

2016-04-01

The AIDA space mission, a collaborative effort between ESA and NASA, aims to characterize the near-Earth asteroid binary (65803) Didymos and to perform a kinetic impactor demonstration on the small moon of the binary system. Our study presents a multi-scale dynamical model of the ejecta cloud produced by a hypervelocity impact, which enables us to compute the ejecta properties at different spatial and time scales. This model is applied to the impact into the small moon of Didymos on October 2022 as considered by the AIDA mission. We model the process by including as much practical information as possible, e.g., the gravitational environment influenced by the non-spherical shapes of the bodies (based on the observed shape of the primary), the solar tides, and the solar radiation pressure. Our simulations show where and for how long the ejecta cloud evolves with time for the considered ejecta initial conditions. This information is used to assess the potential hazard to the ESA Asteroid Impact Mission (AIM) observing spacecraft and to determine the safest positions. This study is performed with support of the European Space Agency and in the framework of the NEOShield-2 project that has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 640351.

Evidence for Strange Stellar Family (Artist Concept)

NASA Technical Reports Server (NTRS)

2007-01-01

This artist concept depicts a quadruple-star system called HD 98800. The system is approximately 10 million years old, and is located 150 light-years away in the constellation TW Hydrae.

HD 98800 contains four stars, which are paired off into doublets, or binaries. The stars in the binary pairs orbit around each other, and the two pairs also circle each other like choreographed ballerinas. One of the stellar pairs, called HD 98800B, has a disk of dust around it, while the other pair does not.

Although the four stars are gravitationally bound, the distance separating the two binary pairs is about 50 astronomical units (AU) -- slightly more than the average distance between our sun and Pluto.

Using NASA's Spitzer Space Telescope, scientists finally have a detailed view of HD 98800B's potential planet-forming disk. Astronomers used the telescope's infrared spectrometer to detect the presence of two belts in the disk made of large dust grains. One belt sits approximately 5.9 AU away from the central binary, or about the distance from the sun to Jupiter, and is likely made up of asteroids and comets. The other belt sits at 1.5 to 2 AU, comparable to the area where Mars and the asteroid belt sit, and is made up of sand-sized dust grains.

Detailed Pictures of Multiple Asteroid Systems in the Main-Belt

NASA Astrophysics Data System (ADS)

Marchis, F.; Emery, J. P.; Enriquez, J. E.; Descamps, P.; Berthier, J.; Vachier, F.; Durech, J.

2011-12-01

Since their discovery less than 10 years ago, ~200 known multiple asteroid systems have been studied with a combination of observing techniques, including adaptive optics, lightcurve photometry, and mid-infrared spectrophotometry. Those observations show that ~15 large (D>100km) asteroids that are known to possess km-sized satellite(s) (22 Kalliope, 45 Eugenia, 87 Sylvia, 93 Minerva, 216 Kleopatra, ...) share common orbital characteristics, implying a common formation scenario: e.g. catastrophic disruption or ejection after an oblique impact. More than 70 smaller (10-15km) binary asteroid systems have been detected through anomalies in their lightcurves and are believed to have formed by fission due to the YORP effect. By comparison with meteorite analog densities, mid-IR data reveal that these systems have a significant porosity (larger than 30%) implying a rubble-pile interior. We will review these key results and discuss their implications for the interior of asteroids in the light of recent space mission results. Future explorations using new ground-based facilities and space mission concepts will be also discussed. This work is supported by the NSF grant AAG-0807468 and NASA grant NNX11AD62G

Investigating the surface and subsurface properties of the Didymos binary asteroid with a landed CubeSat

NASA Astrophysics Data System (ADS)

Murdoch, Naomi; Cadu, Alexandre; Mimoun, David; Karatekin, Ozgur; Garcia, Raphael; Carrasco, José; Garcia de Quiros, Javier; Vasseur, Hugues; Ritter, Birgit; Eubanks, Marshall; Radley, Charles; Dehant, Veronique

2016-04-01

Despite the successes of recent space missions (e.g., Cheng et al., 1997; Fujiwara et al., 2006), there is still no clear understanding of the asteroid internal structure(s). Depending on their size, evolution and physical properties, many different asteroid internal structure models have been suggested from completely cohesive bodies, through to rubble pile objects. The Asteroid Geophysical Explorer (AGEX), a COPINS payload selected by ESA*, will land geophysical instrument packages on the surface of Didymoon; the secondary object in the (65803) Didymos (1996 GT) binary system (Karatekin et al 2016). The instruments will characterize the asteroid surface mechanical properties and probe, for the first time, the sub-surface structure of an asteroid. AGEX will be deployed from AIM on a ballistic transfer to the asteroid surface, several days before the MASCOT-2 package. We expect that AGEX will bounce multiple times before coming to rest on the surface of the asteroid thus providing a unique opportunity to study the asteroid surface properties, perhaps at several locations, using accelerometers. Once stationary, the seismological surface-monitoring phase, using a three-axis set of geophones, can begin. The high speed DART impact will be a major seismic source on Didymoon. However, the seismic payload may also be able to perform seismological investigations using natural seismic sources such as micrometeoroid impacts (e.g., Garcia et al., 2015), thermal cracks (e.g., Delbo et al., 2014), internal quakes due to tidal forces (e.g., Richardson et al. 1998) and other geophysical processes (see Murdoch et al., 2015). We will present the expected signal characteristics of the landing and also of the natural seismic sources that may occur on Didymoon. An understanding of the amplitude and frequency content of such signals is necessary in order to design the optimal geophysical payload for small body exploration using a CubeSat platform. [1.] Cheng, A. et al., Journal of Geophysical Research, 102, E10 (1997) [2.] Delbo, M., et al., Nature, 508, 233-236 (2014) [3.] Fujiwara, A. et al., Science 312, 1330 (2006) [4.] Garcia, R. F. et al., Icarus, 253, 159-168 (2015) [5.] Murdoch, N. et al., ASTEROIDS IV, University of Arizona Press Space Science Series, edited by P. Michel, F. DeMeo and W. Bottke, (2015) [6.] Richardson, D.C. et al., Icarus, 134, 47-79 (1998) [7.] Karatekin et al., The Asteroid Geophysical Explorer (AGEX); Proposal to explore the Didymos System using Cubesats, EGU (2016) *http://www.esa.int/Our_Activities/Space_Engineering_Technology/Asteroid_Impact_Mission/ CubeSat_companions_for_ESA_s_asteroid_mission

Radar evidence for diverse shapes of the primaries among binary near-Earth asteroids

NASA Astrophysics Data System (ADS)

Brozovic, Marina; Benner, Lance; Ford, Thomas; Springmann, Alessondra; Taylor, Patrick; Shepard, Michael; Margot, Jean-Luc; Naidu, Shantanu; Nolan, Michael; Howell, Ellen; Busch, Michael; Giorgini, Jon; Magri, Christopher

2014-11-01

The Arecibo and Goldstone planetary radars have been exceptionally valuable instruments for the discovery of binary and triple asteroids in the near-Earth asteroid (NEA) population. To date, 34 out of 46 known binaries and two ternaries 71% objects total) have been discovered by radar. One of the first discovered and most well studied binary systems is (66391) 1999 KW4 (Ostro et al., 2006). This was the first system with radar evidence for a prominent equatorial bulge, sloped hemispheres, and polar flattening. 1999 KW4 Alpha became a “canonical shape model” for many theoretical studies and numerical simulations on the nature of the binary systems. As the number of binaries detected by radar grew, evidence mounted that not all primaries look like 1999 KW4 Alpha. In fact, (276049) 2002 CE26 (Shepard et al., 2006) and (285263) 1998 QE2 (Springmann et al., 2014) have very rounded shapes without an obvious presence of equatorial ridges. Furthermore, (164121) 2003 YT1 (Nolan et al., in prep.), (1862) Apollo (Ford et al., in prep.), and (363599) 2006 VV2 all have irregular, moderately elongated shapes that show the presence of a bulge at only selected longitudes. All three objects also show elongations of 1.2-1.3, which is still smaller than the mean elongation of ~1.5 in the NEA radar sample. Nevertheless, numerous other primaries have KW4-like shapes such as (185851) 2000 DP107 (Naidu et al., 2011), (311066) 2004 DC (Taylor et al, 2008), and (175706) 1996 FG3 (Benner et al., in prep.). We estimate the abundance of KW4-like objects to be at least 40% of the multiple system population, based on the 41 radar-detected cases. Our results only give the lower bound because not all the dataset have the sufficient SNRs and/or the rotational coverage. Recent Goldstone delay-Doppler images of 2013 WT44 were obtained at nearly pole-on subradar latitude and clearly show evidence of an equatorial bulge, sloped hemispheres, and polar flattening. This has provided one of the strongest arguments to date that KW4-like shapes are real and that they are not artifacts of the shape modeling algorithms. This does not come as a surprise given that KW4-like shapes are strongly motivated by the physics of the rapidly rotating rubble pile.

Results of the 2016 Mexican Asteroid Photometry Campaign

NASA Astrophysics Data System (ADS)

Sada, Pedro V.; Olguin, Lorenzo; Saucedo, Julio C.; Loera-Gonzalez, Pablo; Cantu-Sanchez, Laura; Garza, Jaime R.; Ayala-Gomez, Sandra A.; Aviles, Andres; Perez-Tijerina, Eduardo; Navarro-Meza, Samuiel; Silva, J. S.; Reyes-Ruiz, Mauricio; Segura-Sosa, Juan; Lopez-Valdivia, Ricardo; Alvarez-Santana, F.

2017-07-01

We report the results of the 2016 Mexican Asteroid Photometry Campaign. This year observers from seven different research institutions carried out 34 nights of observations at three Mexican observatories. An uncertain, but long, period of 115.108 ± 0.014 h was estimated for 703 Noëmi from sparse data. A nearly complete lightcurve was obtained for 1305 Pongola (P = 8.0585 ± 0.0003 h). Asteroid 2535 Hämeenlinna turned out to be a binary system where the primary exhibits a rotation period of 3.2311 ± 0.0001 h and the secondary shows an orbital period of 21.20 ± 0.004 h. Asteroid 4775 Hansen (P = 3.1186 ± 0.0001 h) was well observed and showed variations of its lightcurve between two sets of observations separated by about six weeks.

Water transport to circumprimary habitable zones from icy planetesimal disks in binary star systems

NASA Astrophysics Data System (ADS)

Bancelin, D.; Pilat-Lohinger, E.; Maindl, T. I.; Bazsó, Á.

2017-03-01

So far, more than 130 extrasolar planets have been found in multiple stellar systems. Dynamical simulations show that the outcome of the planetary formation process can lead to different planetary architectures (i.e. location, size, mass, and water content) when the star system is single or double. In the late phase of planetary formation, when embryo-sized objects dominate the inner region of the system, asteroids are also present and can provide additional material for objects inside the habitable zone (HZ). In this study, we make a comparison of several binary star systems and aim to show how efficient they are at moving icy asteroids from beyond the snow line into orbits crossing the HZ. We also analyze the influence of secular and mean motion resonances on the water transport towards the HZ. Our study shows that small bodies also participate in bearing a non-negligible amount of water to the HZ. The proximity of a companion moving on an eccentric orbit increases the flux of asteroids to the HZ, which could result in a more efficient water transport on a short timescale, causing a heavy bombardment. In contrast to asteroids moving under the gravitational perturbations of one G-type star and a gas giant, we show that the presence of a companion star not only favors a faster depletion of our disk of planetesimals, but can also bring 4-5 times more water into the whole HZ. However, due to the secular resonance located either inside the HZ or inside the asteroid belt, impacts between icy planetesimals from the disk and big objects in the HZ can occur at high impact speed. Therefore, real collision modeling using a GPU 3D-SPH code show that in reality, the water content of the projectile is greatly reduced and therefore, also the water transported to planets or embryos initially inside the HZ.

SPIN–SPIN COUPLING IN THE SOLAR SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batygin, Konstantin; Morbidelli, Alessandro, E-mail: kbatygin@gps.caltech.edu

The richness of dynamical behavior exhibited by the rotational states of various solar system objects has driven significant advances in the theoretical understanding of their evolutionary histories. An important factor that determines whether a given object is prone to exhibiting non-trivial rotational evolution is the extent to which such an object can maintain a permanent aspheroidal shape, meaning that exotic behavior is far more common among the small body populations of the solar system. Gravitationally bound binary objects constitute a substantial fraction of asteroidal and TNO populations, comprising systems of triaxial satellites that orbit permanently deformed central bodies. In thismore » work, we explore the rotational evolution of such systems with specific emphasis on quadrupole–quadrupole interactions, and show that for closely orbiting, highly deformed objects, both prograde and retrograde spin–spin resonances naturally arise. Subsequently, we derive capture probabilities for leading order commensurabilities and apply our results to the illustrative examples of (87) Sylvia and (216) Kleopatra asteroid systems. Cumulatively, our results suggest that spin–spin coupling may be consequential for highly elongated, tightly orbiting binary objects.« less

Stability and evolution of orbits around the binary asteroid 175706 (1996 FG3): Implications for the MarcoPolo-R mission

NASA Astrophysics Data System (ADS)

Hussmann, Hauke; Oberst, Jürgen; Wickhusen, Kai; Shi, Xian; Damme, Friedrich; Lüdicke, Fabian; Lupovka, Valery; Bauer, Sven

2012-09-01

In support of the MarcoPolo-R mission, we have carried out numerical simulations of spacecraft trajectories about the binary asteroid 175706 (1996 FG3) under the influence of solar radiation pressure. We study the effects of (1) the asteroid's mass, shape, and rotational parameters, (2) the secondary's mass, shape, and orbit parameters, (3) the spacecraft's mass, surface area, and reflectivity, and (4) the time of arrival, and therefore the relative position to the sun and planets. We have considered distance regimes between 5 and 20 km, the typical range for a detailed characterization of the asteroids - primary and secondary - with imaging systems, spectrometers and by laser altimetry. With solar radiation pressure and gravity forces of the small asteroid competing, orbits are found to be unstable, in general. However, limited orbital stability can be found in the so-called Self-Stabilized Terminator Orbits (SSTO), where initial orbits are circular, orbital planes are oriented approximately perpendicular to the solar radiation pressure, and where the orbital plane of the spacecraft is shifted slightly (between 0.2 and 1 km) from the asteroid in the direction away from the sun. Under the effect of radiation pressure, the vector perpendicular to the orbit plane is observed to follow the sun direction. Shape and rotation parameters of the asteroid as well as gravitational perturbations by the secondary (not to mention sun and planets) were found not to affect the results. Such stable orbits may be suited for long radio tracking runs, which will allow for studying the gravity field. As the effect of the solar radiation pressure depends on the spacecraft mass, shape, and albedo, good knowledge of the spacecraft model and persistent monitoring of the spacecraft orientation are required.

Numerical investigation of the dynamical environment of 65803 Didymos

NASA Astrophysics Data System (ADS)

Dell'Elce, L.; Baresi, N.; Naidu, S. P.; Benner, L. A. M.; Scheeres, D. J.

2017-03-01

The Asteroid Impact & Deflection Assessment (AIDA) mission is planning to visit the Didymos binary system in 2022 in order to perform the first demonstration ever of the kinetic impact technique. Binary asteroids are an ideal target for this since the deflection of the secondary body can be accurately measured by a satellite orbiting in the system. However, these binaries offer an extremely rich dynamical environment whose accurate investigation through analytical approaches is challenging at best and requires a significant number of restrictive assumptions. For this reason, a numerical investigation of the dynamical environment in the vicinity of the Didymos system is offered in this paper. After computing various families of periodic orbits, their robustness is assessed in a high-fidelity environment consisting of the perturbed restricted full three-body problem. The results of this study suggest that several nominally stable trajectories, including the triangular libration points, should not be considered as safe as a state vector perturbation may cause the spacecraft to drift from the nominal orbit and possibly impact one of the primary bodies within a few days. Nonetheless, there exist two safe solutions, namely terminator and interior retrograde orbits. The first one is adequate for observation purposes of the entire system and for communications. The second one is more suitable to perform close investigations of the primary body.

The small binary asteroid (939) Isberga

NASA Astrophysics Data System (ADS)

Carry, B.; Matter, A.; Scheirich, P.; Pravec, P.; Molnar, L.; Mottola, S.; Carbognani, A.; Jehin, E.; Marciniak, A.; Binzel, R. P.; DeMeo, F. E.; Birlan, M.; Delbo, M.; Barbotin, E.; Behrend, R.; Bonnardeau, M.; Colas, F.; Farissier, P.; Fauvaud, M.; Fauvaud, S.; Gillier, C.; Gillon, M.; Hellmich, S.; Hirsch, R.; Leroy, A.; Manfroid, J.; Montier, J.; Morelle, E.; Richard, F.; Sobkowiak, K.; Strajnic, J.; Vachier, F.

2015-03-01

In understanding the composition and internal structure of asteroids, their density is perhaps the most diagnostic quantity. We aim here at characterizing the surface composition, mutual orbit, size, mass, and density of the small main-belt binary asteroid (939) Isberga. For that, we conduct a suite of multi-technique observations, including optical lightcurves over many epochs, near-infrared spectroscopy, and interferometry in the thermal infrared. We develop a simple geometric model of binary systems to analyze the interferometric data in combination with the results of the lightcurve modeling. From spectroscopy, we classify Ibserga as a Sq-type asteroid, consistent with the albedo of 0.14-0.06+0.09 (all uncertainties are reported as 3-σ range) we determine (average albedo of S-types is 0.197 ± 0.153, see Pravec et al. (Pravec et al. [2012]. Icarus 221, 365-387). Lightcurve analysis reveals that the mutual orbit has a period of 26.6304 ± 0.0001 h, is close to circular (eccentricity lower than 0.1), and has pole coordinates within 7° of (225°, +86°) in Ecliptic J2000, implying a low obliquity of 1.5-1.5+6.0 deg . The combined analysis of lightcurves and interferometric data allows us to determine the dimension of the system and we find volume-equivalent diameters of 12.4-1.2+2.5 km and 3.6-0.3+0.7 km for Isberga and its satellite, circling each other on a 33 km wide orbit. Their density is assumed equal and found to be 2.91-2.01+1.72 gcm-3 , lower than that of the associated ordinary chondrite meteorites, suggesting the presence of some macroporosity, but typical of S-types of the same size range (Carry [2012]. Planet. Space Sci. 73, 98-118). The present study is the first direct measurement of the size of a small main-belt binary. Although the interferometric observations of Isberga are at the edge of MIDI capabilities, the method described here is applicable to others suites of instruments (e.g., LBT, ALMA).

Stability of binaries. Part II: Rubble-pile binaries

NASA Astrophysics Data System (ADS)

Sharma, Ishan

2016-10-01

We consider the stability of the binary asteroids whose members are granular aggregates held together by self-gravity alone. A binary is said to be stable whenever both its members are orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability analysis of Sharma (Sharma [2015] Icarus, 258, 438-453), that is applicable to binaries with rigid members, to the case of binary systems with rubble members. We employ volume averaging (Sharma et al. [2009] Icarus, 200, 304-322), which was inspired by past work on elastic/fluid, rotating and gravitating ellipsoids. This technique has shown promise when applied to rubble-pile ellipsoids, but requires further work to settle some of its underlying assumptions. The stability test is finally applied to some suspected binary systems, viz., 216 Kleopatra, 624 Hektor and 90 Antiope. We also see that equilibrated binaries that are close to mobilizing their maximum friction can sustain only a narrow range of shapes and, generally, congruent shapes are preferred.

Results of near-Earth-asteroid photometry in the frame of the ASPIN programme

NASA Astrophysics Data System (ADS)

Krugly, Y.; Molotov, I.; Inasaridze, R.; Kvaratskhelia, O.; Aivazyan, V.; Rumyantsev, V.; Belskaya, I.; Golubaev, A.; Sergeev, A.; Shevchenko, V.; Slyusarev, I.; Burkhonov, O.; Ehgamberdiev, S.; Elenin, L.; Voropaev, V.; Koupianov, V.; Gaftonyuk, N.; Baransky, A.; Irsmambetova, T.; Litvinenko, E.; Aliev, A.; Namkhai, T.

2014-07-01

Regular photometric observations aimed for obtaining physical properties of near-Earth asteroids (NEA) are carried out within the Asteroid Search and Photometry Initiative (ASPIN) of the International Scientific Optical Network (ISON). At present, ISON project joins 35 observation facilities in 15 countries with 80 telescopes of different class. Photometric observations of NEAs are carried out at the telescopes with apertures from 20 cm up to 2.6 m equipped with CCD cameras. The obtained lightcurves in the Johnson-Cousins photometric system or in exceptional cases in the integral light (unfiltered photometry) have typical photometric accuracy of 0.01-0.03 mag. The main targets of these observations are near-Earth asteroids as hazardous objects pose a threat for the Earth civilization. The main purpose of the observations is to study characteristics of asteroids such as rotation period, size, and shape of the body, and surface composition. The observations are aimed toward searching binary asteroids, supporting the asteroid radar observations and investigation of the YORP effect. In 2013, we have observed 40 near-Earth asteroids in more than 200 nights. The rotation periods have been determined for 14 NEAs for the first time and, for 6 NEAs, rotation periods were defined more precisely. New rotation periods have been obtained for objects from Aten group: (137805) 1999 YK_5, (329437) 2002 OA_{22}, (367943) Duende (2012 DA_{14}); Apollo: (17188) 1999 WC_2, (137126) 1999 CF_9, (163249) 2002 GT, (251346) 2007 SJ, 2013 TV_{135}; Amor: (9950) ESA, (24445) 2000 PM_8, (137199) 1999 KX_4, (285263) 1998 QE_2, (361071) 2006 AO_4, 2010 XZ_{67}, and refined for (1943) Anteros, (3361) Orpheus, (3752) Camillo, (7888) 1993 UC, (53435) 1999 VM_{40}, (68216) 2001 CV_{26}. NEAs (7888) 1993 UC and (68216) 2001 CV_{26} were found to show signs of a binary nature. To detect possible binary asteroids, we observe the object during several consecutive nights and at several observatories located at different longitudes. In particular, to cover a long time interval and not to miss the eclipse/occultation minima, the binary NEA (285263) 1998 QE_2 has been observed in close dates in Ukraine, Georgia, Tajikistan, Mongolia, the Far East of Russia, and Mexico. To test an influence of the YORP effect on the spin rates, the lightcurves of NEAs (2100) Ra-Shalom, 88710 2001 SL_9, and (138852) 2000 WN_{10} have been obtained. The observations of small NEAs (with diameters smaller 200 m) have revealed very fast rotating NEAs with rotation periods smaller than 2.2 hours for (363305) 2002 NV_{16}, 2000 KA, and 2013 QR_1. Many of our targets were also the targets of the radar observations in the Arecibo and the Goldstone. The obtained results will be presented and the perspectives of the ASPIN programme will be discussed.

The disposition of impact ejecta resulting from the AIDA-DART mission to binary asteroid 65803 Didymos: an independent investigation

NASA Astrophysics Data System (ADS)

Richardson, James E.; O'Brien, David P.

2016-10-01

If all goes as planned, in the year 2020 a joint ESA and NASA mission will be launched that will rendezvous with the near-Earth binary asteroid system 65803 Didymos in the fall of 2022. The European component, the Asteroid Impact & Deflection Assessment (AIDA) spacecraft will arrive first and characterize the system, which consists of a ~800 m diameter primary and a ~160 m diameter secondary, orbiting a common center of mass at a semi-major axis distance of ~1200 m with a orbital period of 11.9 hr. Following system characterization, the AIDA spacecraft will remove to a safe distance while the NASA component, the 300 kg Double Asteroid Redirection Test (DART) spacecraft collides with the trailing edge of the secondary body (with respect to the binary's retrograde mutual orbit). Meanwhile, the AIDA spacecraft will conduct observations of this impact and its aftermath, specifically looking for changes made to the primary, the secondary, and their mutual orbit as a result of the DART collision. Of particular interest is the ballistic flight and final disposition of the ejecta produced by the impact cratering process, not just from the standpoint of scientific study, but also from the standpoint of AIDA spacecraft safety.In this study, we investigate a series of hypothetical DART impacts utilizing a semi-empirical, numerical impact ejecta plume model originally developed for the Deep Impact mission and designed specifically with impacts on small bodies in mind. The resulting excavated mass is discretized into 7200 individual tracer particles, each representing a unique combination of speed, mass, and ejected direction. The trajectory of each tracer is computed numerically under the gravitational influence of both primary and secondary, along with the effects of solar radiation pressure. Each tracer is followed until it either impacts a body or escapes the system, whereupon tracking is continued in the heliocentric frame using an N-body integrator. Various impact scenarios will be explored, along with a number of ejecta particle sizes, with the aim of characterizing the most likely final ejecta dispositions resulting from the DART impact, and the safest vantages from which the AIDA spacecraft can observe this event.

Collapsing Binary Asteroids With YORP And BYORP

NASA Astrophysics Data System (ADS)

Taylor, Patrick A.

2012-05-01

A separated binary system may be collapsed to contact via the removal of angular momentum from the system until a viable tidal end state no longer exists. The thermal YORP and BYORP effects are both capable of removing angular momentum from the system, by spin-down of the components and shrinking the mutual orbit, respectively. The YORP effect, with strength of order that measured for (1862) Apollo [1], can collapse a binary system with equal-mass components in as little as tens of thousands of years (depending on the initial angular momentum), while smaller secondaries require two or more orders of magnitude longer to collapse. BYORP, with a BYORP coefficent of 0.001 [2], is less efficient, especially for smaller secondaries. By these methods, only near-Earth binaries with large mass ratios can collapse within a dynamical lifetime, a population of which is observed by radar with a frequency comparable to separated binaries. [1] Kaasalainen et al., 2007, Nature 446, 420-422. [2] McMahon and Scheeres, 2010, Icarus 209, 494-509.

Stable Orbits in the Didymos Binary Asteroid System - Useful Platforms for Exploration

NASA Astrophysics Data System (ADS)

Damme, Friedrich; Hussmann, Hauke; Wickhusen, Kai; Enrico, Mai; Oberst, Jürgen

2016-04-01

We have analyzed particle motion in binary asteroid systems to search for stable orbits. In particular, we studied the motion of particles near the asteroid 1996 GT (Didymos), proposed as a target for the AIDA mission. The combined gravity fields of the odd-shaped rotating objects moving about each other are complex. In addition, orbiting spacecraft or dust particles are affected by radiation pressure, possibly exceeding the faint gravitational forces. For the numerical integrations, we adopt parameters for size, shape, and rotation from telescopic observations. To simulate the effect of radiation pressure during a spacecraft mission, we apply a spacecraft wing-box shape model. Integrations were carried out beginning in near-circular orbits over 11 days, during which the motion of the particles were examined. Most orbits are unstable with particles escaping quickly or colliding with the asteroid bodies. However, with carefully chosen initial positions, we found stable motion (in the orbiting plane of the secondary) associated with the Lagrangian points (L4 and L5), in addition to horseshoe orbits, where particles move from one of the Lagrangian point to the other. Finally, we examined orbits in 1:2 resonances with the motion of the orbital period of the secondary. Stable conditions depend strongly on season caused by the inclination of the mutual orbit plane with respect to Didymos solar orbit. At larger distance from the asteroid pair, we find the well-known terminator orbits where gravitational attraction is balanced against radiation pressure. Stable orbits and long motion arcs are useful for long tracking runs by radio or Laser instruments and are well-suited for modelling of the ephemerides of the asteroid pair and gravity field mapping. Furthermore, these orbits may be useful as observing posts or as platforms for approach. These orbits may also represent traps for dust particles, an opportunity for dust collection - or possibly a hazard to spacecraft operation.

The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2

NASA Astrophysics Data System (ADS)

Huang, Jiangchuan; Ji, Jianghui; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

2013-12-01

On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 +/- 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 × 1.95 km) +/-10%, respectively, and the direction of the +z axis is estimated to be (250 +/- 5°, 63 +/- 5°) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.

MASCOT2, a Lander to Characterize the Target of an Asteroid Kinetic Impactor Deflection Test (AIM) Mission

NASA Astrophysics Data System (ADS)

Biele, J.; Ulamec, S.; Krause, C.; Cozzoni, B.; Lange, C.; Grundmann, J. T.; Grimm, C.; Ho, T.-M.; Herique, A.; Plettemeier, D.; Grott, M.; Auster, H.-U.; Hercik, D.; Carnelli, I.; Galvez, A.; Philippe, C.; Küppers, M.; Grieger, B.; Gil Fernandez, J.; Grygorczuk, J.

2017-09-01

In the course of the AIDA/AIM mission studies [1,2] a lander, MASCOT2, has been studied to be deployed on the moon of the binary Near-Earth Asteroid system, (65803) Didymos. The AIDA technology demonstration mission, composed of a kinetic impactor, DART, and an observing spacecraft, AIM, has been designed to deliver vital data to determine the momentum transfer efficiency of the kinetic impact and key physical properties of the target asteroid. This will enable derivation of the impact response of the object as a function of its physical properties, a crucial quantitative point besides the qualitative proof that the asteroid has been deflected at all. A landed asset on the target asteroid greatly supports analyzing its dynamical state, mass, geophysical properties, surface and subsurface structure. The lander's main instrument is a bistatic, low frequency radar (LFR) [3a,b] to sound the interior structure of the asteroid. It is supported by a camera (MasCAM) [4], a radiometer (MARA)[5], an accelerometer (DACC [9]), and, optionally regarding the science case, also a magnetometer (MasMAG)[6].

Lunar and Planetary Science XXXV: Asteroids, Meteors, Comets

NASA Technical Reports Server (NTRS)

2004-01-01

Reports included:Long Term Stability of Mars Trojans; Horseshoe Asteroids and Quasi-satellites in Earth-like Orbits; Effect of Roughness on Visible Reflectance Spectra of Planetary Surface; SUBARU Spectroscopy of Asteroid (832) Karin; Determining Time Scale of Space Weathering; Change of Asteroid Reflectance Spectra by Space Weathering: Pulse Laser Irradiation on Meteorite Samples; Reflectance Spectra of CM2 Chondrite Mighei Irradiated with Pulsed Laser and Implications for Low-Albedo Asteroids and Martian Moons; Meteorite Porosities and Densities: A Review of Trends in the Data; Small Craters in the Inner Solar System: Primaries or Secondaries or Both?; Generation of an Ordinary-Chondrite Regolith by Repetitive Impact; Asteroid Modal Mineralogy Using Hapke Mixing Models: Validation with HED Meteorites; Particle Size Effect in X-Ray Fluorescence at a Large Phase Angle: Importance on Elemental Analysis of Asteroid Eros (433); An Investigation into Solar Wind Depletion of Sulfur in Troilite; Photometric Behaviour Dependent on Solar Phase Angle and Physical Characteristics of Binary Near-Earth-Asteroid (65803) 1996 GT; Spectroscopic Observations of Asteroid 4 Vesta from 1.9 to 3.5 micron: Evidence of Hydrated and/or Hydroxylated Minerals; Multi-Wavelength Observations of Asteroid 2100 Ra-Shalom: Visible, Infrared, and Thermal Spectroscopy Results; New Peculiarities of Cometary Outburst Activity; Preliminary Shape Modeling for the Asteroid (25143) Itokawa, AMICA of Hayabusa Mission; Scientific Capability of MINERVA Rover in Hayabusa Asteroid Mission; Characteristics and Current Status of Near Infrared Spectrometer for Hayabusa Mission; Sampling Strategy and Curation Plan of Hayabusa Asteroid Sample Return Mission; Visible/Near-Infrared Spectral Properties of MUSES C Target Asteroid 25143 Itokawa; Calibration of the NEAR XRS Solar Monitor; Modeling Mosaic Degradation of X-Ray Measurements of 433 Eros by NEAR-Shoemaker; Scattered Light Remediation and Recalibration of near Sheomaker s NIS Global Dataaset at 433 Eros; Evaluation of Preparation and Measuring Techniques for Interplanetary Dust Particles for the MIDAS Experiment on Rosetta; Chiron: a Proposed Remote Sensing Prompt Gamma Ray Activation Analysis Instrument for a Nuclear Powered Prometheus Mission;From Present Surveying to Future Prospecting of the Asteroid Belt; Asteroid Physical Properties Probe Microgravity Testing of a Surface Sampling System for Sample Return from Small Solar System Bodies;and Penetrator Coring Apparatus for Cometary Surfaces.

Modeling momentum transfer by the DART spacecraft into the moon of Didymos

NASA Astrophysics Data System (ADS)

Stickle, Angela M.; Atchison, Justin A.; Barnouin, Olivier S.; Cheng, Andy F.; Ernst, Carolyn M.; Richardson, Derek C.; Rivkin, Andy S.

2015-11-01

The Asteroid Impact and Deflection Assessment (AIDA) mission is a joint concept between NASA and ESA designed to test the effectiveness of a kinetic impactor in deflecting an asteroid. The mission is composed of two independent, but mutually supportive, components: the NASA-led Double Asteroid Redirect Test (DART), and the ESA-led Asteroid Impact Monitoring (AIM) mission. The spacecraft will be sent to the near-Earth binary asteroid 65803 Didymos, which makes unusually close approaches to Earth in 2022 and 2024. These close approaches make it an ideal target for a kinetic impactor asteroid deflection demonstration, as it will be easily observable from Earth-based observatories. The ~2 m3, 300 kg DART spacecraft will impact the moon of the binary system at 6.25 km/s. The deflection of the moon will then be determined by the orbiting AIM spacecraft and from ground-based observations by measuring the change in the moon’s orbital period. A modeling study supporting this mission concept was performed to determine the expected momentum transfer to the moon following impact. The combination of CTH hydrocode models, analytical scaling predictions, and N-body pkdgrav simulations helps to constrain the expected results of the kinetic impactor experiment.To better understand the large parameter space (including material strength, porosity, impact location and angle), simulations of the DART impact were performed using the CTH hydrocode. The resultant crater size, velocity imparted to the moon, and momentum transfer were calculated for all cases. For “realistic” asteroid types, simulated DART impacts produce craters with diameters on the order of 10 m, an imparted Δv of 0.5-2 mm/s and a dimensionless momentum enhancement (“beta factor”) of 1.07-5 for targets ranging from a highly porous aggregate to a fully dense rock. These results generally agree with predictions from theoretical and analytical studies. Following impact, pkdgrav simulations of the system evolution track changes in the orbital period of the moon and examine the effects of the shapes of Didymos and its moon on the deflection. These simulations indicate that the shapes of the bodies can influence the subsequent dynamics of the moon.

The Double Asteroid Redirection Test (DART) for the AIDA Mission

NASA Astrophysics Data System (ADS)

Stickle, Angela; Cheng, Andy F.; Michel, Patrick; Barnouin, Olivier S.; Campo Bagatin, Adriano; Miller, Paul L.; Pravec, Petr; Richardson, Derek C.; Schwartz, Stephen R.; Tsiganis, Kleomenis; Ulamec, Stephan; AIDA Impact Modeling and Simulation Working Group

2016-10-01

The Asteroid Impact Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the NASA Double Asteroid Redirection Test (DART) mission, which provides the kinetic impactor, and the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft. DART is a Phase A study supported by NASA, and AIM is a Phase B1 study supported by ESA. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make a close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at ~6 km/s and deflect its trajectory, changing the orbital period of the binary. This change can be measured by Earth-based optical and radar observations. The primary goals of AIDA are to (1) perform a full-scale demonstration of asteroid deflection by kinetic impact; (2) measure the resulting deflection; and (3) validate and improve models for momentum transfer in high-speed impacts on an asteroid. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency from a kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. In addition to a predicted 4.4 minute change in the binary orbit period, assuming unit momentum transfer efficiency, the DART kinetic impact is predicted to induce forced librations of the Didymos secondary of possibly several degrees amplitude. Models predict the impact will create a 6-17 meter diameter crater, depending on target physical properties, and it will release a volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes. Current simulations of the DART impact provide predictions for momentum transfer, crater size, and ejecta mass following impact. Additional work benchmarking impact hydrocodes with one another provides a way to bound the uncertainty in these critical simulations, allowing better predictions for the momentum transfer to the moon of Didymos.

Secular Resonances During Main-Sequence and Post-Main-Sequence Planetary System Dynamics

NASA Astrophysics Data System (ADS)

Smallwood, Jeremy L.

We investigate gravitational perturbations of an asteroid belt by secular resonances. We ap- ply analytic and numerical models to main-sequence and post-main-sequence planetary systems. First, we investigate how the asteroid impact rate on the Earth is affected by the architecture of the planetary system. We find that the nu6 resonance plays an important role in the asteroid collision rate with the Earth. Compared to exoplanetary systems, the solar system is somewhat special in its lack of a super-Earth mass planet in the inner solar system. We therefore consider the effects of the presence of a super-Earth in the terrestrial planet region. We find a significant effect for super-Earths with a mass of around 10 M_{Earth} and a separation greater than about 0.7 AU. These results have implications for the habitability of exoplanetary systems. Secondly, we model white dwarf pollution by asteroids from secular resonances. In the past few decades, observations have revealed signatures of metals polluting the atmospheres of white dwarfs that require a continu- ous accretion of asteroids. We show that secular resonances driven by two outer companions can provide a source of pollution if an inner terrestrial planet is engulfed during the red-giant branch phase. Secular resonances may be a viable mechanism for the pollution of white dwarfs in a variety of exoplanetary system architectures including systems with two giant planets and systems with one giant planet and a binary star companion.

Ejecta cloud from the AIDA space project kinetic impact on the secondary of a binary asteroid: I. mechanical environment and dynamical model

NASA Astrophysics Data System (ADS)

Yu, Yang; Michel, Patrick; Schwartz, Stephen R.; Naidu, Shantanu P.; Benner, Lance A. M.

2017-01-01

An understanding of the post-impact dynamics of ejecta clouds are crucial to the planning of a kinetic impact mission to an asteroid, and also has great implications for the history of planetary formation. The purpose of this article is to track the evolution of ejecta produced by AIDA mission, which targets for kinetic impact the secondary of near-Earth binary asteroid (65803) Didymos on 2022, and to feedback essential informations to AIDA's ongoing phase-A study. We present a detailed dynamic model for the simulation of an ejecta cloud from a binary asteroid that synthesizes all relevant forces based on a previous analysis of the mechanical environment. We apply our method to gain insight into the expected response of Didymos to the AIDA impact, including the subsequent evolution of debris and dust. The crater scaling relations from laboratory experiments are employed to approximate the distributions of ejecta mass and launching speed. The size distribution of fragments is modeled with a power law fitted from observations of real asteroid surface. A full-scale demonstration is simulated using parameters specified by the mission. We report the results of the simulation, which include the computed spread of the ejecta cloud and the recorded history of ejecta accretion and escape. The violent period of the ejecta evolution is found to be short, and is followed by a stage where the remaining ejecta is gradually cleared. Solar radiation pressure proves to be efficient in cleaning dust-size ejecta, and the simulation results after two weeks shows that large debris on polar orbits (perpendicular to the binary orbital plane) has a survival advantage over smaller ejecta and ejecta that keeps to low latitudes.

The Influence of Orbital Resonances on the Water Transport to Objects in the Circumprimary Habitable Zone of Binary Star Systems

NASA Astrophysics Data System (ADS)

Bancelin, David; Pilat-Lohinger, Elke; Maindl, Thomas I.; Ragossnig, Florian; Schäfer, Christoph

2017-06-01

We investigate the role of secular and mean motion resonances on the water transport from a belt of icy asteroids onto planets or embryos orbiting inside the circumprimary habitable zone (HZ) of a binary star system. In addition, the host-star has an accompanying gas giant planet. For a comparison, we perform two case studies where a secular resonance (SR) is located either inside the HZ close to 1.0 au (causing eccentric motion of a planet or embryos therein) or in the asteroid belt, beyond the snow line. In the latter case, a higher flux of icy objects moving toward the HZ is expected. Collisions between asteroids and objects in the HZ are treated analytically. Our purely dynamical study shows that the SR in the HZ boosts the water transport however, collisions can occur at very high impact speeds. In this paper, we treat for the first time, realistic collisions using a GPU 3D-SPH code to assess the water loss in the projectile. Including the water loss into the dynamical results, we get more realistic values for the water mass fraction of the asteroid during an impact. We highlight that collisions occurring at high velocities greatly reduce the water content of the projectile and thus the amount of water transported to planets or embryos orbiting inside the HZ. Moreover, we discuss other effects that could modify our results, namely the asteroid’s surface rate recession due to ice sublimation and the atmospheric drag contribution on the asteroids’ mass loss.

New Hypervelocity Terminal Intercept Guidance Systems for Deflecting/Disrupting Hazardous Asteroids

NASA Astrophysics Data System (ADS)

Lyzhoft, Joshua Richard

Computational modeling and simulations of visual and infrared (IR) sensors are investigated for a new hypervelocity terminal guidance system of intercepting small asteroids (50 to 150 meters in diameter). Computational software tools for signal-to-noise ratio estimation of visual and IR sensors, estimation of minimum and maximum ranges of target detection, and GPU (Graphics Processing Units)-accelerated simulations of the IR-based terminal intercept guidance systems are developed. Scaled polyhedron models of known objects, such as the Rosetta mission's Comet 67P/C-G, NASA's OSIRIS-REx Bennu, and asteroid 433 Eros, are utilized in developing a GPU-based simulation tool for the IR-based terminal intercept guidance systems. A parallelized-ray tracing algorithm for simulating realistic surface-to-surface shadowing of irregular-shaped asteroids or comets is developed. Polyhedron solid-angle approximation is also considered. Using these computational models, digital image processing is investigated to determine single or multiple impact locations to assess the technical feasibility of new planetary defense mission concepts of utilizing a Hypervelocity Asteroid Intercept Vehicle (HAIV) or a Multiple Kinetic-energy Interceptor Vehicle (MKIV). Study results indicate that the IR-based guidance system outperforms the visual-based system in asteroid detection and tracking. When using an IR sensor, predicting impact locations from filtered images resulted in less jittery spacecraft control accelerations than conducting missions with a visual sensor. Infrared sensors have also the possibility to detect asteroids at greater distances, and if properly used, can aid in terminal phase guidance for proper impact location determination for the MKIV system. Emerging new topics of the Minimum Orbit Intersection Distance (MOID) estimation and the Full-Two-Body Problem (F2BP) formulation are also investigated to assess a potential near-Earth object collision risk and the proximity gravity effects of an irregular-shaped binary-asteroid target on a standoff nuclear explosion mission.

Full Two-Body Problem Mass Parameter Observability Explored Through Doubly Synchronous Systems

NASA Astrophysics Data System (ADS)

Davis, Alex Benjamin; Scheeres, Daniel

2018-04-01

The full two-body problem (F2BP) is often used to model binary asteroid systems, representing the bodies as two finite mass distributions whose dynamics are influenced by their mutual gravity potential. The emergent behavior of the F2BP is highly coupled translational and rotational mutual motion of the mass distributions. For these systems the doubly synchronous equilibrium occurs when both bodies are tidally-locked and in a circular co-orbit. Stable oscillations about this equilibrium can be shown, for the nonplanar system, to be combinations of seven fundamental frequencies of the system and the mutual orbit rate. The fundamental frequencies arise as the linear periods of center manifolds identified about the equilibrium which are heavily influenced by each body’s mass parameters. We leverage these eight dynamical constraints to investigate the observability of binary asteroid mass parameters via dynamical observations. This is accomplished by proving the nonsingularity of the relationship between the frequencies and mass parameters for doubly synchronous systems. Thus we can invert the relationship to show that given observations of the frequencies, we can solve for the mass parameters of a target system. In so doing we are able to predict the estimation covariance of the mass parameters based on observation quality and define necessary observation accuracies for desired mass parameter certainties. We apply these tools to 617 Patroclus, a doubly synchronous Trojan binary and flyby target of the LUCY mission, as well as the Pluto and Charon system in order to predict mutual behaviors of these doubly synchronous systems and to provide observational requirements for these systems’ mass parameters

Assessing Shape Characteristics of Jupiter Trojans in the Kepler Campaign 6 Field

NASA Astrophysics Data System (ADS)

Sharkey, Benjamin; Ryan, Erin L.; Woodward, Charles E.

2017-10-01

We report estimates of spin pole orientations and body-centric axis ratios of nine Jupiter Trojan asteroids through convex shape models derived from Kepler K2 photometry. Our sample contains single-component as well as candidate binary systems (identified through lightcurve features). Photometric baselines on the targets covered 7 to 93 full rotation periods. By incorporating a bias against highly elongated physical shapes, spin vector orientations of single-component systems were constrained to several discrete regions. Single-component convex models failed to converge on two binary candidates while two others demonstrated pronounced tapering that may be consistent with concavities of contact binaries. Further work to create two-component models is likely necessary to constrain the candidate binary targets. We find that Kepler K2 photometry provides robust datasets capable of providing detailed information on physical shape parameters of Jupiter Trojans.

Radar Imaging and Characterization of the Binary Near-Earth Asteroid (185851) 2000 DP107

NASA Astrophysics Data System (ADS)

Naidu, S. P.; Margot, J. L.; Taylor, P. A.; Nolan, M. C.; Busch, M. W.; Benner, L. A. M.; Brozovic, M.; Giorgini, J. D.; Jao, J. S.; Magri, C.

2015-08-01

The potentially hazardous asteroid (185851) 2000 DP107 was the first binary near-Earth asteroid to be imaged. Radar observations in 2000 provided images at 75 m resolution that revealed the shape, orbit, and spin-up formation mechanism of the binary. The asteroid made a more favorable flyby of the Earth in 2008, yielding images at 30 m resolution. We used these data to obtain shape models for the two components and to improve the estimates of the mutual orbit, component masses, and spin periods. The primary has a sidereal spin period of 2.7745 ± 0.0007 hr and is roughly spheroidal with an equivalent diameter of 863 m +/- 5%. It has a mass of 4.656+/- 0.43× {10}11 kg and a density of 1381 ± 244 kg m-3. It exhibits an equatorial ridge similar to the (66391) 1999 KW4 primary; however, the equatorial ridge in this case is not as regular and has a ˜300 m diameter concavity on one side. The secondary has a sidereal spin period of 1.77 ± 0.02 days commensurate with the orbital period. The secondary is slightly elongated and has overall dimensions of 377× 314× 268 m (6% uncertainties). Its mass is 0.178+/- 0.021× {10}11 kg and its density is 1047 ± 230 kg m-3. The mutual orbit has a semimajor axis of 2.659 ± 0.08 km, an eccentricity of 0.019 ± 0.01, and a period of 1.7556 ± 0.0015 days. The normalized total angular momentum of this system exceeds the amount required for the expected spin-up formation mechanism. An increase of angular momentum from non-gravitational forces after binary formation is a possible explanation. The two components have similar radar reflectivity, suggesting a similar composition consistent with formation by spin-up. The secondary appears to exhibit a larger circular polarization ratio than the primary, suggesting a rougher surface or subsurface at radar wavelength scales.

Orbital stability close to asteroid 624 Hektor using the polyhedral model

NASA Astrophysics Data System (ADS)

Jiang, Yu; Baoyin, Hexi; Li, Hengnian

2018-03-01

We investigate the orbital stability close to the unique L4-point Jupiter binary Trojan asteroid 624 Hektor. The gravitational potential of 624 Hektor is calculated using the polyhedron model with observational data of 2038 faces and 1021 vertexes. Previous studies have presented three different density values for 624 Hektor. The equilibrium points in the gravitational potential of 624 Hektor with different density values have been studied in detail. There are five equilibrium points in the gravitational potential of 624 Hektor no matter the density value. The positions, Jacobian, eigenvalues, topological cases, stability, as well as the Hessian matrix of the equilibrium points are investigated. For the three different density values the number, topological cases, and the stability of the equilibrium points with different density values are the same. However, the positions of the equilibrium points vary with the density value of the asteroid 624 Hektor. The outer equilibrium points move away from the asteroid's mass center when the density increases, and the inner equilibrium point moves close to the asteroid's mass center when the density increases. There exist unstable periodic orbits near the surface of 624 Hektor. We calculated an orbit near the primary's equatorial plane of this binary Trojan asteroid; the results indicate that the orbit remains stable after 28.8375 d.

The ginger-shaped asteroid 4179 Toutatis: new observations from a successful flyby of Chang'e-2.

PubMed

Huang, Jiangchuan; Ji, Jianghui; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

2013-12-12

On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 ± 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 × 1.95 km) ±10%, respectively, and the direction of the +z axis is estimated to be (250 ± 5°, 63 ± 5°) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.

The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2

PubMed Central

Huang, Jiangchuan; Ji, Jianghui; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

2013-01-01

On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 ± 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 × 1.95 km) ±10%, respectively, and the direction of the +z axis is estimated to be (250 ± 5°, 63 ± 5°) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general. PMID:24336501

Tidal Evolution of Asteroidal Binaries. Ruled by Viscosity. Ignorant of Rigidity.

NASA Astrophysics Data System (ADS)

Efroimsky, Michael

2015-10-01

This is a pilot paper serving as a launching pad for study of orbital and spin evolution of binary asteroids. The rate of tidal evolution of asteroidal binaries is defined by the dynamical Love numbers kl divided by quality factors Q. Common in the literature is the (oftentimes illegitimate) approximation of the dynamical Love numbers with their static counterparts. Since the static Love numbers are, approximately, proportional to the inverse rigidity, this renders a popular fallacy that the tidal evolution rate is determined by the product of the rigidity by the quality factor: {k}l/Q\\propto 1/(μ Q). In reality, the dynamical Love numbers depend on the tidal frequency and all rheological parameters of the tidally perturbed body (not just rigidity). We demonstrate that in asteroidal binaries the rigidity of their components plays virtually no role in tidal friction and tidal lagging, and thereby has almost no influence on the intensity of tidal interactions (tidal torques, tidal dissipation, tidally induced changes of the orbit). A key quantity that overwhelmingly determines the tidal evolution is a product of the effective viscosity η by the tidal frequency χ . The functional form of the torque’s dependence on this product depends on who wins in the competition between viscosity and self-gravitation. Hence a quantitative criterion, to distinguish between two regimes. For higher values of η χ , we get {k}l/Q\\propto 1/(η χ ), {while} for lower values we obtain {k}l/Q\\propto η χ . Our study rests on an assumption that asteroids can be treated as Maxwell bodies. Applicable to rigid rocks at low frequencies, this approximation is used here also for rubble piles, due to the lack of a better model. In the future, as we learn more about mechanics of granular mixtures in a weak gravity field, we may have to amend the tidal theory with other rheological parameters, ones that do not show up in the description of viscoelastic bodies. This line of study provides a tool to exploring the orbital history of asteroidal pairs, as well as of their final spin states.

New observations of (4179) Toutatis from the Chang'e-2 flyby mission and future Chinese missions to asteroids

NASA Astrophysics Data System (ADS)

Ji, J.

2014-07-01

Primitive asteroids are remnant building blocks in the Solar System formation. They provide key clues for us to reach in-depth understanding of the process of planetary formation, the complex environment of early Solar nebula, and even the occurrence of life on the Earth. On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid (4179) Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root with a smaller lobe (head) and a larger lobe (body). Such bifurcated configuration is indicative of a contact binary origin for Toutatis. In addition, the images with a 3-m resolution or higher provide a number of new discoveries about this asteroid, such as an 800-meter basin at the end of the large lobe, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, indicating that Toutatis is probably a rubble-pile asteroid. The Chang'e-2 observations have provided significant new insights into the geological features and the formation and evolution of this asteroid. Moreover, a conceptual introduction to future Chinese missions to asteroids, such as the major scientific objectives, scientific payloads, and potential targets, will be briefly given. The proposed mission will benefit a lot from potential international collaboration in the future.

Hydrocode Models of Mitigation of a 170-Meter-Diameter Asteroid Using Energetic Techniques

NASA Astrophysics Data System (ADS)

Plesko, C. S.; Gisler, G. R.; Heberling, T.; Nouanesengsy, B.; Patchett, J.; Sagert, I.; Tarnowsky, T. J.; Weaver, R.

2017-12-01

Binary asteroid 65803 Didymos is the target of the proposed NASA Double Asteroid Redirection Test (DART) mission. The smaller member of the binary pair, S/2003 (65803) Didymos B, is approximately 170 meters in diameter. Didymos A is spectrally similar to H-LL ordinary chondrites and asteroids Eros and Itokawa, so we assume Didymos B is similar. We also assume it to be a rubble pile aggregate of material from Didymos A, and take further guidance on material properties from the AIM Didymos Reference Model V. 10 (P. Michel et al., 2015). We are modeling deflection attempts by kinetic impactor and nuclear stand-off burst against a hypothetical solo Didymos B asteroid as part of the NASA-NNSA inter-agency collaboration on impact hazard mitigation. The collaboration agreed on model initial conditions at our February 2017 Technical Interchange Meeting. The kinetic impactor is a 63.5 cm-diameter aluminum impactor striking at 10 km/s. We model the stand-off nuclear burst according to procedures described in Barbee et al. (Acta A. 2017) and Dearborn et al. (in press). We will present our model predictions and their implications for planetary defense mission design space.

Radar investigations of near-Earth asteroids at Arecibo and Goldstone

NASA Astrophysics Data System (ADS)

Brozovic, M.; Nolan, M.; Benner, L.; Busch, M.; Howell, E.; Taylor, P.; Springmann, A.; Giorgini, J.; Margot, J.; Magri, C.; Sheppard, M.; Naidu, S.

2014-07-01

Radar observations are a powerful technique to study near-Earth asteroids (NEAs). The Arecibo and Goldstone planetary radars can provide delay-Doppler images that can directly resolve surface features such as concavities, hills, ridges, and boulders. Goldstone's 3.75-m resolution capability is invaluable when attempting to image NEAs with diameters smaller than 50 m. To date, over 430 near-Earth asteroids and 136 main-belt asteroids have been observed with radar. 80 % of the radar-detected NEAs have been observed within the last 10 years. The radar detection rate in the last three years has tripled relative to the average in the previous decade due to an increase in funding and greater scheduling flexibility. Currently, ˜400 observing hours per year at Goldstone and ˜600 observing hours per year at Arecibo are devoted to observing asteroids. We strive to observe all strong and moderately strong imaging targets, Yarkovsky drift candidates, NEOWISE targets, asteroids with very low perihelia that can be used to measure solar oblateness, and as many other detectable asteroids as resources allow. We also regularly attempt to observe any asteroid that is flagged by the Near-Earth Object Human Spaceflight Accessible Targets Study (NHATS) list (http://neo.jpl.nasa.gov/nhats/). To date, we have observed more than 60 NHATS objects at Arecibo and Goldstone. In the past three years, ˜1/3 of the detected asteroids were targets of opportunity (TOOs), some of which we observed within 24 h from when the discoveries were announced. Many TOOs are small, rapidly moving objects that are detectable by radar only within few lunar distances. Radar astrometry is particularly important for these asteroids because they are too faint to be followed for long with optical telescopes. A radar-range measurement often secures their orbit for decades or centuries, where otherwise the object would be lost and require rediscovery. In one of the extreme cases, two delay and two Doppler measurements from Goldstone prevented a newly discovered potentially hazardous asteroid (PHA) 2014 CU_{13} from being lost. The measurements also extended its Earth-encounter predictability by 1000 years. Radar observations of objects that are closer than ˜4 lunar distances (˜10.3 seconds RTT, round-trip-time for signal) previously required coordination between two stations (one for transmit and one for receive) due to the short RTT and need to physically switch between transmit and receive configurations. However, the switching process has been accelerated and recent observations of 2013 XY_8 have shown that Goldstone can now conduct monostatic observations with RTTs of ˜5 seconds. This provides much stronger signal-to-noise ratios for very close targets. With the rapidly growing number of radar detections, some population trends are emerging. The latest statistics show that the fraction of contact binaries has grown to ˜14 % and is now comparable to that of true binaries in the NEA population with diameters larger than 200 m. We are also starting to capture what may be the tail ends of certain sub-populations. For example, we have found two very small binary systems, 2003 SS_{84} and 2004 FG_{11}, that have primaries < 200 m in diameter; we have also found that 2005 AY_{28} and 2013 JR_{28} are contact binaries in the same size range. These objects are at the boundary between gravitationally bound ''rubble piles'' and strength-dominated, possibly monolithic objects. The NEAs are a very diverse population, in which we continue to discover unusual objects. It is difficult to anticipate what the future radar observations may uncover, but surprises are likely.

Chaotic Zones around Rotating Small Bodies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lages, José; Shevchenko, Ivan I.; Shepelyansky, Dima L., E-mail: jose.lages@utinam.cnrs.fr

Small bodies of the solar system, like asteroids, trans-Neptunian objects, cometary nuclei, and planetary satellites, with diameters smaller than 1000 km usually have irregular shapes, often resembling dumb-bells or contact binaries. The spinning of such a gravitating dumb-bell creates around it a zone of chaotic orbits. We determine its extent analytically and numerically. We find that the chaotic zone swells significantly if the rotation rate is decreased; in particular, the zone swells more than twice if the rotation rate is decreased 10 times with respect to the “centrifugal breakup” threshold. We illustrate the properties of the chaotic orbital zones in examples ofmore » the global orbital dynamics about asteroid 243 Ida (which has a moon, Dactyl, orbiting near the edge of the chaotic zone) and asteroid 25143 Itokawa.« less

2007 Mutual events within the binary system of (22) Kalliope

NASA Astrophysics Data System (ADS)

Descamps, P.; Marchis, F.; Pollock, J.; Berthier, J.; Birlan, M.; Vachier, F.; Colas, F.

2008-11-01

In 2007, the asteroid Kalliope will reach one of its annual equinoxes. As a consequence, its small satellite Linus orbiting in the equatorial plane will undergo a season of mutual eclipses and occultations very similar to the one that the Galilean satellites undergo every 6 years. This paper is aimed at preparing a campaign of observations of these mutual events occurring from February to May 2007. This opportunity occurs only under favorable geometric conditions when the Sun and/or the Earth are close to the orbital plane of the system. This is the first international campaign devoted to the observation of photometric events within an asynchronous asteroidal binary system. We took advantage of a reliable orbit solution of Linus to predict a series of 24 mutual eclipses and 12 mutual occultations observable in the spring of 2007. Thanks to the brightness of Kalliope ( mv≃11), these observations are easy to perform even with a small telescope. Anomalous attenuation events could be observed lasting for about 1-3 h with amplitude up to 0.09 mag. The attenuations are of two distinct types that can clearly be identified as primary and secondary eclipses similar to those that have been previously observed in other minor planet binary systems [Pravec, P., Scheirich, P., Kusnirák, P., Sarounová, L., Mottola, S., Hahn, G., Brown, P., Esquerdo, G., Kaiser, N., Krzeminski, Z., Pray, D.P., Warner, B.D., Harris, A.W., Nolan, M.C., Howell, E.S., Benner, L.A.M., Margot, J.-L., Galád, A., Holliday, W., Hicks, M.D., Krugly, Yu.N., Tholen, D., Whiteley, R., Marchis, F., Degraff, D.R., Grauer, A., Larson, S., Velichko, F.P., Cooney, W.R., Stephens, R., Zhu, J., Kirsch, K., Dyvig, R., Snyder, L., Reddy, V., Moore, S., Gajdos, S., Világi, J., Masi, G., Higgins, D., Funkhouser, G., Knight, B., Slivan, S., Behrend, R., Grenon, M., Burki, G., Roy, R., Demeautis, C., Matter, D., Waelchli, N., Revaz, Y., Klotz, A., Rieugné, M., Thierry, P., Cotrez, V., Brunetto, L., Kober, G., 2006. Photometric survey of binary near-Earth asteroids. Icarus 181, 63-93]. With these favorable circumstances, such photometric observations will provide us tight constraints regarding physical properties of Linus such as the size, shape and synodic spin period.

SeisCube Instrument and Environment Considerations for the Didymos System Geophysical Exploration

NASA Astrophysics Data System (ADS)

Cadu, Alexandre; Murdoch, Naomi; Mimoun, David; Karatekin, Ozgur; Garica, Raphaël F.; Carrasco, Jose A.; De Quiros, Francisco G.; Vasseur, Hugues; Eubanks, Marshall; Radley, Charles; Ritter, Birgit; Dehant, Veronique

2016-04-01

In the context of the Asteroid Impact & Deviation Assessment (AIDA) mission proposed by ESA and NASA, the Asteroid Geophysical Explorer (AGEX) mission concept has been selected for a preliminary study phase. Two 3-Unit CubeSats are embedded into the AIM probe and released into the asteroid binary system [1]. SeisCube will be deployed close to the secondary to reach its surface at a low relative velocity in order to stay on the ground after several rebounds, in a similar way that is foreseen for Mascot-2. The purpose of SeisCube is to provide information about the surface, the sub-surface and the internal structure of the asteroid, by analyzing rebound acceleration profile and seismic activity [2]. We describe the considered instrumentation necessary to fulfill the science objectives (gravimeters, accelerometers, geophones, etc.) in terms of measurement dynamics, frequency ranges, acquisition methods and other common budgets for space equipment. We also present the environment considerations which have to be taken into account for the platform and payload designs. The thermal aspect will be particularly discussed since it is a major issue in the airless body exploration [3] [4]. It implies some modifications in the CubeSat structure, integration and thermal regulation to ensure survival and operations under extreme conditions at the asteroid surface. We then describe the platform subsystems needed to ensure the operations after the deployment and the associated budgets and accommodation. As a direct consequence of the previous topics, we will finally discuss the possible trades-off to satisfy the main science requirements and the associated concept of operations. [1] O. Karatekin, D. Mimoun, J. A. Carrasco, N. Murdoch, A. Cadu, R. F. Garcia, F. G. De Quiros, H. Vasseur, B. Ritter, M. Eubanks, C. Radley and V. Dehant, "The Asteroid Geophysical Explorer (AGEX): Proposal to explore Didymos system using Cubsats," in European Geophysical Union, 2016. [2] N. Murdoch, A. Cadu, D. Mimoun, O. Karatekin, R. F. Garcia, J. A. Carrasco, F. G. De Guiros, H. Vasseur, B. Ritter, M. Eubanks, C. Radley and V. Dehart, "Invertigating the surface and subsurface properties of the Didymos binary asteroid with a landed CubeSat," in European Geophysical Union, 2016. [3] J. De Lafontaine and D. Kassing, "Technologies and Concepts for Lunar Surface Exploration," Acta Astronautica, vol. 38, no. 2, pp. 125-129, 1996. [4] S. Ulamec, J. Biele and E. Trollope, "How to survive a Lunar night," Planetary and Space Science, vol. 58, no. 14-15, pp. 1985-1995, 2010.

Dumb-bell-shaped equilibrium figures for fiducial contact-binary asteroids and EKBOs

NASA Astrophysics Data System (ADS)

Descamps, Pascal

2015-01-01

In this work, we investigate the equilibrium figures of a dumb-bell-shaped sequence with which we are still not well acquainted. Studies have shown that these elongated and nonconvex figures may realistically replace the classic “Roche binary approximation” for modeling putative peanut-shaped or contact binary asteroids. The best-fit dumb-bell shapes, combined with the known rotational period of the objects, provide estimates of the bulk density of these objects. This new class of mathematical figures has been successfully tested on the observed light curves of three noteworthy small bodies: main-belt Asteroid 216 Kleopatra, Trojan Asteroid 624 Hektor and Edgeworth-Kuiper-belt object 2001 QG298. Using the direct observations of Kleopatra and Hektor obtained with high spatial resolution techniques and fitting the size of the dumb-bell-shaped solutions, we derived new physical characteristics in terms of equivalent radius, 62.5 ± 5 km and 92 ± 5 km, respectively, and bulk density, 4.4 ± 0.4 g cm-3 and 2.43 ± 0.35 g cm-3, respectively. In particular, the growing inadequacy of the radar shape model for interpreting any type of observations of Kleopatra (light curves, AO images, stellar occultations) in a satisfactory manner suggests that Kleopatra is more likely to be a dumb-bell-shaped object than a “dog-bone.”

Ejection of rocky and icy material from binary star systems: implications for the origin and composition of 1I/`Oumuamua

NASA Astrophysics Data System (ADS)

Jackson, Alan P.; Tamayo, Daniel; Hammond, Noah; Ali-Dib, Mohamad; Rein, Hanno

2018-06-01

In single-star systems like our own Solar system, comets dominate the mass budget of bodies ejected into interstellar space, since they form further away and are less tightly bound. However, 1I/`Oumuamua, the first interstellar object detected, appears asteroidal in its spectra and lack of detectable activity. We argue that the galactic budget of interstellar objects like 1I/`Oumuamua should be dominated by planetesimal material ejected during planet formation in circumbinary systems, rather than in single-star systems or widely separated binaries. We further show that in circumbinary systems, rocky bodies should be ejected in comparable numbers to icy ones. This suggests that a substantial fraction of interstellar objects discovered in future should display an active coma. We find that the rocky population, of which 1I/`Oumuamua seems to be a member, should be predominantly sourced from A-type and late B-star binaries.

Contact binaries in the Trans-neptunian Belt

NASA Astrophysics Data System (ADS)

Thirouin, Audrey; Sheppard, Scott S.

2017-10-01

A contact binary is made up of two objects that are almost touching or in contact with each other. These systems have been found in the Near-Earth Object population, the main belt of asteroids, the Jupiter Trojans, the comet population and even in the Trans-neptunian belt.Several studies suggest that up to 30% of the Trans-Neptunian Objects (TNOs) could be contact binaries (Sheppard & Jewitt 2004, Lacerda 2011). Contact binaries are not resolvable with the Hubble Space Telescope because of the small separation between the system's components (Noll et al. 2008). Only lightcurves with a characteristic V-/U-shape at the minimum/maximum of brightness and a large amplitude can identify these contact binaries. Despite an expected high fraction of contact binaries, 2001 QG298 is the only confirmed contact binary in the Trans-Neptunian belt, and 2003 SQ317 is a candidate to this class of systems (Sheppard & Jewitt 2004, Lacerda et al. 2014).Recently, using the Lowell’s 4.3m Discovery Channel Telescope and the 6.5m Magellan Telescope, we started a search for contact binaries at the edge of our Solar System. So far, our survey focused on about 40 objects in different dynamical groups of the Trans-Neptunian belt for sparse or complete lightcurves. We report the discovery of 5 new potential contact binaries converting the current estimate of potential/confirmed contact binaries to 7 objects. With one epoch of observations per object, we are not able to model in detail the systems, but we derive estimate for basic information such as shape, size, density of both objects as well as the separation between the system’s components. In this work, we will present these new systems, their basic characteristics, and we will discuss the potential main reservoir of contact binaries in the Trans-neptunian belt.

Collisional and Dynamical Evolution of Planetary Systems

NASA Technical Reports Server (NTRS)

Weidenschilling, Stuart J.

2004-01-01

Senior Scientst S. J. Weidenschilling presents his final administrative report in the research program entitled "Collisional and Dynamical Evolution of Planetary Systems," on which he was the Principal Investigator. This research program produced the following publications: 1) "Jumping Jupiters" in binary star systems. F. Marzari, S. J. Weidenschilling, M. Barbieri and V. Granata. Astrophys. J., in press, 2005; 2) Formation of the cores of the outer planets. To appear in "The Outer Planets" (R. Kallenbach, ED), ISSI Conference Proceedings (Space Sci. Rev.), in press, 2005; 3) Accretion dynamics and timescales: Relation to chondrites. S. J. Weidenschilling and J. Cuzzi. In Meteorites and the Early Solar System LI (D. Lauretta et al., Eds.), Univ. of Arizona Press, 2005; 4) Asteroidal heating and thermal stratification of the asteroid belt. A. Ghosh, S. J.Weidenschilling, H. Y. McSween, Jr. and A. Rubin. In Meteorites and the Early Solar System I1 (D. Lauretta et al., Eds.), Univ. of Arizona Press, 2005.

Modeling Momentum Transfer from Kinetic Impacts: Implications for Redirecting Asteroids

DOE PAGES

Stickle, A. M.; Atchison, J. A.; Barnouin, O. S.; ...

2015-05-19

Kinetic impactors are one way to deflect a potentially hazardous object headed for Earth. The Asteroid Impact and Deflection Assessment (AIDA) mission is designed to test the effectiveness of this approach and is a joint effort between NASA and ESA. The NASA-led portion is the Double Asteroid Redirect Test (DART) and is composed of a ~300-kg spacecraft designed to impact the moon of the binary system 65803 Didymos. The deflection of the moon will be measured by the ESA-led Asteroid Impact Mission (AIM) (which will characterize the moon) and from ground-based observations. Because the material properties and internal structure ofmore » the target are poorly constrained, however, analytical models and numerical simulations must be used to understand the range of potential outcomes. Here, we describe a modeling effort combining analytical models and CTH simulations to determine possible outcomes of the DART impact. We examine a wide parameter space and provide predictions for crater size, ejecta mass, and momentum transfer following the impact into the moon of the Didymos system. For impacts into “realistic” asteroid types, these models produce craters with diameters on the order of 10 m, an imparted Δv of 0.5–2 mm/s and a momentum enhancement of 1.07 to 5 for a highly porous aggregate to a fully dense rock.« less

Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

NASA Astrophysics Data System (ADS)

Ji, Jianghui; Jiang, Yun; Zhao, Yuhui; Wang, Su; Yu, Liangliang

2016-01-01

On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

Alien Sunset (Artist Concept)

NASA Technical Reports Server (NTRS)

2007-01-01

Our solitary sunsets here on Earth might not be all that common in the grand scheme of things. New observations from NASA's Spitzer Space Telescope have revealed that mature planetary systems -- dusty disks of asteroids, comets and possibly planets -- are more frequent around close-knit twin, or binary, stars than single stars like our sun. That means sunsets like the one portrayed in this artist's photo concept, and more famously in the movie 'Star Wars,' might be quite commonplace in the universe.

Binary and multiple-star systems are about twice as abundant as single-star systems in our galaxy, and, in theory, other galaxies. In a typical binary system, two stars of roughly similar masses twirl around each other like pair-figure skaters. In some systems, the two stars are very far apart and barely interact with each other. In other cases, the stellar twins are intricately linked, whipping around each other quickly due to the force of gravity.

Astronomers have discovered dozens of planets that orbit around a single member of a very wide stellar duo. Sunsets from these worlds would look like our own, and the second sun would just look like a bright star in the night sky.

But do planets exist in the tighter systems, where two suns would dip below a planet's horizon one by one? Unveiling planets in these systems is tricky, so astronomers used Spitzer to look for disks of swirling planetary debris instead. These disks are made of asteroids, comets and possibly planets. The rocky material in them bangs together and kicks up dust that Spitzer's infrared eyes can see. Our own solar system is swaddled in a similar type of disk.

Surprisingly, Spitzer found more debris disks around the tightest binaries it studied (about 20 stars) than in a comparable sample of single stars. About 60 percent of the tight binaries had disks, while the single stars only had about 20 percent. These snug binary systems are as close or closer than just three times the distance between Earth and the sun. And the disks in these systems were found to circumnavigate both members of the star pair, rather than just one.

Though follow-up studies are needed, the results could mean that planet formation is more common around extra-tight binary stars than single stars. Since these types of systems would experience double sunsets, the artistic view portrayed here might not be fiction.

The original sunset photo used in this artist's concept was taken by Robert Hurt of the Spitzer Science Center at the California Institute of Technology, Pasadena, Calif.

Sizes, Shapes, and Satellites of Asteroids from Occultations

NASA Astrophysics Data System (ADS)

Dunham, David W.; Herald, David; Preston, Steve; Timerson, Brad; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

2016-01-01

For 40 years, the sizes and shapes of many dozens of asteroids have been determined from observations of asteroidal occultations, and over a thousand high-precision positions of the asteroids relative to stars have been measured. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.

ISALE impact simulations in support of AIDA mission

NASA Astrophysics Data System (ADS)

Oklay, Nilda; Vincent, Jean-Baptiste; Michel, Patrick; Schwartz, Stephen

2016-07-01

Introduction: The Asteroid Impact Deflection Assessment (AIDA) mission is a joint project of ESA and NASA with two independent spacecraft. ESA's contribution is an observer satellite called Asteroid Impact Mission (AIM, [1]), and NASA's contribution is a projectile called Double Asteroid Redirection Test (DART, [2]). The target of the mission is a near-Earth binary asteroid system (65803) Didymos. The aim is to study the possibility of deflecting an asteroid by using a kinetic impactor, as well as to characterize the internal properties of the target and test various relevant technologies for other missions. The design is that the DART would impact the secondary of the binary system and AIM would characterize the target asteroid, observe the impact event and measure the changes in the relative orbit after the impact. Impact modeling will be used to interpret the results of the AIDA impact event. There are numerous impact simulation codes, which are planned to be used to understand the AIDA impact results. Therefore an international benchmarking program is ongoing for the comparison of the results of various codes on the defined test cases [3]. We will present the results of the test cases performed by iSALE hydrocode. Modeling: In this work we use the iSALE-2D shock physics code [4], which is based on the SALE hydrocode solution algorithm [5]. To simulate hypervelocity impact processes in solid materials SALE was modified to include an elastoplastic constitutive model, fragmentation models, various EOS, and multiple materials [6, 7]. More recent improvements include a modified strength model [8] and a porosity compaction model [4, 9]. References: [1] Michel P. et al., 2016, ASR, submitted [2] Cheng A. F. et al., (2016) PSS, 121, 27-35 [3] Stickle A. M. et al., (2016). 47th LPSC [4] Wünnemann,K. et al., (2006). Icarus, 180:514-527 [5] Amsden, A., et al., (1980) LANL Report, LA-8095:101p. [6] Melosh, H. J., et al., (1992). J. Geophys. Res., 97(E9):14735-14759 [7] Ivanov, B. A., et al., (1997) Int. J. Imp. Eng., 20:411-430; [8] Collins, G. S., et al., (2004). Met. & Planet. Sci., 39:217-231. [9] Collins, G., et al., (2011) Int. J. Imp. Eng., 38:434-439

Asteroid Evolution: Role of geotechnical properties

NASA Astrophysics Data System (ADS)

Sanchez Lana, Diego P.

2015-08-01

Over the last decade of Planetary research, the scientific community has made many advances in their understanding of the evolution of asteroids in the Solar System. One particular area of fruitful study started with the bold idea that these small planetary bodies could be gravitational aggregates and initially motivated by several different observations and early simulations.If we start with the idea that asteroids are aggregates of different sized components, and not singular monolithic bodies, it is possible to study them with some of the tools that have been used in the fields of Soil Mechanics and Granular Dynamics. In them, parameters such as porosity, cohesive and tensile strength, angles of friction and repose, particle size distributions, stress states, heterogeneity and yield criteria among others, determine how these granular systems will react when subjected to different, changing, external factors. These external factors are believed to have produced and shaped the asteroids that now exist around us and include solar photon momentum, gravitational tides, micro- and macro-impacts and internal energy dissipation.In this presentation we will review what is known about the surface and interiors of rubble pile asteroids, how different theoretical, experimental and simulation tools have been used to study them, how space mission and ground-based observations have shaped our understanding of their physical reality, and what we expect to learn from future missions. The talk will also touch on some of the latest findings obtained by different groups. In particular we will discuss the rotational evolution of self-gravitating aggregates under the influence of the YORP effect and how their angles of friction, tensile strength, porosity, internal structure and density give rise to different disruption modes and the role they play in the formation of asteroids pairs, tumblers and binary systems.

The Discovery and Analysis of a New Type of Wolf-Rayet Star

NASA Astrophysics Data System (ADS)

Nowinski, Matt Clarke

A massive impact event on (4) Vesta is believed to have created the Vesta family of asteroids (Asphaug, 1997). The rotational characteristics of the Vesta family provide important clues about this event, including its timing, the make-up of the resulting debris, the subsequent migration of members of the family into Earth-crossing orbits, and the deposition of the Howardite-Eucrite-Diogenite meteorites on the Earth's surface. This study conducted lightcurve measurements of ten Vp-type asteroids, drawn from an asteroid taxonomy defined by Carvano et al. (2010) and based on the Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC4). These measurements identified a range of asteroid rotation periods from approximately 2.5 to 9.5 hours, as well as a potential synchronous binary system, (15121) 2000 EN14. The lightcurve results were combined with those of other V/Vp-type asteroids available in LightCurve Database (LCDB; Warner et al., 2009), and matched with both WISE diameter/albedo (J. Masiero et al., 2011) and near-infrared spectroscopic (Hardersen et al., 2014-2018) data. This integrated approach identified a set of Vesta family asteroids with relatively fast spin rates, nearly spherical shapes, and loose aggregate compositions. These findings, combined with the non-Maxwellian shape of this population's spin rate distribution, highlighted the importance of thermal Yarkovsky-YORP effects on the evolution of the Vesta family.

Calculating the momentum enhancement factor for asteroid deflection studies

DOE PAGES

Heberling, Tamra; Gisler, Galen; Plesko, Catherine; ...

2017-10-17

The possibility of kinetic-impact deflection of threatening near-Earth asteroids will be tested for the first time in the proposed AIDA (Asteroid Impact Deflection Assessment) mission, involving NASAs DART (Double Asteroid Redirection Test). The impact of the DART spacecraft onto the secondary of the binary asteroid 65803 Didymos at a speed of 5 to 7 km/s is expected to alter the mutual orbit by an observable amount. Furthermore, the velocity transferred to the secondary depends largely on the momentum enhancement factor, typically referred to as beta. Here, we use two hydrocodes developed at Los Alamos, RAGE and PAGOSA, to calculate anmore » approximate value for beta in laboratory-scale benchmark experiments. Convergence studies comparing the two codes show the importance of mesh size in estimating this crucial parameter.« less

Calculating the momentum enhancement factor for asteroid deflection studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heberling, Tamra; Gisler, Galen; Plesko, Catherine

The possibility of kinetic-impact deflection of threatening near-Earth asteroids will be tested for the first time in the proposed AIDA (Asteroid Impact Deflection Assessment) mission, involving NASAs DART (Double Asteroid Redirection Test). The impact of the DART spacecraft onto the secondary of the binary asteroid 65803 Didymos at a speed of 5 to 7 km/s is expected to alter the mutual orbit by an observable amount. Furthermore, the velocity transferred to the secondary depends largely on the momentum enhancement factor, typically referred to as beta. Here, we use two hydrocodes developed at Los Alamos, RAGE and PAGOSA, to calculate anmore » approximate value for beta in laboratory-scale benchmark experiments. Convergence studies comparing the two codes show the importance of mesh size in estimating this crucial parameter.« less

Simulations of hypervelocity impacts for asteroid deflection studies

NASA Astrophysics Data System (ADS)

Heberling, T.; Ferguson, J. M.; Gisler, G. R.; Plesko, C. S.; Weaver, R.

2016-12-01

The possibility of kinetic-impact deflection of threatening near-earth asteroids will be tested for the first time in the proposed AIDA (Asteroid Impact Deflection Assessment) mission, involving two independent spacecraft, NASAs DART (Double Asteroid Redirection Test) and ESAs AIM (Asteroid Impact Mission). The impact of the DART spacecraft onto the secondary of the binary asteroid 65803 Didymos, at a speed of 5 to 7 km/s, is expected to alter the mutual orbit by an observable amount. The velocity imparted to the secondary depends on the geometry and dynamics of the impact, and especially on the momentum enhancement factor, conventionally called beta. We use the Los Alamos hydrocodes Rage and Pagosa to estimate beta in laboratory-scale benchmark experiments and in the large-scale asteroid deflection test. Simulations are performed in two- and three-dimensions, using a variety of equations of state and strength models for both the lab-scale and large-scale cases. This work is being performed as part of a systematic benchmarking study for the AIDA mission that includes other hydrocodes.

The upcoming mutual event season for the Patroclus-Menoetius Trojan binary

NASA Astrophysics Data System (ADS)

Grundy, W. M.; Noll, K. S.; Buie, M. W.; Levison, H. F.

2018-05-01

We present new Hubble Space Telescope and ground-based Keck observations and new Keplerian orbit solutions for the mutual orbit of binary Jupiter Trojan asteroid (617) Patroclus and Menoetius, targets of NASA's Lucy mission. We predict event times for the upcoming mutual event season, which is anticipated to run from late 2017 through mid 2019.

A radar survey of M- and X-class asteroids. III. Insights into their composition, hydration state, & structure

NASA Astrophysics Data System (ADS)

Shepard, Michael K.; Taylor, Patrick A.; Nolan, Michael C.; Howell, Ellen S.; Springmann, Alessondra; Giorgini, Jon D.; Warner, Brian D.; Harris, Alan W.; Stephens, Robert; Merline, William J.; Rivkin, Andrew; Benner, Lance A. M.; Coley, Dan; Clark, Beth Ellen; Ockert-Bell, Maureen; Magri, Christopher

2015-01-01

Using the S-band radar at Arecibo Observatory, we observed thirteen X/M-class asteroids; nine were previously undetected and four were re-observed, bringing the total number of Tholen X/M-class asteroids observed with radar to 29. Of these 29M-class asteroids, 13 are also W-class, defined as M-class objects that also display a 3-μm absorption feature which is often interpreted as the signature of hydrated minerals (Jones, T.D., Lebofsky, L.A., Lewis, J.S., Marley, M.S. [1990]. Icarus 88, 172-192; Rivkin, A.S., Howell, E.S., Britt, D.T., Lebofsky, L.A., Nolan, M.C., Branston, D.D. [1995]. Icarus 117, 90-100; Rivkin, A.S., Howell, E.S., Lebofsky, L.A., Clark, B.E., Britt, D.T. [2000]. Icarus 145, 351-368). Consistent with our previous work (Shepard, M.K. et al. [2008]. Icarus 195, 184-205; Shepard, M.K., Harris, A.W., Taylor, P.A., Clark, B.E., Ockert-Bell, M., Nolan, M.C., Howell, E.S., Magri, C., Giorgini, J.D., Benner, L.A.M. [2011]. Icarus 215, 547-551), we find that 38% of our sample (11 of 29) have radar albedos consistent with metal-dominated compositions. With the exception of 83 Beatrix and 572 Rebekka, the remaining objects have radar albedos significantly higher than the mean S- or C-class asteroid (Magri, C., Nolan, M.C., Ostro, S.J., Giorgini, J.D. [2007]. Icarus 186, 126-151). Seven of the eleven high-radar-albedo asteroids, or 64%, also display a 3-μm absorption feature (W-class) which is thought to be inconsistent with the formation of a metal dominated asteroid. We suggest that the hydration absorption could be a secondary feature caused by low-velocity collisions with hydrated asteroids, such as CI or CM analogs, and subsequent implantation of the hydrated minerals into the upper regolith. There is recent evidence for this process on Vesta (Reddy, V. et al. [2012]. Icarus 221, 544-559; McCord, T.B. et al. [2012]. Nature 491, 83-86; Prettyman, T.H. et al. [2012]. Science 338, 242-246; Denevi, B.W. et al. [2012]. Science 338, 246-249). Eleven members of our sample show bifurcated radar echoes at some rotation phases; eight of these are high radar albedo targets. One interpretation of a bifurcated echo is a contact binary, like 216 Kleopatra, and several of our sample are contact binary candidates. However, evidence for other targets indicates they are not contact binaries. Instead, we hypothesize that these asteroids may have large-scale variations in surface bulk density, i.e. isolated patches of metal-rich and silicate-rich regions at the near-surface, possibly the result of collisions between metal and silicate-rich asteroids.

A Spectroscopic and Mineralogical Study of Multiple Asteroid Systems

NASA Astrophysics Data System (ADS)

Lindsay, Sean S.; Emery, J. P.; Marchis, F.; Enriquez, J.; Assafin, M.

2013-10-01

There are currently ~200 identified multiple asteroid systems (MASs). These systems display a large diversity in heliocentric distance, size/mass ratio, system angular momentum, mutual orbital parameters, and taxonomic class. These characteristics are simplified under the nomenclature of Descamps and Marchis (2008), which divides MASs into four types: Type-1 - large asteroids with small satellites; Type-2 - similar size double asteroids; Type-3 - small asynchronous systems; and Type-4 - contact-binary asteroids. The large MAS diversity suggests multiple formation mechanisms are required to understand their origins. There are currently three broad formation scenarios: 1) ejecta from impacts; 2) catastrophic disruption followed by rotational fission; and 3) tidal disruption. The taxonomic class and mineralogy of the MASs coupled with the average density and system angular momentum provide a potential means to discriminate between proposed formation mechanisms. We present visible and near-infrared (NIR) spectra spanning 0.45 - 2.45 μm for 23 Main Belt MASs. The data were primarily obtained using the Southern Astrophysical Research Telescope (SOAR) Goodman High Throughput Spectrograph (August 2011 - July 2012) for the visible data and the InfraRed Telescope Facility (IRTF) SpeX Spectrograph (August 2008 - May 2013) for the IR data. Our data were supplemented using previously published data when necessary. The asteroids' Bus-DeMeo taxonomic classes are determined using the MIT SMASS online classification routines. Our sample includes 3 C-types, 1 X-type, 1 K-type, 1 L-type, 4 V-types, 10 S-types, 2 Sq- or Q-types, and 1 ambiguous classification. We calculate the 1- and 2-μm band centers, depths, and areas to determine the pyroxene mineralogy (molar Fs and Wo) of the surfaces using empirically derived equations. The NIR band analysis allows us to determine the S-type subclasses, S(I) - S(VII), which roughly tracks olivine-pyroxene chemistry. A comparison of the orbital parameters, physical parameters (size, density, and angular momentum), collisional family membership, and taxonomy is presented in an effort to find correlations, which may give insights to how these MASs formation mechanisms.

Dynamics of ejecta from a binary asteroid impact in the framework of the AIDA mission: a NEOShield-2 contribution

NASA Astrophysics Data System (ADS)

Yu, Y.; Schwartz, S. R.; Michel, P.; Benner, L. A. M.

2015-10-01

The dynamics of the ejecta cloud that results from a binary asteroid impact is one of the tasks of the NEOShield-2 project, funded by the European Commission in its program Horizon 2020. Results from such an investigation will have great relevance to the Phase-A study of the AIDA space mission, a collaborative effort between ESA and NASA, which aims to perform a kinetic impactor demonstration. Our study presents a multi-scale dynamical model of the ejecta cloud produced by a hypervelocity impact, which enables us to check the behaviors of the ejecta at different spatial and time scales. This model is applied to the impact into the small moon of the binary Near- Earth asteroid (65803) Didymos on October 2022 as considered by the AIDA mission. We attempt to model the process by including as much practical information as possible, e.g., the gravitational environment influenced by the non-spherical shapes of the bodies based on observed shape of the primary), the solar tides, and the solar radiation pressure. Our simulations show the general patterns of motion of the ejecta cloud, which we use to assess the potential hazard to an observing spacecraft. We also look into the grain-scale dynamics of the ejecta during this process, which has influence on the re-accumulation of particles orbiting in the vicinity.

313 new asteroid rotation periods from Palomar Transient Factory observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Chan-Kao; Ip, Wing-Huen; Lin, Hsing-Wen

2014-06-10

A new asteroid rotation period survey has been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg{sup 2} in the ecliptic plane, were observed in the R band with a cadence of ∼20 minutes during 2013 February 15-18. We detected 2500 known asteroids with a diameter range of 0.5 km ≤D ≤ 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the 'spin barrier' at ∼2 hr. In contrast to the flat spin-rate distribution of the asteroids with 3 km ≤D ≤ 15 km shownmore » by Pravec et al., our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev day{sup –1}. One superfast rotator candidate and two possible binary asteroids were also found in this work.« less

"Horseshoe" Structures in the Debris Disks of Planet-Hosting Binary Stars

NASA Astrophysics Data System (ADS)

Demidova, T. V.

2018-03-01

The formation of a planetary system from the protoplanetary disk leads to destruction of the latter; however, a debris disk can remain in the form of asteroids and cometary material. The motion of planets can cause the formation of coorbital structures from the debris disk matter. Previous calculations have shown that such a ring-like structure is more stable if there is a binary star in the center of the system, as opposed to a single star. To analyze the properties of the coorbital structure, we have calculated a grid of models of binary star systems with a circumbinary planet moving in a planetesimal disk. The calculations are performed considering circular orbits of the stars and the planet; the mass and position of the planet, as well as the mass ratio of the stars, are varied. The analysis of the models shows that the width of the coorbital ring and its stability significantly depend on the initial parameters of the problem. Additionally, the empirical dependences of the width of the coorbital structure on the parameters of the system have been obtained, and the parameters of the models with the most stable coorbital structures have been determined. The results of the present study can be used for the search of planets around binary stars with debris disks.

Assessment of DSN Communication Coverage for Space Missions to Potentially Hazardous Asteroids

NASA Technical Reports Server (NTRS)

Kegege, Obadiah; Bittner, David; Gati, Frank; Bhasin, Kul

2012-01-01

A communication coverage gap exists for Deep Space Network (DSN) antennas. This communication coverage gap is on the southern hemisphere, centered at approximate latitude of -47deg and longitude of -45deg. The area of this communication gap varies depending on the altitude from the Earth s surface. There are no current planetary space missions that fall within the DSN communication gap because planetary bodies in the Solar system lie near the ecliptic plane. However, some asteroids orbits are not confined to the ecliptic plane. In recent years, Potentially Hazardous Asteroids (PHAs) have passed within 100,000 km of the Earth. NASA s future space exploration goals include a manned mission to asteroids. It is important to ensure reliable and redundant communication coverage/capabilities for manned space missions to dangerous asteroids that make a sequence of close Earth encounters. In this paper, we will describe simulations performed to determine whether near-Earth objects (NEO) that have been classified as PHAs fall within the DSN communication coverage gap. In the study, we reviewed literature for a number of PHAs, generated binary ephemeris for selected PHAs using JPL s HORIZONS tool, and created their trajectories using Satellite Took Kit (STK). The results show that some of the PHAs fall within DSN communication coverage gap. This paper presents the simulation results and our analyses

Constraints on the perturbed mutual motion in Didymos due to impact-induced deformation of its primary after the DART impact

NASA Astrophysics Data System (ADS)

Hirabayashi, Masatoshi; Schwartz, Stephen R.; Yu, Yang; Davis, Alex B.; Chesley, Steven R.; Fahnestock, Eugene G.; Michel, Patrick; Richardson, Derek C.; Naidu, Shantanu P.; Scheeres, Daniel J.; Cheng, Andrew F.; Rivkin, Andrew S.; Benner, Lance A. M.

2017-12-01

Binary near-Earth asteroid (65803) Didymos is the target of the proposed NASA Double Asteroid Redirection Test (DART), part of the Asteroid Impact & Deflection Assessment (AIDA) mission concept. In this mission, the DART spacecraft is planned to impact the secondary body of Didymos, perturbing mutual dynamics of the system. The primary body is currently rotating at a spin period close to the spin barrier of asteroids, and materials ejected from the secondary due to the DART impact are likely to reach the primary. These conditions may cause the primary to reshape, due to landslides or internal deformation, changing the permanent gravity field. Here, we propose that if shape deformation of the primary occurs, the mutual orbit of the system would be perturbed due to a change in the gravity field. We use a numerical simulation technique based on the full two-body problem to investigate the shape effect on the mutual dynamics in Didymos after the DART impact. The results show that under constant volume, shape deformation induces strong perturbation in the mutual motion. We find that the deformation process always causes the orbital period of the system to become shorter. If surface layers with a thickness greater than ∼0.4 m on the poles of the primary move down to the equatorial region due to the DART impact, a change in the orbital period of the system and in the spin period of the primary will be detected by ground-based measurement.

Asteroid Geophysics through a Tidal-BYORP Equilibrium

NASA Astrophysics Data System (ADS)

Jacobson, S. A.; Scheeres, D. J.

2012-12-01

There exists a long-term stable orbital equilibrium for singly synchronous binary asteroids balancing the contractive BYORP (binary Yarkovsky-O'Keefe-Radzievskii-Paddack) effect and the expansive tidal torque from the secondary onto the primary [Jacobson & Scheeres 2011]. Observations of 1996 FG3 determined that this object is consistent with occupying the predicted equilibrium [Scheirich, et al., 2012]. From the torque balance, the important tidal parameters of the primary and BYORP coefficient of the secondary can be directly determined for the first time, albeit degenerately. Singly synchronous systems consist of a rapidly spinning primary and a tidally locked secondary. Two torques evolve the mutual orbit of the system. First, the secondary raises a tidal torque on the primary, and this process expands the semi-major axis of the mutual orbit according to two parameters. The tidal Love number k is related to the strength (rigidity) of the body. The tidal dissipation number Q describes the mechanical energy dissipation. Second, the BYORP torque is the summed torques from all of the incident and exigent photons on the secondary acting on the barycenter of the system. Unless there is a spin-orbit resonance, the torques sum to zero. McMahon & Scheeres [2010] showed that showed that to first order in eccentricity the evolution of the semi-major axis and eccentricity depends only upon a single constant coefficient B determined by the shape of the secondary (size-independent). The BYORP torque can either contract or expand the mutual orbit, however it evolves the eccentricity with the opposite sign. Jacobson & Scheeres [2011] determined that when the BYORP torque is contractive, it can balance the expansive tidal torque. The system evolves to an equilibrium semi-major axis that is stable in eccentricity due to tidal decay overcoming BYORP excitation. If the singly synchronous population occupies this equilibrium, then the three unknown (i.e. unobserved) parameters: Bs Qp/k_p, as shown in the figure. Since the BYORP coefficient is defined to be size independent, the tidal parameters Qp/k_p ∝ Rp. This inverse dependence is different than the predicted dependencies of the classical tidal Love number kp ∝ Rp2 and the ``rubble-pile'' tidal Love number predicted in Goldreich & Sari [2009] kp ∝ Rp. Calculated Bs Qp/ kp for each observed singly synchronous binary asteroid system. The circled system is 1996 FG3. The solid line is the fit Bs Qp/k_p = 2557 Rp and the dashed lines are a facto r of 10 and a factor of 0.01 different.

Unveiling Clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

NASA Technical Reports Server (NTRS)

Lederer, Susan M.; Jensen, Elizabeth; Fane, Michael; Smith, Douglas; Holmes, Jacob; Keller, Lindasy P.; Lindsay, Sean S.; Wooden, Diane H.; Whizin, Akbar; Cintala, Mark J.;

Triple-Crater in Elysium Planitia

NASA Image and Video Library

2015-01-22

This image from NASA Mars Mars Reconnaissance Orbiter shows a triple impact crater in Elysium Planitia near Tartarus Montes, which probably formed when a binary-or even triple-asteroid struck the surface.

A Mobile Asteroid Surface Scout for the AIDA Mission

NASA Astrophysics Data System (ADS)

Ho, Tra Mi; Lange, Caroline; Grimm, Christian; Thimo Grundmann, Jan; Rößler, Johannes; Schröder, Silvio; Skoczylas, Thomas; Ziach, Christian; Biele, Jens; Cozzoni, Barbara; Krause, Christian; Küchemann, Oliver; Maibaum, Michael; Ulamec, Stephan; Lange, Michael; Mierheim, Olaf; Maier, Maximilian; Herique, Alain; Mascot Study Team

2016-04-01

The Asteroid Impact Deflection, AIDA, mission is composed of a kinetic impactor, DART and an observer, the Asteroid Impact Monitor, AIM, carrying among other payload a surface package, MASCOT2 (MSC2). Its proposed concept is based on the MASCOT lander onboard the HAYABUSA2 Mission (JAXA) to near-Earth asteroid (162173) Ryugu. MASCOT is a compact platform ('shoe box size') carrying a suite of 4 scientific instruments and has a landed mass of ~10kg. Equipped with a mobility mechanism, the MASCOT lander is able to upright and relocate on the targeted asteroid; thus providing in-situ data at more than one site. In the context of the AIDA Mission, the MASCOT2 lander would be carried by the AIM spacecraft and delivered onto Didymoon, the secondary object in the (65803) Didymos binary near-Earth asteroid system. Since the mission objectives of the AIM mission within the joint AIDA mission concept differ from JAXA's sample return mission HAYABUSA2, several design changes need to be studied and implemented. To support one of the prime objectives of the AIM mission, the characterization of the bulk physical properties of Didymoon, the main scientific payload of MSC2 is a low-frequency radar (LFR) to investigate the internal structure of the asteroid moon. Since the total science payload on MASCOT2 is limited to approximately 2.3 kg, the mass remaining for a suite of other experiments is in the range of 0.1 to 0.5 kg per instrument. Further requirements have a significant impact on the MSC2 design which will be presented. Among these are the much longer required operational lifetime than for MASCOT on HAYABUSA2, and different conditions on the target body such as an extremely low gravity due to its small size of Ø_[Didymoon] ~ 150m.

Pairs of Asteroids Probably of a Common Origin

NASA Astrophysics Data System (ADS)

Vokrouhlický, David; Nesvorný, David

2008-07-01

We report the first observational evidence for pairs of main-belt asteroids with bodies in each pair having nearly identical orbits. The existence of ~60 pairs identified here cannot be reconciled with random fluctuations of the asteroid orbit density and rather suggests a common origin of the paired objects. We propose that the identified pairs formed by (i) collisional disruptions of km-sized and larger parent asteroids, (ii) Yarkovsky-O'Keefe-Radzievski-Paddack (YORP)-induced spin-up and rotational fission of fast-rotating objects, and/or (iii) splitting of unstable asteroid binaries. In case (i), the pairs would be parts of compact collisional families with many km- and sub-km-size members that should be found by future asteroid surveys. Our dynamical analysis suggests that most identified pairs formed within the past lsim1 Myr, in several cases even much more recently. For example, paired asteroids (6070) Rheinland and (54827) 2001 NQ8 probably separated from their common ancestor only 16.5-19 kyr ago. Given their putatively very recent formation, the identified objects are prime candidates for astronomical observations. The title paraphrases that of Hirayama's 1918 paper "Groups of asteroids probably of a common origin," where the first evidence was given for groups of asteroid fragments produced by disruptive collisions.

Iao: The New Adaptive Optics Visible Imaging and Photometric System for AEOS

DTIC Science & Technology

2008-09-01

observations of binary stars, asteroids and planets such as Mercury and Mars [2,3,4]. The Visible Imager is also used to take time resolved photometry ...role it takes high spatial resolution imagery of resolved targets. These targets are primarily low Earth orbiting satellites acquired for the...albedo pattern: Comparing the AEOS and TES data sets [5] D.T. Hall et al. 2007, Journal of Spacecraft and Rockets, 44, 910-919, Time - Resolved I-Band

Effects of YORP-induced rotational fission on the small size end of the Main Belt asteroid size distribution

NASA Astrophysics Data System (ADS)

Rossi, Alessandro; Jacobson, S.; Marzari, F.; Scheeres, D.; Davis, D. R.

2013-10-01

From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis has strong repercussions for the small size end of the Main Belt asteroid size frequency distribution. These results are consistent with observed asteroid population statistics. The foundation of this model is the asteroid rotation model of Marzari et al. (2011), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis (i.e. when the rotation rate exceeds a critical value, erosion and binary formation occur). The YORP effect timescale for large asteroids with diameters D > ~6 km is longer than the collision timescale in the Main Belt, thus the frequency of large asteroids is determined by a collisional equilibrium (e.g. Bottke 2005), but for small asteroids with diameters D < ~6 km, the asteroid population evolution model confirms that YORP-induced rotational fission destroys small asteroids more frequently than collisions. Therefore, the frequency of these small asteroids is determined by an equilibrium between the creation of new asteroids out of the impact debris of larger asteroids and the destruction of these asteroids by YORP-induced rotational fission. By introducing a new source of destruction that varies strongly with size, YORP-induced rotational fission alters the slope of the size frequency distribution. Using the outputs of the asteroid population evolution model and a 1-D collision evolution model, we can generate this new size frequency distribution and it matches the change in slope observed by the SKADS survey (Gladman 2009). This agreement is achieved with both an accretional power-law or a truncated “Asteroids were Born Big” size frequency distribution (Weidenschilling 2010, Morbidelli 2009).

The Nucleus of Active Asteroid 311P/(2013 P5) PANSTARRS

NASA Astrophysics Data System (ADS)

Jewitt, David; Weaver, Harold; Mutchler, Max; Li, Jing; Agarwal, Jessica; Larson, Stephen

2018-06-01

The unique inner-belt asteroid 311P/PANSTARRS (formerly P/2013 P5) is notable for its sporadic, comet-like ejection of dust in nine distinct epochs spread over ∼250 days in 2013. This curious behavior has been interpreted as the product of localized, equatorward landsliding from the surface of an asteroid rotating at the brink of instability. We obtained new Hubble Space Telescope observations to directly measure the nucleus and to search for evidence of its rapid rotation. We find a nucleus with mid-light absolute magnitude H V = 19.14 ± 0.02, corresponding to an equal-area circle with radius 190 ± 30 m (assuming geometric albedo p V = 0.29). However, instead of providing photometric evidence for rapid nucleus rotation, our data set a lower limit to the light-curve period, P ≥ 5.4 hr. The dominant feature of the light curve is a V-shaped minimum, ∼0.3 mag deep, which is suggestive of an eclipsing binary. Under this interpretation, the time-series data are consistent with a secondary/primary mass ratio, m s /m p ∼ 1:6, a ratio of separation/primary radius, r/r p ∼ 4 and an orbit period ∼0.8 days. These properties lie within the range of other asteroid binaries that are thought to be formed by rotational breakup. While the light-curve period is long, centripetal dust ejection is still possible if one or both components rotate rapidly (≲2 hr) and have small light-curve variation because of azimuthal symmetry. Indeed, radar observations of asteroids in critical rotation reveal “muffin-shaped” morphologies, which are closely azimuthally symmetric and which show minimal light curves. Our data are consistent with 311P being a close binary in which one or both components rotates near the centripetal limit. The mass loss in 2013 suggests that breakup occurred recently and could even be on-going. A search for fragments that might have been recently ejected beyond the Hill sphere reveals none larger than effective radius r e ∼ 10 m.

Observations and Characterization of Binary Near-Earth Asteroid 65803 Didymos, the Target of the AIDA Mission

NASA Astrophysics Data System (ADS)

Naidu, S.; Benner, L.; Brozovic, M.; Ostro, S. J.; Nolan, M. C.; Margot, J. L.; Giorgini, J. D.; Magri, C.; Pravec, P.; Scheirich, P.; Scheeres, D. J.; Hirabayashi, M.

2016-12-01

Binary near-Earth asteroid 65803 Didymos is the target of the proposed Asteroid Impact and Deflection Assessment (AIDA) space mission. The mission consists of two spacecraft, the Demonstration for Autonomous Rendezvous Technology (DART) spacecraft that will impact the asteroid's satellite and the Asteroid Impact Mission (AIM) spacecraft that will observe the impact. We used radar observations obtained at Arecibo and Goldstone in 2003, and lightcurve data from Pravec et al. (2006) to model the shapes, sizes, and spin states of the components. The primary is top shaped and has an equatorial ridge similar to the one seen on 2000 DP107 (Naidu et al. 2015). A 300 m long flat region is also seen along the equator. The primary has an equivalent diameter of 780 m (+/- 10 %) and its extents along the principal axes are 826 m, 813 m, and 786 m (10% uncertainties). It has a spin period of 2.2600 +/- 0.0001 h. A grid search for the spin pole resulted in the best fit at ecliptic (longitude, latitude) = (296, +71) degrees (+/- 15 degrees). This estimate is consistent with the spin pole being aligned to the binary orbit normal at (310, -84) degrees. Dividing the primary mass of 5.24e11 kg (Fang & Margot 2012) by the model volume we estimate a bulk density of 2100 kg m-3 (+/- 30 %). We summed multiple radar runs to estimate the range and Doppler extents of the satellite. We estimated the motion in successive images and used a shift-and-sum technique to mitigate smearing due to translational motion. This boosted the SNRs and allowed us to obtain size and bandwidth estimates of the satellite. The visible range extent of the satellite is roughly 60-75 m at the 15 m resolution of the Arecibo images. Assuming that the true extent is twice the visible extent, we obtain a diameter estimate of 120-150 m. The bandwidth of the satellite suggests a spin period between 9-12 h that is consistent with the orbit period of 11.9 hours and with synchronous rotation.

A path to asteroid bulk densities: Simultaneous size and shape optimization from optical lightcurves and Keck disk-resolved data

NASA Astrophysics Data System (ADS)

Hanus, Josef; Viikinkoski, Matti; Marchis, Franck; Durech, Josef

2015-11-01

A reliable bulk density of an asteroid can be determined from the knowledge of its volume and mass. This quantity provides hints on the internal structure of asteroids and their origin. We compute volume of several asteroids by scaling sizes of their 3D shape models to fit the disk-resolved images, which are available in the Keck Observatory Archive (KOA) and the Virtual Observatory Binary Asteroids Database (VOBAD). The size of an asteroid is optimized together with its shape by the All-Data Asteroid Modelling inversion algorithm (ADAM, Viikinkoski et al., 2015, A&A, 576, A8), while the spin state of the original convex shape model from the DAMIT database is only used as an initial guess for the modeling. Updated sets of optical lightcurves are usually employed. Thereafter, we combine obtained volume with mass estimates available in the literature and derive bulk densities for tens of asteroids with a typical accuracy of 20-50%.On top of that, we also provide a list of asteroids, for which (i) there are already mass estimates with reported uncertainties better than 20% or their masses will be most likely determined in the future from Gaia astrometric observations, and (ii) their 3D shape models are currently unknown. Additional optical lightcurves are necessary in order to determine convex shape models of these asteroids. Our web page (https://asteroid-obs.oca.eu/foswiki/bin/view/Main/Photometry) contains additional information about this observation campaign.

Pluto-Charon: a test of the astrometric approach for finding asteroid satellites

NASA Astrophysics Data System (ADS)

Kikwaya, J.-B.; Thuillot, W.; Berthier, J.

2003-05-01

The astrometric method to find asteroid satellites is based on the search for the reflex effect on the primary object due to the orbital motion of a possible satellite (Monet & Monet 1998, Kikwaya et al. 2002). As reported by Kikwaya et al. (2003), the astrometric signature of a satellite of 146 Lucina may reach several mas. Spectral analysis might then detect the signal under good conditions of signal/noise ratio, with high quality astrometric measurements and large coverage by different sites of observation. However, the astrometric method cannot be applied to any binary system of asteroids. It depends strongly on the mass ratio of the two bodies and the distance between them (Kikwaya et al. 2002). Pluto-Charon provides a good test of this method. Previous works based on direct imaging of Charon show that its period is 6.357 days and the mass ratio is 0.122 (Wasserman et al. 2000), putting this system into the range that can be observed by our method. Using archived photographic observations (1914-1995) and CCD observations from US Naval Observatory, Flagstaff station (1995-1998), Bordeaux observatory (1996-1997) and Mc Donald Observatory (1997), we are analyzing the position of Pluto to see if its wobble effect due to Charon (amplitude around 95 mas) can be detected and if the orbital period of Charon can be recovered through a spectral analysis. If successful, this will reinforce the ability of our astrometric method to find asteroid satellites.

New Radar Images of Asteroid 2014 JO25

NASA Image and Video Library

2017-05-09

This frame from a movie of asteroid 2014 JO25 was generated using radar data collected by NASA 230-foot-wide 70-meter Deep Space Network antenna at Goldstone, California on April 19, 2017. When the observations began 2014 JO25 was 1.53 million miles (2.47 million kilometers) from Earth. By the time the observations concluded, the asteroid was 1.61 million miles (2.59 million kilometers) away. The asteroid has a contact binary structure -- two lobes connected by a neck-like region. The largest of the asteroid's two lobes is estimated to be 2,000 feet (610 meters) across. Asteroid 2014 JO25 approached to within 1.1 million miles (1.8 million kilometers) of Earth on April 19. There are no future flybys by 2014 JO25 as close as this one for more than 400 years. The resolution of the radar images is about 25 feet (7.5 meters) per pixel. 154 images were used to create a movie. The movie can be seen at. https://photojournal.jpl.nasa.gov/catalog/PIA21597

Sizes, Shapes, and Satellites of Asteroids from Occultations

NASA Astrophysics Data System (ADS)

Waring Dunham, David; Herald, David Russell; Preston, Steve; Timerson, Bradley; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

2015-08-01

For 40 years, the sizes and shapes of dozens of asteroids have been determined from observations of asteroidal occultations. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.The release of the Hipparcos and Tycho catalogs in 1997, from ESA’s Hipparcos space mission, revolutionized asteroidal occultation work, increasing the routine accuracy of the predictions and the annual number of observations by an order of magnitude. IOTA developed an efficient procedure for predicting the occultations using a combination of new star catalogs, based on Hipparcos and new star catalogs, generated mainly at the U. S. Naval Observatory (USNO), and new observations of asteroids relative to the improved astrometric nets mainly from USNO’s Flagstaff Astrometric Scanning Transit Telescope and JPL’s Table Mountain Observatory. In addition, many IOTA observers now use inexpensive low-light-level video cameras and specially built GPS video time inserters to accurately time the events. This automation has also allowed some observers to deploy multiple remote video stations across occultation paths. Then, one observer can record several “chords” across the asteroid. The cameras are sensitive enough that easily-hidden telescopes, many of which can be packed in standard air travel suitcases, can be used for many of the predicted occultations. IOTA’s network of regional coordinators collect and reduce the observations, which are deposited annually in Asteroid Occultations V12.0. EAR-A-3-RDR-OCCULTATIONS-V12.0. NASA Planetary Data System, 2014, where they are available to researchers worldwide.

Dynamics of Populations of Planetary Systems (IAU C197)

NASA Astrophysics Data System (ADS)

Knezevic, Zoran; Milani, Andrea

2005-05-01

1. Resonances and stability of extra-solar planetary systems C. Beaugé, N. Callegari, S. Ferraz-Mello and T. A. Michtchenko; 2. Formation, migration, and stability of extrasolar planetary systems Fred C. Adams; 3. Dynamical evolution of extrasolar planetary systems Ji-Lin Zhou and Yi-Sui Sun; 4. Dynamics of planetesimals: the role of two-body relaxation Eiichiro Kokubo; 5. Fitting orbits Andrzej J. Maciejewski, Krzysztof Gozdziewski and Szymon Kozlowski; 6. The secular planetary three body problem revisited Jacques Henrard and Anne-Sophie Libert; 7. Dynamics of extrasolar systems at the 5/2 resonance: application to 47 UMa Dionyssia Psychoyos and John D. Hadjidemetriou; 8. Our solar system as model for exosolar planetary systems Rudolf Dvorak, Áron Süli and Florian Freistetter; 9. Planetary motion in double stars: the influence of the secondary Elke Pilat-Lohinger; 10. Planetary orbits in double stars: influence of the binary's orbital eccentricity Daniel Benest and Robert Gonczi; 11. Astrometric observations of 51 Peg and Gliese 623 at Pulkovo observatory with 65 cm refractor N. A. Shakht; 12. Observations of 61 Cyg at Pulkovo Denis L. Gorshanov, N. A. Shakht, A. A. Kisselev and E. V. Poliakow; 13. Formation of the solar system by instability Evgeny Griv and Michael Gedalin; 14. Behaviour of a two-planetary system on a cosmogonic time-scale Konstantin V. Kholshevnikov and Eduard D. Kuznetsov; 15. Boundaries of the habitable zone: unifying dynamics, astrophysics, and astrobiology Milan M. Cirkovic; 16. Asteroid proper elements: recent computational progress Fernando Roig and Cristian Beaugé; 17. Asteroid family classification from very large catalogues Anne Lemaitre; 18. Non-gravitational perturbations and evolution of the asteroid main belt David Vokrouhlicky, M. Broz and W. F. Bottke, D. Nesvorny and A. Morbidelli; 19. Diffusion in the asteroid belt Harry Varvoglis; 20. Accurate model for the Yarkovsky effect David Capek and David Vokrouhlicky; 21. The population of asteroids in the 2:1 mean motion resonance with Jupiter revised Miroslav Broz, D. Vokrouhlicky, F. Roig, D. Nesvorny, W. F. Bottke and A. Morbidelli; 22. On the reliability of computation of maximum Lyapunov Characteristic Exponents for asteroids Zoran Knezevic and Slobodan Ninkovic; 23. Nekhoroshev stability estimates for different models of the Trojan asteroids Christos Efthymiopoulos; 24. The role of the resonant 'stickiness' in the dynamical evolution of Jupiter family comets A. Alvarez-Canda and F. Roig; 25. Regimes of stability and scaling relations for the removal time in the asteroid belt: a simple kinetic model and numerical tests Mihailo Cubrovic; 26. Virtual asteroids and virtual impactors Andrea Milani; 27. Asteroid population models Alessandro Morbidelli; 28. Linking Very Large Telescope asteroid observations M. Granvik, K. Muinonen, J. Virtanen, M. Delbó, L. Saba, G. De Sanctis, R. Morbidelli, A. Cellino and E. Tedesco; 29. Collision orbits and phase transition for 2004 AS1 at discovery Jenni Virtanen, K. Muinonen, M. Granvik and T. Laakso; 30. The size of collision solutions in orbital elements space G. B. Valsecchi, A. Rossi, A. Milani and S. R. Chesley; 31. Very short arc orbit determination: the case of asteroid 2004 FU162 Steven R. Chesley; 32. Nonlinear impact monitoring: 2-dimensional sampling Giacomo Tommei; 33. Searching for gravity assisted trajectories to accessible near-Earth asteroids Stefan Berinde; 34. KLENOT - Near Earth and other unusual objects observations Michal Kocer, Jana Tichá and M. Tichy; 35. Transport of comets to the Inner Solar System Hans Rickman; 36. Nongravitational Accelerations on Comets Steven R. Chesley and Donald K. Yeomans; 37. Interaction of planetesimals with the giant planets and the shaping of the trans-Neptunian belt Harold F. Levison and Alessandro Morbidelli; 38. Transport of comets to the outer p

The Asteroid Impact and Deflection Assessment (AIDA) mission: Science Proximity Operations

NASA Astrophysics Data System (ADS)

Barnouin, Olivier; Bellerose, Julie; Carnelli, Ian; Carrol, Kieran; Ciarletti, Valérie; Cheng, Andrew F.; Galvez, Andres; Green, Simon F.; Grieger, Bjorn; Hirabayashi, Masatoshi; Herique, Alain; Kueppers, Michael; Minton, David A.; Mellab, Karim; Michel, Patrick; Rivkin, Andrew S.; Rosenblatt, Pascal; Tortora, Paolo; Ulamec, Stephan; Vincent, Jean-Baptiste; Zannoni, Marco

2016-10-01

The moon of the near-Earth binary asteroid 65803 Didymos is the target of the Asteroid Impact and Deflection Assessment (AIDA) mission. This mission is a joint effort between NASA and ESA to investigate the effectiveness of a kinetic impactor in deflecting an asteroid. The mission is composed of two components: the NASA-led Double Asteroid Redirect Test (DART) that will impact Didymos' moon (henceforth Didymos B), and the ESA-led Asteroid Impact Mission (AIM) that will survey the Didymos system. Both will undertake proximity operations to characterize the physical and dynamical properties of the Didymos system that are of maximum importance in the joint AIDA mission to understand the factors at play when assessing the mometum transfer that follows DART's impact into Didymos B. Using much of ESA's Rosetta experience, the AIM mission will undertake proximity operations both before and after DART's impact. AIM's chracterization includes measuring the precise orbital configuration, masses, internal properties, surface geology and regolith properties of the primary and secondary, using visible and thermal imaging, radar measurements and radio science data. AIM will also release the small MASCOT-2 lander, as well as a suite of a CubeSats to help achieve these objectives. DART proximity observations include two phases of imaging. The first makes use of a suite of long range images that will add light curve data to what will be collected from Earth. These data will refine the orbit period of Didymos B, and provide constraints for modeling the shape of both Didymos A and B. The second phase begins just under an hour before impact when resolved imaging of the Didymos system provides further shape model constraints for the visble parts of both Didymos A and B, some possible constraints on the mass of Didymos B and key geological information of both objects and the impact site. In this presentation, we will summarize the proximity operations undertaken by both DART and AIM needed to achieve the scientific objectives of the AIDA mission using a broad suite of scientific experiments.

Asteroid 1999 JD6

NASA Image and Video Library

2015-07-31

This collage of radar images of near-Earth asteroid 1999 JD6 was collected by NASA scientists on July 25, 2015. The images show the rotation of the asteroid, which made its closest approach on July 24 at 9:55 p.m. PDT (12:55 a.m. EDT on July 25) at a distance of about 4.5 million miles (7.2 million kilometers, or about 19 times the distance from Earth to the moon). The asteroid appears to be a contact binary -- an asteroid with two lobes that are stuck together. These views, which are radar echoes, were obtained by pairing NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California, with the 330-foot (100-meter) National Science Foundation Green Bank Telescope in West Virginia. Using this approach, the Goldstone antenna beams a radar signal at an asteroid and Green Bank receives the reflections. The technique, referred to as a bistatic observation, dramatically improves the amount of detail that can be seen in radar images. The new views obtained with the technique show features as small as about 25 feet (7.5 meters) wide. The images show the asteroid is highly elongated, with a length of approximately 1.2 miles (2 kilometers) on its long axis. http://photojournal.jpl.nasa.gov/catalog/PIA19647

Geostability of Didymos, the target of the AIDA mission

NASA Astrophysics Data System (ADS)

Zhang, Yun; Richardson, Derek C.; Barnouin, Olivier; Maurel, Clara; Michel, Patrick; Schwartz, Stephen R.; Ballouz, Ronald; Benner, Lance A. M.; Naidu, Shantanu P.

2016-10-01

As the target of the proposed Asteroid Impact & Deflection Assessment (AIDA) mission [1, 2], the near-Earth binary asteroid 65803 Didymos represents a special class of binary asteroid, those whose primaries are at risk of rotational disruption [3]. To support the AIDA mission and gain a better understanding of these binary systems, we investigate the structural stability and dynamic behavior of the Didymos primary and the orbital stability of the secondary using a Soft-Sphere Discrete Element Method (SSDEM) [4]. The primary and the secondary are modeled as granular assemblies. In the first step of this study, the primary is artificially spun up to the current spin period of 2.26 h using a quasi-static spin-up procedure without considering the secondary [5]. The effects of arrangement and size distribution of constituent particles, bulk density, spin-up path, interparticle friction, and cohesion strength on the dynamic behavior of self-gravitating aggregates are numerically explored. The results show that the strength and stability of a spinning self-gravitating aggregate depend strongly on its internal configuration and material parameters, while its failure mode and mechanism are affected by its internal configuration and the cohesion strength. When cohesion is not included, the Didymos primary rubble-pile model can maintain its shape at the current observed spin rate within the uncertainty of the observed bulk density (< 2.7 g/cc) using material parameters with friction angle of ~30°, which most cohesionless sands can sustain. In the second step, the effect of the secondary on the stability of the primary is studied. The secondary can stably orbit the primary without including cohesion. The results show that the presence of the secondary will slightly reduce the stability of the primary. Our study provides some constraints on the possible physical properties of the Didymos primary.References: [1] Michel et al. 2016, ASR 57, 2529; [2] Cheng et al. 2016, P&SS 127, 27; [3] Olivier et al. 2015, DPS 47; [4] Schwartz et al. 2012, Granul. Matter 14, 363; [5] Zhang et al. 2016, in preparation.

Two cubesat mission to study the Didymos asteroid system

NASA Astrophysics Data System (ADS)

Wahlund, J.-E.; Vinterhav, E.; Trigo-Rodríguez, J. M.; Hallmann, M.; Barabash, S.; Ivchenko, N.

2015-10-01

Among the growing interest about asteroid impact hazard mitigation in our community the Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to use a kinetic impactor to demonstrate its capability as reliable deflection system [1]. As a part of the AIDA mission, we have proposed a set of two three-axis stabilized 3U CubeSats (with up to 5 science sensors) to simultaneously rendezvous at close range (<500m) with both the primary and the secondary component of the Didymos asteroid system. The CubeSats will be hosted on the ESA component of the AIDA mission, the monitoring satellite AIM (Asteroid Impact Mission). The CubeSats will characterise the magnetization, the main bulk chemical composition and presence of volatiles as well as do superresolution surface imaging of the Didymos components. The CubeSats will also support the plume characterisation resulting from the DART impact (Double Asteroid Redirection Test, a NASA component of the AIDA mission) at much closer range than the AIM main spacecraft, and provide imaging, composition, and temperature of the plume material. At end of the mission, the two CubeSats can optionally land on one of the asteroids for continued science operation. The science sensors consist of a dual fluxgate magnetometer (MAG), one miniaturized volatile composition analyser (VCA), a narrow angle camera (NAC) and a Video Emission Spectrometer (VES) with a diffraction grating for allowing a sequential chemical study of the emission spectra associated with the impact flare and the expanding plume. Consequently, the different envisioned instruments onboard the CubeSats can provide significant insight into the complex response of asteroid materials during impacts that has been theoretically studied using different techniques [2]. The two CubeSats will remain stowed in CubeSat dispensers aboard the main AIM spacecraft. They will be deployed and commissioned before the AIM impactor reaches the secondary and record the impact event from a closer vantage point than the main spacecraft. The two CubeSats are equipped with relative navigation systems capable of estimating the spacecraft position relative to the asteroids and propulsion system that allow them to operate close to the asteroid bodies. The two CubeSats will rely on mapping data relayed via the AIM main spacecraft but operate autonomously and individually based on schedules and navigation maps uploaded from ground. AIDA's target is the binary Apollo asteroid 65803 Didymos that is also catalogued as Potentially Hazardous Asteroid (PHA) because it experiences close approaches to Earth. Didymos' primary has a diameter of ˜800 meters and the secondary is ˜150 m across. Both bodies are separated about 1.1 km [3]. The rotation period and asymmetry of the secondary object is unknown, and it might be tidally locked to the larger primary body. At least the primary body is expected to be associated with ordinary chondrite material, consisting mostly of silicates, and metal, but the earlier made Xk classification suggested a rubble-pile type with large amount of volatile content. The secondary companion spectral class is unknown, but the total mass of the system suggests that the secondary companion could be of similar class. Detailed empirical information on the physical properties of the Didymos asteroid system, in particular the magnetic field, the (mineralogical) surface composition, the internal composition via the bulk density, the ages of surface units through crater counts and other morphological surface features is valuable in order to make progress in the asteroid field of science. Furthermore, the periodic effect of such a close dynamic system in the presence and temporal displacement of the surface regolith is EPSC Abstracts Vol. 10, EPSC2015-698, 2015 European Planetary Science Congress 2015 c Author(s) 2015 EPSC European Planetary Science Congress unknown, and could be followed using close-up video systems provided by the CubeSats. In conclusion, the proposed two CubeSats as part of the AIDA mission can therefore contribute significantly, since they can monitor the Didymos asteroid components at a very close range around hundred meters, and at the same time monitor in-situ an impact plume when it is created.

Formation of Kuiper-belt binaries through multiple chaotic scattering encounters with low-mass intruders

NASA Astrophysics Data System (ADS)

Astakhov, Sergey A.; Lee, Ernestine A.; Farrelly, David

2005-06-01

The discovery that many trans-Neptunian objects exist in pairs, or binaries, is proving invaluable for shedding light on the formation, evolution and structure of the outer Solar system. Based on recent systematic searches it has been estimated that up to 10 per cent of Kuiper-belt objects might be binaries. However, all examples discovered to date are unusual, as compared with near-Earth and main-belt asteroid binaries, for their mass ratios of the order of unity and their large, eccentric orbits. In this article we propose a common dynamical origin for these compositional and orbital properties based on four-body simulations in the Hill approximation. Our calculations suggest that binaries are produced through the following chain of events. Initially, long-lived quasi-bound binaries form by two bodies getting entangled in thin layers of dynamical chaos produced by solar tides within the Hill sphere. Next, energy transfer through gravitational scattering with a low-mass intruder nudges the binary into a nearby non-chaotic, stable zone of phase space. Finally, the binary hardens (loses energy) through a series of relatively gentle gravitational scattering encounters with further intruders. This produces binary orbits that are well fitted by Kepler ellipses. Dynamically, the overall process is strongly favoured if the original quasi-bound binary contains comparable masses. We propose a simplified model of chaotic scattering to explain these results. Our findings suggest that the observed preference for roughly equal-mass ratio binaries is probably a real effect; that is, it is not primarily due to an observational bias for widely separated, comparably bright objects. Nevertheless, we predict that a sizeable population of very unequal-mass Kuiper-belt binaries is probably awaiting discovery.

High-Resolution Bistatic Radar Imaging of Near-Earth Asteroids in 2015 using New Capabilities of Goldstone and Green Bank Telescopes

NASA Astrophysics Data System (ADS)

Naidu, S.; Benner, L.; Brozovic, M.; Giorgini, J. D.; Jao, J. S.; Lee, C. G.; Busch, M.; Ghigo, F. D.; Ford, A.; Kobelski, A.; Marshall, S.

2015-12-01

We present new results from bistatic Goldstone to Green Bank Telescope (GBT) high-resolution radar imaging of near-Earth asteroids (NEAs). Previously, most radar observations used either the 305-m Arecibo radar or the 70-m DSS-14 radar at Goldstone. Following the installation of new data-taking equipment at the GBT in late 2014, the number of bistatic Goldstone/GBT observations has increased substantially. Receiving Goldstone radar echoes at the 100-m GBT improves the signal-to-noise ratios (SNRs) two- to three-fold relative to monostatic reception at DSS-14. The higher SNRs allow us to obtain higher resolution images than is possible with DSS-14 both transmitting and receiving. Thus far in 2015, we have used the GBT receiver in combination with the 450 kW DSS-14 antenna and a new low-power 80kW transmitter on the 34-m DSS-13 antenna at the Goldstone complex to image five and two NEAs respectively. Asteroids 2005 YQ96, 2004 BL86, and 1994 AW1 are binary systems. 2011 UW158 has a spin period of 36 minutes that is unusually fast among asteroids its size (~500 m). 1999 JD6 is a deeply bifurcated double-lobed object. 2015 HM10 is an elongated 80 m asteroid with a spin period of 22 minutes. Our best images of these objects resolve the surface with resolutions of 3.75 m and reveal numerous features. Such images are useful to estimate the 3D shape, spin state, and other physical and dynamical properties of the objects. This knowledge is of particular interest for spacecraft mission planning, impact threat assessment, and resource utilization. Over the long term, such observations will help answer fundamental questions regarding the origin of the diversity in asteroid morphologies, the importance of spin-up mechanisms and collisional influences, the interior structure and thermal properties of asteroids, and the variety of dynamical states.

APPLICATION OF GAS DYNAMICAL FRICTION FOR PLANETESIMALS. II. EVOLUTION OF BINARY PLANETESIMALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grishin, Evgeni; Perets, Hagai B.

2016-04-01

One of the first stages of planet formation is the growth of small planetesimals and their accumulation into large planetesimals and planetary embryos. This early stage occurs long before the dispersal of most of the gas from the protoplanetary disk. At this stage gas–planetesimal interactions play a key role in the dynamical evolution of single intermediate-mass planetesimals (m{sub p} ∼ 10{sup 21}–10{sup 25} g) through gas dynamical friction (GDF). A significant fraction of all solar system planetesimals (asteroids and Kuiper-belt objects) are known to be binary planetesimals (BPs). Here, we explore the effects of GDF on the evolution of BPs embedded inmore » a gaseous disk using an N-body code with a fiducial external force accounting for GDF. We find that GDF can induce binary mergers on timescales shorter than the disk lifetime for masses above m{sub p} ≳ 10{sup 22} g at 1 au, independent of the binary initial separation and eccentricity. Such mergers can affect the structure of merger-formed planetesimals, and the GDF-induced binary inspiral can play a role in the evolution of the planetesimal disk. In addition, binaries on eccentric orbits around the star may evolve in the supersonic regime, where the torque reverses and the binary expands, which would enhance the cross section for planetesimal encounters with the binary. Highly inclined binaries with small mass ratios, evolve due to the combined effects of Kozai–Lidov (KL) cycles with GDF which lead to chaotic evolution. Prograde binaries go through semi-regular KL evolution, while retrograde binaries frequently flip their inclination and ∼50% of them are destroyed.« less

Shape, size and multiplicity of main-belt asteroids I. Keck Adaptive Optics survey.

PubMed

Marchis, F; Kaasalainen, M; Hom, E F Y; Berthier, J; Enriquez, J; Hestroffer, D; Le Mignant, D; de Pater, I

2006-11-01

This paper presents results from a high spatial resolution survey of 33 main-belt asteroids with diameters >40 km using the Keck II Adaptive Optics (AO) facility. Five of these (45 Eugenia, 87 Sylvia, 107 Camilla, 121 Hermione, 130 Elektra) were confirmed to have satellite. Assuming the same albedo as the primary, these moonlets are relatively small (∼5% of the primary size) suggesting that they are fragments captured after a disruptive collision of a parent body or captured ejecta due to an impact. For each asteroid, we have estimated the minimum size of a moonlet that can positively detected within the Hill sphere of the system by estimating and modeling a 2-σ detection profile: in average on the data set, a moonlet located at 2/100 × R(Hill) (1/4 × R(Hill)) with a diameter larger than 6 km (4 km) would have been unambiguously seen. The apparent size and shape of each asteroid was estimated after deconvolution using a new algorithm called AIDA. The mean diameter for the majority of asteroids is in good agreement with IRAS radiometric measurements, though for asteroids with a D < 200 km, it is underestimated on average by 6-8%. Most asteroids had a size ratio that was very close to those determined by lightcurve measurements. One observation of 104 Klymene suggests it has a bifurcated shape. The bi-lobed shape of 121 Hermione described in Marchis et al. [Marchis, F., Hestroffer, D., Descamps, P., Berthier, J., Laver, C., de Pater, I., 2005c. Icarus 178, 450-464] was confirmed after deconvolution. The ratio of contact binaries in our survey, which is limited to asteroids larger than 40 km, is surprisingly high (∼6%), suggesting that a non-single configuration is common in the main-belt. Several asteroids have been analyzed with lightcurve inversions. We compared lightcurve inversion models for plane-of-sky predictions with the observed images (9 Metis, 52 Europa, 87 Sylvia, 130 Elektra, 192 Nausikaa, and 423 Diotima, 511 Davida). The AO images allowed us to determine a unique photometric mirror pole solution, which is normally ambiguous for asteroids moving close to the plane of the ecliptic (e.g., 192 Nausikaa and 52 Europa). The photometric inversion models agree well with the AO images, thus confirming the validity of both the lightcurve inversion method and the AO image reduction technique.

Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2011 June - September

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2012-01-01

Lightcurves for 28 asteroids were obtained at the Palmer Divide Observatory (PDO) from 2011 June to September: 903 Nealley, 1103 Sequoia, 2052 Tamriko, 2083 Smither, 2150 Nyctimene, 2272 Montezuma, 2306 Bauschinger, 4125 Lew Allen, 5571 Lesliegreen, (7660) 1993 VM1, 7933 Magritte, (16256) 2000 JM2, (16959) 1998 QE17, (17822) 1998 FM135, (18890) 2000 EV26, (27568) 2000 PT6, (31898) 2000 GC1, (32953) 1996 GF19, (32928) 1995 QZ, (33356) 1999 AM3, (35055) 1984 RB, (54234) 2000 JD16, (60365) 2000 AT109, (62117) 2000 RC102, (67404) 2000 PG26, 70030 Margaretmiller, (140428) 2001 TT94, (282081) 2000 NG. Observations of 70030 Margaretmiller indicate that the asteroid is a probable binary with a secondary period being detected but no mutual events.

Asteroid masses with Gaia from ground and space-based observations

NASA Astrophysics Data System (ADS)

Ivantsov, Anatoliy; Hestroffer, Daniel; Thuillot, William; Bancelin, David

2013-04-01

Determination of masses of large asteroids is one of the expected scientific outputs from the future Gaia astrometric space mission. With the exception of binary asteroids or fly-by with a space probe, the error in mass determination depends on the size of perturbation effect produced on the motion of small asteroids. Considering the 5 years nominal duration of the Gaia mission, there will be mutual close encounters between asteroids occurring either close to the beginning or to the end of the mission. So that the maximum of deflection angle pertained to the perturbation maxima will not be observed directly by Gaia. Since astrometric data of the perturbed body before and after the encounter are mandatory to derive a perturber mass, the precision of mass determinations based solely on the Gaia observations will deteriorate in such cases. The possible way out consists in acquiring ground-based observations of high astrometric precision in time either before or after the Gaia operations, as it was suggested in [1]. By adding such data, it is expected to increase the number of derived asteroids masses [2]. This paper updates earlier predictions of encounters of large asteroids with smaller ones, e.g. [3], in terms of newly discovered asteroids and available ground-based observations. The method used consists in the computation of the offsets in right ascension and declination between the unperturbed and perturbed solutions fitted to the available observations for each small (perturbed) asteroid. For the purpose of decreasing CPU time, a special filter was applied based on the solution of the two-body problem and systematical search for close encounters, e.g. less than 0.1 A.U., of all known asteroids with the large (perturber) ones. The obtained list of asteroids-candidates was used as the input file for the mentioned above accurate calculations. Such a procedure was used for a few asteroids in [2]. The maximum visible offset corresponds to the dates when the complementary ground-based observations will be useful. [1] Hestroffer, D., Thuillot, W., Mouret, S., Colas, F., Tanga, P., Mignard, F., Delbo, M., Carry, B.: Ground-based observations of solar system bodies in complement to Gaia, SF2A-2008: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics, 30 June - 4 July 2008, Paris, France, 2008. [2] Mouret, S., Hestroffer, D., and Mignard, F.: Asteroid masses and Gaia, Astronomy and Astrophysics, Vol. 472, pp. 1017-1027, 2007. [3] Mouret, S.: Investigations on the dynamics of minor planets with GAIA: orbits, masses and fundamental physics, PhD thesis, Paris Observatory, 2007. [4] Hilton, J.L., Seidelmann, P.K., and Middour, J.: Prospects for determining asteroid masses, Astronomical Journal, Vol. 112, pp. 2319-2329, 1996.

Radar Movie of Asteroid 1999 JD6

NASA Image and Video Library

2015-07-31

This frame from a movie made from radar images of asteroid 1999 JD6 was collected by NASA scientists on July 25, 2015. The images show the rotation of the asteroid, which made its closest approach on July 24 at 9:55 p.m. PDT (12:55 a.m. EDT on July 25) at a distance of about 4.5 million miles (7.2 million kilometers, or about 19 times the distance from Earth to the moon). The asteroid appears to be a contact binary -- an asteroid with two lobes that are stuck together. The radar images show the asteroid is highly elongated, with a length of approximately 1.2 miles (2 kilometers) on its long axis. These images are radar echoes, which are more like a sonogram than a photograph. The views were obtained by pairing NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California, with the 330-foot (100-meter) National Science Foundation Green Bank Telescope in West Virginia. Using this approach, the Goldstone antenna beams a radar signal at an asteroid and Green Bank receives the reflections. The technique, referred to as a bistatic observation, dramatically improves the amount of detail that can be seen in radar images. The new views obtained with the technique show features as small as about 25 feet (7.5 meters) wide. http://photojournal.jpl.nasa.gov/catalog/PIA19646

Re-accumulation of Asteroids to Equilibrium Figures

NASA Astrophysics Data System (ADS)

Hestroffer, D.; Tanga, P.; Richardson, D. C.; Berthier, J.; Cellino, A.; Durech, J.; Michel, P.

2008-09-01

Since their formation, asteroids since their formation have experienced little physical, geological or thermal evolution. Like comets they are thought to be among the most pristine remnants of the early solar system. One physical process, however, has played a major role since the ancient times: collisions. Dynamical families were produced by catastrophic collisions involving large enough energy to break the parent body. Other lines of evidence suggest that catastrophic collisions can also produce rubble-piles, i.e., loosely bound of post-collisional aggregates that re-accumulate to form a single body, and are kept together by gravity. The main objective of this work is to understand if—and under what conditions—Jacobi ellipsoids or other equilibrium figures can be obtained naturally by this way. This is done by performing numerical experiments simulating the re-accumulation process, and by performing high-angular resolution observations in order to better constrain the shape and density of the targets. It is shown that the outcomes of reaccumulation events tend to produce a rather narrow variety of possible shapes, and in some cases also binary systems.

Additional spectra of asteroid 1996 FG3, backup target of the ESA MarcoPolo-R mission

NASA Astrophysics Data System (ADS)

de León, J.; Lorenzi, V.; Alí-Lagoa, V.; Licandro, J.; Pinilla-Alonso, N.; Campins, H.

2013-08-01

Context. Near-Earth binary asteroid (175706) 1996 FG3 is the current backup target of the ESA MarcoPolo-R mission, selected for the study phase of ESA M3 missions. It is a primitive (C-type) asteroid that shows significant variation in its visible and near-infrared spectra. Aims: Here we present new visible and near-infrared spectra of 1996 FG3. We compare our new data with other published spectra, analysing the variation in the spectral slope. The asteroid will not be observable again over the next three years at least. Methods: We obtained visible and near-infrared spectra using DOLORES and NICS instruments, respectively, at the Telescopio Nazionale Galileo (TNG), a 3.6 m telescope located at El Roque de los Muchachos Observatory in La Palma, Spain. To compare with other published spectra of the asteroid, we computed the spectral slope S', and studied any plausible correlation of this quantity with the phase angle (α). Results: In the case of visible spectra, we find a variation in spectral slope of ΔS' = 0.15 ± 0.10%/103 Å/° for 3°<α< 18°, which is in good agreement with the values found in the literature for the phase reddening effect. In the case of the near-infrared, there seems to be a trend between the reddening of the spectra and the phase angle, excluding one point. We find a variation in the slope of ΔS' = 0.04 ± 0.08%/103 Å/° for 6° < α < 51°. Our computed variation in S' is in good agreement with the only two values found in the literature for the phase reddening in the near-infrared. Conclusions: The variation in the spectral slope of asteroid 1996 FG3 shows a trend with the phase angle at the time of the observations, both in the visible and the near-infrared. It is worth noting that, to fully explain this spectral variability we should take into account other factors, like the position of the secondary component of the binary asteroid 1999 FG3 with respect to the primary, or the spin axis orientation at the time of the observations. More data are necessary for an analysis of this kind.

Tidal torques on infrequently colliding particle disks in binary systems and the truncation of the asteroid belt

NASA Technical Reports Server (NTRS)

Franklin, F. A.; Lecar, M.; Lin, D. N. C.; Papaloizou, J.

1980-01-01

Conditions leading to the truncation, at the 2:1 resonance, of a disk of infrequently colliding particles surrounding the primary of a binary system are studied numerically and analytically. Attention is given to the case in which the mass ratio, q, is sufficiently small (less than about 0.1) and the radius of the disk centered on the primary allowably larger, so that first-order orbit-orbit resonances between ring material and the secondary can lie within it. Collisions are found to be less frequent than q to the -2/3 power orbital periods (the period of the forced eccentricity at the 2:1 resonance), and truncation occurs and Kirkwood gaps are produced only if the particle eccentricity is less than some critical value, estimated to be of order q to the 5/9 power, or approximately 0.02 for the sun-Jupiter case having q equal to 10 to the -3rd power.

Tidal evolution of close binary asteroid systems

NASA Astrophysics Data System (ADS)

Taylor, Patrick A.; Margot, Jean-Luc

2010-12-01

We provide a generalized discussion of tidal evolution to arbitrary order in the expansion of the gravitational potential between two spherical bodies of any mass ratio. To accurately reproduce the tidal evolution of a system at separations less than 5 times the radius of the larger primary component, the tidal potential due to the presence of a smaller secondary component is expanded in terms of Legendre polynomials to arbitrary order rather than truncated at leading order as is typically done in studies of well-separated system like the Earth and Moon. The equations of tidal evolution including tidal torques, the changes in spin rates of the components, and the change in semimajor axis (orbital separation) are then derived for binary asteroid systems with circular and equatorial mutual orbits. Accounting for higher-order terms in the tidal potential serves to speed up the tidal evolution of the system leading to underestimates in the time rates of change of the spin rates, semimajor axis, and mean motion in the mutual orbit if such corrections are ignored. Special attention is given to the effect of close orbits on the calculation of material properties of the components, in terms of the rigidity and tidal dissipation function, based on the tidal evolution of the system. It is found that accurate determinations of the physical parameters of the system, e.g., densities, sizes, and current separation, are typically more important than accounting for higher-order terms in the potential when calculating material properties. In the scope of the long-term tidal evolution of the semimajor axis and the component spin rates, correcting for close orbits is a small effect, but for an instantaneous rate of change in spin rate, semimajor axis, or mean motion, the close-orbit correction can be on the order of tens of percent. This work has possible implications for the determination of the Roche limit and for spin-state alteration during close flybys.

Constraints on the perturbed mutual motion in Didymos due to impact-induced deformation of its primary after the DART impact

NASA Astrophysics Data System (ADS)

Hirabayashi, M.; Schwartz, S. R.; Yu, Y.; Davis, A. B.; Chesley, S. R.; Fahnestock, E.; Michel, P.; Richardson, D. C.; Naidu, S.; Scheeres, D. J.; Cheng, A. F.; Rivkin, A.; Benner, L.

2017-12-01

(65803) Didymos is a binary near-Earth asteroid that consists of a top-shaped primary body rotating at a spin period of 2.26 hr and a secondary body orbiting around it at an orbital period of 11.92 hr. This asteroid is the target of the proposed NASA Double Asteroid Redirection Test (DART), which is part of the Asteroid Impact & Deflection Assessment (AIDA) mission concept. The goal of DART is to impact the secondary with the spacecraft and measure the momentum transfer by observing the perturbation of the orbital period of the system after the impact. Achieving this goal requires careful accounting for physical uncertainties that prevent accurate measurement of the momentum transfer. Here, we examine a scenario that might affect the momentum transfer measurement and a possible solution to avoiding issues due to this scenario. The primary's spin period is close to the spin barrier of rubble-pile asteroids, i.e., 2.3 hr. Also, some particles ejected from the secondary due to the DART impact may reach the primary and induce landslides or internal deformation of the primary, changing the gravity field. We have developed a numerical simulation technique for investigating how the mutual orbit of the system varies due to symmetric shape deformation of the primary along its spin axis after the DART impact. We find that if the deformation process occurs, the orbital period can change significantly, depending on the magnitude of the shape deformation. The mission currently plans a nearly head-on collision of the DART impactor with the secondary, making the orbital period of the system shorter. Our simulations show that since the deformation process always causes the primary to become more oblate, it shortens the orbital period as well. We also propose precise measurement of the primary's spin state to determine the deformation of the primary. This relies on the fact that any deformation process changes the spin state of the primary consistent with angular momentum conservation. Further investigations on this problem may improve the accuracy of the momentum transfer measurement for the AIDA mission.

The Observing Working Group for the Asteroid Impact & Delfection Assessment (AIDA) Mission

NASA Astrophysics Data System (ADS)

Osip, David J.; Rivkin, Andrew S.; Pravec, Petr; Moskovitz, Nicholas; Thirouin, Audrey; Scheirich, Peter; Oszkiewicz, Dagmara Anna; Richardson, Derek C.; Polishook, David; Ryan, William; Thomas, Cristina; Busch, Michael W.; Cheng, Andrew F.; Michel, Patrick; AIDA Observing Working Group

2016-10-01

The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint ESA-NASA mission concept currently under study. AIDA has two components: the Double Asteroid Redirect Test (DART) is the US component designed to demonstrate a kinetic impactor, while the Asteroid Impact Mission (AIM) spacecraft is on station to do a thorough pre- and post-impact survey of the Didymos system.Members of the DART and AIM Investigation teams have been organized into several joint and independent working groups. While there is overlap in subject matter and membership between the groups, we focus here on the activities of the Observing Working Group.The first work by the group was undertaken during the spring of 2015, before DART entered Phase A. During this period Didymos made an apparition reaching roughly V ~ 20.5 in brightness, and our top priority was constraining which of two very different pole positions for the Didymos system was correct. Several telescopes in the 2-4-m aperture range around the world attempted observations. An observed mutual event allowed the one pole position to be ruled out. Didymos is now thought to be a low-obliquity, retrograde rotator, similar to many other asteroid binary systems and consistent with expectations from a YORP-driven origin for the satellite.We have begun planning for the 2017 apparition, occurring in the first half of the year. Didymos will be ~20% brighter at opposition than the 2015 apparition. Scaling from the successful observations with the 4.3-m Lowell Discovery Channel Telescope indicates that we will need telescopes at least 4 m (or larger, for some of the tasks, or at times longer before or after the opposition) in primary diameter for the advanced characterization in 2017.Currently, we have four goals for this apparition: 1) confirming the preferred retrograde pole position; 2) gathering data to allow BYORP-driven changes in the mutual orbit to potentially be determined by later observations; 3) establishing whether or not the secondary is in synchronous rotation with the primary; and 4) constraining the inclination of the satellite orbit.

NASA Double Asteroid Redirection Test (DART) Trajectory Validation and Robutness

NASA Technical Reports Server (NTRS)

Sarli, Bruno V.; Ozimek, Martin T.; Atchison, Justin A.; Englander, Jacob A.; Barbee, Brent W.

2017-01-01

The Double Asteroid Redirection Test (DART) mission will be the first to test the concept of a kinetic impactor. Several studies have been made on asteroid redirection and impact mitigation, however, to this date no mission tested the proposed concepts. An impact study on a representative body allows the measurement of the effects on the target's orbit and physical structure. With this goal, DART's objective is to verify the effectiveness of the kinetic impact concept for planetary defense. The spacecraft uses solar electric propulsion to escape Earth, fly by (138971) 2001 CB21 for impact rehearsal, and impact Didymos-B, the secondary body of the binary (65803) Didymos system. This work focuses on the heliocentric transfer design part of the mission with the validation of the baseline trajectory, performance comparison to other mission objectives, and assessment of the baseline robustness to missed thrust events. Results show a good performance of the selected trajectory for different mission objectives: latest possible escape date, maximum kinetic energy on impact, shortest possible time of flight, and use of an Earth swing-by. The baseline trajectory was shown to be robust to a missed thrust with 1% of fuel margin being enough to recover the mission for failures of more than 14 days.

The quadrupole model for rigid-body gravity simulations

NASA Astrophysics Data System (ADS)

Dobrovolskis, Anthony R.; Korycansky, D. G.

2013-07-01

We introduce two new models for gravitational simulations of systems of non-spherical bodies, such as comets and asteroids. In both models, one body (the "primary") may be represented by any convenient means, to arbitrary accuracy. In our first model, all of the other bodies are represented by small gravitational "molecules" consisting of a few point masses, rigidly linked together. In our second model, all of the other bodies are treated as point quadrupoles, with gravitational potentials including spherical harmonic terms up to the third degree (rather than only the first degree, as for ideal spheres or point masses). This quadrupole formulation may be regarded as a generalization of MacCullagh's approximation. Both models permit the efficient calculation of the interaction energy, the force, and the torque acting on a small body in an arbitrary external gravitational potential. We test both models for the cases of a triaxial ellipsoid, a rectangular parallelepiped, and "duplex" combinations of two spheres, all in a point-mass potential. These examples were chosen in order to compare the accuracy of our technique with known analytical results, but the ellipsoid and duplex are also useful models for comets and asteroids. We find that both approaches show significant promise for more efficient gravitational simulations of binary asteroids, for example. An appendix also describes the duplex model in detail.

Lucy: Navigating a Jupiter Trojan Tour

NASA Technical Reports Server (NTRS)

Stanbridge, Dale; Williams, Ken; Williams, Bobby; Jackman, Coralie; Weaver, Hal; Berry, Kevin; Sutter, Brian; Englander, Jacob

2017-01-01

In January 2017, NASA selected the Lucy mission to explore six Jupiter Trojan asteroids. These six bodies, remnants of the primordial material that formed the outer planets, were captured in the Sun-Jupiter L4 and L5 Lagrangian regions early in the solar system formation. These particular bodies were chosen because of their diverse spectral properties and the chance to observe up close for the first time two orbiting approximately equal mass binaries, Patroclus and Menoetius. KinetX, Inc. is the primary navigation supplier for the Lucy mission. This paper describes preliminary navigation analyses of the approach phase for each Trojan encounter.

Voyage to Troy: A mission concept for the exploration of the Trojan asteroids

NASA Astrophysics Data System (ADS)

Saikia, S.; Das, A.; Laipert, F.; Dapkus, C.; Kendall, J.; Bowling, T.; Steckloff, J.; Holbert, S.; Graves, K.; Anthony, T.; Bobick, R.; Huang, Y.; Stuart, J.; Longuski, J.; Minton, D.

2014-07-01

The Trojan asteroids, located at Jupiter's L4 and L5 Lagrange points, are a potential source of insights into long-standing questions on the origin and early history of the Solar System. The 2013 Planetary Science Decadal Survey recommends a Trojan Tour and Rendezvous mission as high-priority among medium-class missions. A dedicated mission to the Trojan asteroids could confirm or refute multiple theories to correctly explain the Trojan asteroids' current location, characteristics, and behavior. In-depth and conclusive evidence for the Trojan asteroids' internal and external make-up as well as dynamical behavior hav been challenging due to limitations of ground- and space-based observations. Notwithstanding these limitations, it has been inferred that there are two distinct sub- populations that are distinguishable in visible and near-infrared spectra (redder and less red) within the swarms. These spectral groupings have not yet been conclusively linked to physical characteristics (e.g. size) or other observed parameters (e.g. albedo) of the primordial bodies. NASA's Jet Propulsion Laboratory's concept studies for Decadal Survey evaluated three concepts for missions to Trojan asteroids: each utilizing chemical- solar-electric, and radioisotope-electric for propulsion. Both Solar and Advanced Stirling Radioisotope Generators were considered for power [2]. We present a new conceptual mission to explore the Trojan asteroids that achieves the science goals prioritized in the 2013 Planetary Science Decadal Survey. The proposed mission aims to study both a redder and less red asteroid for the surface mineralogical and elemental composition, state of surface regolith, evidence and consequences of external modification processes such as collisional evolution, space weathering, and irradiation. Some potential targets in the L4 Greek camp currently under consideration for this mission include Achilles, Hektor and Agamemnon (redder) and Eurybates, Deipylos and Kalchas (less red). Hektor is currently thought to be a contact binary with a companion in an unusually inclined orbit and presents itself as a target with diverse knowledge to offer. The possibility of potentially gathering data from a Hilda asteroid en route to the Trojans is also being investigated. The mission would consist of the rendezvous of one or two Trojan asteroids along with further flybys. Candidate instruments are a thermal mapper, multispectral imagers, gamma-ray, neutron, and UV-spectrometers, and a LIDAR. The mission is designed within the constraints of NASA New Frontiers mission with a less than 10-year trajectory. The mission concept will help in the future Trojan mission concept studies.

Shape, size and multiplicity of main-belt asteroids I. Keck Adaptive Optics survey

PubMed Central

Marchis, F.; Kaasalainen, M.; Hom, E.F.Y.; Berthier, J.; Enriquez, J.; Hestroffer, D.; Le Mignant, D.; de Pater, I.

2008-01-01

This paper presents results from a high spatial resolution survey of 33 main-belt asteroids with diameters >40 km using the Keck II Adaptive Optics (AO) facility. Five of these (45 Eugenia, 87 Sylvia, 107 Camilla, 121 Hermione, 130 Elektra) were confirmed to have satellite. Assuming the same albedo as the primary, these moonlets are relatively small (∼5% of the primary size) suggesting that they are fragments captured after a disruptive collision of a parent body or captured ejecta due to an impact. For each asteroid, we have estimated the minimum size of a moonlet that can positively detected within the Hill sphere of the system by estimating and modeling a 2-σ detection profile: in average on the data set, a moonlet located at 2/100 × RHill (1/4 × RHill) with a diameter larger than 6 km (4 km) would have been unambiguously seen. The apparent size and shape of each asteroid was estimated after deconvolution using a new algorithm called AIDA. The mean diameter for the majority of asteroids is in good agreement with IRAS radiometric measurements, though for asteroids with a D < 200 km, it is underestimated on average by 6–8%. Most asteroids had a size ratio that was very close to those determined by lightcurve measurements. One observation of 104 Klymene suggests it has a bifurcated shape. The bi-lobed shape of 121 Hermione described in Marchis et al. [Marchis, F., Hestroffer, D., Descamps, P., Berthier, J., Laver, C., de Pater, I., 2005c. Icarus 178, 450–464] was confirmed after deconvolution. The ratio of contact binaries in our survey, which is limited to asteroids larger than 40 km, is surprisingly high (∼6%), suggesting that a non-single configuration is common in the main-belt. Several asteroids have been analyzed with lightcurve inversions. We compared lightcurve inversion models for plane-of-sky predictions with the observed images (9 Metis, 52 Europa, 87 Sylvia, 130 Elektra, 192 Nausikaa, and 423 Diotima, 511 Davida). The AO images allowed us to determine a unique photometric mirror pole solution, which is normally ambiguous for asteroids moving close to the plane of the ecliptic (e.g., 192 Nausikaa and 52 Europa). The photometric inversion models agree well with the AO images, thus confirming the validity of both the lightcurve inversion method and the AO image reduction technique. PMID:19081813

Re-accumulation Scenarios Governing Final Global Shapes of Rubble-Pile Asteroids

NASA Astrophysics Data System (ADS)

Hestroffer, Daniel; Tanga, P.; Comito, C.; Paolicchi, P.; Walsh, K.; Richardson, D. C.; Cellino, A.

2009-05-01

Asteroids, since the formation of the solar system, are known to have experienced catastrophic collisions, which---depending on the impact energy---can produce a major disruption of the parent body and possibly give birth to asteroid families or binaries [1]. We present a general study of the final shape and dynamical state of asteroids produced by the re-accumulation process following a catastrophic disruption. Starting from a cloud of massive particles (mono-disperse spheres) with given density and velocity distributions, we analyse the final shape, spin state, and angular momentum of the system from numerical integration of a N-body gravitational system (code pkdgrav [2]). The re-accumulation process itself is relatively fast, with a dynamical time corresponding to the spin-period of the final body (several hours). The final global shapes---which are described as tri-axial ellipsoids---exhibit slopes consistent with a degree of shear stress sustained by interlocking particles. We point out a few results: -the final shapes are close to those of hydrostatic equilibrium for incompressible fluids, preferably Maclaurin spheroid rather than Jacobi ellipsoids -for bodies closest to the sequence of hydrostatic equilibrium, there is a direct relation between spin, density and outer shape, suggesting that the outer surface is nearly equipotential -the evolution of the shape during the process follows a track along a gradient of potential energy, without necessarily reaching its minimum -the loose random packing of the particles implies low friction angle and hence fluid-like behaviour, which extends the results of [3]. Future steps of our analysis will include feature refinements of the model initial conditions and re-accumulation process, including impact shakings, realistic velocity distributions, and non equal-sized elementary spheres. References [1] Michel P. et al. 2001. Science 294, 1696 [2] Leinhardt Z.M. et al. 2000. Icarus 146, 133 [3] Richardson D.C. et al. 2005. Icarus 173, 349

Planetesimals Born Big by Clustering Instability?

NASA Technical Reports Server (NTRS)

Cuzzi, Jeffrey N.; Hartlep, Thomas; Simon, Justin I.; Estrada, Paul R.

2017-01-01

Roughly 100km diameter primitive bodies (today's asteroids and TNOs; [1]) are thought to be the end product of so-called "primary accretion". They dominated the initial mass function of planetesimals, and precipitated the onset of a subsequent stage, characterized by runaway gravitational effects, which proceeded onwards to planetary mass objects, some of which accreted massive gas envelopes. Asteroids are the parents of primitive meteorites; meteorite data suggest that asteroids initially formed directly from freelyfloating nebula particles in the mm-size range. Unfortunately, the process by which these primary 100km diameter planetesimals formed remains problematic. We review the most diagnostic primitive parent body observations, highlight critical aspects of the nebula context, and describe the issues facing various primary accretion models. We suggest a path forward that combines current scenarios of "turbulent concentration" (TC) and "streaming instabilities" (SI) into a triggered formation process we call clustering instability (CI). Under expected conditions of nebula turbulence, the success of these processes at forming terrestrial region (mostly silicate) planetesimals requires growth by sticking into aggregates in the several cm size range, at least, which is orders of magnitude more massive than allowed by current growth-by-sticking models using current experimental sticking parameters [2-4]. The situation is not as dire in the ice-rich outer solar system; however, growth outside of the snowline has important effects on growth inside of it [4] and at least one aspect of outer solar system planetesimals (high binary fraction) supports some kind of clustering instability.

Planetesimals Born Big by Clustering Instability?

NASA Technical Reports Server (NTRS)

Cuzzi, Jeffrey N.; Hartlep, Thomas; Simon, Justin I.; Estrada, Paul R.

2017-01-01

Roughly 100km diameter primitive bodies (today's asteroids and TNOs; [1]) are thought to be the end product of so-called "primary accretion". They dominated the initial mass function of planetesimals, and precipitated the onset of a subsequent stage, characterized by runaway gravitational effects, which proceeded onwards to planetary mass objects, some of which accreted massive gas envelopes. Asteroids are the parents of primitive meteorites; meteorite data suggest that asteroids initially formed directly from freelyfloating nebula particles in the mm-size range. Unfortunately, the process by which these primary 100km diameter planetesimals formed remains problematic. We review the most diagnostic primitive parent body observations, highlight critical aspects of the nebula context, and describe the issues facing various primary accretion models. We suggest a path forward that combines current scenarios of "turbulent concentration" (TC) and "streaming instabilities" (SI) into a triggered formation process we call clustering instability (CI). Under expected conditions of nebula turbulence, the success of these processes at forming terrestrial region (mostly silicate) planetesimals requires growth by sticking into aggregates in the several cm size range, at least, which is orders of magnitude more massive than allowed by current growth-by-sticking models using current experimental sticking parameters [2-4]. The situation is not as dire in the ice-rich outer solar system; however, growth outside of the snowline has important effects on growth inside of it [4] and at least one aspect of outer solar system planetesimals (high binary fraction) supports some kind of clustering instability

Trajectory Design Employing Convex Optimization for Landing on Irregularly Shaped Asteroids

NASA Technical Reports Server (NTRS)

Pinson, Robin M.; Lu, Ping

2016-01-01

Mission proposals that land spacecraft on asteroids are becoming increasingly popular. However, in order to have a successful mission the spacecraft must reliably and softly land at the intended landing site with pinpoint precision. The problem under investigation is how to design a propellant optimal powered descent trajectory that can be quickly computed onboard the spacecraft, without interaction from the ground control. The propellant optimal control problem in this work is to determine the optimal finite thrust vector to land the spacecraft at a specified location, in the presence of a highly nonlinear gravity field, subject to various mission and operational constraints. The proposed solution uses convex optimization, a gravity model with higher fidelity than Newtonian, and an iterative solution process for a fixed final time problem. In addition, a second optimization method is wrapped around the convex optimization problem to determine the optimal flight time that yields the lowest propellant usage over all flight times. Gravity models designed for irregularly shaped asteroids are investigated. Success of the algorithm is demonstrated by designing powered descent trajectories for the elongated binary asteroid Castalia.

1I/‘Oumuamua as a Tidal Disruption Fragment from a Binary Star System

NASA Astrophysics Data System (ADS)

Ćuk, Matija

2018-01-01

1I/‘Oumuamua is the first known interstellar small body, probably being only about 100 m in size. Against expectations based on comets, ‘Oumuamua does not show any activity and has a very elongated figure, and it also exhibits undamped rotational tumbling. In contrast, ‘Oumuamua’s trajectory indicates that it was moving with the local stars, as expected from a low-velocity ejection from a relatively nearby system. Here, I assume that ‘Oumuamua is typical of 100 m interstellar objects and speculate on its origins. I find that giant planets are relatively inefficient at ejecting small bodies from inner solar systems of main-sequence stars, and that binary systems offer a much better opportunity for ejections of non-volatile bodies. I also conclude that ‘Oumuamua is not a member of a collisional population, which could explain its dramatic difference from small asteroids. I observe that 100 m small bodies are expected to carry little mass in realistic collisional populations and that occasional events, when whole planets are disrupted in catastrophic encounters, may dominate the interstellar population of 100 m fragments. Unlike the Sun or Jupiter, red dwarf stars are very dense and are capable of thoroughly tidally disrupting terrestrial planets. I conclude that ‘Oumuamua may have originated as a fragment from a planet that was tidally disrupted and then ejected by a dense member of a binary system, which could explain its peculiarities.

Light-Curve Survey of Jupiter Trojan Asteroids

NASA Astrophysics Data System (ADS)

Duffard, R.; Melita, M.; Ortiz, J. L.; Licandro, J.; Williams, I. P.; Jones, D.

2008-09-01

Trojan asteroids are an interesting population of minor bodies due to their dynamical characteristics, their physical properties and that they are relatively isolated located at the snow-line The main hypotheses about the origin of the Jupiter Trojans assumed that they formed either during the final stages of the planetary formation (Marzari & Scholl 1998), or during the epoch of planetary migration (Morbidelli et al. 2005), in any case more than 3.8 Gy. ago. The dynamical configuration kept the Trojans isolated from the asteroid Main Belt throughout the history of the Solar System. In spite of eventual interactions with other populations of minor bodies like the Hildas, the Jupiter family comets, and the Centaurs, their collisional evolution has been dictated mostly by the intrapopulation collisions (Marzari et al. 1996, 1997). Therefore, the Jupiter Trojans may be considered primordial bodies, whose dynamical and physical properties can provide important clues about the environment of planetary formation. The available sample of Jupiter Trojans light-curves is small and mainly restricted to the largest objects. According to the MPC-website (updated last in March 2006), the present sample of rotation periods and light-curve-amplitudes of the Jupiter Trojan asteroids is composed by 25 objects with some information about their periods and by 10 of them with only an amplitude estimation. A survey of contact binary Trojan asteroids has been done by Mann et al. 2007, where they have recorded more than 100 amplitudes from sparse-sampled light-curves and very-wellresolved rotational periods. More than 2000 Trojan asteroids have been discovered up to date, so, there is an urgent need to enlarge the sample of intrinsic rotation periods and accurate light-curve amplitudes and to extend it to smaller sizes. Results and Discusions We requested 26 nights of observation in the second semester of 2007, to begin with the survey. They were scheduled for the following instruments: the WFC, Isaac Newton Telescope (ING, 2.5m, 7 nights), CAHA (2.2m, 6 nights), CCD direct OSN (1.5m, 6 nights) and CCD direct, JS (CASLEO, 2.15m, 7 nights). From these observations we have constructed the differential photometry light-curves of 15 Trojan asteroids. Plots showing the actual light curves and the quality assessment of our estimation of the rotational period can be downloaded from: http://www.df.uba.ar/users/melita/PICT07/PICT07.ht ml. See table 1 for the main results. In figure 1 we show the known periods of the Trojan asteroids as a function of their size. Some of these data are still of poor quality. It remains to be confirmed the reality of the clustering of small objects at small periods, so, there is a need to improve those rotation rates with reliable standard photometry produced at an instrument of larger aperture. Also, a lack of data for the biggest objects is apparent from this figure. In figure 2 we show a plot of the Rmagnitude amplitude variation as a function of the absolute magnitude. Most of the objects are from the survey of contact binaries by Mann et al. 2007. This plot seems to indicate that the extreme elongations recorded previously are constrained to the largest objects. Our data follows the trend of a negative slope, but given the error-bars involved, it remains to be confirmed if smaller objects tend to be more spherical.

Discovery of a Satellite to Asteroid Family Member (702) Alauda

NASA Astrophysics Data System (ADS)

Margot, Jean-Luc; Rojo, P.

2007-10-01

Rojo and Margot [1] reported the discovery of a satellite to (702) Alauda from adaptive-optics imaging with the European Southern Observatory (ESO) 8-m Very Large Telescope (VLT) on Cerro Paranal, Chile. (702) Alauda (a = 3.2 AU, e = 0.02, i = 21 deg) has been identified as the largest member of a dynamical family [2,3], suggesting a possible origin of the satellite in the family formation event. The diameter of (702) Alauda is given in the IRAS Minor Planet Survey (IMPS) as 194.73 +/- 3.2 km [4]. If the primary and secondary have similar albedoes, the diameter of the satellite is about 5.5 km. This is based on the measured flux ratio between primary and secondary of 1250, possibly the largest ever observed for solar system binaries with adaptive optics. This is the first satellite discovered to a large minor planet of type B in the SMASSII taxonomy, which is defined by a linear featureless spectrum with bluish to neutral slope [5]. B-types are carbonaceous asteroids that are not well characterized. The mass and density estimates of B-type (2) Pallas vary by 50% [6,7]. Our ongoing determination of the satellite orbit will provide mass and density estimates for (702) Alauda. [1] Rojo and Margot, CBET 1016, 2007. [2] Foglia and Masi 2004, Minor Planet Bull. 41, 100. [3] Gil-Hutton 2006, Icarus 183, 93. [4] Tedesco 2002, AJ 123, 1056. [5] Bus and Binzel 2002, Icarus 158, 146. [6] Hilton 2002, Asteroids III, 103. [7] Britt et al. 2002, Asteroids III, 485.

Discovery of a Satellite around a Near-Earth Asteroid

NASA Astrophysics Data System (ADS)

1997-07-01

In the course of the major observational programme of asteroids by the Institute of Planetary Exploration of the German Aerospace Research Establishment (DLR) [1] in Berlin, two of the staff astronomers, Stefano Mottola and Gerhard Hahn , have discovered a small satellite (moon) orbiting the asteroid (3671) Dionysus. The new measurements were obtained with the DLR CCD Camera attached at the 60-cm Bochum telescope at the ESO La Silla Observatory in Chile. This is only the second known case of an asteroid with a moon. Moons and planets Until recently, natural satellites were only known around the major planets . The Moon orbits the Earth, there are two tiny moons around Mars, each of the giant planets Jupiter, Saturn, Uranus and Neptune has many more, and even the smallest and outermost, Pluto, is accompanied by one [2]. However, the new discovery now strengthens the belief of many astronomers that some, perhaps even a substantial number of the many thousands of minor planets (asteroids) in the solar system may also possess their own moons. The first discovery of a satellite orbiting an asteroid was made by the NASA Galileo spacecraft, whose imagery, obtained during a fly-by of asteroid (253) Ida in August 1993, unveiled a small moon that has since been given the name Dactyl. (3671) Dionysus: an Earth-crossing asteroid In the framework of the DLR asteroid monitoring programme, image sequences are acquired to measure an asteroid's brightness variations caused by the changing amount of sunlight reflected from the asteroid's illuminated surface as it spins, due to its irregular shape. The brightness variations may be used to derive the asteroid's rotational properties, such as speed of rotation and spin axis orientation. Asteroid Dionysus [3] was put on the observing list because it belongs to a special class of asteroids, the members of which occasionally come very close to the Earth and have a small, but non-negligible chance of colliding with our planet. Most of these objects move in highly elliptical orbits that lie partly inside, partly outside that of the Earth. They are accordingly referred to as `Earth-crossing asteroids' or Apollo-type asteroids , after the proto-type of this group, (1862) Apollo, that was discovered in 1932 by Karl Reinmuth in Heidelberg [4]. The orbital characteristics of Dionysus lead to moderately close approaches to the Earth every 13 years, with the one in 1997 being the first since its discovery that is favourable for extensive observations. On July 6, 1997, it passed within 17 million km of our planet. At that time it was visible from the southern hemisphere with a moderately-sized telescope as a relatively fast-moving object. The strange lightcurve of asteroid (3671) Dionysus Caption to ESO PR Photo 20/97 [GIF, 10k] The first observations of the brightness of this asteroid in late May 1997 showed a `normal' two-maxima-two-minima lightcurve (change of brightness with time), typical of rotating non-spherical bodies. The period of rotation was 2.7 hours, i.e., this asteroid spins almost nine times as fast as the Earth. However lightcurves observed on two subsequent nights were strikingly different from the previous ones. In both cases a deeper and shifted dip was seen, indicative of an attenuation - an additional dimming of the sunlight reflected by the asteroid, cf. ESO Press Photo 20/97 . The observers hypothesised that these lightcurve features were due to an eclipse by an unknown object moving in an orbit around (3671) Dionysus , thereby covering part of the illuminated surface of the asteroid at regular time intervals [5]. Fortunately, this hypothesis can be checked, because the phenomenon should then repeat itself periodically. Accordingly, the DLR scientists made a prediction for the next occurences of dips in the lightcurve, based on the time difference between the two observed events. Confirmation of the satellite Contacts were made with observers located at other observatories, in order to secure lightcurve coverage over a longer period of time than was possible from La Silla alone. As a result, a series of lightcurve measurements were performed from June 3 to 9 in close cooperation with Petr Pravec and Lenka Sarounova working at the Ondrejov Observatory, near Prague in the Czech Republic. Luckily, the weather conditions were favourable at both sites and the dips in the lightcurve were indeed observed at the predicted times. Based on the four well observed events, it was then possible to determine a period of 1.155 days for their occurence. Thus, the hypothesis of a satellite orbiting around Dionysus was confirmed. As a result, the International Astronomical Union's Minor Planet Center located in Cambridge (MA, USA) promptly gave a provisional designation to the new satellite - S/1997 (3671) 1 . How big is Dionysus? Meanwhile, in Hawaii, the world's largest infrared telescope was being trained on Dionysus to obtain information about its size and composition. Alan Harris , also a scientist from the DLR in Berlin, and John Davies from the Joint Astronomy Centre in Hilo, Hawaii, observed the thermal infrared radiation emitted by Dionysus with the 3.8-m United Kingdom Infrared Telescope (UKIRT) situated on Mauna Kea. Similar observations over a broader spectral range were also made by the European Space Agency's orbiting Infrared Space Observatory. The thermal or "heat" radiation emitted by an asteroid depends on its size and the amount of sunlight it absorbs (darker bodies being warmer). In the case of Dionysus the measured radiation was much weaker than expected, indicating that the asteroid has an intrinsically bright (reflective) surface and is only about 1 km in diameter. This is much smaller than (253) Ida, the only other asteroid known to have a moon, which is about 60 km across. Further observations Eventually it should be possible to determine the orbital radius of the satellite, its size and the inclination of its orbital plane. In order to obtain the data necessary for these determinations, observations will be continued during the present period of good visibility that lasts until September-October 1997. For this reason the discoverers have initiated an international observation campaign devoted to the study of this intriguing object and now involving astronomers from many countries. How common are such satellites? Satellites in orbit around small bodies in the solar system - asteroids and cometary nuclei - have been predicted on theoretical grounds for a long time, even though there is no consensus among planetary scientists about the actual numbers of such systems. Hints about the existence of asteroid satellites also come from the presence of double impact craters on the Moon and other planetary surfaces. This suggests that the projectiles forming these craters were `double' asteroids. Moreover, measurements obtained when an asteroid passes in front of a relatively bright star (a so-called `occultation') have on a few occasions shown features which could be interpreted as due to the presence of a satellite. However, because of the difficult nature of such measurements, it has never been possible to draw unambiguous conclusions. The existence of double asteroids was invoked earlier by Petr Pravec and Gerhard Hahn to explain the unusual features observed in the lightcurves of two other Earth-approaching asteroids 1991 VH and 1994 AW1 . In the case of Dionysus , however, it is possible to predict eclipse events and to confirm them by subsequent measurements. There is therefore mounting evidence that asteroid binary systems might be comparatively common. Observational programmes like the present one by the DLR and Ondrejov groups will help to verify this possibility. Where to find additional information Detailed and up-to-date information about (3671) Dionysus can be found in the Web at the following URL: http://earn.dlr.de/dionysus. Notes: [1] This institute and its parent organisation are known in Germany as Institut fuer Planetenerkundung and Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR) . [2] See ESO Press Release 09/94 of 18 May 1994. [3] Asteroids are small solid planetary bodies revolving around the Sun in orbits that are mostly located in the so-called Main Asteroid Belt, confined between the orbits of Mars and Jupiter. Most of them are thought to be fragments derived from catastrophic, past collisions between larger asteroids. By mid-1997, the orbits of about 8000 asteroids in the solar system were sufficiently well known to allow them to be officially numbered by the rules of the International Astronomical Union. (3671) Dionysus was discovered in 1984 at the Palomar Observatory (California, USA) and is named after the Greek god of wine. [4] The gravitational influence of the giant planet Jupiter can modify the orbits of asteroids located in particular regions of the Main Belt (the effect is refered to as `orbital perturbations'). As a result, the orbit of an asteroid may `cross' that of a major planet, and eventually it may become a NEO , i.e. a near-Earth object. The orbits of NEO's are highly unstable over times comparable to the age of the solar system. This instability can result in a collision with one of the terrestrial (inner) planets, or with the Sun, or in the ejection of the asteroid out of the solar system. The present orbit of (3671) Dionysus is such that this object is not likely to collide with the Earth in the foreseeable future. [5] The method of analyzing the lightcurve of Dionysus consists of `removing' (subtracting) the normal short-period brightness variations due to rotation of the asteroid and plotting the residuals against time, cf. Press Photo 20/97. The residual lightcurve shows a clear resemblance with typical lightcurves of eclipsing binary stellar systems (in which two stars move around each other, producing mutual eclipses) and leads to a model of two bodies revolving around a common gravitational centre, in an orbital plane containing both the Earth and the Sun. How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org../). ESO Press Photos may be reproduced, if credit is given to the European Southern Observatory.

A Brief Glossary of Commonly Used Astronomical Terms.

ERIC Educational Resources Information Center

Harrington, Sherwood

A glossary of 50 astronimical terms is presented. Among terms included are: Asteroid; Big Bang; Binary Star; Black Hole; Comet; Constellation; Eclipse; Equinox; Galaxy; Globular Cluster; Local Group; Magellanic Clouds; Nebula; Neutron Star; Nova; Parsec; Quasar; Radio Astronomy; Red Giant; Red Shift; S.E.T.I.; Solstice; Supernova; and White Dwarf.…

The Complex History of Trojan Asteroids

NASA Astrophysics Data System (ADS)

Emery, J. P.; Marzari, F.; Morbidelli, A.; French, L. M.; Grav, T.

The Trojan asteroids, orbiting the Sun in Jupiter's stable Lagrange points, provide a unique perspective on the history of our solar system. As a large population of small bodies, they record important gravitational interactions in the dynamical evolution of the solar system. As primitive bodies, their compositions and physical properties provide windows into the conditions in the solar nebula in the region in which they formed. In the past decade, significant advances have been made in understanding their physical properties, and there has been a revolution in thinking about the origin of Trojans. The ice and organics generally presumed to be a significant part of Trojan composition have yet to be detected directly, although the low density of the binary system Patroclus (and possibly low density of the binary/moonlet system Hektor) is consistent with an interior ice component. By contrast, fine-grained silicates that appear to be similar to cometary silicates in composition have been detected, and a color bimodality may indicate distinct compositional groups among the Trojans. Whereas Trojans had traditionally been thought to have formed near 5 AU, a new paradigm has developed in which the Trojans formed in the proto-Kuiper belt, and were scattered inward and captured in the Trojan swarms as a result of resonant interactions of the giant planets. Whereas the orbital and population distributions of current Trojans are consistent with this origin scenario, there are significant differences between current physical properties of Trojans and those of Kuiper belt objects. These differences may be indicative of surface modification due to the inward migration of objects that became the Trojans, but understanding of appropriate modification mechanisms is poor and would benefit from additional laboratory studies. Many open questions about this intriguing population remain, and the future promises significant strides in our understanding of Trojans. The time is ripe for a spacecraft mission to the Trojans, to transform these objects into geologic worlds that can be studied in detail to unravel their complex history.

The formation of Kuiper-belt binaries through exchange reactions.

PubMed

Funato, Yoko; Makino, Junichiro; Hut, Piet; Kokubo, Eiichiro; Kinoshita, Daisuke

2004-02-05

Recent observations have revealed that an unexpectedly high fraction--a few per cent--of the trans-Neptunian objects (TNOs) that inhabit the Kuiper belt are binaries. The components have roughly equal masses, with very eccentric orbits that are wider than a hundred times the radius of the primary. Standard theories of binary asteroid formation tend to produce close binaries with circular orbits, so two models have been proposed to explain the unique characteristics of the TNOs. Both models, however, require extreme assumptions regarding the size distribution of the TNOs. Here we report a mechanism that is capable of producing binary TNOs with the observed properties during the early stages of their formation and growth. The only required assumption is that the TNOs were initially formed through gravitational instabilities in the protoplanetary dust disk. The basis of the mechanism is an exchange reaction in which a binary whose primary component is much more massive than the secondary interacts with a third body, whose mass is comparable to that of the primary. The low-mass secondary component is ejected and replaced by the third body in a wide but eccentric orbit.

Highlights of the LINEAR survey

NASA Astrophysics Data System (ADS)

Palaversa, L.

2014-07-01

Lincoln Near-Earth Asteroid Research asteroid survey (LINEAR) observed proximately 10,000 deg2 of the northern sky in period roughly from 1998 to 2013. Long baseline of observations combined with good cadence and depth (14.5 < rSDSS < 17.5) provides excellent basis for investigation of variable and transient objects in this relatively faint and underexplored part of the sky. Details covering the repurposing of this survey for use in time domain astronomy, creation of a highly reliable catalogue of approximately 7,200 periodically variable stars (RR Lyrae, eclipsing binaries, SX Phe stars and LPVs) as well as search for optical signatures of exotic transient events (such as tidal disruption event candidates), are presented.

Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2011 December - 2012 March

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2012-07-01

Lightcurves for 41 asteroids were obtained at the Palmer Divide Observatory (PDO) from 2011 December to 2012 March: 77 Frigga, 2933 Amber, 3352 McAuliffe, 3483 Svetlov, 4031 Mueller, 5378 Ellyett, 5579 Uhlherr, 5771 Somerville, 6087 Lupo, 6602 Gilclark, (6618) 1936 SO, 6635 Zuber, (8404) 1995 AN, (9873) 1992 GH, (11058) 1991 PN10, (16421) 1988 BJ, (16426) 1988 EC, (16585) 1992 QR, 16589 Hastrup, 18368 Flandrau, (19537) 1999 JL8, (23974) 1999 CK12, (24465) 2000 SX155, (26383) 1999 MA2, (30856) 1991 XE, (39618) 1994 LT, (45898) 2000 XQ49, (47983) 2000 XX13, (49566) 1999 CM106, (49678) 1999 TQ7, (50991) 2000 GK94, (57739) 2001 UF162, (63260) 2001 CN, (69350) 1993 YP, 79316 Huangshan, (82066) 2000 XG15, (82078) 2001 AH46, (105155) 2000 NG26, (141018) 2001 WC47, (256700) 2008 AG3, (320125) 2007 EQ185. Two asteroids showed indications of being binary. Analysis of the data for near-Earth asteroid, 3352 McAuliffe showed a second period of 20.86 h but no obvious mutual events (occultations and/or eclipses). The Hungaria asteroid, (24465) 2000 SX15, displayed similar characteristics. Furthermore, the primary (or only) period of 3.256 h cannot be reconciled with analysis from previous apparitions. Three asteroids showed signs of being in non-principal axis rotation (NPAR, "tumbling"). New values for absolute magnitude (H) were found for several Hungaria asteroids using either derived or assumed values of G. These new values were compared against those used in the WISE mission to determine diameters and albedos. In all cases where the WISE results featured an unusually high albedo for the asteroid in question, the new value of H resulted in an albedo that was significantly lower and closer to the expected value for type E asteroids, which are the likely members of the Hungaria collisional family.

Observing Campaign for Potential Deep Impact Flyby Target 163249 (2002 GT)

NASA Technical Reports Server (NTRS)

Pittichova, Jana; Chesley, S. R.; Abell, P. A.; Benner, L. A. M.

2012-01-01

The Deep Impact spacecraft is currently on course for a Jan. 4, 2020 flyby of the sub-kilometer near-Earth asteroid 163249 (2002 GT). The re-targeting will be complete with a final small maneuver scheduled for Oct. 4, 2012. 2002 GT, which is also designated as a Potentially Hazardous Asteroid (PHA), has a well-determined orbit and is approx 800 m in diameter (H=18.3). Little more is known about the nature of this object, but in mid-2013 it will pass near the Earth, affording an exceptional opportunity for ground-based characterization. At this apparition 2002 GT will be in range of Arecibo. In addition to Doppler measurements, radar delay observations with precisions of a few microseconds are expected and have a good chance of revealing whether the system is binary or not. The asteroid will be brighter than 16th mag., which will facilitate a host of observations at a variety of wavelengths. Light curve measurements across a wide range of viewing perspectives will reveal the rotation rate and ultimately lead to strong constraints on the shape and pole orientation. Visible and infrared spectra will constrain the mineralogy, taxonomy, albedo and size. Along with the radar observations, optical astrometry will further constrain the orbit, both to facilitate terminal guidance operations and to potentially reveal nongravitational forces acting on the asteroid. Coordinating all of these observations will be a significant task and we encourage interested observers to collaborate in this effort. The 2013 apparition of 2002 GT represents a unique opportunity to characterize a potential flyby target, which will aid interpretation of the high-resolution flyby imagery and aid planning and development of the flyby imaging sequence. The knowledge gained from this flyby will be highly relevant to the human exploration program at NASA, which desires more information on the physical characteristics of sub-kilometer near-Earth asteroids.

Robotic Reconnaissance Missions to Small Bodies and Their Potential Contributions to Human Exploration

NASA Technical Reports Server (NTRS)

Abell, P. A.; Rivkin, A. S.

2015-01-01

Introduction: Robotic reconnaissance missions to small bodies will directly address aspects of NASA's Asteroid Initiative and will contribute to future human exploration. The NASA Asteroid Initiative is comprised of two major components: the Grand Challenge and the Asteroid Mission. The first component, the Grand Challenge, focuses on protecting Earth's population from asteroid impacts by detecting potentially hazardous objects with enough warning time to either prevent them from impacting the planet, or to implement civil defense procedures. The Asteroid Mission involves sending astronauts to study and sample a near- Earth asteroid (NEA) prior to conducting exploration missions of the Martian system, which includes Phobos and Deimos. The science and technical data obtained from robotic precursor missions that investigate the surface and interior physical characteristics of an object will help identify the pertinent physical properties that will maximize operational efficiency and reduce mission risk for both robotic assets and crew operating in close proximity to, or at the surface of, a small body. These data will help fill crucial strategic knowledge gaps (SKGs) concerning asteroid physical characteristics that are relevant for human exploration considerations at similar small body destinations. Small Body Strategic Knowledge Gaps: For the past several years NASA has been interested in identifying the key SKGs related to future human destinations. These SKGs highlight the various unknowns and/or data gaps of targets that the science and engineering communities would like to have filled in prior to committing crews to explore the Solar System. An action team from the Small Bodies Assessment Group (SBAG) was formed specifically to identify the small body SKGs under the direction of the Human Exploration and Operations Missions Directorate (HEOMD), given NASA's recent interest in NEAs and the Martian moons as potential human destinations [1]. The action team organized the SKGs into four broad themes: 1) Identify human mission targets; 2) Understand how to work on and interact with the small body surface; 3) Understand the small body environment and its potential risk/benefit to crew, systems, and operational assets; and 4) Understand the small body resource potential. Each of these themes were then further subdivided into categories to address specific SKG issues. Robotic Precursor Contributions to SKGs: Robotic reconnaissance missions should be able to address specific aspects related to SKG themes 1 through 4. Theme 1 deals with the identification of human mission targets within the NEA population. The current guideline indicates that human missions to fastspinning, tumbling, or binary asteroids may be too risky to conduct successfully from an operational perspective. However, no spacecraft mission has been to any of these types of NEAs before. Theme 2 addresses the concerns about interacting on the small body surface under microgravity conditions, and how the surface and/or sub-surface properties affect or restrict the interaction for human exploration. The combination of remote sensing instruments and in situ payloads will provide good insight into the asteroid's surface and subsurface properties. SKG theme 3 deals with the environment in and around the small body that may present a nuisance or hazard to any assets operating in close proximity. Impact and surface experiments will help address issues related to particle size, particle longevity, internal structure, and the near-surface mechanical stability of the asteroid. Understanding or constraining these physical characteristics are important for mission planning. Theme 4 addresses the resource potential of the small body. This is a particularly important aspect of human exploration since the identification and utilization of resources is a key aspect for deep space mission architectures to the Martian system (i.e., Phobos and Deimos). Conclusions: Robotic reconnaissance of small bodies can provide a wealth of information relevant to the science and planetary defense of NEAs. However, such missions to investigate NEAs can also provide key insights into small body strategic knowledge gaps and contribute to the overall success for human exploration missions to asteroids.

BILLIARDS: Baseline Instrumented Lithology Lander, Inspector and Asteroid Redirection Demonstration System

NASA Technical Reports Server (NTRS)

Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent

2015-01-01

BILLIARDS Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System Proposed demonstration mission for Billiard-Ball concept Select asteroid pair with natural close approach to minimize cost and complexity Primary Objectives Rendezvous with a small (10m), near Earth (alpha) asteroid Maneuver the alpha asteroid to a collision with a 100m (beta) asteroid Produce a detectable deflection or disruption of the beta asteroid Secondary objectives Contribute knowledge of asteroid composition and characteristics Contribute knowledge of small-body formation Opportunity for international collaboration

Orbit of the Patroclus-Menoetius Binary, a Lucy Mission Target

NASA Astrophysics Data System (ADS)

Noll, Keith

2016-10-01

We are proposing to observe Trojan binary asteroid (617) Patroclus-Menoetius, one of the targets of the Lucy mission. Lucy was selected as the next Discovery mission on January 4, 2017, for launch in October 2021. Observations this year are needed to establish the mutual orbit of the binary, which is of critical importance for mission planning. The mutual orbit phase is essentially undetermined from the accumulation of orbit period uncertainty since last measured in 2010. Orbital phase is needed in order to be able to predict the timing of mutual events that will begin late in 2017. These mutual events are essential to planning for the Lucy mission, especially in establishing the precise orientation of the mutual orbit plane and ascending node that is critical to early planning for flyby encounter design and capabilities.

Asteroids IV

NASA Astrophysics Data System (ADS)

Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

Asteroids are fascinating worlds. Considered the building blocks of our planets, many of the authors of this book have devoted their scientific careers to exploring them with the tools of our trade: ground- and spacebased observations, in situ space missions, and studies that run the gamut from theoretical modeling efforts to laboratory work. Like fossils for paleontologists, or DNA for geneticists, they allow us to construct a veritable time machine and provide us with tantalizing glimpses of the earliest nature of our solar system. By investigating them, we can probe what our home system was like before life or even the planets existed. The origin and evolution of life on our planet is also intertwined with asteroids in a different way. It is believed that impacts on the primordial Earth may have delivered the basic components for life, with biology favoring attributes that could more easily survive the aftermath of such energetic events. In this fashion, asteroids may have banished many probable avenues for life to relative obscurity. Similarly, they may have also prevented our biosphere from becoming more complex until more recent eras. The full tale of asteroid impacts on the history of our world, and how human life managed to emerge from myriad possibilities, has yet to be fully told. The hazard posed by asteroid impacts to our civilization is low but singular. The design of efficient mitigation strategies strongly relies on asteroid detection by our ground- and spacebased surveys as well as knowledge of their physical properties. A more positive motivation for asteroid discovery is that the proximity of some asteroids to Earth may allow future astronauts to harvest their water and rare mineral resources for use in exploration. A key goal of asteroid science is therefore to learn how humans and robotic probes can interact with asteroids (and extract their materials) in an efficient way. We expect that these adventures may be commonplace in the future. Asteroids, like planets, are driven by a great variety of both dynamical and physical mechanisms. In fact, images sent back by space missions show a collection of small worlds whose characteristics seem designed to overthrow our preconceived notions. Given their wide range of sizes and surface compositions, it is clear that many formed in very different places and at different times within the solar nebula. These characteristics make them an exciting challenge for researchers who crave complex problems. The return of samples from these bodies may ultimately be needed to provide us with solutions. In the book Asteroids IV, the editors and authors have taken major strides in the long journey toward a much deeper understanding of our fascinating planetary ancestors. This book reviews major advances in 43 chapters that have been written and reviewed by a team of more than 200 international authorities in asteroids. It is aimed to be as comprehensive as possible while also remaining accessible to students and researchers who are interested in learning about these small but nonetheless important worlds. We hope this volume will serve as a leading reference on the topic of asteroids for the decade to come. We are deeply indebted to the many authors and referees for their tremendous efforts in helping us create Asteroids IV. We also thank the members of the Asteroids IV scientific organizing committee for helping us shape the structure and content of the book. The conference associated with the book, "Asteroids Comets Meteors 2014" held June 30-July 4, 2014, in Helsinki, Finland, did an outstanding job of demonstrating how much progress we have made in the field over the last decade. We are extremely grateful to our host Karri Muinonnen and his team. The editors are also grateful to the Asteroids IV production staff, namely Renée Dotson and her colleagues at the Lunar and Planetary Institute, for their efforts, their invaluable assistance, and their enthusiasm; they made life as easy and pleasant as possible for the editors, authors, and referees. They also thank Richard Binzel, the General Editor of the Space Science Series, for his strong support and advice during this process, as well as the staff at the University of Arizona Press. Finally, editor Patrick Michel would like to thank his wife Delphine, who married him on June 14, 2013, almost at the birth of the book process. He is grateful that she was willing to put up with him as he spent many of his nights and weekends working on the book. Thanks to her support, their trajectories are as bounded as a perfectly stable asteroid binary system, and this was probably the best way to experience from the start what her life would be like with a researcher! Co-editor Bottke would also like to thank his wife Veronica and his children Kristina-Marie, Laura, and Julie, who make up his own favorite asteroid family. Since Asteroids III, the size distribution of the family members has been steadily changing, and who knows how many tiny new members it will contain by Asteroids V! Co-editor DeMeo would like to thank her husband Alfredo for his support and encouragement throughout the process of creating this book. They met at the beginning of her career in research, becoming an asteroid pair and now continuing on the same orbit in life.

International Asteroid Mission (IAM)

NASA Astrophysics Data System (ADS)

Yamaguchi, Ryuuji

1991-07-01

International Asteroid Mission (IAM) is a program aimed at developing resources of asteroids abundantly existing near the earth. This report describes the research results of design project of the International Space University (ISU) held in 1990 at Tront-York University. ISU research and asteroid survey results, and the manned asteroid mining mission are outlined. Classification of asteroids existing near the earth and asteroid resource processing and use analyses are conducted. Asteroid selection flow charts are introduced, and the 1982HR-Orpheus is selected as a candidate asteroid because it takes an approaching orbit toward the earth, requires small delta V, and possesses abundant carbonaceous chondrites. Characteristics of 1982HR-Orpheus are presented. Mission requirements, mission outlines, transportation systems, and mining and processing systems for manned asteroid mining missions are presented.

Results of Observations of Occultations of Stars by Main-Belt and Trojan Asteroids, and the Promise of Gaia

NASA Astrophysics Data System (ADS)

Dunham, David W.; Herald, David Russell; Preston, Steven; Loader, Brian; Bixby Dunham, Joan

2016-10-01

For 40 years, the sizes and shapes of scores of asteroids have been determined from observations of asteroidal occultations, and many hundreds of high-precision positions of the asteroids relative to stars have been measured. Earlier this year, the 3000th observation of an asteroidal occultation was documented. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations. The first observations were timed visually, but now nearly all observations are either video-recorded, or recorded with CCD drift scans, allowing small magnitude-drop events to be recorded, and resulting in more consistent results. Techniques have been developed allowing one or two observers to set up multiple stations with small telescopes, video cameras, and timers, thereby recording many chords, even across a whole asteroid; some examples will be shown.Later this year, the first release of Gaia data will allow us to greatly improve the vast star catalog that we use for both predicting and analyzing these events. Although the first asteroidal data will wait until the 4th Gaia release, before that, we can greatly improve the orbits of asteroids that have occulted 3 or more stars in the past so that we can start computing the paths of future occultations by them to few km accuracy. In a couple of years, we'll be able to realistically predict one to two orders of magnitude more events than we can now, allowing efforts to be concentrated on smaller objects of the highest scientific interest, including some comets.

Recent Arecibo Radar Observations of Main-Belt Asteroids.

NASA Astrophysics Data System (ADS)

Shepard, Michael K.; Howell, Ellen; Nolan, Michael; Taylor, Patrick; Springmann, Alessondra; Giorgini, Jon; Benner, Lance; Magri, Christopher

2014-11-01

We recently observed main-belt asteroids 12 Victoria (Tholen S-class, Bus L-class), 246 Asporina (A-class), and 2035 Stearns with the S-band (12 cm) Arecibo radar. Signal-to-noise ratios for Asporina and Stearns were only strong enough for continuous-wave (CW) analysis. Signal-to-noise ratios for Victoria were high enough for delay-Doppler imaging. Stearns exhibited a high radar polarization ratio of unity, higher than any other main-belt E-class, but similar to near-Earth E-class asteroids [Benner et al. Icarus 198, 294-304, 2008; Shepard et al. Icarus 215, 547-551, 2011]. The A-class asteroids show spectral absorption features consistent with olivine and have been suggested as the source of pallasite meteorites or the rare brachinites [Cruikshank and Hartmann, Science 223, 281-283, 1984]. The radar cross-section measured for Asporina leads to a radar albedo estimate of 0.11, suggesting a low near-surface bulk density, and by inference, a low metal content. This suggests that the brachinites are a better analog for Asporina than the iron-rich pallasites. Victoria has been observed by radar in the past and the continuous-wave echoes suggest it has a large concavity or is a contact binary [Mitchell et al. Icarus 118, 105-131, 1995]. Our new imaging observations should determine which is more likely.

The EURONEAR Lightcurve Survey of Near Earth Asteroids

NASA Astrophysics Data System (ADS)

Vaduvescu, O.; Macias, A. Aznar; Tudor, V.; Predatu, M.; Galád, A.; Gajdoš, Š.; Világi, J.; Stevance, H. F.; Errmann, R.; Unda-Sanzana, E.; Char, F.; Peixinho, N.; Popescu, M.; Sonka, A.; Cornea, R.; Suciu, O.; Toma, R.; Santos-Sanz, P.; Sota, A.; Licandro, J.; Serra-Ricart, M.; Morate, D.; Mocnik, T.; Diaz Alfaro, M.; Lopez-Martinez, F.; McCormac, J.; Humphries, N.

2017-08-01

This data paper presents lightcurves of 101 near Earth asteroids (NEAs) observed mostly between 2014 and 2017 as part of the EURONEAR photometric survey using 11 telescopes with diameters between 0.4 and 4.2 m located in Spain, Chile, Slovakia and Romania. Most targets had no published data at the time of observing, but some objects were observed in the same period mainly by B. Warner, allowing us to confirm or improve the existing results. To plan the runs and select the targets, we developed the public Long Planning tool in PHP. For preliminary data reduction and rapid follow-up planning we developed the LiDAS pipeline in Python and IRAF. For final data reduction, flux calibration, night linkage and Fourier fitting, we used mainly MPO Canopus. Periods of 18 targets are presented for the first time, and we could solve or constrain rotation for 16 of them. We secured periods for 45 targets (U˜ 3), found candidate periods for other 16 targets (U˜ 2), and we propose tentative periods for other 32 targets (U˜ 1). We observed 7 known or candidate binary NEAs, fiting 3 of them (2102 Tantalus, 5143 Heracles and 68348). We observed 8 known or candidate tumbling NEAs, deriving primary periods for 3 objects (9400, 242708 and 470510). We evidenced rapid oscillations (few minutes) and could fit fast tentative periods TP2 for 5 large newly suggested tumbling or binary candidates (27346, 112985, 285625, 377732, 408980), probably discovering at least one new binary NEA (2011 WO41). We resolved periods of 4 special objects which include two proposed space mission targets (163249 and 101955 Bennu), one very fast rotator NEA discovered by EURONEAR (2014 NL52) and the "Halloween asteroid" (2015 TB145). Using Mercator in simultaneous 3 band MAIA imaging, we could evidence for the first time clear variation in the color lightcurves of 10 NEAs. The periods derived from the g- r color lightcurves are found to match individual band period fits for 4 NEAs (27346, 86067, 112985 and 275976).

The Geomorphology of Comet Churymov-Gerasimenko As Revealed By Rosetta/Osiris: Implicationsfor Past Collisional Evolution

NASA Astrophysics Data System (ADS)

Marchi, S.; A'Hearn, M. F.; Barbieri, C.; Barucci, M. A.; Besse, S.; Cremonese, G.; Ip, W. H.; Keller, H. U.; Koschny, D.; Kuhrt, E.; Lamy, P. L.; Marzari, F.; Massironi, M.; Pajola, M.; Rickman, H.; Rodrigo, R.; Sierks, H.; Snodgrass, C.; Thomas, N.; Vincent, J. B.

2014-12-01

In this paper we present the major geomorphological features of comet Churymov-Gerasimenko (C-G), with emphasis on those that may have formed through collisional processes. The C-G nucleus has been imaged with the Rosetta/OSIRIS camera system at varying spatial resolution. At the moment of this writing the maximum spatial resolution achieved is ~20 meter per pixel, and it will improve to reach the unprecedented centimeter-scale in November 2014. This resolution should allow us to identify and characterize pits, lineaments and blocks that could be the result of collisional evolution. Indeed, C-G has spent some 1000 years on orbits crossing the main asteroid belt, and a much longer time in the outer solar system. Collisions may have, therefore, shaped the morphology of the nucleus in various ways. Previously imaged Jupiter Family Comets (e.g., Tempel 1) show significant numbers of pits and lineaments, some of which could be due to collisions. Additional proposed formation mechanisms are related to cometary activity processes, such as volatile outgassing.In addition to small scale features, the overall shape of C-G could also provide insights into the role of collisional processes. A striking feature is that C-G's shape is that of a contact binary. Similar shapes have been observed on rocky asteroids (e.g., Itokawa) and are generally interpreted as an indication of their rubble pile nature. A possibility is that C-G underwent similar processes, and therefore it may be constituted by reaccumulated fragments ejected from a larger precursor. An alternative view is that the current shape is the result of inhomogeneous outgassing activity, which may have dug a ~1-km deep trench responsible for the apparent contact binary shape.The role of the various proposed formation mechanisms (collisional vs outgassing) for both small scale and global features will be investigated and their implications for the evolution of C-G will be discussed.

Dynamical and Physical Properties of 65803 Didymos, the Proposed AIDA Mission Target

NASA Astrophysics Data System (ADS)

Richardson, Derek C.; Barnouin, Olivier S.; Benner, Lance A. M.; Bottke, William; Campo Bagatin, Adriano; Cheng, Andrew F.; Eggl, Siegfried; Hamilton, Douglas P.; Hestroffer, Daniel; Hirabayashi, Masatoshi; Maurel, Clara; McMahon, Jay W.; Michel, Patrick; Murdoch, Naomi; Naidu, Shantanu P.; Pravec, Petr; Rivkin, Andrew S.; Rosenblatt, Pascal; Sarid, Gal; Scheeres, Daniel J.; Scheirich, Peter; Tsiganis, Kleomenis; Zhang, Yun; AIDA Dynamical and Physical Properties of Didymos Working Group

2016-10-01

Binary near-Earth asteroid (NEA) 65803 Didymos is the proposed Asteroid Impact & Deflection Assessment (AIDA) mission target, combining an orbiter [1] and a kinetic impactor for a planned encounter in fall 2022 [2]. The Dynamical and Physical Properties of Didymos Working Group supports this mission by addressing questions related to understanding the dynamical state of the system and inferring physical properties. Didymos is an Apollo-class NEA that likely reached its current orbit by exiting the inner main belt near or within the nu-6 resonance (> 82% chance) [3]. Remote observations [4] show Didymos is spectroscopically most consistent with ordinary chondrites. The diameters of the binary components are measured to be about 780 and 160 m [5]. A model of the short-term binary dynamics suggests possible librations of the secondary with up to ~10-deg amplitude, depending on its axial ratio. However, an equilibrium orbital and rotational solution is consistent with a libration amplitude of only ~1 deg. The primary, with an estimated 2.1 g/cc bulk density (uncertainty 30%) has a possibly super-critical rotation period of 2.26 h that may imply a cohesive strength of several tens of Pa. At this rate, perturbed regolith material may go through take-off/landing cycles and cause loss of fines due to solar radiation pressure. Based on a continuum analysis [6], the internal structure would likely fail before the equatorial region. A discrete analysis [7,8] shows that a minimum of 2.5 g/cc bulk density is needed for the structure to hold without cohesion. The system may be subject to weak thermal radiation forces (BYORP) with a period drift of no greater than 1 s/yr [9]. Experiments using the ISAE-SUPAERO drop tower [10] are underway to model the possible deployment of a lander on the secondary. References: [1] Michel et al. 2016, ASR 57, 2529; [2] Cheng et al. 2016, P&SS 127, 27; [3] Granvik et al. 2015, DPS 47, 214.07; [4] Dunn et al. 2013, LPSC 44, 1719; [5] Osip et al. 2016, this meeting; [6] Hirabayashi & Scheeres 2015, IAU 29, 2256185; [7] Barnouin et al. 2015, DPS 47, 402.09; [8] Zhang et al. 2016, this meeting; [9] McMahon et al. 2016, LPSC 47, 1903; [10] Sunday et al. 2016, Rev. Sci. Instr., accepted.

Gemini and Keck Observations of Slowly Rotating, Bilobate Active Asteroid (300163)

NASA Astrophysics Data System (ADS)

Waniak, Waclaw; Drahus, Michal

2016-10-01

One of the most puzzling questions regarding Active Asteroids is the mechanism of their activation. While some Active Asteroids show protracted and often recurrent mass loss, consistent with seasonal ice sublimation, some other eject dust impulsively as a result of a catastrophic disruption (e.g. Jewitt et al. 2015, Asteroids IV, 221). It has been suggested that ice can be excavated from the cold near-surface interior by an impact (Hsieh & Jewitt 2006, Science 312, 561) or, for small objects susceptible to YORP torques, by near-critical spin rate (Sheppard & Trujillo 2014, AJ 149, 44). But impact and rapid spin can also cause a catastrophic disruption (e.g. Jewitt et al. 2015, Asteroids IV, 221). It therefore becomes apparent that the different types of mass loss observed in Active Asteroids can be best classified and understood based on the nucleus spin rates (Drahus et al. 2015, ApJL 802, L8), but unfortunately the rotation periods have been measured for a very limited number of these objects. With this in mind we have initiated a survey of light curves of small Active Asteroids on the largest ground-based optical telescopes. Here we present the results for (300163), also known as 288P and 2006 VW139, which is a small 2.6-km sized asteroid that exhibited a comet-like activity over 100 days in the second half of 2011 (Hsieh et al. 2012, ApJL 748, L15; Licandro et al. 2013, A&A 550, A17; Agarwal et al. 2016, AJ 151, 12). Using Keck/DEIMOS and Gemini/GMOS-S working in tandem on UT 2015 May 21-22 we have detected an inactive nucleus and measured a complete, dense, high-S/N rotational light curve. The light curve has a double-peaked period of 16 hours, an amplitude of 0.4 mag, and moderately narrow minima suggesting a bilobate or contact-binary shape. The long rotation period clearly demonstrates a non-rotational origin of activity of this object, consistent with an impact. Furthermore, among the five small Active Asteroids with known rotation periods (300163) is only the second object with a confirmed slow spin rate, the other three rotating rapidly, near the limit of rotational stability. This suggests that rotation- and impact-driven origin of activity can be comparably common among small asteroids.

New Variable Stars Discovered by Data Mining Images Taken during Recent Asteroid Photometric Observations. II. Results from July 2015 through December 2016

NASA Astrophysics Data System (ADS)

Papini, R.; Marchini, A.; Salvaggio, F.; Agnetti, D.; Bacci, P.; Banfi, M.; Bianciardi, G.; Collina, M.; Franco, L.; Galli, G.; Milani, M. G. A.; Lopresti, C.; Marino, G.; Rizzuti, L.; Ruocco, N.; Quadri, U.

2017-12-01

This paper follows the previous publication of new variables discovered at Astronomical Observatory, DSFTA, University of Siena, while observing asteroids in order to determine their rotational periods. Usually, this task requires time series images acquisition on a single field for as long as possible on a few nights not necessarily consecutive. Checking continually this "goldmine" allowed us to discover 57 variable stars not yet listed in catalogues or databases. While most of the new variables are eclipsing binaries, a few belong to the RR Lyrae or delta Scuti class. Since asteroid work is definitely a time-consuming activity, coordinated campaigns of follow-up with other observatories have been fundamental in order to determine the elements of the ephemeris and sometimes the right subclass of variability. Further observations of these new variables are therefore strongly encouraged in order to better characterize these stars, especially pulsating ones whose data combined with those taken during professional surveys seem to suggest the presence of light curve amplitude and period variations.

THE PHYSICAL CHARACTERIZATION OF THE POTENTIALLY HAZARDOUS ASTEROID 2004 BL86: A FRAGMENT OF A DIFFERENTIATED ASTEROID

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, Vishnu; Sanchez, Juan A.; Takir, Driss

The physical characterization of potentially hazardous asteroids (PHAs) is important for impact hazard assessment and evaluating mitigation options. Close flybys of PHAs provide an opportunity to study their surface photometric and spectral properties that enable the identification of their source regions in the main asteroid belt. We observed PHA (357439) 2004 BL86 during a close flyby of the Earth at a distance of 1.2 million km (0.0080 AU) on 2015 January 26, with an array of ground-based telescopes to constrain its photometric and spectral properties. Lightcurve observations showed that the asteroid was a binary and subsequent radar observations confirmed themore » binary nature and gave a primary diameter of 300 m and a secondary diameter of 50–100 m. Our photometric observations were used to derive the phase curve of 2004 BL86 in the V-band. Two different photometric functions were fitted to this phase curve, the IAU H–G model and the Shevchenko model. From the fit of the H–G function we obtained an absolute magnitude of H = 19.51 ± 0.02 and a slope parameter of G = 0.34 ± 0.02. The Shevchenko function yielded an absolute magnitude of H = 19.03 ± 0.07 and a phase coefficient b = 0.0225 ± 0.0006. The phase coefficient was used to calculate the geometric albedo (Ag) using the relationship found by Belskaya and Schevchenko, obtaining a value of Ag = 40% ± 8% in the V-band. With the geometric albedo and the absolute magnitudes derived from the H–G and the Shevchenko functions we calculated the diameter (D) of 2004 BL86, obtaining D = 263 ± 26 and D = 328 ± 35 m, respectively. 2004 BL86 spectral band parameters and pyroxene chemistry are consistent with non-cumulate eucrite meteorites. A majority of these meteorites are derived from Vesta and are analogous with surface lava flows on a differentiated parent body. A non-diagnostic spectral curve match using the Modeling for Asteroids tool yielded a best-match with non-cumulate eucrite Bereba. Three other near-Earth asteroids (1993 VW, 1998 KK17, and 2000 XH44) that were observed by Burbine et al. also have spectral properties similar to 2004 BL86. The presence of eucrites with anomalous oxygen isotope ratios compared to the howardites, eucrites, and diogenites meteorites from Vesta suggests the possible presence of multiple differentiated bodies in the inner main belt or the contamination of Vesta’s surface with exogenic material. The spectral properties of both anomalous and Vestan eucrites are degenerate, making it difficult to identify the parent bodies of anomalous eucrites in the main belt and the NEO population using remote sensing. This makes it difficult to link 2004 BL86 directly to Vesta, although the Vesta family is the largest contributor of V-types to near-Earth space.« less

Observations of Planet Crossing Asteroids

NASA Technical Reports Server (NTRS)

Tholen, David J.; Whiteley, Robert J.; Lambert, Joy; Connelley, Michael; Salyk, Colette

2002-01-01

The goals of this research were the physical and dynamical characterization of planet crossing asteroids (Earth crossers, Mars crossers, Centaurs, and Pluto crossers, meaning trans-Neptunian objects), including colorimetry, rotational studies, and astrometry. Highlights are listed as follows: 1) Produced one doctoral dissertation (R. J. Whiteley, A Compositional and Dynamical Survey of the Near-Earth Asteroids). A key result is the fraction of Q-type asteroids among the near-Earth population was found to be about one-third; 2) Had prediscovery image showing the binary nature of trans-Neptunian object 1998 WW31, which is the first TNO to have a satellite found in orbit around it; 3) Discovery of shortest known rotation period for any asteroid (2000 D08, rotation period 78 seconds); it is just one of several fast-rotating small asteroids observed during the course of this project; 4) Discovery of a Centaur asteroid (1998 QM107) with, at the time, the smallest known orbital eccentricity among the Centaurs (0.13) and nearly in a 1:1 resonance with Uranus (semimajor axis of 19.9 AU); 5) Discovery of Apollo-type asteroid 1999 OW3, with a surprisingly bright absolute magnitude of 14.6 (estimated diameter of 4.6 km), brightest Apollo found in that calendar year; 6) Discovery of Aten-type asteroid 2000 SG344, which has the highest cumulative Earth impact probability among the near-Earth asteroids and a very Earth-similar orbit; 7) Instrumental in repairing the orbit of a numbered near-Earth asteroid for which prediscovery observations had been mis-attributed to it (2000 VN2); 8) Second-opposition recovery of 30-meter diameter Apollo-type asteroid 1998 KY26 in early 2002 when it was at a favorable magnitude of 24.8; 9) Primary contributor of astrometric observations of the CONTOUR fragments to the CONTOUR project following the failure of the spacecraft s kick motor; and 10) Development of orbit and ephemeris computation code that handles short observational arcs, observations at small solar elongations where indeterminacy is a known problem, and a small number of observations (including just two). Starting in 2000 November, the Spaceguard Central Node began prioritizing near-Earth asteroids in need of astrometric observation. Our own follow-up efforts relied on these listings, with emphasis given to the faintest objects where the combination of a 2.2-m telescope and a site with subarcsecond seeing produces a limiting magnitude close to 25, which represents a unique and valuable capability. The attached table, last updated in August, demonstrates the arc-lengthening capabilities of a faint limiting magnitude. Tabulated are the arc lengths before and after our observation(s), whether our observation is the last one available for the object in question, and the approximate magnitude of the object at the time of the observation.

Asteroid Impact Deflection and Assessment (AIDA) mission - Full-Scale Modeling and Simulation of Ejecta Evolution and Fates

NASA Astrophysics Data System (ADS)

Fahnestock, Eugene G.; Yu, Yang; Hamilton, Douglas P.; Schwartz, Stephen; Stickle, Angela; Miller, Paul L.; Cheng, Andy F.; Michel, Patrick; AIDA Impact Simulation Working Group

2016-10-01

The proposed Asteroid Impact Deflection and Assessment (AIDA) mission includes NASA's Double Asteroid Redirection Test (DART), whose impact with the secondary of near-Earth binary asteroid 65803 Didymos is expected to liberate large amounts of ejecta. We present efforts within the AIDA Impact Simulation Working Group to comprehensively simulate the behavior of this impact ejecta as it moves through and exits the system. Group members at JPL, OCA, and UMD have been working largely independently, developing their own strategies and methodologies. Ejecta initial conditions may be imported from output of hydrocode impact simulations or generated from crater scaling laws derived from point-source explosion models. We started with the latter approach, using reasonable assumptions for the secondary's density, porosity, surface cohesive strength, and vanishingly small net gravitational/rotational surface acceleration. We adopted DART's planned size, mass, closing velocity, and impact geometry for the cratering event. Using independent N-Body codes, we performed Monte Carlo integration of ejecta particles sampled over reasonable particle size ranges, and over launch locations within the crater footprint. In some cases we scaled the number of integrated particles in various size bins to the estimated number of particles consistent with a realistic size-frequency distribution. Dynamical models used for the particle integration varied, but all included full gravity potential of both primary and secondary, the solar tide, and solar radiation pressure (accounting for shadowing). We present results for the proportions of ejecta reaching ultimate fates of escape, return impact on the secondary, and transfer impact onto the primary. We also present the time history of reaching those outcomes, i.e., ejecta clearing timescales, and the size-frequency distribution of remaining ejecta at given post-impact durations. We find large numbers of particles remain in the system for several weeks after impact. Clearing timescales are nonlinearly dependent on particle size as expected, such that only the largest ejecta persist longest. We find results are strongly dependent on the local surface geometry at the modeled impact locations.

Asteroid volatiles inventory

NASA Technical Reports Server (NTRS)

Lebofsky, L. A.; Jones, T. D.; Herbert, F.

1989-01-01

Asteroids appear in light of telescopic and meteority studies to be the most accessible repositories of early solar system history available. In the cooler regions of the outer asteroid belt, apparently unaffected by severe heating, the C, P, and D populations appear to harbor significant inventories of volatiles; the larger primordial belt population may have had an even greater percentage of volatile-rich, low-albedo asteroids, constituting a potent asteroid for veneering early terrestrial planet atmospheres. The volatile-rich asteroids contain carbon, structurally bound and adsorbed water, as well as remnants of interstellar material predating the solar system.

The 1986 DA and 1986 EB: M-class asteroids in near-Earth orbits

NASA Technical Reports Server (NTRS)

Gradie, Jonathan; Tedesco, Edward

1987-01-01

The Earth-approaching asteroid population is composed of asteroids in orbits with short lifetimes compared with the age of the solar system. These objects which are comprised of Aten, Apollo, and Amor asteroids must be replenished from either cometary or mainbelt asteroid sources since lifetimes against collision with or ejection by a planet are on the order of 10 to 100 million years. The physical study of Earth-approaching asteroids is constrained by the generally long period between favorable apparitions and poorly known orbits. Broadband spectrophotometry on the Johnson UBVR system and the Eight-Color Asteroid Survey system were obtained at Kitt Peak National Observatory and on the Johnson JHK system and at 10 and 20 microns at the NASA Infrared Telescope Facility at Mauna Kea Observatory. These observations were used to determine the absolute visual magnitudes and to derive the visual geometric albedos and diameters on the IRAS system. The spectral reflectance properties and geometric albedos of the M-class asteroids are consistent compositions analogous to the iron nickel meteorites or the enstatite-metal assemblages of the enstatite chondrites. The issue of the source(s) of the near-Earth asteroids population was examined by comparing the classifications on the scheme employed by Gradie and Tedesco of 38 such asteroids. Most of the near-Earth objects is indeed the asteroid belt as the observations suggest, then a method for removing extinct nuclei of short period comets must be found since the rate of production of short period comets from the long period comets is relatively large.

Main-belt asteroid exploration - Mission options for the 1990s

NASA Technical Reports Server (NTRS)

Yen, C.-W. L.

1982-01-01

Mission configurations, propulsion systems, and target bodies for possible NASA asteroid exploration projects are examined. Noting that an announced delay in the development of a solar electric propulsion system has led to a consideration of chemical rocket systems, asteroid missions are grouped in terms of five potential areas for investigation, each successively further from the sun. The Shuttle-launched IUS is suggested as the prime candidate for boosting probes into trajectories for asteroid rendezvous with a number of the 3000 known asteroids. Planetary swingbys are mentioned as the only suitable method for satisfying the large energy requirements of the asteroid missions. Performance analyses are presented of the IUS 2-stage/Star-48 and Centaur vehicles, and sample missions to Fortuna, Anahita, and Urania in 1990 and further missions to the middle, outer, and Trojans asteroids are outlined.

Capturing asteroids into bound orbits around the earth: Massive early return on an asteroid terminal defense system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hills, J.G.

1992-02-06

Nuclear explosives may be used to capture small asteroids (e.g., 20--50 meters in diameter) into bound orbits around the earth. The captured objects could be used for construction material for manned and unmanned activity in Earth orbit. Asteroids with small approach velocities, which are the ones most likely to have close approaches to the Earth, require the least energy for capture. They are particularly easy to capture if they pass within one Earth radius of the surface of the Earth. They could be intercepted with intercontinental missiles if the latter were retrofit with a more flexible guiding and homing capability.more » This asteroid capture-defense system could be implemented in a few years at low cost by using decommissioned ICMs. The economic value of even one captured asteroid is many times the initial investment. The asteroid capture system would be an essential part of the learning curve for dealing with larger asteroids that can hit the earth.« less

Reflectance spectrophotometry (about 0.5-1.0 micron) of oute-belt asteroids - Implications for primitive, organic solar system material

NASA Technical Reports Server (NTRS)

Vilas, F.; Smith, B. A.

1985-01-01

The surface compositions of outer-belt asteroids were used to obtain information about the origin of these asteroids. High-resolution CCD reflectance spectra of 21 asteroids, primarily P class, were examined for compositional information. Distinct slope changes are observed that suggest that these asteroids are the remnants of a compositional gradation of planetesimals in the outer solar system, which were retained selectively in location when other material was ejected from the solar system. Other data suggest that this gradation could extend through the orbits of Uranus and Neptune.

First results of the seven-color asteroid survey

NASA Astrophysics Data System (ADS)

Clark, Beth E.; Bell, Jeffrey F.; Fanale, Fraser P.; Lucey, Paul G.

1993-03-01

The new Seven-Color infrared filter system (SCAS), designed specifically to capture the essential mineralogical information present in asteroid spectra, is composed of seven broad-band filters which allow for IR observations of objects as faint as 17th magnitude. The first test of the SCAS system occurred in Jul. 1992. In four nights at the IRTF on Mauna Kea, Hawaii, over 67 objects were observed. Five of the observations were to test the new system for accuracy relative to previous observations with the high-resolution 52 Color Infrared Survey and with the Eight-Color Asteroid Survey (ECAS). In three cases, the match with previous data was good. In two cases, the match to previous observations was not as good. In addition, sixty S-Type asteroids were measured with the SCAS system. Forty of those asteroids were also observed with the ECAS system. Among the new observations is infrared data of 371 Bohemia, a main belt asteroid which was classified 'QSV' according to its UBV colors in the taxonomic system of D.J. Tholen. There are no corresponding ECAS data for 371. Q-type asteroids are of special interest as they are proposed to be the elusive parent bodies of the ordinary chondrite meteorites. Most Q-types are Earth-crossing asteroids and have not yet been observed in the infrared (except, perhaps, 371). Positive identification of a large main belt Q-type would be of major importance in the scheme of the geological structure of the asteroid belt. Without visible wavelength data, however, the classification of 371 Bohemia remains ambiguous. An attempt to conjoin Bohemia SCAS data with ECAS data of both a typical Q-Type asteroid and an average S-Type asteroid is shown. This figure thus illustrates the importance of visible wavelength data to the SCAS system. In other words, without ECAS data of 371 Bohemia we cannot use its spectral characteristics to identify it as a possible parent body of ordinary chondrite meteorites.

Application of a Novel Long-Reach Manipulator Concept to Asteroid Redirect Missions

NASA Technical Reports Server (NTRS)

Dorsey, John T.; Doggett, William R.; Jones, Thomas C.; King, Bruce D.

2015-01-01

A high priority mission currently being formulated by NASA is to capture all or part of an asteroid and return it to cis-lunar space for examination by an astronaut crew. Two major mission architectures are currently being considered: in the first (Mission Concept A), a spacecraft would rendezvous and capture an entire free flying asteroid (up to 14 meters in diameter), and in the second (Mission Concept B), a spacecraft would rendezvous with a large asteroid (which could include one of the Martian moons) and retrieve a boulder (up to 4 meters in diameter). A critical element of the mission is the system that will capture the asteroid or boulder material, enclose it and secure it for the return flight. This paper describes the design concepts, concept of operations, structural sizing and masses of capture systems that are based on a new and novel Tendon- Actuated Lightweight In-Space MANipulator (TALISMAN) general-purpose robotic system. Features of the TALISMAN system are described and the status of its technology development is summarized. TALISMAN-based asteroid material retrieval system concepts and concepts-of-operations are defined for each asteroid mission architecture. The TALISMAN-based capture systems are shown to dramatically increase operational versatility while reducing mission risk. Total masses of TALISMAN-based systems are presented, reinforcing the mission viability of using a manipulator-based approach for the asteroid redirect mission.

Binary asteroid population. 3. Secondary rotations and elongations

NASA Astrophysics Data System (ADS)

Pravec, P.; Scheirich, P.; Kušnirák, P.; Hornoch, K.; Galád, A.; Naidu, S. P.; Pray, D. P.; Világi, J.; Gajdoš, Š.; Kornoš, L.; Krugly, Yu. N.; Cooney, W. R.; Gross, J.; Terrell, D.; Gaftonyuk, N.; Pollock, J.; Husárik, M.; Chiorny, V.; Stephens, R. D.; Durkee, R.; Reddy, V.; Dyvig, R.; Vraštil, J.; Žižka, J.; Mottola, S.; Hellmich, S.; Oey, J.; Benishek, V.; Kryszczyńska, A.; Higgins, D.; Ries, J.; Marchis, F.; Baek, M.; Macomber, B.; Inasaridze, R.; Kvaratskhelia, O.; Ayvazian, V.; Rumyantsev, V.; Masi, G.; Colas, F.; Lecacheux, J.; Montaigut, R.; Leroy, A.; Brown, P.; Krzeminski, Z.; Molotov, I.; Reichart, D.; Haislip, J.; LaCluyze, A.

2016-03-01

We collected data on rotations and elongations of 46 secondaries of binary and triple systems among near-Earth, Mars-crossing and small main belt asteroids. 24 were found or are strongly suspected to be synchronous (in 1:1 spin-orbit resonance), and the other 22, generally on more distant and/or eccentric orbits, were found or are suggested to have asynchronous rotations. For 18 of the synchronous secondaries, we constrained their librational angles, finding that their long axes pointed to within 20° of the primary on most epochs. The observed anti-correlation of secondary synchroneity with orbital eccentricity and the limited librational angles agree with the theories by Ćuk and Nesvorný (Ćuk, M., Nesvorný, D. [2010]. Icarus 207, 732-743) and Naidu and Margot (Naidu, S.P., Margot, J.-L. [2015]. Astron. J. 149, 80). A reason for the asynchronous secondaries being on wider orbits than synchronous ones may be longer tidal circularization time scales at larger semi-major axes. The asynchronous secondaries show relatively fast spins; their rotation periods are typically < 10 h. An intriguing observation is a paucity of chaotic secondary rotations; with an exception of (35107) 1991 VH, the secondary rotations are single-periodic with no signs of chaotic rotation and their periods are constant on timescales from weeks to years. The secondary equatorial elongations show an upper limit of a2 /b2 ∼ 1.5 . The lack of synchronous secondaries with greater elongations appears consistent, considering uncertainties of the axis ratio estimates, with the theory by Ćuk and Nesvorný that predicts large regions of chaotic rotation in the phase space for a2 /b2 ≳√{ 2 } . Alternatively, secondaries may not form or stay very elongated in gravitational (tidal) field of the primary. It could be due to the secondary fission mechanism suggested by Jacobson and Scheeres (Jacobson, S.A., Scheeres, D.J. [2011]. Icarus 214, 161-178), as its efficiency is correlated with the secondary elongation. Sharma (Sharma, I. [2014]. Icarus 229, 278-294) found that rubble-pile satellites with a2 /b2 ≲ 1.5 are more stable to finite structural perturbations than more elongated ones. It appears that more elongated secondaries, if they originally formed in spin fission of parent asteroid, are less likely to survive intact and they more frequently fail or fission.

Taxonomy of asteroids. [according to polarimetric, spectrophotometric, radiometric, and UBV photometric data

NASA Technical Reports Server (NTRS)

Bowell, E.; Chapman, C. R.; Gradie, J. C.; Zellner, B.; Morrison, D.

1978-01-01

A taxonomic system for asteroids is discussed which is based on seven directly observable parameters from polarimetry, spectrophotometry, radiometry, and UBV photometry. The classification scheme is entirely empirical and independent of specific mineralogical interpretations. Five broad classes (designated C, S, M, E, and R), as well as an 'unclassifiable' designation, are defined on the basis of observational data for 523 asteroids. Computer-generated type classifications and derived diameters are given for the 523 asteroids, and the application of the classification procedure is illustrated. Of the 523 asteroids classified, 190 are identified as C objects, 141 as S type, 13 as type M, three as type E, three as type R, 55 as unclassifiable, and 118 as ambiguous. The present taxonomic system is compared with several other asteroid classification systems.

New Variable Stars Discovered by Data Mining Images Taken During Recent Asteroid Photometric Observations. Results from the Year 2015

NASA Astrophysics Data System (ADS)

Papini, R.; Franco, L.; Marchini, A.; Salvaggio, F.

2015-12-01

During the past year the authors observed several asteroids for the purpose of determining the rotational period. Typically, this task requires a time series images acquisition on a single field for all the night, weather permitting, for a few nights although not consecutive. Routinely checking this "goldmine," allowed us to discover 14 variable stars not yet listed in catalogs or databases. While the most of the new variables are eclipsing binaries (GSC 01394-01889, GSC 00853-00371, CSS_J171124.7-004042, GSC05065-00218, UCAC4-386-142199, UCAC4 398-127457, UCAC4 384-148138, UCAC4 398-127590, UCAC4-383-155837, GSC-05752-01113, GSC 05765-01271), a few belong to RR Lyrae class (UCAC4 388-136835, 2MASS J20060657-1230376, UCAC4 386-142583). Since asteroid work is definitely time-consuming, follow-up is quite a difficult task for a small group. Further observations of these new variables are therefore strongly encouraged in order to better characterize these stars, especially RR Lyrae ones whose data combined with those taken during professional surveys seem to suggest the presence of a Blazhko effect.

Momentum harvesting techniques for solar system travel

NASA Technical Reports Server (NTRS)

Willoughby, Alan J.

1990-01-01

Astronomers are lately estimating there are 400,000 Earth visiting asteroids larger than 100 meters in diameter. These asteroids are accessible sources of building materials, propellants, oxygen, water, and minerals which also constitute a huge momentum reserve, potentially usable for travel throughout the solar system. To use this momentum, these stealthy objects must be tracked and the extraction of the momentum wanted must be learned. Momentum harvesting by momentum transfer from asteroid to spacecraft, and by using the momentum of the extraterrestrial material to help deliver itself to the destination are discussed. A net and tether concept is the suggested means of asteroid capture, the basic momentum exchange process. The energy damping characteristics of the tether will determine the velocity mismatch that can be tolerated, and hence the amount of momentum that can be harvested per capture. As it plays out of its reel, drag on the tether steadily accelerates the spacecraft. A variety of concepts for riding and using the asteroid after capture are discussed. The hitchhiker uses momentum transfer only. The beachcomber, the caveman, the swinger, the prospector, and the rock wrecker also take advantage of raw asteroidal materials. The chemist and the hijacker go further, they process the asteroid into propellant. Or, an 'asteroid railway system' could evolve with each hijacked asteroid becoming a scheduled train. Travelers could board the space railway system assured that water, oxygen, and propellants await them.

Special issue on asteroids - Introduction

NASA Astrophysics Data System (ADS)

Novaković, Bojan; Hsieh, Henry H.; Gronchi, Giovanni F.

2018-04-01

The articles in this special issue are devoted to asteroids, small solar system bodies that primarily populate a region between the orbits of Mars and Jupiter, known as the asteroid belt, but can also be found throughout the Solar System. Asteroids are considered to be a key to understanding the formation and evolution of our planetary system. Their properties allow us to test current theoretical models and develop new theoretical concepts pertaining to evolutionary processes in the Solar System. There have been major advances in asteroid science in the last decade, and that trend continues. Eighteen papers accepted for this special issue cover a wide range of asteroid-related subjects, pushing the boundaries of our understanding of these intriguing objects even further. Here we provide the reader with a brief overview of these thrilling papers, with an invitation for interested scientists to read each work in detail for a better understanding of these recent cutting edge results. As many topics in asteroid science remain open challenges, we hope that this special issue will be an important reference point for future research on this compelling topic.

Antimatter applied for Earth protection from asteroid collision

NASA Technical Reports Server (NTRS)

Satori, Shin; Kuninaka, Hitoshi; Kuriki, Kyoichi

1990-01-01

An Earth protection system against asteroids and meteorites in colliding orbit is proposed. The system consists of detection and deorbiting systems. Analyses are given for the resolution of microwave optics, the detectability of radar, the orbital plan of intercepting operation, and the antimatter mass require for totally or partially blasting the asteroid. Antimatter of 1 kg is required for deorbiting an asteroid 200 m in diameter. An experimental simulation of antimatter cooling and storage is planned. The facility under construction is discussed.

Asteroid 2017 FZ2 et al.: signs of recent mass-shedding from YORP?

NASA Astrophysics Data System (ADS)

de la Fuente Marcos, C.; de la Fuente Marcos, R.

2018-01-01

The first direct detection of the asteroidal Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, a phenomenon that changes the spin states of small bodies due to thermal reemission of sunlight from their surfaces, was obtained for (54509) YORP 2000 PH5. Such an alteration can slowly increase the rotation rate of asteroids, driving them to reach their fission limit and causing their disruption. This process can produce binaries and unbound asteroid pairs. Secondary fission opens the door to the eventual formation of transient but genetically related groupings. Here, we show that the small near-Earth asteroid (NEA) 2017 FZ2 was a co-orbital of our planet of the quasi-satellite type prior to their close encounter on 2017 March 23. Because of this flyby with the Earth, 2017 FZ2 has become a non-resonant NEA. Our N-body simulations indicate that this object may have experienced quasi-satellite engagements with our planet in the past and it may return as a co-orbital in the future. We identify a number of NEAs that follow similar paths, the largest named being YORP, which is also an Earth's co-orbital. An apparent excess of NEAs moving in these peculiar orbits is studied within the framework of two orbit population models. A possibility that emerges from this analysis is that such an excess, if real, could be the result of mass shedding from YORP itself or a putative larger object that produced YORP. Future spectroscopic observations of 2017 FZ2 during its next visit in 2018 (and of related objects when feasible) may be able to confirm or reject this interpretation.

A Parameter Study on the Effect of Impactor Size for NASA’s DART Mission

NASA Astrophysics Data System (ADS)

Truitt, Amanda; Weaver, Robert; Gisler, Galen

2018-06-01

We have modeled the impact of the Double Asteroid Redirection Test (DART) spacecraft into the binary near-Earth asteroid (65803) Didymos. While the primary object is approximately 800 meters across, its secondary body (“moonlet” Didymoon) has a diameter of 150 meters, which is thought to be a much more typical size for the kind of asteroid that would pose a hazard to Earth. DART will be the first demonstration of the kinetic impact technique to change the motion of an asteroid in space, an important consideration for understanding our capabilities in planetary defense of Near-Earth Asteroids. Recent modeling of this impact has used full-density solid aluminum spheres with a mass of approximately 500 kg. Many of the published scaling laws for crater size and diameter as well as ejecta modeling assume this type of impactor, although the actual spacecraft shape being considered for the DART Mission impact is not solid and does not contain a solid dedicated kinetic impactor – rather, the spacecraft itself is considered the impactor. Since the 500 kg hollow spacecraft is significantly larger (~100 x 100 x 200 cm) in size than a solid aluminum sphere (radius ~ 36 cm) the resulting impact dynamics are quite different. Here we have modeled both types of impacts and compare the results of the simulations for crater size, depth, and ejecta for a solid sphere (R = 36 cm) and cylindrical spacecraft (R = 20, 50, and 100 cm), while maintaining a constant mass and material density. This work will allow for a more robust comparison of the momentum enhancement β-factor, which describes the gain in a momentum transfer exerted by the impacting spacecraft on a Near-Earth Object due to ejecta momentum escape. (LA-UR-18-21571)

DE-STARLITE: A directed energy planetary defense mission

NASA Astrophysics Data System (ADS)

Kosmo, Kelly; Pryor, Mark; Lubin, Philip; Hughes, Gary B.; O'Neill, Hugh; Meinhold, Peter; Suen, Jonathan; Riley, Jordan; Griswold, Janelle; Cook, Brianna V.; Johansson, Isabella E.; Zhang, Qicheng; Walsh, Kevin; Melis, Carl; Kangas, Miikka; Bible, Johanna; Motta, Caio; Brashears, Travis; Mathew, Shana; Bollag, Justin

2014-09-01

This paper presents the motivation behind and design of a directed energy planetary defense system that utilizes laser ablation of an asteroid to impart a deflecting force on the target. The proposed system is called DE-STARLITE for Directed Energy System for Targeting of Asteroids and ExploRation - LITE as it is a small, stand-on unit of a larger standoff DE-STAR system. Pursuant to the stand-on design, ion engines will propel the spacecraft from low-Earth orbit (LEO) to the near-Earth asteroid (NEA). During laser ablation, the asteroid itself becomes the "propellant"; thus a very modest spacecraft can deflect an asteroid much larger than would be possible with a system of similar mission mass using ion beam deflection (IBD) or a gravity tractor. DE-STARLITE is capable of deflecting an Apophis-class (325 m diameter) asteroid with a 15-year targeting time. The mission fits within the rough mission parameters of the Asteroid Redirect Mission (ARM) program in terms of mass and size and has much greater capability for planetary defense than current proposals and is readily scalable to the threat. It can deflect all known threats with sufficient warning.

Birth of an Earth-like Planet (Artist concept)

NASA Technical Reports Server (NTRS)

2007-01-01

This artist's conception shows a binary-star, or two-star, system, called HD 113766, where astronomers suspect a rocky Earth-like planet is forming around one of the stars. At approximately 10 to 16 million years old, astronomers suspect this star is at just the right age for forming rocky planets. The system is located approximately 424 light-years away from Earth.

The two yellow spots in the image represent the system's two stars. The brown ring of material circling closest to the central star depicts a huge belt of dusty material, more than 100 times as much as in our asteroid belt, or enough to build a Mars-size planet or larger. The rocky material in the belt represents the early stages of planet formation, when dust grains clump together to form rocks, and rocks collide to form even more massive rocky bodies called planetesimals. The belt is located in the middle of the system's terrestrial habitable zone, or the region around a star where liquid water could exist on any rocky planets that might form. Earth is located in the middle of our sun's terrestrial habitable zone.

Using NASA's Spitzer Space Telescope, astronomers learned that the belt material in HD 113866 is more processed than the snowball-like stuff that makes up infant solar systems and comets, which contain pristine ingredients from the early solar system. However, it is not as processed as the stuff found in mature planets and asteroids. This means that the dust belt is made out of just the right mix of materials to be forming an Earth-like planet. It is composed mainly of rocky silicates and metal sulfides (like fool's gold), similar to the material found in lava flows.

The white outer ring shows a concentration of icy dust also detected in the system. This material is at the equivalent position of the asteroid belt in our solar system, but only contains about one-sixth as much material as the inner ring. Astronomers say it is not clear from the Spitzer observations if anything is occurring in the icy belt, but they believe it could be a source of water later on for the planet that grows from the inner warm ring.

All-Sky Census of Variable Stars from the ATLAS Survey

NASA Astrophysics Data System (ADS)

Heinze, Aren Nathaniel; Tonry, John; Denneau, Larry; Stalder, Brian

2018-01-01

The Asteroid Terrestrial-Impact Last Alert Survey uses two custom-built 0.5 meter telescopes to scan the whole accessible sky down to magnitude 19.5 every two nights, with a cadence optimized to detect small asteroids on their 'final plunge' toward impact with Earth. This cadence is also well suited to the detection of variable stars with a huge range of periods and properties, while ATLAS' use of two filters provides additional scientific depth. From the first two years of ATLAS data we have constructed a catalog of several hundred thousand variable objects with periods from one hour to hundreds of days. These include RR Lyrae stars, Cepheids, eclipsing binaries, spotted stars, ellipsoidal variables, Miras; and other objects both regular and irregular. We describe the construction of this catalog, including our multi-step confirmation process for genuine variables; some big-picture scientific conclusions; and prospects for more detailed results.

The binary Asteroid 22 Kalliope: Linus orbit determination on the basis of speckle interferometric observations

NASA Astrophysics Data System (ADS)

Sokova, I. A.; Sokov, E. N.; Roschina, E. A.; Rastegaev, D. A.; Kiselev, A. A.; Balega, Yu. Yu.; Gorshanov, D. L.; Malogolovets, E. V.; Dyachenko, V. V.; Maksimov, A. F.

2014-07-01

In this paper we present the orbital elements of Linus satellite of 22 Kalliope asteroid. Orbital element determination is based on the speckle interferometry data obtained with the 6-m BTA telescope operated by SAO RAS. We processed 9 accurate positions of Linus orbiting around the main component of 22 Kalliope between 10 and 16 December, 2011. In order to determine the orbital elements of the Linus we have applied the direct geometric method. The formal errors are about 5 mas. This accuracy makes it possible to study the variations of the Linus orbital elements influenced by different perturbations over the course of time. Estimates of six classical orbital elements, such as the semi-major axis of the Linus orbit a = 1109 ± 6 km, eccentricity e = 0.016 ± 0.004, inclination i = 101° ± 1° to the ecliptic plane and others, are presented in this work.

OSIRIS-REx A NASA Mission to a Near Earth Asteroid!...and Other Recent Happenings in the Solar System

NASA Technical Reports Server (NTRS)

Moreau, Michael C.

2015-01-01

The OSIRIS-REx Mission launches in 2016 Arrives at Asteroid Bennu-2018 Returns a sample to Earth -2023 The mission, OSIRIS-REx, will visit an asteroid and return a sample from the early Solar System to help us understand how our Solar System formed.

Comet/Asteroid Protection System (CAPS): A Space-Based System Concept for Revolutionizing Earth Protection and Utilization of Near-Earth Objects

NASA Technical Reports Server (NTRS)

Mazanek, Daniel D.; Roithmayr, Carlos M.; Antol, Jeffrey; Kay-Bunnell, Linda; Werner, Martin R.; Park, Sang-Young; Kumar, Renjith R.

2002-01-01

There exists an infrequent, but significant hazard to life and property due to impacting asteroids and comets. There is currently no specific search for long-period comets, smaller near-Earth asteroids, or smaller short-period comets. These objects represent a threat with potentially little or no warning time using conventional ground-based telescopes. These planetary bodies also represent a significant resource for commercial exploitation, long-term sustained space exploration, and scientific research. The Comet/Asteroid Protection System (CAPS) would expand the current detection effort to include long-period comets, as well as small asteroids and short-period comets capable of regional destruction. A space-based detection system, despite being more costly and complex than Earth-based initiatives, is the most promising way of expanding the range of detectable objects, and surveying the entire celestial sky on a regular basis. CAPS is a future spacebased system concept that provides permanent, continuous asteroid and comet monitoring, and rapid, controlled modification of the orbital trajectories of selected bodies. CAPS would provide an orbit modification system capable of diverting kilometer class objects, and modifying the orbits of smaller asteroids for impact defense and resource utilization. This paper provides a summary of CAPS and discusses several key areas and technologies that are being investigated.

A cheaper, faster, better way to detect water of hydration on Solar System bodies

NASA Technical Reports Server (NTRS)

Vilas, Faith

1994-01-01

The 3.0-micrometers water of hydration absorption feature observed in the IR photometry of many low-albedo and some medium-albedo asteroids strongly correlates with the 0.7-micrometers Fe(+2) to Fe(+3) oxidized iron absorption feature observed in narrowband spectrophotometry of these asteroids. Using this relationship, an empirical algorithm for predicting the presence of water of hydration in the surface material of a Solar System body using photometry obtained through the Eight-Color Asteroid Survey nu (0.550 micrometers), w (0.701 micrometers), and x (0.853 micrometers) filters was developed and applied to the ECAS photometry of asteroids and outer planet satellites. The percentage of objects in low-albedo, outer main-belt asteroid classes that test positively for water of hydration increases from P to B to C to G class and correlates linearly with the increasing mean albedos of those objects testing positively. The medium-albedo M-class asteroids do not test positively in large number using this algorithm. Aqueously altered asteroids dominate the Solar System population between heliocentric distances of 2.6 to 3.5 AU, bracketing the Solar System region where the aqueous alteration mechanism operated most strongly. One jovian satellite, J VI Himalia, and one saturnian satellite. Phoebe, tested positively for water of hydration, supporting the hypothesis that these may be captured C-class asteroids from a postaccretional dispersion. The proposed testing technique could be applied to an Earth-based survey of asteroids or a space-probe study of an asteroid's surface characteristic in order to identify a potential water source.

A cheaper, faster, better way to detect water of hydration on Solar System bodies

NASA Astrophysics Data System (ADS)

Vilas, Faith

1994-10-01

The 3.0-micrometers water of hydration absorption feature observed in the IR photometry of many low-albedo and some medium-albedo asteroids strongly correlates with the 0.7-micrometers Fe(+2) to Fe(+3) oxidized iron absorption feature observed in narrowband spectrophotometry of these asteroids. Using this relationship, an empirical algorithm for predicting the presence of water of hydration in the surface material of a Solar System body using photometry obtained through the Eight-Color Asteroid Survey nu (0.550 micrometers), w (0.701 micrometers), and x (0.853 micrometers) filters was developed and applied to the ECAS photometry of asteroids and outer planet satellites. The percentage of objects in low-albedo, outer main-belt asteroid classes that test positively for water of hydration increases from P to B to C to G class and correlates linearly with the increasing mean albedos of those objects testing positively. The medium-albedo M-class asteroids do not test positively in large number using this algorithm. Aqueously altered asteroids dominate the Solar System population between heliocentric distances of 2.6 to 3.5 AU, bracketing the Solar System region where the aqueous alteration mechanism operated most strongly. One jovian satellite, J VI Himalia, and one saturnian satellite. Phoebe, tested positively for water of hydration, supporting the hypothesis that these may be captured C-class asteroids from a postaccretional dispersion. The proposed testing technique could be applied to an Earth-based survey of asteroids or a space-probe study of an asteroid's surface characteristic in order to identify a potential water source.

Asteroid impacts on terrestrial planets: the effects of super-Earths and the role of the ν6 resonance

NASA Astrophysics Data System (ADS)

Smallwood, Jeremy L.; Martin, Rebecca G.; Lepp, Stephen; Livio, Mario

2018-01-01

With N-body simulations of a planetary system with an asteroid belt, we investigate how the asteroid impact rate on the Earth is affected by the architecture of the planetary system. We find that the ν6 secular resonance plays an important role in the asteroid collision rate with the Earth. Compared to exoplanetary systems, the Solar system is somewhat special in its lack of a super-Earth mass planet in the inner Solar system. We therefore first consider the effects of the presence of a super-Earth in the terrestrial planet region. We find a significant effect for super-Earths with a mass of around 10 M⊕ and a separation greater than about 0.7 au. For a super-Earth which is interior to the Earth's orbit, the number of asteroids colliding with Earth increases the closer the super-Earth is to the Earth's orbit. This is the result of multiple secular resonance locations causing more asteroids to be perturbed on to Earth-crossing orbits. When the super-Earth is placed exterior to Earth's orbit, the collision rate decreases substantially because the ν6 resonance no longer exists in the asteroid belt region. We also find that changing the semimajor axis of Saturn leads to a significant decrease in the asteroid collision rate, though increasing its mass increases the collision rate. These results may have implications for the habitability of exoplanetary systems.

Epsilon Eridani Inner Asteroid Belt

NASA Image and Video Library

2017-09-14

SCI2017_0004: Artist's illustration of the Epsilon Eridani system showing Epsilon Eridani b, right foreground, a Jupiter-mass planet orbiting its parent star at the outside edge of an asteroid belt. In the background can be seen another narrow asteroid or comet belt plus an outermost belt similar in size to our solar system's Kuiper Belt. The similarity of the structure of the Epsilon Eridani system to our solar system is remarkable, although Epsilon Eridani is much younger than our sun. SOFIA observations confirmed the existence of the asteroid belt adjacent to the orbit of the Jovian planet. Credit: NASA/SOFIA/Lynette Cook

COLLISIONALLY BORN FAMILY ABOUT 87 SYLVIA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vokrouhlicky, David; Nesvorny, David; Bottke, William F.

There are currently more than 1000 multi-opposition objects known in the Cybele population, adjacent and exterior to the asteroid main belt, allowing a more detailed analysis than was previously possible. Searching for collisionally born clusters in this population, we find only one statistically robust case: a family of objects about (87) Sylvia. We use a numerical model to simulate the Sylvia family long-term evolution due to gravitational attraction from planets and thermal (Yarkovsky) effects and to explain its perturbed structure in the orbital element space. This allows us to conclude that the Sylvia family must be at least several hundredsmore » of million years old, in agreement with evolutionary timescales of Sylvia's satellite system. We find it interesting that other large Cybele-zone asteroids with known satellites-(107) Camilla and (121) Hermione-do not have detectable families of collisional fragments about them (this is because we assume that binaries with large primary and small secondary components are necessarily impact generated). Our numerical simulations of synthetic clusters about these asteroids show they would suffer a substantial dynamical depletion by a combined effect of diffusion in numerous weak mean-motion resonances and Yarkovsky forces provided their age is close to {approx}4 billion years. However, we also believe that a complete effacement of these two families requires an additional component, very likely due to resonance sweeping or other perturbing effects associated with the late Jupiter's inward migration. We thus propose that both Camilla and Hermione originally had their collisional families, as in the Sylvia case, but they lost them in an evolution that lasted a billion years. Their satellites are the only witnesses of these effaced families.« less

Comet/Asteroid Protection System (CAPS): Preliminary Space-Based Concept and Study Results

NASA Technical Reports Server (NTRS)

Mazanek, Daniel D.; Roithmayr, Carlos M.; Antol, Jeffrey; Park, Sang-Young; Koons, Robert H.; Bremer, James C.; Murphy, Douglas G.; Hoffman, James A.; Kumar, Renjith R.; Seywald, Hans

2005-01-01

There exists an infrequent, but significant hazard to life and property due to impacting asteroids and comets. There is currently no specific search for long-period comets, smaller near-Earth asteroids, or smaller short-period comets. These objects represent a threat with potentially little or no warning time using conventional ground-based telescopes. These planetary bodies also represent a significant resource for commercial exploitation, long-term sustained space exploration, and scientific research. The Comet/Asteroid Protection System (CAPS) is a future space-based system concept that provides permanent, continuous asteroid and comet monitoring, and rapid, controlled modification of the orbital trajectories of selected bodies. CAPS would expand the current detection effort to include long-period comets, as well as small asteroids and short-period comets capable of regional destruction. A space-based detection system, despite being more costly and complex than Earth-based initiatives, is the most promising way of expanding the range of detectable objects, and surveying the entire celestial sky on a regular basis. CAPS would provide an orbit modification system capable of diverting kilometer class objects, and modifying the orbits of smaller asteroids for impact defense and resource utilization. This Technical Memorandum provides a compilation of key related topics and analyses performed during the CAPS study, which was performed under the Revolutionary Aerospace Systems Concepts (RASC) program, and discusses technologies that could enable the implementation of this future system.

Solar System evolution from compositional mapping of the asteroid belt.

PubMed

DeMeo, F E; Carry, B

2014-01-30

Advances in the discovery and characterization of asteroids over the past decade have revealed an unanticipated underlying structure that points to a dramatic early history of the inner Solar System. The asteroids in the main asteroid belt have been discovered to be more compositionally diverse with size and distance from the Sun than had previously been known. This implies substantial mixing through processes such as planetary migration and the subsequent dynamical processes.

Evolution of the inner asteroid belt: Paradigms and paradoxes from spectral studies

NASA Technical Reports Server (NTRS)

Gaffey, Michael J.

1987-01-01

Recent years have witnessed a significant increase in the sophistication of asteroidal surface material characterizations derived from spectral data. An extensive data base of moderate to high spectral resolution, visible and near-infrared asteroid spectra is now available. Interpretive methodologies and calibrations were developed to determine phase abundance and composition in olivine-pyroxene assemblages and to estimate NiFe metal abundance from such spectra. A modified version of the asteroid classifications system more closely parallels the mineralogic variations of the major inner belt asteroid types. These improvements permit several general conclusions to be drawn concerning the nature of inner belt objects; their history, and that of the inner solar system; and the relationship between the asteroids and meteorites. Essentially all large belt asteroids have or are fragments of parent bodies which have undergone strong post-accretionary heating, varying degrees of melting and magmatic differentiation, and subsequent collisional disruption. These asteroids show a systematic, but not yet well characterized, mineralogic variation with semi-major axis. This suggests that the S-type asteroid families represent relatively recent collisions onto the cores of previously disrupted parent bodies.

The asteroid 2014 JO25

NASA Astrophysics Data System (ADS)

Vodniza, Alberto; Pereira, Mario

2017-10-01

The asteroid 2014 JO25 was discovered by A. D. Grauer at the Mt. Lemmon Survey on May 2014, and Joe Masiero used observations from the NEOWISE in 2014 to estimate a diameter of 650 meters [1]. However, using the radio telescope at Arecibo-Puerto Rico, astronomers obtained radar images on April 17-2017 and Edgar Rivera Valentín (scientist at Arecibo) said: “We found 2014 JO25 is a contact binary asteroid, two space rocks that were originally separate bodies, and each segment is about 640 meters and 670 meters, for a total of about 1.3 km long. Its rotation is of 3.5 hours” [2]. This asteroid flew past Earth on April 19 at a distance of about 4.6 lunar distances from the Earth. This was the closest approach by an asteroid since 4179 Toutatis. Toutatis flew past Earth on September 2004 at a distance of about 4 lunar distances from the Earth [3]. In April 12-2020 the asteroid will be at a minimum possible distance of 0.1617280 A.U from Earth [4]. From our observatory, located in Pasto-Colombia, we obtained a lot of pictures. Our data was published by the Minor Planet Center [5] and also appears at the web page of NEODyS [6]. Astrometry and photometry were carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity=0.88454+/-0.00152, semi-major axis= 2.0573+/- 0.0216 A.U, orbital inclination=25.22+/-0.10 deg, longitude of the ascending node =30.6530+/-0.0032 deg, argument of perihelion=49.586+/-0.012 deg, mean motion = 0.33402+/-0.00527 deg/d, perihelion distance=0.237524+/-0.000644 A.U, aphelion distance=3.8770+/-0.0449 A.U, absolute magnitude =18.1. The parameters were calculated based on 164 observations. Dates: 2017 April: 22 to 24 with mean residual=0.22 arcseconds.The asteroid has an orbital period of 2.95 years.[1] https://echo.jpl.nasa.gov/asteroids/2014JO25/2014JO25_planning.html[2] http://earthsky.org/astronomy-essentials/large-asteroid-2014-jo25-close-april-19-2017-how-to-see[3] https://cneos.jpl.nasa.gov/news/news196.html[4] http://newton.dm.unipi.it/neodys/index.php?pc=1.1.8&n=2014JO25[5] http://www.minorplanetcenter.net/db_search/show_object?utf8=%E2%9C%93&object_id=2014+JO25[6] http://newton.dm.unipi.it/neodys/index.php?pc=2.1.2&o=H78&ab=8

Momentum harvesting techniques for solar system travel

NASA Technical Reports Server (NTRS)

Willoughby, Alan J.

1991-01-01

Astronomers are lately estimating there are 400,000 earth visiting asteroids larger than 100 meters in diameter. These asteroids are uniquely accessible sources of building materials, propellants, oxygen, water, and minerals. They also constitute a huge momentum reserve, potentially usable for travel throughout the solar system. To use this momentum, these stealthy objects must be tracked and the ability to extract the desired momentum obtained. Momentum harvesting by momentum transfer from asteroid to spacecraft, and by using the momentum of the extraterrestrial material to help deliver itself to its destination is discussed. The purpose is neither to quantify nor justify the momentum exchange processes, but to stimulate collective imaginations with some intriguing possibilities which emerge when momentum as well as material is considered. A net and tether concept is the suggested means of asteroid capture, the basic momentum exchange process. The energy damping characteristics of the tether determines the velocity mismatch that can be tolerated, and hence the amount of momentum that can be harvested per capture. As the tether plays out of its reel, drag on the tether steadily accelerates the spacecraft and dilutes, in time, the would-be collision. A variety of concepts for riding and using asteroids after capture are introduced. The hitchhiker uses momentum transfer only. The beachcomber, the caveman, the swinger, the prospector, and the rock wrecker also take advantage of raw asteroid materials. The chemist and the hijacker go further, they process the asteroid into propellants. Or, an asteroid railway system could be constructed with each hijacked asteroid becoming a scheduled train. Travelers could board this space railway system assured that water, oxygen propellants, and shielding await them. Austere space travel could give way to comforts, with a speed and economy impossible without nature's gift of earth visiting asteroids.

A record of planet migration in the main asteroid belt.

PubMed

Minton, David A; Malhotra, Renu

2009-02-26

The main asteroid belt lies between the orbits of Mars and Jupiter, but the region is not uniformly filled with asteroids. There are gaps, known as the Kirkwood gaps, in distinct locations that are associated with orbital resonances with the giant planets; asteroids placed in these locations will follow chaotic orbits and be removed. Here we show that the observed distribution of main belt asteroids does not fill uniformly even those regions that are dynamically stable over the age of the Solar System. We find a pattern of excess depletion of asteroids, particularly just outward of the Kirkwood gaps associated with the 5:2, the 7:3 and the 2:1 Jovian resonances. These features are not accounted for by planetary perturbations in the current structure of the Solar System, but are consistent with dynamical ejection of asteroids by the sweeping of gravitational resonances during the migration of Jupiter and Saturn approximately 4 Gyr ago.

Compositional studies of primitive asteroids

NASA Technical Reports Server (NTRS)

Vilas, Faith

1991-01-01

Primitive asteroids in the solar system (C, P, D class and associated subclasses) are believed to have undergone less thermal processing compared with the differential (S class) asteroids. Telescopic spectra of C class asteroids show effects of aqueous alteration products produced when heating of the asteroids was sufficient to melt surface water, but not strong enough to produce differentiation. Spectrum analysis of P and D class asteroids suggests that aqueous alteration terminated in the outer belt and did not operate at the distance of Jupiter's orbit.

The origin of planetary impactors in the inner solar system.

PubMed

Strom, Robert G; Malhotra, Renu; Ito, Takashi; Yoshida, Fumi; Kring, David A

2005-09-16

Insights into the history of the inner solar system can be derived from the impact cratering record of the Moon, Mars, Venus, and Mercury and from the size distributions of asteroid populations. Old craters from a unique period of heavy bombardment that ended approximately 3.8 billion years ago were made by asteroids that were dynamically ejected from the main asteroid belt, possibly due to the orbital migration of the giant planets. The impactors of the past approximately 3.8 billion years have a size distribution quite different from that of the main belt asteroids but very similar to that of near-Earth asteroids.

REBOUND-ing Off Asteroids: An N-body Particle Model for Ejecta Dynamics on Small Bodies

NASA Astrophysics Data System (ADS)

Larson, Jennifer; Sarid, Gal

2017-10-01

Here we describe our numerical approach to model the evolution of ejecta clouds. Modeling with an N-body particle method enables us to study the micro-dynamics while varying the particle size distribution. A hydrodynamic approach loses many of the fine particle-particle interactions included in the N-body particle approach (Artemieva 2008).We use REBOUND, an N-body integration package (Rein et al. 2012) developed to model various dynamical systems (planetary orbits, ring systems, etc.) with high resolution calculations at a lower performance cost than other N-body integrators (Rein & Tamayo 2017). It offers both symplectic (WHFast) and non-symplectic (IAS15) methods (Rein & Spiegel 2014, Rein & Tamayo 2015). We primarily use the IAS15 integrator due to its robustness and accuracy with short interaction distances and non-conservative forces. We implemented a wrapper (developed in Python) to handle changes in time step and integrator at different stages of ejecta particle evolution.To set up the system, each particle is given a velocity away from the target body’s surface at a given angle within a defined ejecta cone. We study the ejecta cloud evolution beginning immediately after an impact rather than the actual impact itself. This model considers effects such as varying particle size distribution, radiation pressure, perturbations from a binary component, particle-particle collisions and non-axisymmetric gravity of the target body. Restrictions on the boundaries of the target body’s surface define the physical shape and help count the number of particles that land on the target body. Later, we will build the central body from individual particles to allow for a wider variety of target body shapes and topographies.With our particle modeling approach, individual particle trajectories are tracked and predicted on short, medium and long timescales. Our approach will be applied to modeling of the ejecta cloud produced during the Double Asteroid Redirection Test (DART) impact (Cheng et al. 2016, Schwartz et al. 2016). We will present some preliminary results of our applied model and possible applications to other asteroid impact events and Centaur ring formation mechanisms.

Example Solar Electric Propulsion System asteroid tours using variational calculus

NASA Technical Reports Server (NTRS)

Burrows, R. R.

1985-01-01

Exploration of the asteroid belt with a vehicle utilizing a Solar Electric Propulsion System has been proposed in past studies. Some of those studies illustrated multiple asteroid rendezvous with trajectories obtained using approximate methods. Most of the inadequacies of those approximations are overcome in this paper, which uses the calculus of variations to calculate the trajectories and associated payloads of four asteroid tours. The modeling, equations, and solution techniques are discussed, followed by a presentation of the results.

Example Solar Electric Propulsion System asteroid tours using variational calculus

NASA Astrophysics Data System (ADS)

Burrows, R. R.

1985-06-01

Exploration of the asteroid belt with a vehicle utilizing a Solar Electric Propulsion System has been proposed in past studies. Some of those studies illustrated multiple asteroid rendezvous with trajectories obtained using approximate methods. Most of the inadequacies of those approximations are overcome in this paper, which uses the calculus of variations to calculate the trajectories and associated payloads of four asteroid tours. The modeling, equations, and solution techniques are discussed, followed by a presentation of the results.

The Main Asteroid Belt: The Crossroads of the Solar System

NASA Astrophysics Data System (ADS)

Michel, Patrick

2015-08-01

Orbiting the Sun between Mars and Jupiter, main belt asteroids are leftover planetary building blocks that never accreted enough material to become planets. They are therefore keys to understanding how the Solar System formed and evolved. They may also provide clues to the origin of life, as similar bodies may have delivered organics and water to the early Earth.Strong associations between asteroids and meteorites emerged thanks to multi-technique observations, modeling, in situ and sample return analyses. Spacecraft images revolutionized our knowledge of these small worlds. Asteroids are stunning in their diversity in terms of physical properties. Their gravity varies by more orders of magnitude than its variation among the terrestrial planets, including the Moon. Each rendezvous with an asteroid thus turned our geological understanding on its head as each asteroid is affected in different ways by a variety of processes such as landslides, faulting, and impact cratering. Composition also varies, from ice-rich to lunar-like to chondritic.Nearly every asteroid we see today, whether of primitive or evolved compositions, is the product of a complex history involving accretion and one or more episodes of catastrophic disruption that sometimes resulted in families of smaller asteroids that have distinct and indicative petrogenic relationships. These families provide the best data to study the impact disruption process at scales far larger than those accessible in laboratory. Tens, perhaps hundreds, of early asteroids grew large enough to thermally differentiate. Their traces are scattered pieces of their metal-rich cores and, more rarely, their mantles and crusts.Asteroids represent stages on the rocky road to planet formation. They have great stories to tell about the formation and evolution of our Solar System as well as other planetary systems: asteroid belts seem common around Sun-like stars. We will review our current knowledge on their properties, their link to other populations in the different parts of the Solar System, and the space missions devoted to these tracers of our origins, which, for a small fraction, are also potentially hazardous.

Optimised low-thrust mission to the Atira asteroids

NASA Astrophysics Data System (ADS)

Di Carlo, Marilena; Romero Martin, Juan Manuel; Ortiz Gomez, Natalia; Vasile, Massimiliano

2017-04-01

Atira asteroids are recently-discovered celestial bodies characterised by orbits lying completely inside the heliocentric orbit of the Earth. The study of these objects is difficult due to the limitations of ground-based observations: objects can only be detected when the Sun is not in the field of view of the telescope. However, many asteroids are expected to exist in the inner region of the Solar System, many of which could pose a significant threat to our planet. In this paper, a small, low-cost, mission to visit the known Atira asteroids and to discover new Near Earth Asteroids (NEA) is proposed. The mission is realised using electric propulsion. The trajectory is optimised to maximise the number of visited asteroids of the Atira group using the minimum propellant consumption. During the tour of the Atira asteroids an opportunistic NEA discovery campaign is proposed to increase our knowledge of the asteroid population. The mission ends with a transfer to an orbit with perihelion equal to Venus's orbit radius. This orbit represents a vantage point to monitor and detect asteroids in the inner part of the Solar System and provide early warning in the case of a potential impact.

Long-term influence of asteroids on planet longitudes and chaotic dynamics of the solar system

NASA Astrophysics Data System (ADS)

Woillez, E.; Bouchet, F.

2017-11-01

Over timescales much longer than an orbital period, the solar system exhibits large-scale chaotic behavior and can thus be viewed as a stochastic dynamical system. The aim of the present paper is to compare different sources of stochasticity in the solar system. More precisely we studied the importance of the long term influence of asteroids on the chaotic dynamics of the solar system. We show that the effects of asteroids on planets is similar to a white noise process, when those effects are considered on a timescale much larger than the correlation time τϕ ≃ 104 yr of asteroid trajectories. We computed the timescale τe after which the effects of the stochastic evolution of the asteroids lead to a loss of information for the initial conditions of the perturbed Laplace-Lagrange secular dynamics. The order of magnitude of this timescale is precisely determined by theoretical argument, and we find that τe ≃ 104 Myr. Although comparable to the full main-sequence lifetime of the sun, this timescale is considerably longer than the Lyapunov time τI ≃ 10 Myr of the solar system without asteroids. This shows that the external sources of chaos arise as a small perturbation in the stochastic secular behavior of the solar system, rather due to intrinsic chaos.

An interstellar origin for Jupiter's retrograde co-orbital asteroid

NASA Astrophysics Data System (ADS)

Namouni, F.; Morais, M. H. M.

2018-06-01

Asteroid (514107) 2015 BZ509 was discovered recently in Jupiter's co-orbital region with a retrograde motion around the Sun. The known chaotic dynamics of the outer Solar system have so far precluded the identification of its origin. Here, we perform a high-resolution statistical search for stable orbits and show that asteroid (514107) 2015 BZ509 has been in its current orbital state since the formation of the Solar system. This result indicates that (514107) 2015 BZ509 was captured from the interstellar medium 4.5 billion years in the past as planet formation models cannot produce such a primordial large-inclination orbit with the planets on nearly coplanar orbits interacting with a coplanar debris disc that must produce the low-inclination small-body reservoirs of the Solar system such as the asteroid and Kuiper belts. This result also implies that more extrasolar asteroids are currently present in the Solar system on nearly polar orbits.

Rotation Period Determination for 5143 Heracles

NASA Astrophysics Data System (ADS)

Pilcher, Frederick; Briggs, John W.; Franco, Lorenzo; Inasaridze, Raguli Ya.; Krugly, Yurij N.; Molotiv, Igor E.; Klinglesmith, Daniel A., III; Pollock, Joe; Pravec, Petr

2012-07-01

The Earth crossing minor planet 5143 Heracles made in late 2011 its closest approach to Earth since discovery. A consortium of observers found a synodic rotation period near 2.706 hours and amplitude increasing from 0.08 ±0.02 magnitudes at phase angle 20 degrees to 0.18 ±0.03 magnitudes at phase angle 87 degrees, with 3 unequal maxima and minima per cycle. Magnitude parameters H = 14.10 ±0.04 and G = 0.08 ±0.02 are found, and the color index V-R = 0.42 ±0.07. For an asteroid of taxonomic class Q, a suggested albedo pv = 0.20 ±0.05 yields estimated diameter D = 4.5 ±0.7 km. Three possible binary events were recorded, but these are insufficient for binary detection to be secure. Retrograde rotation is suggested.

The UV reflectance of Patroclus: Exploring the surface composition and origins of Jupiter Trojans

NASA Astrophysics Data System (ADS)

Molyneux, Pippa

2017-08-01

(617) Patroclus is a binary system comprising two almost equally sized Trojan asteroids, Patroclus and Menoetius. (617) Patroclus has never been observed in the UV spectral region, which contains important diagnostic features of major Trojan surface constituents inferred from fits to visible-near IR spectra. Previous spectral observations have not been spatially resolved, precluding a direct spectral comparison of the two bodies. We propose to obtain full surface UV reflectance maps of both Patroclus and Menoetius using the STIS G230L mode, to search for characteristic absorption features of silicates, carbons/graphites and NH3, which together make up the major inferred Jupiter Trojan surface constituents, and for signs of ''spectral bluing'' that occurs for space-weathered objects. The Jupiter Trojans are believed to represent the most readily accessible Kuiper Belt material in the solar system, having been scattered from that region to their current orbits following a dynamical instability. A direct spectral comparison of Patroclus and Menoetius, indicating whether the objects share a common origin and evolution, will explore the hypothesis that the system is a rare binary survivor of this scattering. (617) Patroclus is also a target of the upcoming Lucy mission, and constraints on surface composition would represent a valuable input to instrument configuration and observation planning work for the mission. As Lucy will not carry a UV instrument, the proposed observations would remain unique and complementary to the results of the mission.

Depletion of the Outer Asteroid Belt

PubMed

Liou; Malhotra

1997-01-17

During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.

Depletion of the Outer Asteroid Belt

NASA Technical Reports Server (NTRS)

Liou, Jer-Chyi; Malhotra, Renu

1997-01-01

During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.

Evidence for the late formation of hydrous asteroids from young meteoritic carbonates.

PubMed

Fujiya, Wataru; Sugiura, Naoji; Hotta, Hideyuki; Ichimura, Koji; Sano, Yuji

2012-01-17

The accretion of small bodies in the Solar System is a fundamental process that was followed by planet formation. Chronological information of meteorites can constrain when asteroids formed. Secondary carbonates show extremely old (53)Mn-(53)Cr radiometric ages, indicating that some hydrous asteroids accreted rapidly. However, previous studies have failed to define accurate Mn/Cr ratios; hence, these old ages could be artefacts. Here we develop a new method for accurate Mn/Cr determination, and report a reliable age of 4,563.4+0.4/-0.5 million years ago for carbonates in carbonaceous chondrites. We find that these carbonates have identical ages, which are younger than those previously estimated. This result suggests the late onset of aqueous activities in the Solar System. The young carbonate age cannot be explained if the parent asteroid accreted within 3 million years after the birth of the Solar System. Thus, we conclude that hydrous asteroids accreted later than differentiated and metamorphosed asteroids.

Tidal Distortion and Disruption of Earth-Crossing Asteroids

NASA Astrophysics Data System (ADS)

Richardson, D. C.; Bottke, W. F.

1996-09-01

There is mounting evidence that most km-sized objects in the solar system are ``rubble-piles'', fragile objects composed of loose collections of smaller components all held together by self-gravity rather than tensile strength. The evidence includes: (a) the paucity of fast rotating km-sized asteroids (Harris, 1996, LPSC 27, 977); (b) the tidal disruption of Comet Shoemaker-Levy 9 (SL9) and observations of crater chains on the Moon and Galilean satellites (Schenk et al., 1996, Icarus 121, 149); (c) observations of extremely large craters on Phobos, Gaspra, and Ida; and (d) hydrocode models that realistically treat asteroid impacts (Love and Ahrens, 1996, Icarus, in press). Accordingly, we predict that Earth's tidal forces play a major role in the evolution of rubble-pile Earth-crossing objects (ECOs). By modeling close encounters between the Earth and our rubble-piles (for details, see Bottke et al., this issue), we found that Earth's tidal forces can make the progenitors undergo: (a) ``SL9-type'' disruption (formation of clumps of roughly equal size along the fragment train; this outcome may explain specific crater chains seen on the Moon); (b) mass shedding (over half of the primary remains intact; in many cases, the shed fragments go into orbit around the progenitor, producing binary asteroids, which could explain the population of doublet craters seen on the terrestrial planets (Bottke and Melosh, 1996, Nature 381, 51)); (c) reshaping accompanied by spin-up or spin-down (this mechanism could explain the large aspect ratio (2.76), unusual shape, and short rotation period (5.2 hours) of 1620 Geographos as well as the short rotation periods of many other ECOs). Mass shedding events for ECOs occur more frequently at low velocities relative to Earth than at high velocities, corresponding to low (e, i) values. Thus, Earth's tidal forces should be most effective at disrupting large ECOs (and producing small bodies) in this region. This localized disruption mechanism may explain observations by Rabinowitz et al. (1993, Nature 363, 704), who claim to see an ``excess'' number of small ECOs (D < 50 m) at low (e, i) relative to their expectation based on the number of large ECOs seen elsewhere.

A Cubesat Asteroid Mission: Propulsion Trade-offs

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Oleson, Steven R.; McGuire, Melissa L.; Bur, Michael J.; Burke, Laura M.; Fittje, James E.; Kohout, Lisa L.; Fincannon, James; Packard, Thomas W.; Martini, Michael C.

2014-01-01

A conceptual design was performed for a 6-U cubesat for a technology demonstration to be launched on the NASA Space Launch System (SLS) test launch EM-1, to be launched into a free-return translunar trajectory. The mission purpose was to demonstrate use of electric propulsion systems on a small satellite platform. The candidate objective chosen was a mission to visit a Near-Earth asteroid. Both asteroid fly-by and asteroid rendezvous missions were analyzed. Propulsion systems analyzed included cold-gas thruster systems, Hall and ion thrusters, incorporating either Xenon or Iodine propellant, and an electrospray thruster. The mission takes advantage of the ability of the SLS launch to place it into an initial trajectory of C3=0.

The Fall and Recovery of the Tagish Lake Meteorite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hildebrand, Alan R.; McCausland, Phil J.; Brown, Peter G.

2006-03-01

The Tagish Lake C2 (ungrouped) carbonaceous chondrite fall of January 18, 2000 delivered >10 kg of one of the most primitive and physically weak meteorites yet studied. In this paper we report the detailed circumstances of the fall and the recovery of all documented Tagish Lake fragments. We also provide measurements of bulk physical properties (mass, grain and bulk density), bulk triple oxygen-isotope ratios, and short-lived cosmogenic radionuclides counts for several fragments. Ground eyewitnesses and recorded observations of the Tagish Lake fireball event provide a refined estimate of the fireball trajectory, and hence, its pre-atmospheric orbit. From its calculated orbitmore » and its similarity to the remotely-sensed properties of the D and P-class asteroids, the Tagish Lake carbonaceous chondrite represents these outer belt asteroids, and is not of cometary origin. The bulk oxygen-isotope compositions reported here are among the highest known for meteorites. These data plot just below the Terrestrial Fractionation Line, following a trend similar to the CM meteorite mixing line. The bulk density of the Tagish Lake material (1.66 ±0.02 g/cm3) is the same, within error, as the total bulk densities of many C-class and especially D- and P-class asteroids. The high microporosity of Tagish Lake samples (~40%) provides an obvious candidate material for the composition of low bulk density primitive asteroids such as Phobos, Deimos and the P-class binary 87 Sylvia, without requiring a substantial contribution from macroporosity in the form of ice, thick regolith or “rubble pile” assemblages with large interior voids.« less

Dynamical evolution of the Cybele asteroids

NASA Astrophysics Data System (ADS)

Carruba, V.; Nesvorný, D.; Aljbaae, S.; Huaman, M. E.

2015-07-01

The Cybele region, located between the 2J:-1A and 5J:-3A mean-motion resonances, is adjacent and exterior to the asteroid main belt. An increasing density of three-body resonances makes the region between the Cybele and Hilda populations dynamically unstable, so that the Cybele zone could be considered the last outpost of an extended main belt. The presence of binary asteroids with large primaries and small secondaries suggested that asteroid families should be found in this region, but only relatively recently the first dynamical groups were identified in this area. Among these, the Sylvia group has been proposed to be one of the oldest families in the extended main belt. In this work we identify families in the Cybele region in the context of the local dynamics and non-gravitational forces such as the Yarkovsky and stochastic Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects. We confirm the detection of the new Helga group at ≃3.65 au, which could extend the outer boundary of the Cybele region up to the 5J:-3A mean-motion resonance. We obtain age estimates for the four families, Sylvia, Huberta, Ulla, and Helga, currently detectable in the Cybele region, using Monte Carlo methods that include the effects of stochastic YORP and variability of the solar luminosity. The Sylvia family should be T = 1220 ± 40 Myr old, with a possible older secondary solution. Any collisional Cybele group formed prior to the Late Heavy Bombardment would have been most likely completely dispersed in the jumping Jupiter scenario of planetary migration.

Direct and indirect capture of near-Earth asteroids in the Earth-Moon system

NASA Astrophysics Data System (ADS)

Tan, Minghu; McInnes, Colin; Ceriotti, Matteo

2017-09-01

Near-Earth asteroids have attracted attention for both scientific and commercial mission applications. Due to the fact that the Earth-Moon L1 and L2 points are candidates for gateway stations for lunar exploration, and an ideal location for space science, capturing asteroids and inserting them into periodic orbits around these points is of significant interest for the future. In this paper, we define a new type of lunar asteroid capture, termed direct capture. In this capture strategy, the candidate asteroid leaves its heliocentric orbit after an initial impulse, with its dynamics modeled using the Sun-Earth-Moon restricted four-body problem until its insertion, with a second impulse, onto the L2 stable manifold in the Earth-Moon circular restricted three-body problem. A Lambert arc in the Sun-asteroid two-body problem is used as an initial guess and a differential corrector used to generate the transfer trajectory from the asteroid's initial obit to the stable manifold associated with Earth-Moon L2 point. Results show that the direct asteroid capture strategy needs a shorter flight time compared to an indirect asteroid capture, which couples capture in the Sun-Earth circular restricted three-body problem and subsequent transfer to the Earth-Moon circular restricted three-body problem. Finally, the direct and indirect asteroid capture strategies are also applied to consider capture of asteroids at the triangular libration points in the Earth-Moon system.

Working Group Reports and Presentations: Asteroids

NASA Technical Reports Server (NTRS)

Lewis, John

2006-01-01

The study and utilization of asteroids will be an economical way to enable exploration of the solar system and extend human presence in space. There are thousands of near-earth objects (NEOs) that we will be able to reach. They offer resources, transportation, and exploration platforms, but also present a potential threat to civilization. Asteroids play a catastrophic role in the history of the Earth. Geological records indicate a regular history of massive impacts, which astronomical observations confirm is likely to continue with potentially devastating consequences. However, study and exploration of near earth asteroids can significantly increase advanced warning of an Earth impact, and potentially lead to the technology necessary to avert such a collision. Efforts to detect and prevent cataclysmic events would tend to foster and likely require international cooperation toward a unified goal of self-preservation. Exploration of asteroids will help us to understand our history and perhaps save our future. Besides the obvious and compelling scientific and security drivers for asteroid research and exploration, there are numerous engineering and industrial applications for near-term asteroid exploration. We have strong evidence that some asteroids are metal rich. Some are water and organic rich. They can be reached with a very low fuel cost compared to other solar system destinations. Once we reach them, there are efficient, simple extraction technologies available that would facilitate utilization. In addition, the costs of returning extracted resources from asteroids will be a fraction of the cost to return similar resources from the moon to Low Earth Orbit (LEO). These raw materials, extracted and shipped at relatively low cost, can be used to manufacture structures, fuel, and products which could be used to foster mankind s further exploration of the solar system. Asteroids also have the potential to offer transport to several destinations in the solar system. In addition to Mars and the Asteroid belt, it is possible to nudge the orbits of NEOs to provide convenient transport to other destinations. Resources to support life on these long voyages may be gathered from the host asteroid itself. As asteroids travel over a wide range of inclinations and ranges, they offer possible platforms to perform scientific investigations. These include unique vantage point observations of the sun and planets. These observations can help us to understand solar activity and space weather. They also afford us an opportunity to see how the earth looks from afar with different perspectives. When we look for planets outside of our solar system, these observations will help us to calibrate our data. Asteroids may also be used as platforms to support very long baseline interferometry with unprecedented angular resolutions.

Project RAMA: Reconstructing Asteroids Into Mechanical Automata

NASA Technical Reports Server (NTRS)

Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric

2017-01-01

Many interesting ideas have been conceived for building space-based infrastructure in cislunar space. From O'Neill's space colonies, to solar power satellite farms, and even prospecting retrieved near earth asteroids. In all the scenarios, one thing remained fixed - the need for space resources at the outpost. To satisfy this need, O'Neill suggested an electromagnetic railgun to deliver resources from the lunar surface, while NASA's Asteroid Redirect Mission called for a solar electric tug to deliver asteroid materials from interplanetary space. At Made In Space, we propose an entirely new concept. One which is scalable, cost effective, and ensures that the abundant material wealth of the inner solar system becomes readily available to humankind in a nearly automated fashion. We propose the RAMA architecture, which turns asteroids into self-contained spacecraft capable of moving themselves back to cislunar space. The RAMA architecture is just as capable of transporting conventional-sized asteroids on the 10-meter length scale as transporting asteroids 100 meters or larger, making it the most versatile asteroid retrieval architecture in terms of retrieved-mass capability. This report describes the results of the Phase I study funded by the NASA NIAC program for Made In Space to establish the concept feasibility of using space manufacturing to convert asteroids into autonomous, mechanical spacecraft. Project RAMA, Reconstituting Asteroids into Mechanical Automata, is designed to leverage the future advances of additive manufacturing (AM), in-situ resource utilization (ISRU) and in-situ manufacturing (ISM) to realize enormous efficiencies in repeated asteroid redirect missions. A team of engineers at Made In Space performed the study work with consultation from the asteroid mining industry, academia, and NASA. Previous studies for asteroid retrieval have been constrained to studying only asteroids that are both large enough to be discovered, and small enough to be captured and transported using Earth-launched propulsion technology. Project RAMA is not forced into this constraint. The mission concept studied involved transporting a much larger approximately 50-meter asteroid to cislunar space. Demonstration of transport of a 50-meter-class asteroid has several ground-breaking advantages. First, the returned material is of an industrial, rather than just scientific, quantity (greater than 10,000 tonnes versus approximately10s of tonnes). Second, the "useless" material in the asteroid is gathered and expended as part of the asteroid's propulsion system, allowing the returned asteroid to be considerably "purer" than a conventional asteroid retrieval mission. Third, the infrastructure used to convert and return the asteroid is reusable, and capable of continually returning asteroids to cislunar space.

Compositional Variegation of Large-Diameter Low-Albedo Asteroids

NASA Astrophysics Data System (ADS)

Vilas, F.; Jarvis, K. S.; Anz-Meador, T. D.; Thibault, C. A.; Sawyer, S. R.; Fitzsimmons, A.

1997-07-01

Asteroids showing signs of aqueous alteration and thermal metamorphism in visible/near IR spectroscopy and photometry (C, G, F, B, and P classes) ranging from 0.37 - 0.90mu m dominate the asteroid population at heliocentric distances of 2.6 - 3.5 AU. Age dating of meteorites indicates that the Solar System was subjected to a major heating event 4.5 Gyr ago. Recent meteoritic research has produced evidence of a carbonaceous chondrite subjected to two separate aqueous alteration events with a metamorphic heating inbetween (Krot et al., 1997, submitted). Models of the effects of heating by electromagnetic induction or decay of short-lived radionuclides combined with models of the early collisional history of the Solar System after Jupiter's formation indicate that asteroids observed today can be divided into two groups by diameter. Those asteroids having diameters greater than 100 km were mixed by multiple collisions but remain as gravitationally bound rubble piles. Asteroids with diameters less than 100 km should show more compositional diversity. Vilas and Sykes (1996, Icarus, v. 124, 483) have shown using ECAS photometry that this compositional difference exists. Those asteroids having diameters greater than 100 km should be individually homogeneous, with spectral differences showing the combined effects of a primordial compositional gradient in the asteroid belt with thermal metamorphism. We address the significance of spatially-resolved spectra of 42 asteroids to the collective origin of these asteroids.

A three-parameter asteroid taxonomy

NASA Technical Reports Server (NTRS)

Tedesco, Edward F.; Williams, James G.; Matson, Dennis L.; Veeder, Glenn J.; Gradie, Jonathan C.

1989-01-01

Broadband U, V, and x photometry together with IRAS asteroid albedos have been used to construct an asteroid classification system. The system is based on three parameters (U-V and v-x color indices and visual geometric albedo), and it is able to place 96 percent of the present sample of 357 asteroids into 11 taxonomic classes. It is noted that all but one of these classes are analogous to those previously found using other classification schemes. The algorithm is shown to account for the observational uncertainties in each of the classification parameters.

The Shape of Near-Earth Asteroid 275677 (2000 RS11) From Inversion of Arecibo and Goldstone Radar Images

NASA Astrophysics Data System (ADS)

Brauer, Kaley; Busch, Michael W.; Benner, Lance A. M.; Brozovic, Marina; Howell, Ellen S.; Nolan, Michael C.; Springmann, Alessondra; Giorgini, Jon D.; Taylor, Patrick A.; Jao, Joseph S.

2015-11-01

We observed near-Earth asteroid 2000 RS11 with the Arecibo and Goldstone planetary radars during a 0.035 au approach in March 2014, obtaining delay-Doppler images between March 13 and March 17. The finest-resolution images have range resolution of 7.5 m/pixel and show that RS11 is a contact binary with complex topography. We used the SHAPE software package (Magri et al., Icarus 186, 156-160 2007) to create a physical model of RS11 and its spin state from these delay-Doppler images.The rotation period of RS11 is well constrained from optical lightcurves, P = 4.444 ± 0.001 h (Warner et al., Minor Planet Bulletin 41, 160; 2014 and Benishek, Minor Planet Bulletin 41, 257; 2014). We found two possible pole directions and corresponding shape models, mirror images of one another, which provide equally good fits to the radar data. RS11’s pole direction is either (λ , β) = (155°, 30°) ± 10° or (335°, -30°) ± 10° in J2000 ecliptic coordinates. The most likely pole directions of RS11 are not aligned with the heliocentric orbit normal and instead have an obliquity within 10° of 56° or 124°.Our best-fit shape models are 1400-vertex polyhedra comprising two lobes in contact. The lengths of RS11’s principal axes are 698 ± 71 m, 578 ± 59 m, and 758 ± 77 m. RS11 has a volume of 0.086 ± 0.026 km^3. The long axis of RS11’s larger lobe is 751 ± 77 m and the long axis of the smaller lobe is 398 ± 41 m; the volume ratio between these lobes is roughly 2.7 ± 10%. Spectral data informs us that RS11 is an S-class object (Lazzarin et al., Icarus 169, 379; 2004).RS11's shape is unusual compared with those of other contact binary NEAs imaged by radar. Its larger lobe is flattened. Additionally, while the neck between the smaller and larger lobes of most contact binaries is located near the larger lobe's longest principal axis (such as in the cases of 25143 Itokawa and 4179 Toutatis), RS11's neck is near its larger lobe's shortest principal axis. RS11 is the first asteroid of this type for which we have a shape model.

Calculation methods for estimating the prospects of a space experiment by means of impact by asteroid Apophis on the Moon surface

NASA Astrophysics Data System (ADS)

Ostrik, A. V.; Kazantsev, A. M.

2018-01-01

The problem of principal change of asteroid 99952 (Apophis) orbit is formulated. Aim of this change is the termination of asteroid motion in Solar system. Instead of the passive rescue tactics from asteroid threat, an option is proposed for using the asteroid for setting up a large-scale space experiment on the impact interaction of the asteroid with the Moon. The scientific and methodical apparatus for calculating the possibility of realization, searching and justification the scientific uses of this space experiment is considered.

V-type asteroids investigation in support to the NASA DAWN mission

NASA Astrophysics Data System (ADS)

de Sanctis, Maria Cristina; Migliorini, Alessandra; Lazzaro, Daniela; Luzia, Flavia; Ammannito, Eleonora; Capria, Maria Teresa; Filacchione, Gianrico; Mottola, Stefano; Boschin, Walter; Fiorenzano, Aldo; Ghinassi, Francesca

4Vesta crust composition suggests that it has undergone extensive differentiation and resur-facing. It is the only large basaltic asteroid known at present (McCord, (1970); McFadden et al., (1977); Binzel, et al., (1997)), and it could be the smallest differentiated body of the Solar System. The NASA mission DAWN, launched on September 2007, is intended to deeper investigate the mineralogical properties of 4Vesta, in order to shed light on this puzzle (Russell et al., 2007). Although 4Vesta is the only large object in the Solar System which shows an almost intact basaltic crust, however an increasing number of small asteroids with a similar surface composition as 4Vesta were discovered thanks to ground-based telescopes (Xu et al., (1995); Burbine et al., (2001); Alvarez-Candal, et al. (2006)), posing the fundamental problem of the presence and distribution of basaltic material in the Solar System. Many of these asteroids were found to be spectrally and dynamically linked to 4Vesta, and they are known as the Vesta family. However, the scenario is much more complicated, because many Main Belt Asteroids, classified as V-type asteroids, were discovered near but not dynamically linked to 4Vesta. However, numerical simulations indicate that a relatively large fraction of the original Vesta family members may have evolved out of the family borders (Nesvorny et al., 2008); on the other hand, this seems not to be true for the low inclined asteroids, for which instead a different origin must be assumed. At present, more than 500 asteroids are classified as potentially V-type asteroids, thanks to new photometric investigation (Roig and Gil-Hutton, (2006); Roig et al., (2008); Moskoviz et al., (2008)). Some of these objects possibly belong to the Vesta-family, according to dynamical considerations, while other asteroids seem to be not clearly related to Vesta. Ground-based observations allow to investigate the spectral properties and hence the miner-alogical composition of such asteroids, which are thought to be linked to 4Vesta, because of their colors, but they are still unclassified. Asteroids were selected among the Vesta and non-Vesta family. The selected asteroids are potentially fragments coming from 4Vesta, after a cratering event on the asteroid. The possible co-existence of distinct mineralogical groups among the V-type asteroids is suggested by previous asteroid observations (Duffard et al., 2004). In this work, we present spectra of V type asteroids. Asteroids belonging to the Vesta family and those classified as non-Vesta family are compared, in order to point out similarities and differences. Results are based on observations obtained with the Telescopio Nazionale Galileo, a 3.5m-telescope in LaPalma. The proposed work is intended to support the future observations of 4Vesta, by DAWN.

REVIEWS OF TOPICAL PROBLEMS: Satellites of asteroids

NASA Astrophysics Data System (ADS)

Prokof'eva, Valentina V.; Tarashchuk, V. P.; Gor'kavyi, N. N.

1995-06-01

More than 6000 asteroids in the Solar System have now been discovered and enumerated, and about 500 of them have been investigated in detail by different methods. This rewiew gives observational evidence which indicates that no fewer than 10% of asteroids may be composed of two or more bodies. This was supported by the detection of a satellite of the asteroid Ida by the Galileo spacecraft. This discovery symbolises the change of both observational and theoretical paradigms. Space and ground observations of asteroids by modern teghniques may give extensive new data for modelling double asteroids. The analysis of problems of stability, formation and dynamics of asteroid satellites shows that their sphere of stable motion extends up to several hundred asteroid radii. The idea that the origin of the asteroid satellites may be explained in the frame of a unified accretion model of planetary satellite formation is proposed and justified.

Periodic motion near non-principal-axis rotation asteroids

NASA Astrophysics Data System (ADS)

Shang, Haibin; Wu, Xiaoyu; Qin, Xiao; Qiao, Dong

2017-11-01

The periodic motion near non-principal-axis (NPA) rotation asteroids is proved to be markedly different from that near uniformly rotating bodies due to the complex spin state with precession, raising challenges in terms of the theoretical implications of dynamical systems. This paper investigates the various periodic motions near the typical NPA asteroid 4179 Toutatis, which will contribute to the understanding of the dynamical environments near the widespread asteroids in the Solar system. A novel method with the incorporation of the ellipsoid-mascon gravitational field model and global optimization is developed to efficiently locate periodic solutions in the system. The numerical results indicate that abundant periodic orbits appear near the NPA asteroids. These various orbits are theoretically classified into five topological types with special attention paid to the cycle stability. Although the concept of classical family disappears in our results, some orbits with the same topological structure constitute various generalized `families' as the period increases. Among these `families' a total of 4 kinds of relationships between orbits, including rotation, evolution, distortion and quasi-symmetry, are found to construct the global mapping of these types. To cover the rotation statuses of various NPA asteroids, this paper also discusses the variation of periodic orbits with diverse asteroid spin rates, showing that the scales of some orbits expand, shrink or almost annihilate as the system period changes; meanwhile, their morphology and topology remain unchanged.

Periodic Orbit Families in the Gravitational Field of Irregular-shaped Bodies

NASA Astrophysics Data System (ADS)

Jiang, Yu; Baoyin, Hexi

2016-11-01

The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.

Catching a Rolling Stone: Dynamics and Control of a Spacecraft and an Asteroid

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.; Shen, Haijun; Jesick, Mark C; Cornelius, David M

2013-01-01

In a recent report, a robotic spacecraft mission is proposed for the purpose of collecting a small asteroid, or a small part of a large one, and transporting it to an orbit in the Earth-Moon system. Such an undertaking will require solutions to many of the engineering problems associated with deflection of an asteroid that poses a danger to Earth. In both cases, it may be necessary for a spacecraft to approach an asteroid from a nearby position, hover for some amount of time, move with the same angular velocity as the asteroid, descend, perhaps ascend, and finally arrest the angular velocity of the asteroid. Dynamics and control in each of these activities is analyzed in order to determine the velocity increments and control torque that must be provided by a reaction control system, and the mass of the propellant that will be consumed. Two attitude control algorithms are developed, one to deal with synchronizing the spacecraft s angular velocity with that of the asteroid, and the other to arrest the asteroid s angular velocity. A novel approach is proposed for saving fuel in the latter case.

Evaluating Different Scenarios for the Formation and Early Evolution of the Asteroid Belt

NASA Astrophysics Data System (ADS)

O'Brien, David P.; Walsh, Kevin J.

2014-11-01

The asteroid belt is dynamically excited, depleted in mass relative to the surface mass density of the rest of the Solar System, and contains numerous diverse taxonomic classes of asteroids that are partly, but not completely, radially mixed. In the 'classical' scenario of Solar System formation, the excitation, depletion and radial mixing of the asteroid belt is best explained by the effect of planetary embryos that are initially present in the primordial asteroid belt region [1-3]. In the more recent 'Grand Tack' scenario proposed by Walsh et al. [4], the early inward-then-outward migration of Jupiter in the gas disk initially depletes, then repopulates the asteroid belt with material scattered from both interior and exterior to Jupiter. Here we will examine in detail the model asteroid distributions resulting from these two scenarios for a range of parameters, and compare them to observational constraints on the current distribution of asteroids in the Solar System. We will also address the possible effects that late-stage planetesimal-driven migration and resonance-crossing of Jupiter and Saturn in the Nice Model [eg. 5,6] may have on the final asteroid distribution.[1] G.W. Wetherill, Icarus 100, 307-325 (1992)[2] J.-M. Petit et al., Icarus 153, 338-347 (2001)[3] D.P. O'Brien t al., Icarus 191, 434-452 (2007)[4] K.J. Walsh et al., Nature 475, 206-209 (2011)[5] K. Tsiganis et al., Nature 435, 459-461 (2005)[6] A. Morbidelli et al., AJ 140, 1391-1401 (2010)

Gaia-GOSA: An interactive service for coordination of asteroid observation campaigns

NASA Astrophysics Data System (ADS)

Santana-Ros, Toni; Bartczak, Przemyslaw; Michalowski, Tadeusz; Marciniak, Anna; Butkiewicz-Bak, Magda; Dudziński, Grzegorz

2016-10-01

We describe the Gaia-Ground-based Observational Service for Asteroids (www.gaiagosa.eu), which is a website aiming to facilitate asteroid observers in contributing to the Gaia mission by gathering lightcurves of selected targets.There are many asteroids which lightcurves cannot be covered during one observing run, like slow rotators,with periods longer than 12 hours. There are also targets with periods commensurate with the Earth's day, sotheir lightcurves cannot be covered by observing from one site only. There are also targets of special interest,like binary objects, where a large amount of data is needed. For all targets like those mentioned above, acoordination of observers is needed, also to avoid unnecessary duplication of data gathering.To that end we have created Gaia-GOSA, a web service which allows coordination between observers, focuseson interesting targets and may avoid observers to unnecessary gather data of the same object at the sametime. Furthermore, it is not necessary to be an advanced observer to contribute to the project. The websiteprepares the observing plan, providing all the necessary information to point your telescope. Thesubscription is free and observers with any level of experience are welcome.All the data gathered by Gaia-GOSA users will be reduced and analyzed by astronomers from the Astronomical Observatory of Adam Mickiewicz University in Poznan (AO AMU). The resulting catalogue, containing all the lightcurves obtained, will be used to enhance the results of the Gaia (cornerstone European Space Agency's mission) inversion algorithm.The project has been developed under funding from the European Space Agency (ESA) and initially was only devoted to help users in planning photometric observations of asteroids. However, in this poster we also present an extended version of the website, which also aims to publish predictions of stellar occultations for selected targets. This work has been done in the framework of the Small Bodies: Near and Far (SBNAF) research project, which has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement no 687378.

Internal gravity, self-energy, and disruption of comets and asteroids

NASA Astrophysics Data System (ADS)

Dobrovolskis, Anthony R.; Korycansky, D. G.

2018-03-01

The internal gravity and self-gravitational energy of a comet, asteroid, or small moon have applications to their geophysics, including their formation, evolution, cratering, and disruption, the stresses and strains inside such objects, sample return, eventual asteroid mining, and planetary defense strategies for potentially hazardous objects. This paper describes the relation of an object's self-energy to its collisional disruption energy, and shows how to determine an object's self-energy from its internal gravitational potential. Any solid object can be approximated to any desired accuracy by a polyhedron of sufficient complexity. An analytic formula is known for the gravitational potential of any homogeneous polyhedron, but it is widely believed that this formula applies only on the surface or outside of the object. Here we show instead that this formula applies equally well inside the object. We have used these formulae to develop a numerical code which evaluates the self-energy of any homogeneous polyhedron, along with the gravitational potential and attraction both inside and outside of the object, as well as the slope of its surface. Then we use our code to find the internal, external, and surface gravitational fields of the Platonic solids, asteroid (216) Kleopatra, and comet 67P/Churyumov-Gerasimenko, as well as their surface slopes and their self-gravitational energies. We also present simple spherical, ellipsoidal, cuboidal, and duplex models of Kleopatra and comet 67P, and show how to generalize our methods to inhomogeneous objects and magnetic fields. At present, only the self-energies of spheres, ellipsoids, and cuboids (boxes) are known analytically (or semi-analytically). The Supplementary Material contours the central potential and self-energy of homogeneous ellipsoids and cuboids of all aspect ratios, and also analytically the self-gravitational energy of a "duplex" consisting of two coupled spheres. The duplex is a good model for "contact binary" comets and asteroids; in fact, most comets seem to be bilobate, and might be described better as "dirty snowmen" than as "dirty snowballs".

Triple Asteroid System Triples Asteroid Observers Interest

NASA Image and Video Library

2009-08-06

NASA Deep Space Network, Goldstone radar images show triple asteroid 1994 CC, which consists of a central object approximately 700 meters 2,300 feet in diameter and two smaller moons that orbit the central body. Animation available at the Photojournal

The formation mechanism of 4179 Toutatis' elongated bilobed structure in a close Earth encounter scenario

NASA Astrophysics Data System (ADS)

Hu, Shoucun; Ji, Jianghui; Richardson, Derek C.; Zhao, Yuhui; Zhang, Yun

2018-07-01

The optical images of near-Earth asteroid 4179 Toutatis acquired by Chang'e-2 spacecraft show that Toutatis has an elongated contact binary configuration, with the contact point located along the long axis. We speculate that such configuration may have resulted from a low-speed impact between two components. In this work, we performed a series of numerical simulations and compared the results with the optical images, to examine the mechanism and better understand the formation of Toutatis. Herein, we propose a scenario that an assumed separated binary precursor could undergo a close encounter with Earth, leading to an impact between the primary and secondary, and the elongation is caused by Earth's tide. The precursor is assumed to be a doubly synchronous binary with a semimajor axis of 4Rp (radius of primary) and the two components are represented as spherical cohesionless self-gravitating granular aggregates. The mutual orbits are simulated in a Monte Carlo routine to provide appropriate parameters for our N-body simulations of impact and tidal distortion. We employ the PKDGRAV package with a soft-sphere discrete element method to explore the entire scenarios. The results show that contact binary configurations are natural outcomes under this scenario, whereas the shape of the primary is almost not affected by the impact of the secondary. However, our simulations further provide an elongated contact binary configuration best matching to the shape of Toutatis at an approaching distance rp = 1.4-1.5 Re (Earth radius), indicative of a likely formation scenario for configurations of Toutatis-like elongated contact binaries.

The formation mechanism of 4179 Toutatis' elongated bi-lobed structure in a close Earth encounter scenario

NASA Astrophysics Data System (ADS)

Hu, Shoucun; Ji, Jianghui; Richardson, Derek C.; Zhao, Yuhui; Zhang, Yun

2018-04-01

The optical images of near-Earth asteroid 4179 Toutatis acquired by Chang'e-2 spacecraft show that Toutatis has an elongated contact binary configuration, with the contact point located along the long axis. We speculate that such configuration may have resulted from a low-speed impact between two components. In this work, we performed a series of numerical simulations and compared the results with the optical images, to examine the mechanism and better understand the formation of Toutatis. Herein we propose an scenario that an assumed separated binary precursor could undergo a close encounter with Earth, leading to an impact between the primary and secondary, and the elongation is caused by Earth's tide. The precursor is assumed to be a doubly synchronous binary with a semi-major axis of 4 Rp (radius of primary) and the two components are represented as spherical cohesionless self-gravitating granular aggregates. The mutual orbits are simulated in a Monte Carlo routine to provide appropriate parameters for our N-body simulations of impact and tidal distortion. We employ the pkdgrav package with a soft-sphere discrete element method (SSDEM) to explore the entire scenarios. The results show that contact binary configurations are natural outcomes under this scenario, whereas the shape of the primary is almost not affected by the impact of the secondary. However, our simulations further provide an elongated contact binary configuration best-matching to the shape of Toutatis at an approaching distance rp = 1.4 ˜ 1.5 Re (Earth radius), indicative of a likely formation scenario for configurations of Toutatis-like elongated contact binaries.

Mapping stable direct and retrograde orbits around the triple system of asteroids (45) Eugenia

NASA Astrophysics Data System (ADS)

Araujo, R. A. N.; Moraes, R. V.; Prado, A. F. B. A.; Winter, O. C.

2017-12-01

It is widely accepted that knowing the composition and the orbital evolution of asteroids might help us to understand the process of formation of the Solar system. It is also known that asteroids can represent a threat to our planet. Such an important role has made space missions to asteroids a very popular topic in current astrodynamics and astronomy studies. Taking into account the increasing interest in space missions to asteroids, especially to multiple systems, we present a study that aims to characterize the stable and unstable regions around the triple system of asteroids (45) Eugenia. The goal is to characterize the unstable and stable regions of this system and to make a comparison with the system 2001 SN263, which is the target of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) mission. A new concept was used for mapping orbits, by considering the disturbance received by the spacecraft from all perturbing forces individually. This method has also been applied to (45) Eugenia. We present the stable and unstable regions for particles with relative inclination between 0° and 180°. We found that (45) Eugenia presents larger stable regions for both prograde and retrograde cases. This is mainly because the satellites of this system are small when compared to the primary body, and because they are not close to each other. We also present a comparison between these two triple systems, and we discuss how these results can guide us in the planning of future missions.

Meteorite spectroscopy and characterization of asteroid surface materials

NASA Technical Reports Server (NTRS)

Gaffey, Michael J.

1991-01-01

The analysis of visible and near-infrared reflectance spectra is the primary means to determine surface mineralogy and petrology of individual asteroids. These individual studies provide the data to investigate the broader relationships between the asteroids and meteorites and between asteroids at different heliocentric distances. The main purpose is to improve the understanding of the origin, evolution, and inter-relationships of the asteroids; of their relationships to the meteorites; and of the processes active and the conditions present in the early inner solar system. Empirical information from the study of asteroids and the meteorites is essential to the adequate development and testing of the theoretical models for the accretion of the terrestrial planets, and for their early post-accretionary evolution. The recent results are outined in the following sections: (1) asteroid igneous processes, and (2) spinel-bearing asteroids and the nebular compositional gradient.

Spacecraft Conceptual Design for Returning Entire Near-Earth Asteroids

NASA Technical Reports Server (NTRS)

Brophy, John R.; Oleson, Steve

2012-01-01

In situ resource utilization (ISRU) in general, and asteroid mining in particular are ideas that have been around for a long time, and for good reason. It is clear that ultimately human exploration beyond low-Earth orbit will have to utilize the material resources available in space. Historically, the lack of sufficiently capable in-space transportation has been one of the key impediments to the harvesting of near-Earth asteroid resources. With the advent of high-power (or order 40 kW) solar electric propulsion systems, that impediment is being removed. High-power solar electric propulsion (SEP) would be enabling for the exploitation of asteroid resources. The design of a 40-kW end-of-life SEP system is presented that could rendezvous with, capture, and subsequently transport a 1,000-metric-ton near-Earth asteroid back to cislunar space. The conceptual spacecraft design was developed by the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team at the Glenn Research Center in collaboration with the Keck Institute for Space Studies (KISS) team assembled to investigate the feasibility of an asteroid retrieval mission. Returning such an object to cislunar space would enable astronaut crews to inspect, sample, dissect, and ultimately determine how to extract the desired materials from the asteroid. This process could jump-start the entire ISRU industry.

Disruptive collisions as the origin of 67P/C-G and small bilobate comets

NASA Astrophysics Data System (ADS)

Michel, Patrick; Schwartz, Stephen R.; Jutzi, Martin; Marchi, Simone; Richardson, Derek C.; Zhang, Yun

2016-10-01

Images of comets sent by spacecraft have shown us that bilobate shapes seem to be common in the cometary population. This has been most recently evidenced by the images of comet 67P/C-G obtained by the ESA Rosetta mission, which show a low-density elongated body interpreted as a contact binary. The origin of such bilobate comets has been thought to be primordial because it requires the slow accretion of two bodies that become the two main components of the final object. However, slow accretion does not only occur during the primordial phase of the Solar System, but also later during the reaccumulation processes immediately following collisional disruptions of larger bodies. We perform numerical simulations of disruptions of large bodies. We demonstrate that during the ensuing gravitational phase, in which the generated fragments interact under their mutual gravity, aggregates with bi-lobed or elongated shapes formed form by reaccumulation at speeds that are at or below the range of those assumed in primordial accretion scenarios [1]. The same scenario has been demonstrated to occur in the asteroid belt to explain the origin of asteroid families [2] and has provided insight into the shapes of thus-far observed asteroids such as 25143 Itokawa [3]. Here we show that it is also a more general outcome that applies to disruption events in the outer Solar System. Moreover, we show that high temperature regions are very localized during the impact process, which solves the problem of the survival of organics and volatiles in the collisional process. The advantage of this scenario for the formation of small bilobate shapes, including 67P/C-G, is that it does not necessitate a primordial origin, as such disruptions can occur at later stages of the Solar System. This demonstrates how such comets can be relatively young, consistent with other studies that show that these shapes are unlikely to be formed early on and survive the entire history of the Solar System [4].[1] Schwartz, S.R. et al. 2016, in preparation; [2] Michel, P. et al. 2001, Science 294, 1696; [3] Michel, P., Richardson, D.C. 2013, A&A 554, L1; [4] Jutzi, M. et al. 2016 submitted to A&A.

Parameter-Study Of The Thermal Yarkovsky Effect Acting On Neas

NASA Astrophysics Data System (ADS)

Polishook, David; Prialnik, D.; Rosenberg, E.; Brosch, N.

2010-10-01

We study the relevant parameters for the thermal Yarkovsky effect acting on Near-Earth Asteroids (NEAs), specifically the rotation period and rotation axis. The study uses a quasi 3-D thermal model to derive the temperature map over the surface of the asteroid, and the thermal thrust is calculated. The model (Prialnik et al. 2004, Rosenberg and Prialnik 2006), uses an implicit scheme to numerically solve the equations that describe the asteroid and its thermal evolution. The results show how the thermal thrust is stronger for fast-rotating asteroids, as heat is emitted from their surface on the evening side, increasing the tangential component of the thermal thrust. Moreover, we show the differences in the thermal thrust between asteroids with different perihelion distances, and how this can explain the observed distribution of asteroids in the inner Solar System on the spin-perihelion plane. Our results suggest that many asteroids within the inner Solar System may have retrograde spins. Acknowledgements: D. Polishook is grateful for an Ilan Ramon doctoral scholarship from the Israeli Ministry of Science.

Reverse Asteroids: Searching for an Effective Tool to Combat Asteroid Belt Misconceptions

NASA Astrophysics Data System (ADS)

Summers, F.; Eisenhamer, B.

2014-12-01

The public 'knows' that asteroid belts are densely packed and dangerous for spaceships to cross. Visuals from "Star Wars" to, unfortunately, the recent "Cosmos" TV series have firmly established this astronomical misconception. However, even scientifically correct graphics, such as the Minor Planet Center's plot of the inner solar system, reinforces that view. Each pixel in the image is more than a million kilometers in width, making an accurate representation of the object density impossible.To address this widespread misconception, we are investigating an educational exercise built around a computer interactive that we call "Reverse Asteroids". In the arcade classic video game, the asteroids came to the player's spaceship. For our reverse implementation, we consider an inquiry-based activity in which the spaceship must go hunting for the asteroids, using a database of real objects in our solar system. Both 3D data visualization and basic statistical analysis play crucial roles in bringing out the true space density within the asteroid belt, and perhaps a reconciliation between imagination and reality. We also emphasize that a partnership of scientists and educators is fundamental to the success of such projects.

Design of the optical communication system for the asteroid impact mission

NASA Astrophysics Data System (ADS)

Heese, C.; Sodnik, Z.; Carnelli, I.

2017-09-01

The Asteroid Impact Mission (AIM) is part of the joint Asteroid Impact and Deflection Assessment (AIDA) project of ESA, DLR, Observatoire de la Côte d'Ázur, NASA, and Johns Hopkins University Applied Physics Laboratory (JHU/APL).

Experiments on asteroids using hard landers

NASA Technical Reports Server (NTRS)

Turkevich, A.; Economou, T.

1978-01-01

Hard lander missions to asteroids are examined using the Westphal penetrator study as a basis. Imagery and chemical information are considered to be the most significant science to be obtained. The latter, particularly a detailed chemical analysis performed on an uncontaminated sample, may answer questions about the relationships of asteroids to meteorites and the place of asteroids in theories of the formation of the solar system.

Spin vectors of asteroids 21 Lutetia, 196 Philomela, 250 Bettina, 337 Devosa, and 804 Hispania

NASA Technical Reports Server (NTRS)

Michalowski, Tadeusz

1992-01-01

Such parameters as shape, orientation of spin axis, prograde or retrograde rotation are important for understanding the collisional evolution of asteroids since the primordial epochs of solar system history. These parameters remain unknown for most asteroids and poorly constrained for all but a few. This work presents results for five asteroids: 21, 196, 250, 337, and 804.

Water in the Early Solar System: Infrared Studies of Aqueously Altered and Minimally Processed Asteroids

NASA Astrophysics Data System (ADS)

McAdam, Margaret M.

This thesis investigates connections between low albedo asteroids and carbonaceous chondrite meteorites using spectroscopy. Meteorites and asteroids preserve information about the early solar system including accretion processes and parent body processes active on asteroids at these early times. One process of interest is aqueous alteration. This is the chemical reaction between coaccreted water and silicates producing hydrated minerals. Some carbonaceous chondrites have experienced extensive interactions with water through this process. Since these meteorites and their parent bodies formed close to the beginning of the Solar System, these asteroids and meteorites may provide clues to the distribution, abundance and timing of water in the Solar nebula at these times. Chapter 2 of this thesis investigates the relationships between extensively aqueously altered meteorites and their visible, near and mid-infrared spectral features in a coordinated spectral-mineralogical study. Aqueous alteration is a parent body process where initially accreted anhydrous minerals are converted into hydrated minerals in the presence of coaccreted water. Using samples of meteorites with known bulk properties, it is possible to directly connect changes in mineralogy caused by aqueous alteration with spectral features. Spectral features in the mid-infrared are found to change continuously with increasing amount of hydrated minerals or degree of alteration. Building on this result, the degrees of alteration of asteroids are estimated in a survey of new asteroid data obtained from SOFIA and IRTF as well as archived the Spitzer Space Telescope data. 75 observations of 73 asteroids are analyzed and presented in Chapter 4. Asteroids with hydrated minerals are found throughout the main belt indicating that significant ice must have been present in the disk at the time of carbonaceous asteroid accretion. Finally, some carbonaceous chondrite meteorites preserve amorphous iron-bearing materials that formed through disequilibrium condensation in the disk. These materials are readily destroyed in parent body processes so their presence indicates the meteorite/asteroid has undergone minimal parent body processes since the time of accretion. Presented in Chapter 3 is the spectral signature of meteorites that preserve significant amorphous iron-bearing materials and the identification of an asteroid, (93) Minerva, that also appears to preserve these materials.

Ultraviolet to near-infrared spectroscopy of the potentially hazardous, low delta-V asteroid (175706) 1996 FG3. Backup target of the sample return mission MarcoPolo-R

NASA Astrophysics Data System (ADS)

Perna, D.; Dotto, E.; Barucci, M. A.; Fornasier, S.; Alvarez-Candal, A.; Gourgeot, F.; Brucato, J. R.; Rossi, A.

2013-07-01

Context. Primitive near-Earth asteroids (NEAs) are important subjects of study for current planetary research. Their investigation can provide crucial information on topics such as the formation of the solar system, the emergence of life, and the mitigation of the risk of asteroid impact. Sample return missions from primitive asteroids have been scheduled or are being studied by space agencies, including the MarcoPolo-R mission selected for the assessment study phase of ESA M3 missions. Aims: We want to improve our knowledge of the surface composition and physical nature of the potentially hazardous, low delta-V asteroid (175706) 1996 FG3, backup target of MarcoPolo-R. This intriguing object shows an as-yet unexplained spectral variability. Methods: We performed spectroscopic observations of 1996 FG3 using the visible spectrograph DOLORES at the Telescopio Nazionale Galileo (TNG), and the UV-to-NIR X-Shooter instrument at the ESO Very Large Telescope (VLT). Results: We find featureless spectra and we classify 1996 FG3 as a primitive Xc-type in the Bus-DeMeo taxonomy. Based on literature comparison, we confirm the spectral variability of this object at near-infrared (NIR) wavelengths, and find that spectral variations exist also for the visible spectral region. Phase reddening cannot explain such variations. Obtained with the same observational conditions for the whole 0.3-2.2 μm range, our X-Shooter spectrum allowed a proper comparison with the RELAB meteorite database. A very good fit is obtained with the very primitive C2 Tagish Lake carbonaceous chondrite (pressed powder), confirming 1996 FG3 as a suitable target for a sample return mission from primitive NEAs. Conclusions: We hypothesize a compacted/cemented surface for 1996 FG3, like that observed by the Hayabusa mission on (25143) Itokawa, with the possible presence of regions showing different degrees of surface roughness. This variegation could be related to the binary nature of 1996 FG3, but to check this hypothesis further observations are necessary. Based on observations carried out at the European Southern Observatory (ESO), Chile (programme 088.C-0695), and with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias (programme AOT25/TAC13).

Surprise! The oft-ignored Moon might actually be important for changing the spins of asteroids during Earth flybys

NASA Astrophysics Data System (ADS)

Tuttle Keane, James; Siu, Hosea C.; Moskovitz, Nicholas A.; Binzel, Richard P.

2015-11-01

Analysis near-Earth asteroid archival data has revealed that asteroids with Earth MOIDs (minimum orbit intersection distance; a proxy for flyby distance) smaller than 1.0-1.5 lunar distances have a systematically larger dispersion in spin rate than more distant flybys (Siu, et al. 2015, DPS). While tidal torques during close encounters are expected to alter the spin states of asteroids (e.g. Scheeres et al. 2000, Icarus), there is no intrinsic reason to expect the observed sharp transition in spin rate distribution at 1.0-1.5 lunar distances, as tidal forces drop off smoothly with distance.While the Moon itself is too diminutive to directly alter the spin-states of asteroids, we show that its presence is enough to significantly affect asteroid encounter trajectories. Asteroids entering the Earth-Moon system are subject to three-body dynamics (due to the combined gravitational effects of the Earth and Moon). Depending on the flyby geometry, the Moon can act as a temporary sink for the asteroid's geocentric orbital energy. This allows some fraction of asteroids to have closer approaches with the Earth than expected when considering the Earth-Moon barycenter alone. In rare cases (~0.1%) this process enables the capture of temporary moons around the Earth (Granvik et al. 2012, Icarus). Asteroids that undergo these "enhanced" flybys can have both closer-than-expected encounter distances (resulting in more significant tidal perturbations), and repeated encounters with the Earth and Moon before leaving the system (resulting in the accumulation of multiple tidal interactions). By numerically solving the circular restricted three-body problem, we show that this process naturally produces a sharp transition in the asteroid population: asteroids with MOIDs less than 1.5 lunar distances can undergo these enhanced close approaches, possibly explaining the sharp transition in the dispersion of asteroid spin rates at this distance. Future work will investigate the efficiency of this process, and the relationship between the physical response of the asteroid to tidal perturbations and the statistical distribution of asteroid spin rates.

Astronomy in Georgia - Present Status and Perspectives

NASA Astrophysics Data System (ADS)

Todua, M.

2016-09-01

Astronomy in Georgia is generally represented in Abastumani Astrophysical Observatory found in 1932. It is one of the leading scientific institutes in the country. Main fields of research are solar system bodies (including near-Earth asteroids), various aspects of solar physics, stellar astronomy (including binary stars and open clusters), extragalactic objects (AGNs), theoretical astrophysics, cosmology, atmospheric and solar-terrestrial physics. Several telescopes are operational today, as well as the instruments for atmospheric studies. In 2007 the Observatory was integrated with Ilia State University, merging scientific research and education which facilitated the growth of a new generation of researchers. There are groups of astronomers and astrophysicists in other Georgian universities and institutions as well. Georgian scientists collaborate with research centers and universities worldwide. Research groups participate in various international scientific projects. The interest in astronomy in Georgia has been growing, which increases future perspectives of its development in the country.

Amor: Investigating The Triple Asteroid System 2001 SN263

NASA Astrophysics Data System (ADS)

Jones, T.; Bellerose, Julie; Lee, P.; Prettyman, T.; Lawrence, D.; Smith, P.; Gaffey, M.; Nolan, M.; Goldsten, J.; Thomas, P.; Veverka, J.; Farquhar, R.; Heldmann, J.; Reddy, V.; Williams, B.; Chartres, J.; DeRosee, R.; Dunham, D.

2010-10-01

The Amor mission will rendezvous and land at the triple Near-Earth Asteroid system (153591) 2001 SN263 and execute detailed, in-situ science investigations. The spacecraft reaches 2001 SN263 by using a two-year ΔVEGA (ΔV-Earth Gravity Assist) trajectory with a relatively low launch C3 of 33.5 km2/s2. Rendezvous will enable reconnaissance activities including global and regional imaging, shape modeling, system dynamics, and compositional mapping. After landing, Amor will conduct in-situ imaging (panoramic to microscopic scale) and compositional measurements to include elemental abundance. The main objectives are to 1) establish in-situ the long-hypothesized link between C-type asteroids and the primitive carbonaceous chondrite (CC) meteorites, 2) investigate the nature, origin and evolution of C-type asteroids, and 3) investigate the origin and evolution of a multiple asteroid system. The mission also addresses the distribution of volatiles and organic materials, impact hazards, and resources for future exploration. Amor is managed by NASA Ames Research Center in partnership with Orbital Sciences, KinetX, MDA, and Draper with heritage instruments provided by Ball Aerospace, JHU/APL, and Firestar Engineering. The science team brings experience from NEAR, Hayabusa, Deep Impact, Dawn, LCROSS, Kepler, and Mars missions. In this paper, we describe the science, mission design, and main operational challenges of performing in-situ science at this triple asteroid system. Challenges include landing on the asteroid components, thermal environment, short day-night cycles, and the operation of deployed instruments in a low gravity (10^-5 g) environment.

Scenarios which may lead to the rise of an asteroid-based technical civilisation

NASA Astrophysics Data System (ADS)

Kecskes, Csaba

2002-05-01

In a previous paper, the author described a hypothetical development path of technical civilisations which has the following stages: planet dwellers, asteroid dwellers, interstellar travellers, interstellar space dwellers. In this paper, several scenarios are described which may cause the rise of an asteroid-based technical civilisation. Before such a transition may take place, certain space technologies must be developed fully (now these exist only in very preliminary forms): closed-cycle biological life support systems, space manufacturing systems, electrical propulsion systems. After mastering these technologies, certain events may provide the necessary financial means and social impetus for the foundation of the first asteroid-based colonies. In the first scenario, a rich minority group becomes persecuted and they decide to leave the Earth. In the second scenario, a "cold war"-like situation exists and the leaders of the superpowers order the creation of asteroid-based colonies to show off their empires' technological (and financial) grandiosity. In the third scenario, the basic situation is similar to the second one, but in this case the asteroids are not just occupied by the colonists. With several decades of hard work, an asteroid can be turned into a kinetic energy weapon which can provide the same (or greater) threat as the nuclear arsenal of a present superpower. In the fourth scenario, some military asteroids are moved to Earth-centred orbits and utilised as "solar power satellites" (SPS). This would be a quite economical solution because a "military asteroid" already contains most of the important components of an SPS (large solar collector arrays, power distribution devices, orbit modifying rocket engine), one should add only a large microwave transmitter.

Scenarios which may lead to the rise of an asteroid-based technical civilisation.

PubMed

Kecskes, Csaba

2002-05-01

In a previous paper, the author described a hypothetical development path of technical civilisations which has the following stages: planet dwellers, asteroid dwellers, interstellar travellers, interstellar space dwellers. In this paper, several scenarios are described which may cause the rise of an asteroid-based technical civilisation. Before such a transition may take place, certain space technologies must be developed fully (now these exist only in very preliminary forms): closed-cycle biological life support systems, space manufacturing systems, electrical propulsion systems. After mastering these technologies, certain events may provide the necessary financial means and social impetus for the foundation of the first asteroid-based colonies. In the first scenario, a rich minority group becomes persecuted and they decide to leave the Earth. In the second scenario, a "cold war"-like situation exists and the leaders of the superpowers order the creation of asteroid-based colonies to show off their empires' technological (and financial) grandiosity. In the third scenario, the basic situation is similar to the second one, but in this case the asteroids are not just occupied by the colonists. With several decades of hard work, an asteroid can be turned into a kinetic energy weapon which can provide the same (or greater) threat as the nuclear arsenal of a present superpower. In the fourth scenario, some military asteroids are moved to Earth-centred orbits and utilised as "solar power satellites" (SPS). This would be a quite economical solution because a "military asteroid" already contains most of the important components of an SPS (large solar collector arrays, power distribution devices, orbit modifying rocket engine), one should add only a large microwave transmitter. c2002 Elsevier Science Ltd. All rights reserved.

Planetary Formation and Dynamics in Binary Systems

NASA Astrophysics Data System (ADS)

Xie, J. W.

2013-01-01

As of today, over 500 exoplanets have been detected since the first exoplanet was discovered around a solar-like star in 1995. The planets in binaries could be common as stars are usually born in binary or multiple star systems. Although current observations show that the planet host rate in multiple star systems is around 17%, this fraction should be considered as a lower limit because of noticeable selection effects against binaries in planet searches. Most of the current known planet-bearing binary systems are S-types, meaning the companion star acts as a distant satellite, typically orbiting the inner star-planet system over 100 AU away. Nevertheless, there are four systems with a smaller separation of 20 AU, including the Gamma Cephei, GJ 86, HD 41004, and HD 196885. In addition to the planets in circumprimary (S-type) orbits discussed above, planets in circumbinary (P-type) orbits have been found in only two systems. In this thesis, we mainly study the planet formation in the S-type binary systems. In chapter 1, we first summarize current observational facts of exoplanets both in single-star and binary systems, then review the theoretical models of planet formation, with special attention to the application in binary systems. Perturbative effects from stellar companions render the planet formation process in binary systems even more complex than that in single-star systems. The perturbations from a binary companion can excite planetesimal orbits, and increase their mutual impact velocities to the values that might exceed their escape velocity or even the critical velocity for the onset of eroding collisions. The intermediate stage of the formation process---from planetesimals to planetary embryos---is thus the most problematic. In the following chapters, we investigate whether and how the planet formation goes through such a problematic stage. In chapter 2, we study the effects of gas dissipation on the planetesimals' mutual accretion. We find that in a dissipating gas disk, all the planetesimals eventually converge toward the same forced orbits regardless of their size, leading to the much lower impact velocities. This process progressively increases the net mass accretion and can even trigger the runaway growth for large planetesimals. In chapter 3, for the first time, we adopt a 3-dimensional approach to investigate the planetesimals' mutual accretion in binary systems. We find that the inclusion of a small inclination between the binary orbital plane and the circumstellar disk plane leads to the realization of the differential orbital phasing in 3-dimensional space. In such a case, impacts mainly occur between similar-sized bodies with the impact velocities being significantly reduced, and thus the planetesimal accretion is more favored. In chapter 4, we investigate the planet formation in a specific system, the habitable zone of Alpha Centauri B. For the first time, we develop a scaling method to estimate the planetesimal collisional timescale in binary systems. We find that the accretion-favorable conditions satisfied at 1˜2 AU from Alpha Centauri B after the first 10^5 years. However, the planetesimal accretion is significantly less efficient as compared to the single star case. Our results suggest that the formation of Earth-like planets through the accretion of km-sized planetesimals is possible in Alpha Centauri B, while the formation of gaseous giant planets is not favorable. In chapter 5, we outline a new concept, which we call the ``snowball'' growth mode. In this snowball phase, the isolated planetesimals move in the Keplerian orbits, and grow solely via the direct accretion of subcentimeter-sized dust entrained with the gas in the protoplanetary disk. Using a simplified model in which the planetesimals are progressively produced from the dust, we find that the snowball growth phase can be the dominant mode to transfer mass from the dust to planetesimals. The snowball growth mode could provide an alternative explanation for the turnover point in the size distribution of the present-day asteroid belt. For the specific case of close binaries such as Alpha Centauri, the snowball growth mode provides a safe way for the bodies to grow through the problematic range with a size of 1˜50 km. In chapter 6, we investigate the intermediate stages of the planet formation in highly inclined cases. We find that the gas drag plays a crucial role in the evolution of the planetesimals' semi-major axis, and the results can be generally divided into two categories, i.e., the Kozai-on regime and the Kozai-off regime. For both regimes, a robust outcome over a wide range of parameters is that, the planetesimals migrate/jump inwards and pile up, leading to a severely truncated and dense planetesimal disk around the primary. In this compact and dense disk, the collision rates are high but the relative velocities are low, providing conditions which are favorable for the planetesimal growth, and potentially allow for the subsequent formation of planets. Finally, we summarize this thesis in chapter 7. Many open questions still remain in current research field of planet formation in binary systems, and the current Kepler project provides an unprecedented opportunity for such researches. A comprehensive understanding of planets in binaries requires placing them in a bigger context to include the formation and evolution of stars and/or clusters.

Shape and spin of asteroid 967 Helionape

NASA Astrophysics Data System (ADS)

Apostolovska, G.; Kostov, A.; Donchev, Z.; Bebekovska, E. Vchkova; Kuzmanovska, O.

2018-04-01

Knowledge of the spin and shape parameters of the asteroids is very important for understanding of the conditions during the creation of our planetary system and formation of asteroid populations. The main belt asteroid and Flora family member 967 Helionape was observed during five apparitions. The observations were made at the Bulgarian National Astronomical Observatory (BNAO) Rozhen, since March 2006 to March 2016. Lihtcurve inversion method (Kaasalainen et al. (2001)), applied on 12 relative lightcurves obtained at various geometric conditions of the asteroid, reveals the spin vector, the sense of rotation and the preliminary shape model of the asteroid. Our aim is to contribute in increasing the set of asteroids with known spin and shape parameters. This could be done with dense lightcurves, obtained during small number of apparitions, in combination with sparse data produced by photometric asteroid surveys such as the Gaia satellite (Hanush (2011)).

Sending an Instrument to Psyche, the Largest Metal Asteroid in the Solar System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burks, Morgan

In a few years, an instrument designed and built by Lawrence Livermore National Laboratory researchers will be flying hundreds of millions of miles through space to explore a rare, largely metal asteroid. The Livermore gamma ray spectrometer will be built in collaboration with researchers from the Johns Hopkins Applied Physics Laboratory for the first-ever visit to Psyche, the largest metal asteroid in the solar system.

Probable Disastrous Consequences of Collision Between Unknown Small (100 m) Asteroids with Known (Approximately 1 km) Near Earth Orbiting (NEO) Asteroids

NASA Technical Reports Server (NTRS)

Smalley, Larry

2003-01-01

The long-term stability of the Solar System is not well understood. Ironically its stability is taken for granted even though our knowledge of all the constituents [comets, asteroids. (The Asteroid Belt between Mars and Jupiter, Trojan Asteroids, Kuiper belt, Ort Cloud), planetoids, planets, moons, etc], and its long-term dynamics cannot be easily computed. At best one might say that the solar system is chaotic, but much of the time it seems to exists near a quasi-stationary state. An asteroid that passes near the Earth regularly returns with clock-like precision. Taking into account every known detail of its path through the solar system, its orbit is calculated forward thousands of years with no untoward calamity on the horizon. And then one day, this passive visitor slams into the Earth during a sunny afternoon picnic! Can this happen? Unfortunately, this is a real possibility in the ordinary history of the solar system. In fact our knowledge of the solar system in the small is sketchy, as will be pointed out. Events, which lie outside our awareness, can precipitate disasters that we may perceive when it's too late to launch effective counter measures. In this work, one such scenario is described and the direct consequences for the Earth are calculated.

The Physical, Geological, and Dynamical Nature of Asteroid (101955) Bennu - Target of OSIRIS-REx

NASA Astrophysics Data System (ADS)

Lauretta, Dante

2014-11-01

OSIRIS-REx will survey asteroid (101955) Bennu to understand its properties, assess its resource potential, refine the impact hazard, and return a sample to Earth. This mission launches in 2016. Bennu is different from all other near-Earth asteroids previously visited by spacecraft. (433) Eros, target of the NEAR-Shoemaker mission, and (25143) Itokawa, target of Hayabusa, are both high-albedo, S-type asteroids with irregular shapes. In contrast, Bennu has a low albedo, is a B-type asteroid, and has a distinct spheroidal shape. While Eros and Itokawa are similar to ordinary chondrites, Bennu is likely related to carbonaceous chondrites, meteorites that record the history of volatiles and organic compounds in the early Solar System.We performed an extensive campaign to determine the properties of Bennu. This investigation provides information on the orbit, shape, mass, rotation state, radar response, photometric, spectroscopic, thermal, regolith, and environmental properties of Bennu. Combining these data with cosmochemical and dynamical models yields a hypothetical timeline for Bennu’s formation and evolution. Bennu is an ancient object that has witnessed over 4.5 Gyr of Solar System history. Its chemistry and mineralogy were established within the first 10 Myr of the Solar System. It likely originated as a discrete asteroid in the main belt ~0.7 - 2 Gyr ago as a fragment from the catastrophic disruption of a large, carbonaceous asteroid. It was delivered to near-Earth space via a combination of Yarkovsky-induced drift and interaction with giant-planet resonances. During its journey, YORP processes and planetary encounters modified Bennu’s spin state, potentially reshaping and resurfacing the asteroid. Bennu is a Potentially Hazardous Asteroids with an ~1-in-2700 chance of impacting the Earth in the late 22nd century. It will most likely end its dynamical life by falling into the Sun. The highest probability for a planetary impact is with Venus, followed by the Earth. There is a chance that Bennu will be ejected from the inner Solar System after a close encounter with Jupiter. OSIRIS-REx will return samples from this intriguing asteroid in September 2023.

Evidence for a near-Earth asteroid belt

NASA Technical Reports Server (NTRS)

Rabinowitz, D. L.; Gehrels, T.; Scotti, J. V.; Mcmillan, R. S.; Perry, M. L.; Wisniewski, W.; Larson, S. M.; Howell, E. S.; Mueller, B. E. A.

1993-01-01

In January 1991, the 0.9-m Spacewatch telescope made the first observation of an asteroid outside Earth's atmosphere but in the neighborhood of the Earth-moon system. Since then, more than 40 Earth-approaching asteroids have been discovered, including 13 smaller than 50 m. Using these data, one of us has shown that there is an excess of Earth-approaching asteroids with diameters less than 50 m, relative to the population inferred from the distribution of larger objects. Here we argue that these smaller objects - characterized by low eccentricities, widely ranging inclinations and unusual spectral properties - form a previously undetected asteroid belt concentrated near Earth. The recent discovery of additional small Earth-approaching asteroids supports this conclusion.

OSIRIS-REx Asterod Sample Return Mission

NASA Technical Reports Server (NTRS)

Nakamura-Messinger, Keiki; Connolly, Harold C. Jr.; Messenger, Scott; Lauretta, Dante S.

2017-01-01

OSIRIS-REx is NASA's third New Frontiers Program mission, following New Horizons that completed a flyby of Pluto in 2015 and the Juno mission to Jupiter that has just begun science operations. The OSIRIS-REx mission's primary objective is to collect pristine surface samples of a carbonaceous asteroid and return to Earth for analysis. Carbonaceous asteroids and comets are 'primitive' bodies that preserved remnants of the Solar System starting materials and through their study scientists can learn about the origin and the earliest evolution of the Solar System. The OSIRIS-REx spacecraft was successfully launched on September 8, 2016, beginning its seven year journey to asteroid 101955 Bennu. The robotic arm will collect 60-2000 grams of material from the surface of Bennu and will return to Earth in 2023 for worldwide distribution by the Astromaterials Curation Facility at NASA Johnson Space Center. The name OSIRIS-REx embodies the mission objectives (1) Origins: Return and analyze a sample of a carbonaceous asteroid, (2) Spectral Interpretation: Provide ground-truth for remote observation of asteroids, (3) Resource Identification: Determine the mineral and chemical makeup of a near-Earth asteroid (4) Security: Measure the non-gravitational that changes asteroidal orbits and (5) Regolith Explorer: Determine the properties of the material covering an asteroid surface. Asteroid Bennu may preserve remnants of stardust, interstellar materials and the first solids to form in the Solar System and the molecular precursors to the origin of life and the Earth's oceans. Bennu is a potentially hazardous asteroid, with an approximately 1 in 2700 chance of impacting the Earth late in the 22nd century. OSIRIS-REx collects from Bennu will help formulate the types of operations and identify mission activities that astronauts will perform during their expeditions. Such information is crucial in preparing for humanity's next steps beyond low Earthy orbit and on to deep space destinations.

V-type candidates and Vesta family asteroids in the Moving Objects VISTA (MOVIS) catalogue

NASA Astrophysics Data System (ADS)

Licandro, J.; Popescu, M.; Morate, D.; de León, J.

2017-04-01

Context. Basaltic asteroids (spectrally classified as V-types) are believed to be fragments of large differentiated bodies. The majority of them are found in the inner part of the asteroid belt, and are current or past members of the Vesta family. Recently, some V-type asteroids have been discovered far from the Vesta family supporting the hypothesis of the presence of multiple basaltic asteroids in the early solar system. The discovery of basaltic asteroids in the outer belt challenged the models of the radial extent and the variability of the temperature distribution in the early solar system. Aims: We aim to identify new basaltic V-type asteroids using near-infrared colors of 40 000 asteroids observed by the VHS-VISTA survey and compiled in the MOVIS-C catalogue. We also want to study their near-infrared colors and to study the near-infrared color distribution of the Vesta dynamical family. Methods: We performed a search in the MOVIS-C catalogue of all the asteroids with (Y-J) and (J-Ks) in the range (Y-J) ≥ 0.5 and (J-Ks) ≤ 0.3, associated with V-type asteroids, and studied their color distribution. We have also analyzed the near-infrared color distribution of 273 asteroid members of the Vesta family and compared them with the albedo and visible colors from WISE and SDSS data. We determined the fraction of V-type asteroids in the family. Results: We found 477 V-type candidates in MOVIS-C, 244 of them outside the Vesta dynamical family. We identified 19 V-type asteroids beyond the 3:1 mean motion resonance, 6 of them in the outer main belt, and 16 V-types in the inner main belt with proper inclination Ip ≤ 3.0°, well below the inclination of the Vesta family. We computed that 85% of the members of the Vesta dynamical family are V-type asteroids, and only 1-2% are primitive class asteroids and unlikely members of the family. Conclusions: This work almost doubles the sample of basaltic asteroid candidates in regions outside the Vesta family. Spectroscopic studies in the near-infrared and dynamical studies are needed to confirm their basaltic composition and to determine their origin.

Looking into the evolution of granular asteroids in the Solar System

NASA Astrophysics Data System (ADS)

Sánchez, Paul; Scheeres, Daniel; Hirabayashi, Masatoshi; Tardivel, Simon

2017-06-01

By now it has been accepted that most of the small asteroids in the Solar System are granular aggregates kept together by gravitational and possibly, cohesive forces. These aggregates can form, deform and disrupt over millennia subjected to different internal and external factors that would ultimately determine how they evolve over time. Parameters such as porosity, cohesive and tensile strength, angles of friction, particle size distributions, stress states, heterogeneity and yield criteria among others, determine how these granular systems will react when subjected to different, changing, external factors. These external factors include solar photon momentum, gravitational tides, micro- and macro-impacts and are believed to have produced and shaped the current asteroid population. In our research we use a combination of Soil Mechanics theory, Soft-Sphere Discrete Element Method (SSDEM) Simulations and Orbital Mechanics in order to understand how simulated, homogeneous and heterogeneous, ellipsoidal and spherical gravitational aggregates, a crude but useful representation of an asteroid, evolve when rotated to the point of disruption. Then, we compare our results to the shapes of observed asteroids as well as to the disruption patterns of a few active asteroids. Our results lead us to believe that the different shapes of observed asteroids as well as their unique disruption patterns could give us clues about their internal structure, strength and geophysical properties in general.

Escape of asteroids from the Hecuba gap

NASA Astrophysics Data System (ADS)

Michtchenko, T.; Ferraz-Mello, S.

1997-12-01

The dynamics of the 2/1 mean-motion asteroidal resonance with Jupiter is studied by numerical integration of the equations of motion of the Sun-Jupiter-Saturn-asteroid system. The measurement of the fundamental asteroidal frequencies by means of Fourier and wavelet analyses allows us to construct the web of the secular, secondary and Kozai resonances inside the 2/1- resonance boundaries. The structure of the phase space of the 2/1 resonance is discussed with emphasis on the acting depletion mechanisms due to presence of these inner resonances. Special attention is paid to the study of the middle-eccentricity depleted region. The importance of the great inequality of the Jupiter-Saturn system in the acceleration of the diffusion processes in this region is pointed out. The existence of a group of asteroids like (3789) Zhongguo, inside the 2/1 resonance, is also discussed.

A Ground Systems Template for Remote Sensing Systems

NASA Astrophysics Data System (ADS)

McClanahan, Timothy P.; Trombka, Jacob I.; Floyd, Samuel R.; Truskowski, Walter; Starr, Richard D.; Clark, Pamela E.; Evans, Larry G.

2002-10-01

Spaceborne remote sensing using gamma and X-ray spectrometers requires particular attention to the design and development of reliable systems. These systems must ensure the scientific requirements of the mission within the challenging technical constraints of operating instrumentation in space. The Near Earth Asteroid Rendezvous (NEAR) spacecraft included X-ray and gamma-ray spectrometers (XGRS), whose mission was to map the elemental chemistry of the 433 Eros asteroid. A remote sensing system template, similar to a blackboard systems approach used in artificial intelligence, was identified in which the spacecraft, instrument, and ground system was designed and developed to monitor and adapt to evolving mission requirements in a complicated operational setting. Systems were developed for ground tracking of instrument calibration, instrument health, data quality, orbital geometry, solar flux as well as models of the asteroid's surface characteristics, requiring an intensive human effort. In the future, missions such as the Autonomous Nano-Technology Swarm (ANTS) program will have to rely heavily on automation to collectively encounter and sample asteroids in the outer asteroid belt. Using similar instrumentation, ANTS will require information similar to data collected by the NEAR X-ray/Gamma-Ray Spectrometer (XGRS) ground system for science and operations management. The NEAR XGRS systems will be studied to identify the equivalent subsystems that may be automated for ANTS. The effort will also investigate the possibility of applying blackboard style approaches to automated decision making required for ANTS.

Compositional study of asteroids in the Erigone collisional family using visible spectroscopy at the 10.4m GTC

NASA Astrophysics Data System (ADS)

Morate, David; de León, Julia; De Prá, Mário; Licandro, Javier; Cabrera-Lavers, Antonio; Campins, Humberto; Pinilla-Alonso, Noemí; Alí-Lagoa, Víctor

2015-11-01

Asteroid families are formed by the fragments produced by the disruption of a common parent body (Bendjoya & Zappalà 2002). Primitive asteroids in the solar system are believed to have undergone less thermal processing than the S-complex asteroids. Thus, study of primitive asteroid families provides information about the solar system formation period. The Erigone collisional family, together with other three families (Polana, Clarissa and Sulamitis), are believed to be the origin of the two primitive Near-Earth asteroids that are the main targets of the NASA’s OSIRIS-REx ((101955) Bennu) and JAXA’s Hayabusa 2 ((162173) 1999 JU3) missions (Campins et al. 2010; Campins et al. 2013; Lauretta et al. 2010; Tsuda et al. 2013). These spacecrafts will visit the asteroids, and a sample of their surface material will be returned to Earth. Understanding of the families that are considered potential sources will enhance the scientific return of the missions. The main goal of the work presented here is to characterize the Erigone collisional family. Asteroid (163) Erigone has been classified as a primitive object (Bus 1999; Bus & Binzel 2002), and we expect the members of this family to be consistent with the spectral type of the parent body. We have obtained visible spectra (0.5-0.9 μm) for 101 members of the Erigone family, using the OSIRIS instrument at the 10.4m Gran Telescopio Canarias. We performed a taxonomical classification of these asteroids, finding that the number of primitive objects in our sample is in agreement with the hypothesis of a common parent body. In addition, we have found a significant fraction of asteroids in our sample that present evidences of aqueous alteration. Study of aqueous alterations is important, as it can give information on the heating processes of the early Solar System, and for the associated astrobiological implications (it has been suggested that the Earth’s present water supply was brought here by asteroids, instead of comets, in opposition to previous explanations (Morbidelli et al. 2000).

Control of asteroid retrieval trajectories to libration point orbits

NASA Astrophysics Data System (ADS)

Ceriotti, Matteo; Sanchez, Joan Pau

2016-09-01

The fascinating idea of shepherding asteroids for science and resource utilization is being considered as a credible concept in a not too distant future. Past studies identified asteroids which could be efficiently injected into manifolds which wind onto periodic orbits around collinear Lagrangian points of the Sun-Earth system. However, the trajectories are unstable, and errors in the capture maneuver would lead to complete mission failure, with potential danger of collision with the Earth, if uncontrolled. This paper investigates the controllability of some asteroids along the transfers and the periodic orbits, assuming the use of a solar-electric low-thrust system shepherding the asteroid. Firstly, an analytical approach is introduced to estimate the stability of the trajectories from a dynamical point of view; then, a numerical control scheme based on a linear quadratic regulator is proposed, where the gains are optimized for each trajectory through a genetic algorithm. A stochastic simulation with a Monte Carlo approach is used to account for different perturbed initial conditions and the epistemic uncertainty on the asteroid mass. Results show that only a small subset of the considered combinations of trajectories/asteroids are reliably controllable, and therefore controllability must be taken into account in the selection of potential targets.

BAOBAB (Big And Outrageously Bold Asteroid Belt) Project

NASA Technical Reports Server (NTRS)

Mcfadden, L. A.; Thomas, C. A; Englander, J. A.; Ruesch, O.; Hosseini, S.; Goossens, S. J.; Mazarico, E. M.; Schmerr, N.

2017-01-01

One of the intriguing results of NASA's Dawn mission is the composition and structure of the Main Asteroid Belt's only known dwarf planet, Ceres [1]. It has a top layer of dehydrated clays and salts [2] and an icy-rocky mantle [3,4]. It is widely known that the asteroid belt failed to accrete as a planet by resonances between the Sun and Jupiter. About 20-30 asteroids >100 km diameter are probably differentiated protoplanets [5]. 1) how many more and which ones are fragments of protoplanets? 2) How many and which ones are primordial rubble piles left over from condensation of the solar nebula? 3) How would we go about gaining better and more complete characterization of the mass, interior structure and composition of the Main Belt asteroid population? 4) What is the relationship between asteroids and ocean worlds? Bulk parameters such as the mass, density, and porosity, are important to characterize the structure of any celestial body, and for asteroids in particular, they can shed light on the conditions in the early solar system. Asteroid density estimates exist but currently they are often based on assumed properties of taxonomic classes, or through astronomical survey data where interactions with asteroids are weak at best resulting in large measurement uncertainty. We only have direct density estimates from spacecraft encounters for a few asteroids at this time. Knowledge of the asteroids is significant not only to understand their role in solar system workings, but also to assess their potential as space resources, as impact hazards on Earth, or even as harboring life forms. And for the distant future, we want to know if the idea put forth in a contest sponsored by Physics Today, to surface the asteroids into highly reflecting, polished surfaces and use them as a massively segmented mirror for astrophysical exploration [6], is feasible.

Stability criteria for wide binary stars harboring Oort Clouds

NASA Astrophysics Data System (ADS)

Calandra, M. F.; Correa-Otto, J. A.; Gil-Hutton, R. A.

2018-03-01

Context. In recent years, several numerical studies have been done in the field of the stability limit. Although, many of them included the analysis of asteroids or planets, is not possible to find in the literature any work on how the presence of a binary star could affect other possible configurations in a three-body problem. In order to develop this subject we consider other structures like Oort Clouds in wide binary systems. Regarding the existence of Oort Clouds in extrasolar systems there are recent works that do not reject its possible existence. Aim. The aim of this work is to obtain the stability limit for Oort Cloud objects considering different masses of the secondary star and zero and non-zero inclinations of the particles. We improve our numerical treatment getting a mathematical fit that allows us to find the limit and compare our results with other previous works in the field. Methods: We use a symplectic integrator to integrate binary systems where the primary star is m1 = 1 M⊙ and the secondary, m2, takes 0.25 M⊙ and 0.66 M⊙ in two sets of simulations S1 and S2. The orbital parameters of the secondary star were varied in order to study different scenarios. We also used two different integration times (one shorter than the other) and included the presence of 1000 to 10 000 massless particles in circular orbits to form the Oort Cloud. The particles were disposed in four different inclination planes to investigate how the presence of the binary companion could affect the stability limit. Results: Using the Maximum Eccentricity Method, emax, together with the critical semimajor axis acrit we found that the emax criteria could reduce the integration times to find the limit. For those cases where the particles were in inclined orbits we found that there are particle groups that survive the integration time with a high eccentricity. These particle groups are found for our two sets of simulations, meaning that they are independent of the secondary mass. We also find for the co-planar case that the numerical value of the stability limit for retrograde orbits is higher than those found for prograde orbits. These results are in agreement with several published studies. Finally, the results obtained in this work allow us to build a numerical expression depending of the mass ratio, e2 and ip to find acrit, which can be compared with other recent works in the field.

Investigation of the interior of primordial asteroids and the origin of the Earth's water: The INSIDER space mission

NASA Astrophysics Data System (ADS)

Vernazza, P.; Lamy, P.

2014-07-01

Today's asteroid belt may not only be populated by objects that formed in situ, typically between 2.2 and 3.3 au, but also by bodies that formed over a very large range of heliocentric distances. It is currently proposed that both the early (<5 Myrs after Solar System formation) and late (>700 Myrs after Solar System formation) dynamical evolution of the Solar System was governed by giant planet migrations that led to the insertion of inner (1--3 au) as well as outer (4--13 au) small bodies in the asteroid belt. Taken altogether, the current dynamical models are able to explain many striking features of the asteroid belt including i) its incredible compositional diversity deduced mainly from spectroscopic observations and meteorites measurements, and ii) the evidence of radial mixing experienced by the various asteroid classes (e.g., S-, C-types) after their formation. In a broad stroke, the idea that the asteroid belt is a condensed version of the primordial Solar System is progressively emerging. The asteroid belt therefore presents the double advantage of being easily accessible and of offering crucial tests for the formation models of the Solar System by exploring the building blocks predicted by models of i) the telluric planets, ii) the giant planet cores, iii) the giant planets' satellites, and iv) outer small bodies such TNOs and comets. It also appears as an ideal place to search for the origin of Earth's water. Up to now, only a few asteroid classes (e.g., several S-types) have been visited by spacecraft and the focus of these in situ measurements has been mainly to give a geological context to ground based observations as well as strengthen/validate their interpretation. Most of the tantalizing discoveries of asteroid missions have been realized via images of the objects surfaces. Time has come for asteroid space science to reach a new milestone by extending the reconnaissance of the Belt's diversity and addressing new science questions. The scientific objectives of the INSIDER mission, to be proposed in response to the 2014 ESA call for an M-class mission, require the exploration of diverse primordial asteroids --- possibly the smallest surviving protoplanets of our Solar System --- in order to constrain the earliest stages of planetesimal formation thus avoiding the effect of destructive collisions, which produce extensively processed rubble piles. Our science objectives that justify in situ measurements in the context of an M-class mission and that are expected to lead to significant breakthroughs include: - The exploration of the diversity of the asteroid belt - The first investigation of the internal structure of asteroids - The origin of water on Earth The proposed mission scenario consists in i) successive rendez-vous followed by orbit insertion of two and possibly three large (D>100 km) objects, ii) one or two small landing modules (MASCOT type) to perform cosmochemical measurements (D/H ratio, O isotopes). The potential targets would include 24 Themis and 10 Hygiea. Meeting our science objectives requires instruments (such as radar, seismometers to be dropped to the surface, magnetometer, high resolution laser-desorption-ionization mass spectrometer to analyse the surface samples) not flown so far during past asteroids missions along with the traditional powerhouses, such as cameras and spectrometers.

Overview of Mission Design for NASA Asteroid Redirect Robotic Mission Concept

NASA Technical Reports Server (NTRS)

Strange, Nathan; Landau, Damon; McElrath, Timothy; Lantoine, Gregory; Lam, Try; McGuire, Melissa; Burke, Laura; Martini, Michael; Dankanich, John

2013-01-01

Part of NASA's new asteroid initiative would be a robotic mission to capture a roughly four to ten meter asteroid and redirect its orbit to place it in translunar space. Once in a stable storage orbit at the Moon, astronauts would then visit the asteroid for science investigations, to test in space resource extraction, and to develop experience with human deep space missions. This paper discusses the mission design techniques that would enable the redirection of a 100-1000 metric ton asteroid into lunar orbit with a 40-50 kW Solar Electric Propulsion (SEP) system.

The hierarchical stability of the seven known large size ratio triple asteroids using the empirical stability parameters.

PubMed

Liu, Xiaodong; Baoyin, Hexi; Marchis, Franck

In this study, the hierarchical stability of the seven known large size ratio triple asteroids is investigated. The effect of the solar gravity and primary's J 2 are considered. The force function is expanded in terms of mass ratios based on the Hill's approximation and the large size ratio property. The empirical stability parameters are used to examine the hierarchical stability of the triple asteroids. It is found that the all the known large size ratio triple asteroid systems are hierarchically stable. This study provides useful information for future evolutions of the triple asteroids.

New infrared spectral data for 27 asteroids: An investigation of meteorite- asteroid relationships by using the modified Gaussian model

NASA Astrophysics Data System (ADS)

Gietzen, Katherine M.

2009-09-01

Asteroids provide unique insights into the origin and early history of the solar system. Since asteroids are considered to be fairly pristine, studying them provides opportunities to learn more about the primordial solar system, its materials, processes and history. Since the discovery in 1801 of the first asteroid, Ceres, during the era when everyone was searching for the "missing planet", astronomers have been trying to understand what they are, where they came from, why they exist and what they can tell us about how our solar system formed and evolved. Within the asteroid population are a number of sub-populations, the primary division is due to the locations of the asteroids. There are the Main Belt Asteroid (MBA) population that resides between the orbits of Mars and Jupiter (1.8 - 3.5 AU) and the Near-Earth Asteroid (NEA) population whose orbits have an aphelion <= 1.3 AU. Within both the MBA and NEA populations are further subdivisions (taxonomic classes) based on physical properties of the asteroids such as albedo, spectral curve and probable composition. There have been a number of taxonomic classification schemes, the most current iteration splits the asteroids into three complexes (C, S, and X) that combined are comprised of twenty-six distinct taxonomic classes. Since the lifetimes of the NEAs are short (10 6 - 10 7 yrs), it is thought that the NEA population is and continues to be populated by the MBA population through various mechanisms like resonances and thermal forces. We have conducted a statistical comparison of the two populations as a whole, by complexes and individual taxonomic classes and found significant differences as well as similarities. On the surface, it appears that the NEA population is not representative of the MBA population. There are voids and relatively small numbers in taxonomic classes that exist in the NEA when compared to the MBA population and there are some important similarities. There are, however, biases that this analysis does not address that may explain our findings. The asteroid taxonomy classification schemas are based on visible wavelength spectra. There are ~2500 classified asteroids of which only a very small percentage have spectra in the infrared wavelength ranges. Here we demonstrate, using asteroid 1989 ML, the need for more asteroid spectra in the near-infrared wavelength range which contains much compositional information. We show that in the visible wavelengths spectra of several meteorites of very different types match the spectrum of 1989 ML. Finally, we examine twenty-seven S and possible S Complex asteroid spectra. We find that most contain pyroxenes in the monoclinic form (clinopyroxene). Clinopyroxenes can contain calcium; however, there are some that do not. The cases of Ca-free clinopyroxenes are rare on Earth, but are readily found in the type 3 unequilibrated ordinary chondrites. Analyses of the asteroids and ordinary chondrites were conducted using the Modified Gaussian Model (MGM) and the Band Area Ratio. We also examined two terrestrial Ca-free clinopyroxenes using the MGM. From our results we conclude that the surfaces of S Complex asteroids are consistent with the type 3 unequilibrated ordinary chondrites.

Observations of Spacecraft Targets, Unusual Asteroids, and Targets of Opportunity

NASA Technical Reports Server (NTRS)

Tholen, David J.

1998-01-01

Obtain physical and astrometric observations of: (1) spacecraft targets to support mission operations; (2) known asteroids with unusual orbits to help determine their origin; and (3) newly discovered minor planets (including both asteroids and comets) that represent a particular opportunity to add significant new knowledge of the Solar System.

Overview of the Mission Design Reference Trajectory for NASA's Asteroid Redirect Robotic Mission

NASA Technical Reports Server (NTRS)

Mcguire, Melissa L.; Strange, Nathan J.; Burke, Laura M.; McCarty, Steven L.; Lantoine, Gregory B.; Qu, Min; Shen, Haijun; Smith, David A.; Vavrina, Matthew A.

2017-01-01

The National Aeronautics and Space Administration's (NASA's) recently cancelled Asteroid Redirect Mission was proposed to rendezvous with and characterize a 100 m plus class near-Earth asteroid and provide the capability to capture and retrieve a boulder off of the surface of the asteroid and bring the asteroidal material back to cislunar space. Leveraging the best of NASA's science, technology, and human exploration efforts, this mission was originally conceived to support observation campaigns, advanced solar electric propulsion, and NASA's Space Launch System heavy-lift rocket and Orion crew vehicle. The asteroid characterization and capture portion of ARM was referred to as the Asteroid Redirect Robotic Mission (ARRM) and was focused on the robotic capture and then redirection of an asteroidal boulder mass from the reference target, asteroid 2008 EV5, into an orbit near the Moon, referred to as a Near Rectilinear Halo Orbit where astronauts would visit and study it. The purpose of this paper is to document the final reference trajectory of ARRM and the challenges and unique methods employed in the trajectory design of the mission.

Constraints on the Detection of the Solar Nebula's Oxidation State Through Asteroid Observations

NASA Technical Reports Server (NTRS)

Abell, P. A.; Gaffey, M. J.; Hardersen, P. S.

2005-01-01

Introduction: Asteroids represent the only in situ surviving population of planetesimals from the formation of the inner solar system and therefore include materials from the very earliest stages of solar system formation. Hence, these bodies can provide constraints on the processes and conditions that were present during this epoch and can be used to test current models and theories describing the late solar nebula, the early solar system and subsequent planetary accretion. From detailed knowledge of asteroid mineralogic compositions the probable starting materials, thermal histories, and oxidation states of asteroid parent bodies can be inferred. If such data can be obtained from specific mainbelt source regions, then this information can be used to map out the formation conditions of the late solar nebula within the inner solar system and possibly distinguish any trends in oxidation state that may be present.

1991 Urey Prize Lecture: Physical evolution in the solar system - Present observations as a key to the past

NASA Technical Reports Server (NTRS)

Binzel, Richard P.

1992-01-01

The present evaluation of the use of new observational methods for exploring solar system evolutionary processes gives attention to illustrative cases from the constraining of near-earth asteroid sources and the discovery of main-belt asteroid fragments which indicate Vesta to be a source of basaltic achondrite meteorites. The coupling of observational constraints with numerical models clarifies cratering and collisional evolution for both main-belt and Trojan asteroids.

Arecibo Radar Observation of Near-Earth Asteroids: Expanded Sample Size, Determination of Radar Albedos, and Measurements of Polarization Ratios

NASA Astrophysics Data System (ADS)

Lejoly, Cassandra; Howell, Ellen S.; Taylor, Patrick A.; Springmann, Alessondra; Virkki, Anne; Nolan, Michael C.; Rivera-Valentin, Edgard G.; Benner, Lance A. M.; Brozovic, Marina; Giorgini, Jon D.

2017-10-01

The Near-Earth Asteroid (NEA) population ranges in size from a few meters to more than 10 kilometers. NEAs have a wide variety of taxonomic classes, surface features, and shapes, including spheroids, binary objects, contact binaries, elongated, as well as irregular bodies. Using the Arecibo Observatory planetary radar system, we have measured apparent rotation rate, radar reflectivity, apparent diameter, and radar albedos for over 350 NEAs. The radar albedo is defined as the radar cross-section divided by the geometric cross-section. If a shape model is available, the actual cross-section is known at the time of the observation. Otherwise we derive a geometric cross-section from a measured diameter. When radar imaging is available, the diameter was measured from the apparent range depth. However, when radar imaging was not available, we used the continuous wave (CW) bandwidth radar measurements in conjunction with the period of the object. The CW bandwidth provides apparent rotation rate, which, given an independent rotation measurement, such as from lightcurves, constrains the size of the object. We assumed an equatorial view unless we knew the pole orientation, which gives a lower limit on the diameter. The CW also provides the polarization ratio, which is the ratio of the SC and OC cross-sections.We confirm the trend found by Benner et al. (2008) that taxonomic types E and V have very high polarization ratios. We have obtained a larger sample and can analyze additional trends with spin, size, rotation rate, taxonomic class, polarization ratio, and radar albedo to interpret the origin of the NEAs and their dynamical processes. The distribution of radar albedo and polarization ratio at the smallest diameters (≤50 m) differs from the distribution of larger objects (>50 m), although the sample size is limited. Additionally, we find more moderate radar albedos for the smallest NEAs when compared to those with diameters 50-150 m. We will present additional trends we find in this data set.

Asteroids Search Results in Large Photographic Sky Surveys

NASA Astrophysics Data System (ADS)

Shatokhina, S. V.; Kazantseva, L. V.; Yizhakevych, O. M.; Eglitis, I.; Andruk, V. M.

Photographic observations of XX century contained numerous and varied information about all objects and events of the Universe fixed on plates. The original and interesting observations of small bodies of the Solar system in previous years can be selected and used for various scientific tasks. Existing databases and online services can help make such selection easily and quickly. The observations of chronologically earlier ppositions, photometric evaluation of brightness for long periods of time allow refining the orbits of asteroids and identifying various non-stationaries. Photographic observations of Northern Sky Survey project and observations of clusters in UBVR bands were used for global search for small bodies of Solar system. Total we founded 2486 positions of asteroids and 13 positions of comets. All positions were compared with ephemeris. It was found that 80 positions of asteroids have a moment of observation preceding their discovery, and 19 of them are chronologically the earliest observations of these asteroids in the world.

Instabilities in the Sun-Jupiter-Asteroid three body problem

NASA Astrophysics Data System (ADS)

Urschel, John C.; Galante, Joseph R.

2013-03-01

We consider dynamics of a Sun-Jupiter-Asteroid system, and, under some simplifying assumptions, show the existence of instabilities in the motions of an asteroid. In particular, we show that an asteroid whose initial orbit is far from the orbit of Mars can be gradually perturbed into one that crosses Mars' orbit. Properly formulated, the motion of the asteroid can be described as a Hamiltonian system with two degrees of freedom, with the dynamics restricted to a "large" open region of the phase space reduced to an exact area preserving map. Instabilities arise in regions where the map has no invariant curves. The method of MacKay and Percival is used to explicitly rule out the existence of these curves, and results of Mather abstractly guarantee the existence of diffusing orbits. We emphasize that finding such diffusing orbits numerically is quite difficult, and is outside the scope of this paper.

Asteroid exploration and utilization

NASA Technical Reports Server (NTRS)

Radovich, Brian M.; Carlson, Alan E.; Date, Medha D.; Duarte, Manny G.; Erian, Neil F.; Gafka, George K.; Kappler, Peter H.; Patano, Scott J.; Perez, Martin; Ponce, Edgar

1992-01-01

The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources possessed by asteroids have enormous potential for aiding and enhancing human space exploration as well as life on Earth. Project STONER (Systematic Transfer of Near Earth Resources) is based on mining an asteroid and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plan for humans to utilize asteroid resources. Project STONER is divided into two parts: asteroid selection and explorer spacecraft design. The spacecraft design team is responsible for the selection and integration of the subsystems: GNC, communications, automation, propulsion, power, structures, thermal systems, scientific instruments, and mechanisms used on the surface to retrieve and store asteroid regolith. The sample return mission scenario consists of eight primary phases that are critical to the mission.

Compositional Variation in Large-Diameter Low-Albedo asteroids

NASA Astrophysics Data System (ADS)

Vilas, F.; Jarvis, K. S.; Thibault, C. A.; Sawyer, S. R.

2000-12-01

Age dating of meteorites indicates that the Solar System was subjected to a major heating event 4.5 Gyr ago. Models of the effects of heating by electromagnetic induction or decay of short-lived radionuclides combined with models of the early collisional history of the Solar System after Jupiter's formation indicate that asteroids observed today can be divided into two groups by diameter. Those asteroids having diameters greater than 100 km were mixed by multiple collisions but remain as gravitationally bound rubble piles. Asteroids with diameters less than 100 km should show more compositional diversity. Vilas and Sykes (1996, Icarus, 124) have shown using ECAS photometry that this compositional difference exists. The larger diameter group should be individually homogenous, with spectral differences showing the combined effects of a primordial compositional gradient in the asteroid belt with thermal metamorphism. We address the significance of 36 rotationally-resolved spectra of larger-diameter low-albedo asteroids of the C class (and subclasses B, F, G) and P class in the visible and Near-IR spectral regions. This work was supported by the NASA Planetary Astronomy program.

On the Origin of Chaos in the Asteroid Belt

NASA Technical Reports Server (NTRS)

Murray, N.; Holman, M.; Potter, M.

1998-01-01

We consider the effect of gravitational perturbations from Jupiter on the dynamics of asteroids, when Jupiter is itself perturbed by Saturn. The presence of Saturn introduces a number of additional frequencies into Jupiters orbit. These frequencies in turn produce chaos in narrow regions on either side of the chaotic zones associated with the mean motion resonances between the asteroids and Jupiter. The resonant arguments of these three-body resonances contain the longitudes of Jupiter and the asteroid together with either the secular frequency 9-6, or the longitude of Saturn. Resonances involving the longitude of Saturn are analogs of the Laplace resonance in the Jovian satellite system. We show that many three-body resonances involving the longitude of Saturn are chaotic. We give simple expressions for the width of the chaotic region and the associated Lyapunov time. In some cases the chaos can produce a diffusive growth in the 4 eccentricity of the asteroid that leads to ejection of the asteroid on times shorter than the age of the solar system. We give simple estimates for the diffusion time. Finally, we present the results of numerical integrations testing the theory.

Negative Searches for Evidence of Aqueous Alteration on Asteroid Surfaces

NASA Technical Reports Server (NTRS)

Vilas, F.

2005-01-01

Small bodies in the Solar System preserve evidence of the processes occurring during early Solar System formation, unlike the larger planets that undergo continuous churning of their surfaces. We study these bodies to understand what processes affected different stages of Solar System formation. The action of aqueous alteration (the alteration of material by the interaction of that material with liquid formed by the melting of incorporated ice) of near-subsurface material has been inferred to occur on many asteroids based on the spectrophotometric evidence of phyllosilicates and iron alteration minerals. The definitive indication of aqueous alteration is the 3.0- micron absorption feature attributed to structural hydroxyl (OH) and interlayer and adsorbed water (H2O) in phyllosilicates (clays) (hereafter water of hydration). A weak absorption feature centered near 0.7 microns attributed to an Fe (2+) right arrow Fe (3+) charge transfer transition in oxidized iron in phyllosilicates has been observed in the reflectance spectra and photometry of approximately 50% of the main-belt C-class asteroids. An approximately 85% correlation between this 0.7- micron feature and the 3.0- micron water of hydration absorption feature was found among the low-albedo asteroids. The feature is usually centered near 0.68 microns in asteroid spectra, and ranges in wavelength from approximately 0.57 to 0.83 microns. Serendipitously, three of the Eight Color Asteroid Survey filters the v (0.550 microns), w (0.701 microns), and x (0.853 microns)-bracket this feature well, and can be used to determine the presence of this feature in the reflectance properties of an asteroid, and probe the aqueous alteration history of larger samples of asteroid data. Two efforts to search for evidence of aqueous alteration based on the presence of this 0.7- micron absorption feature are presented here.

Band of Rubble

NASA Technical Reports Server (NTRS)

2005-01-01

This artist's animation illustrates a massive asteroid belt in orbit around a star the same age and size as our Sun. Evidence for this possible belt was discovered by NASA's Spitzer Space Telescope when it spotted warm dust around the star, presumably from asteroids smashing together.

The view starts from outside the belt, where planets like the one shown here might possibly reside, then moves into to the dusty belt itself. A collision between two asteroids is depicted near the end of the movie. Collisions like this replenish the dust in the asteroid belt, making it detectable to Spitzer.

The alien belt circles a faint, nearby star called HD 69830 located 41 light-years away in the constellation Puppis. Compared to our own solar system's asteroid belt, this one is larger and closer to its star - it is 25 times as massive, and lies just inside an orbit equivalent to that of Venus. Our asteroid belt circles between the orbits of Mars and Jupiter.

Because Jupiter acts as an outer wall to our asteroid belt, shepherding its debris into a series of bands, it is possible that an unseen planet is likewise marshalling this belt's rubble. Previous observations using the radial velocity technique did not locate any large gas giant planets, indicating that any planets present in this system would have to be the size of Saturn or smaller.

Asteroids are chunks of rock from 'failed' planets, which never managed to coalesce into full-sized planets. Asteroid belts can be thought of as construction sites that accompany the building of rocky planets.

Analyzing Serendipitous Asteroid Observations in Imaging Data using PHOTOMETRYPIPELINE

NASA Astrophysics Data System (ADS)

Ard, Christopher; Mommert, Michael; Trilling, David E.

2016-10-01

Asteroids are nearly ubiquitous in the night sky, making them present in the majority of imaging data taken every night. Serendipitous asteroid observations represent a treasure trove to Solar System researchers: accurate positional measurements of asteroids provide important constraints on their sometimes highly uncertain orbits, whereas calibrated photometric measurements can be used to establish rotational periods, intrinsic colors, or photometric phase curves.We present an add-on to the PHOTOMETRYPIPELINE (PP, github.com/mommermi/photometrypipeline, see Poster presentation 123.42) that identifies asteroids that have been observed serendipitously and extracts astrometry and calibrated photometry for these objects. PP is an open-source Python 2.7 software suite that provides image registration, aperture photometry, photometric calibration, and target identification with only minimal human interaction.Asteroids are identified based on approximate positions that are pre-calculated for a range of dates. Using interpolated coordinates, we identify potential asteroids that might be in the observed field and query their exact positions and positional uncertainties from the JPL Horizons system. The method results in robust astrometry and calibrated photometry for all asteroids in the field as a function of time. Our measurements will supplement existing photometric databases of asteroids and improve their orbits.We present first results using this procedure based on imaging data from the Vatican Advanced Technology Telescope.This work was done in the framework of NAU's REU summer program that is supported by NSF grant AST-1461200. PP was developed in the framework of the "Mission Accessible Near-Earth Object Survey" (MANOS) and is supported by NASA SSO grants NNX15AE90G and NNX14AN82G.

Oxygen isotope variation in stony-iron meteorites.

PubMed

Greenwood, R C; Franchi, I A; Jambon, A; Barrat, J A; Burbine, T H

2006-09-22

Asteroidal material, delivered to Earth as meteorites, preserves a record of the earliest stages of planetary formation. High-precision oxygen isotope analyses for the two major groups of stony-iron meteorites (main-group pallasites and mesosiderites) demonstrate that each group is from a distinct asteroidal source. Mesosiderites are isotopically identical to the howardite-eucrite-diogenite clan and, like them, are probably derived from the asteroid 4 Vesta. Main-group pallasites represent intermixed core-mantle material from a single disrupted asteroid and have no known equivalents among the basaltic meteorites. The stony-iron meteorites demonstrate that intense asteroidal deformation accompanied planetary accretion in the early Solar System.

Methods of determination of periods in the motion of asteroids

NASA Astrophysics Data System (ADS)

Bien, R.; Schubart, J.

Numerical techniques for the analysis of fundamental periods in asteroidal motion are evaluated. The specific techniques evaluated were: the periodogram analysis procedure of Wundt (1980); Stumpff's (1937) system of algebraic transformations; and Labrouste's procedure. It is shown that the Labrouste procedure permitted sufficient isolation of single oscillations from the quasi-periodic process of asteroidal motion. The procedure was applied to the analysis of resonance in the motion of Trojan-type and Hilda-type asteroids, and some preliminary results are discussed.

OSIRIS-REx Asteroid Sample Return Mission Image Analysis

NASA Astrophysics Data System (ADS)

Chevres Fernandez, Lee Roger; Bos, Brent

2018-01-01

NASA’s Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) mission constitutes the “first-of-its-kind” project to thoroughly characterize a near-Earth asteroid. The selected asteroid is (101955) 1999 RQ36 (a.k.a. Bennu). The mission launched in September 2016, and the spacecraft will reach its asteroid target in 2018 and return a sample to Earth in 2023. The spacecraft that will travel to, and collect a sample from, Bennu has five integrated instruments from national and international partners. NASA's OSIRIS-REx asteroid sample return mission spacecraft includes the Touch-And-Go Camera System (TAGCAMS) three camera-head instrument. The purpose of TAGCAMS is to provide imagery during the mission to facilitate navigation to the target asteroid, confirm acquisition of the asteroid sample and document asteroid sample stowage. Two of the TAGCAMS cameras, NavCam 1 and NavCam 2, serve as fully redundant navigation cameras to support optical navigation and natural feature tracking. The third TAGCAMS camera, StowCam, provides imagery to assist with and confirm proper stowage of the asteroid sample. Analysis of spacecraft imagery acquired by the TAGCAMS during cruise to the target asteroid Bennu was performed using custom codes developed in MATLAB. Assessment of the TAGCAMS in-flight performance using flight imagery was done to characterize camera performance. One specific area of investigation that was targeted was bad pixel mapping. A recent phase of the mission, known as the Earth Gravity Assist (EGA) maneuver, provided images that were used for the detection and confirmation of “questionable” pixels, possibly under responsive, using image segmentation analysis. Ongoing work on point spread function morphology and camera linearity and responsivity will also be used for calibration purposes and further analysis in preparation for proximity operations around Bennu. Said analyses will provide a broader understanding regarding the functionality of the camera system, which will in turn aid in the fly-down to the asteroid, as it will allow the pick of a suitable landing and sample location.

The Advanced Jovian Asteroid Explorer (AJAX)

NASA Astrophysics Data System (ADS)

Murchie, S. L.; Adams, E. Y.; Mustard, J. F.; Rivkin, A.; Peplowski, P. N.

2015-12-01

The Advanced Jovian Asteroid eXplorer (AJAX) is the first mission to characterize the geology, morphology, geophysical properties, and chemistry of a Trojan asteroid. The Decadal Survey outlined a notional New Frontiers class Trojan asteroid rendezvous mission to conduct geological, elemental composition, mineralogical, and geophysical investigations. AJAX, our Discovery mission proposal, addresses the Decadal Survey science goals by using a focused payload and an innovative mission design. By responding to the most important questions about the Trojan asteroids, AJAX advances our understanding of all of the Solar System. Are these objects a remnant population of the local primordial material from which the outer planets and their satellites formed, or did they originate in the Kuiper Belt? Landed measurements of major and minor elements test hypotheses for the Trojan asteroid origin, revealing the outer Solar System dynamical history. How and when were prebiotic materials delivered to the terrestrial planets? AJAX's landed measurements include C and H concentrations, necessary to determine their inventories of volatiles and organic compounds, material delivered to the inner Solar System during the Late Heavy Bombardment. What chemical and geological processes shaped the small bodies that merged to form the planets in our Solar System? AJAX investigates the asteroid internal structure, geology, and regolith by using global high-resolution stereo and multispectral imaging, determining density and estimating interior porosity by measuring gravity, and measuring regolith mechanical properties by landing. AJAX's science phase starts with search for natural satellites and dust lifted by possible cometary activity and shape and pole position determination. AJAX descends to lower altitudes for global mapping, and conducts a low flyover for high-resolution surface characterization and measurement of hydrogen abundance. Finally, it deploys a small landed package, which measures elemental abundances and physical properties of the regolith. AJAX's science data will result in an improved understanding of the early stages of planetary accretion by comparing a Trojan asteroid with near-Earth targets of OSIRIS-REx, Hayabusa 2, and NEAR, and the Kuiper Belt-derived targets of Rosetta and New Horizons.

Directed energy missions for planetary defense

NASA Astrophysics Data System (ADS)

Lubin, Philip; Hughes, Gary B.; Eskenazi, Mike; Kosmo, Kelly; Johansson, Isabella E.; Griswold, Janelle; Pryor, Mark; O'Neill, Hugh; Meinhold, Peter; Suen, Jonathan; Riley, Jordan; Zhang, Qicheng; Walsh, Kevin; Melis, Carl; Kangas, Miikka; Motta, Caio; Brashears, Travis

2016-09-01

Directed energy for planetary defense is now a viable option and is superior in many ways to other proposed technologies, being able to defend the Earth against all known threats. This paper presents basic ideas behind a directed energy planetary defense system that utilizes laser ablation of an asteroid to impart a deflecting force on the target. A conceptual philosophy called DE-STAR, which stands for Directed Energy System for Targeting of Asteroids and exploration, is an orbiting stand-off system, which has been described in other papers. This paper describes a smaller, stand-on system known as DE-STARLITE as a reduced-scale version of DE-STAR. Both share the same basic heritage of a directed energy array that heats the surface of the target to the point of high surface vapor pressure that causes significant mass ejection thus forming an ejection plume of material from the target that acts as a rocket to deflect the object. This is generally classified as laser ablation. DE-STARLITE uses conventional propellant for launch to LEO and then ion engines to propel the spacecraft from LEO to the near-Earth asteroid (NEA). During laser ablation, the asteroid itself provides the propellant source material; thus a very modest spacecraft can deflect an asteroid much larger than would be possible with a system of similar mission mass using ion beam deflection (IBD) or a gravity tractor. DE-STARLITE is capable of deflecting an Apophis-class (325 m diameter) asteroid with a 1- to 15-year targeting time (laser on time) depending on the system design. The mission fits within the rough mission parameters of the Asteroid Redirect Mission (ARM) program in terms of mass and size. DE-STARLITE also has much greater capability for planetary defense than current proposals and is readily scalable to match the threat. It can deflect all known threats with sufficient warning.

Optimal design of near-Earth asteroid sample-return trajectories in the Sun-Earth-Moon system

NASA Astrophysics Data System (ADS)

He, Shengmao; Zhu, Zhengfan; Peng, Chao; Ma, Jian; Zhu, Xiaolong; Gao, Yang

2016-08-01

In the 6th edition of the Chinese Space Trajectory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-km-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selection, escape from and capture by the Earth-Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital resonance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid exploration.

Volatiles in asteroids

NASA Astrophysics Data System (ADS)

Campins, H.

2014-07-01

For more than three decades, hydrated minerals have been identified in asteroids. The distribution of these minerals among asteroid spectral types and heliocentric distance has been somewhat unexpected, and there is also diversity in the composition of these hydrated minerals (e.g., Takir and Emery 2012). In addition, water ice and organic molecules have been detected on two asteroids (Campins et al. 2010; Rivkin and Emery 2010; Licandro et al. 2011) and water vapor is emanating from (1) Ceres (Küppers et al. 2014). These discoveries have important implications on current views of primitive asteroids, the nature of active asteroids or main-belt comets, the dynamics of the early Solar System, and the delivery of water and organic molecules to the Earth. They are also relevant to several space missions, including Dawn, Gaia, Hayabusa2, OSIRIS-REx ,and WISE.

Visual and near-IR spectrophotometry of asteroids

NASA Technical Reports Server (NTRS)

Lebofsky, Larry A.

1991-01-01

We have been continuing our studies of the spectral properties of dark asteroids in the solar system. From these studies we expect to learn about the distribution of volatile materials, such as water in clay materials (water of hydration) and how the asteroids may relate to the comets. Our most recent work has been concentrating on simultaneous visual and near infrared photometry near Earth, main belt, and trojan asteroids. We have made observations of some unusual asteroids such as Chiron, which has recently shown cometary activity, and 944 Hidalgo, which has a comet-like orbit. We have also begun studies of the small, dark satellites of Mars and Jupiter in order to understand better how they may relate to the steroids. Could they actually be captured asteroids or comets?

Roadmap of next generation minor body explorations in Japan

NASA Astrophysics Data System (ADS)

Yano, H.

As of the early 2004, more than 250,000 minor bodies in the solar system have been detected. Among them, several thousands of asteroids are determined orbital elements well and even multi-band spectroscopic observation from ground enables us to classify taxonomy of them in statistically valid numbers. On the other hand, there have been several 10,000s of meteorite and cosmic dust samples already collected in the terrestrial environment. Thus, asteroid studies in statistical manners are practically conducted by ground observation and meteoritic analyses. It is a unique contribution of planetary exploration to provide the ground truth which bridges between abundant database of the ground observation and that of the meteoritic analyses, by bringing samples back to the Earth from a particular asteroid investigated in-situ. In May 2003, JAXA/ISAS successfully launched the Hayabusa (MUSES-C) spacecraft as the first kind of such minor body exploration, which will bring surface samples of an S-type NEO back to the Earth in mid 2007. Many of Japanese planetary scientists hope to advance such sample return strategies as their new expertise in the post-Hayabusa era. Now the ISAS new minor body exploration working group is about to start. Mission candidates include multiple sample returns from known spectra asteroids, in order to complete the asteroid taxonomy-meteoritic connection issue as early as possible (next 10-20 years) with possible international collaborations. One of such ideas is the multiple rendezvous sample return mission to known spectra NEOs of both primitive types (i.e., C, P/D) and differentiated types (e.g., V, M). Another is fly-by investigation and sample collection of multiple asteroids that belong to a single main-belt family. It will provide direct information of the interior as well as collisional history of their parent body, a refractory planetesimal disrupted by mutual collisions in the early stage of the Solar System evolution. One scenario targets the Koronis family including the Ida-Gaspra system, the only family asteroid visited by spacecraft in the past, and its dust band. Another aims the Nysa-Polana Family, which has several spectral types. Also what ISAS is planning is the solar powered sail mission which will make fly-by observations of main belt asteroids as well as Jovian Trojan asteroids, most of which are D-type asteroids with the absence of water absorption lines. Understanding generic connections among the Trojans, short-period cometary nucleus and the outermost D-type asteroids in the main belt may be a clue of how to distinguish between asteroids and comets, depending upon where they originated with respect to heliocentric distance in the early solar system.

PERIODIC ORBIT FAMILIES IN THE GRAVITATIONAL FIELD OF IRREGULAR-SHAPED BODIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Yu; Baoyin, Hexi, E-mail: jiangyu_xian_china@163.com

The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixedmore » energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.« less

Asteroid and Comet Census from WISE

NASA Image and Video Library

2010-10-04

This frame from a video demonstrates how NASA Wide-field Infrared Survey Explorer surveys asteroids and comets in the solar system. Perspective shown here is looking down from high above Earth North Pole, a kind of bird eye view of the solar system.

Using ANTS to explore small body populations in the solar system.

NASA Astrophysics Data System (ADS)

Clark, P. E.; Rilee, M.; Truszkowski, W.; Curtis, S.; Marr, G.; Chapman, C.

2001-11-01

ANTS (Autonomous Nano-Technology Swarm), a NASA advanced mission concept, is a large (100 to 1000 member) swarm of pico-class (1 kg) totally autonomous spacecraft that prospect the asteroid belt. Little data is available for asteroids because the vast majority are too small to be observed except in close proximity. Light curves are available for thousands of asteroids, confirmed trajectories for tens of thousands, detailed shape models for approximately ten. Asteroids originated in the transitional region between the inner (rocky) and outer (solidified gases) solar system. Many have remained largely unmodified since formation, and thus have more primitive composition than planetary surfaces. Determination of the systematic distribution of physical and compositional properties within the asteroid population is crucial in the understanding of solar system formation. The traditional exploration approach of using few, large spacecraft for sequential exploration, could be improved. Our far more cost-effective approach utilizes distributed intelligence in a swarm of tiny highly maneuverable spacecraft, each with specialized instrument capability (e.g., advanced computing, imaging, spectrometry). NASA is at the forefront of Intelligent Software Agents (ISAs) research, performing experiments in space and on the ground to advance deliberative and collaborative autonomous control techniques. The advanced development under consideration here is in the use of ISAs at a strategic level, to explore remote frontiers of the solar system, potentially involving a large class of objects such as asteroids. Supervised clusters of spacecraft operate simultaneously within a broadly defined framework of goals to select targets (> 1000) from among available candidates while developing scenarios for studying targets. Swarm members use solar sails to fly directly to asteroids > 1 kilometer in diameter, and then perform maneuvers appropriate for the instrument carried, ranging from hovering to orbiting. Selected members return with data and are replaced as needed.

Observation of freakish-asteroid-discovered-resembles support my idea that many dark comets were arrested and lurked in the solar system after every impaction

NASA Astrophysics Data System (ADS)

Cao, Dayong

2014-03-01

New observations show that some asteroids are looked like comets. http://www.astrowatch.net/2013/11/freakish-asteroid-discovered-resembles.html, http://www.astrowatch.net/2013/11/astronomers-puzzle-over-newfound.html. It supports my idea that ``many dark comets with very special tilted orbits were arrested and lurked in the solar system'' - ``Sun's companion-dark hole seasonal took its dark comets belt and much dark matter to impact near our earth. And some of them probability hit on our earth. So this model kept and triggered periodic mass extinctions on our earth every 25 to 27 million years. After every impaction, many dark comets with very special tilted orbits were arrested and lurked in the solar system. Because some of them picked up many solar matter, so it looked like the asteroids. When the dark hole-Tyche goes near the solar system again, they will impact near planets.'' The idea maybe explains why do the asteroid looks like the comet? Where are the asteroids come from? What relationship do they have with the impactions and extinctions? http://meetings.aps.org/link/BAPS.2011.CAL.C1.7, http://meetings.aps.org/Meeting/CAL12/Event/181168, http://meetings.aps.org/link/BAPS.2013.MAR.H1.267. During 2009 to 2010, I had presented there are many dark comets like dark Asteroids near the orbit of Jupiter in ASP Meetings. In 2010, NASA's WISE found them. http://meetings.aps.org/link/BAPS.2011.APR.K1.17, http://www.nasa.gov/mission_pages/WISE/news/wise20100122.html Avoid Earth Extinction Associ.

Geotechnical Tests on Asteroid Simulant Orgueil

NASA Technical Reports Server (NTRS)

Garcia, Alexander D'marco

2017-01-01

In the last 100 years, the global population has more than quadrupled to over seven billion people. At the same time, the demand for food and standard of living has been increasing which has amplified the global water use by nearly eight times from approximately 500 to 4000 cu km per yr from 1900 to 2010. With the increasing concern to sustain the growing population on Earth it is necessary to seek other approaches to ensure that our planet will have resources for generations to come. In recent years, the advancement of space travel and technology has allowed the idea of mining asteroids with resources closer to becoming a reality. During the duration of the internship at NASA Kennedy Space Center, several geotechnical tests were conducted on BP-1 lunar simulant and asteroid simulant Orgueil. The tests that were conducted on BP-1 was to practice utilizing the equipment that will be used on the asteroid simulant and the data from those tests will be omitted from report. Understanding the soil mechanics of asteroid simulant Orgueil will help provide basis for future technological advances and prepare scientists for the conditions they may encounter when mining asteroids becomes reality in the distant future. Distinct tests were conducted to determine grain size distribution, unconsolidated density, and maximum density. Once the basic properties are known, the asteroid simulant will be altered to different levels of compaction using a vibrator table to see how compaction affects the density. After different intervals of vibration compaction, a miniature vane shear test will be conducted. Laboratory vane shear testing is a reliable tool to investigate strength anisotropy in the vertical and horizontal directions of a very soft to stiff saturated fine-grained clayey soil. This test will provide us with a rapid determination of the shear strength on the undisturbed compacted regolith. The results of these tests will shed light on how much torque is necessary to drill through the surface of an asteroid. Most of the known asteroids are believed to be left over material during the formation of the solar system that never accreted to form planets. Asteroids can be found in several groups such as Trojan Asteroids, Near Earth Asteroids (NEAs) and the main asteroid belt. The Trojan Asteroids orbit the 4th and 5th Lagrange points of major planets in the Solar System while the NEA's have orbits that are close to and sometimes intersect with Earths orbit and the Main Asteroid Belt which is found between the orbit of Mars and Jupiter. Gravitational perturbations can alter the orbit of asteroids in the Main Asteroid Belt causing them to move closer to earth causing them to become in the NEA class.

Rubble-Pile Minor Planet Sylvia and Her Twins

NASA Astrophysics Data System (ADS)

2005-08-01

VLT NACO Instrument Helps Discover First Triple Asteroid One of the thousands of minor planets orbiting the Sun has been found to have its own mini planetary system. Astronomer Franck Marchis (University of California, Berkeley, USA) and his colleagues at the Observatoire de Paris (France) [1] have discovered the first triple asteroid system - two small asteroids orbiting a larger one known since 1866 as 87 Sylvia [2]. "Since double asteroids seem to be common, people have been looking for multiple asteroid systems for a long time," said Marchis. "I couldn't believe we found one." The discovery was made with Yepun, one of ESO's 8.2-m telescopes of the Very Large Telescope Array at Cerro Paranal (Chile), using the outstanding image' sharpness provided by the adaptive optics NACO instrument. Via the observatory's proven "Service Observing Mode", Marchis and his colleagues were able to obtain sky images of many asteroids over a six-month period without actually having to travel to Chile. ESO PR Photo 25a/05 ESO PR Photo 25a/05 Orbits of Twin Moonlets around 87 Sylvia [Preview - JPEG: 400 x 516 pix - 145k] [Normal - JPEG: 800 x 1032 pix - 350k] ESO PR Photo 25b/05 ESO PR Photo 25b/05 Artist's impression of the triple asteroid system [Preview - JPEG: 420 x 400 pix - 98k] [Normal - JPEG: 849 x 800 pix - 238k] [Full Res - JPEG: 4000 x 3407 pix - 3.7M] [Full Res - TIFF: 4000 x 3000 pix - 36.0M] Caption: ESO PR Photo 25a/05 is a composite image showing the positions of Remus and Romulus around 87 Sylvia on 9 different nights as seen on NACO images. It clearly reveals the orbits of the two moonlets. The inset shows the potato shape of 87 Sylvia. The field of view is 2 arcsec. North is up and East is left. ESO PR Photo 25b/05 is an artist rendering of the triple system: Romulus, Sylvia, and Remus. ESO Video Clip 03/05 ESO Video Clip 03/05 Asteroid Sylvia and Her Twins [Quicktime Movie - 50 sec - 384 x 288 pix - 12.6M] Caption: ESO PR Video Clip 03/05 is an artist rendering of the triple asteroid system showing the large asteroid 87 Sylvia spinning at a rapid rate and surrounded by two smaller asteroids (Remus and Romulus) in orbit around it. This computer animation is also available in broadcast quality to the media (please contact Herbert Zodet). One of these asteroids was 87 Sylvia, which was known to be double since 2001, from observations made by Mike Brown and Jean-Luc Margot with the Keck telescope. The astronomers used NACO to observe Sylvia on 27 occasions, over a two-month period. On each of the images, the known small companion was seen, allowing Marchis and his colleagues to precisely compute its orbit. But on 12 of the images, the astronomers also found a closer and smaller companion. 87 Sylvia is thus not double but triple! Because 87 Sylvia was named after Rhea Sylvia, the mythical mother of the founders of Rome [3], Marchis proposed naming the twin moons after those founders: Romulus and Remus. The International Astronomical Union approved the names. Sylvia's moons are considerably smaller, orbiting in nearly circular orbits and in the same plane and direction. The closest and newly discovered moonlet, orbiting about 710 km from Sylvia, is Remus, a body only 7 km across and circling Sylvia every 33 hours. The second, Romulus, orbits at about 1360 km in 87.6 hours and measures about 18 km across. The asteroid 87 Sylvia is one of the largest known from the asteroid main belt, and is located about 3.5 times further away from the Sun than the Earth, between the orbits of Mars and Jupiter. The wealth of details provided by the NACO images show that 87 Sylvia is shaped like a lumpy potato, measuring 380 x 260 x 230 km (see ESO PR Photo 25a/05). It is spinning at a rapid rate, once every 5 hours and 11 minutes. The observations of the moonlets' orbits allow the astronomers to precisely calculate the mass and density of Sylvia. With a density only 20% higher than the density of water, it is likely composed of water ice and rubble from a primordial asteroid. "It could be up to 60 percent empty space," said co-discoverer Daniel Hestroffer (Observatoire de Paris, France). "It is most probably a "rubble-pile" asteroid", Marchis added. These asteroids are loose aggregations of rock, presumably the result of a collision. Two asteroids smacked into each other and got disrupted. The new rubble-pile asteroid formed later by accumulation of large fragments while the moonlets are probably debris left over from the collision that were captured by the newly formed asteroid and eventually settled into orbits around it. "Because of the way they form, we expect to see more multiple asteroid systems like this." Marchis and his colleagues will report their discovery in the August 11 issue of the journal Nature, simultaneously with an announcement that day at the Asteroid Comet Meteor conference in Armação dos Búzios, Rio de Janeiro state, Brazil.

Chondrites, S asteroids, and space weathering: Thumping noises from the coffin?

NASA Technical Reports Server (NTRS)

Fanale, F. P.; Clark, B. E.

1993-01-01

Most of the spectral characteristics of ordinary chondrites and S-asteroids in the visible and infrared can be reduced to three numerical values. These values represent the depth of the absorption band resulting from octahedrally coordinated Fe(sup 2+), the reflectance at 0.56 microns and the slope of the continuum (as measured according to convention). By plotting these three characteristics, it is possible to immediately compare the spectral characteristics of large numbers of ordinary chondrites and S-asteroids. Commonality of spectral characteristics between these populations can thus be evaluated on the basis of overlap in position on three two-coordinate systems: albedo vs. band depth, band depth vs. slope, and slope vs. albedo. In order to establish identity, members of the two populations must overlap on all three of these independent parameter spaces. In this coordinate system, spectra of 23 ordinary chondrites (representing all metamorphic grades), and 39 S-asteroids were compared. It was found that there was no overlap between the two populations in terms of the slope vs. band depth parameters, nor were most chondrites identical to the S-asteroids with respect to the other criteria. However, the controversial question remains: Where are the parent bodies of the chondrites? Perhaps an even more critical question is: Where are our samples of the S-asteroids? Considering the geography of the asteroid belt and the theory that early solar-system electromagnetic induction heating differentiated protoasteroids in the inner portion of the main belt, it was suggested that although S-asteroids and ordinary chondrites have very similar mineralogy, the S-asteroids are mixtures of metallic nickel iron and silicates which resulted from magmatism induced by electromagnetic heating whereas chondrites were only slightly metamorphosed nebular condensates. In this scenario chondrites would have been derived from a population of bodies with thermal lag times so short that they were not subjected to melting during the phase of the electromagnetic induction heating event but only to various degrees of pervasive metamorphism. Furthermore, these objects would then have been too small to be observed and systematically included in the library of asteroidal spectra. It was also suggested that the parametric distribution of S-asteroid spectra could be reproduced by mixing various proportions of NiFe meteorite and achondritic materials. This has also been demonstrated in the laboratory.

Solar Power at Play

NASA Astrophysics Data System (ADS)

2007-03-01

For the very first time, astronomers have witnessed the speeding up of an asteroid's rotation, and have shown that it is due to a theoretical effect predicted but never seen before. The international team of scientists used an armada of telescopes to discover that the asteroid's rotation period currently decreases by 1 millisecond every year, as a consequence of the heating of the asteroid's surface by the Sun. Eventually it may spin faster than any known asteroid in the solar system and even break apart. ESO PR Photo 11a/07 ESO PR Photo 11a/07 Asteroid 2000 PH5 "The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect is believed to alter the way small bodies in the Solar System rotate," said Stephen Lowry (Queens University Belfast, UK), lead-author of one of the two companion papers in which this work is reported [1, 2]. "The warming caused by sunlight hitting the surfaces of asteroids and meteoroids leads to a gentle recoil effect as the heat is released," he added. "By analogy, if one were to shine light on a propeller over a long enough period, it would start spinning." Although this is an almost immeasurably weak force, its effect over millions of years is far from negligible. Astronomers believe the YORP effect may be responsible for spinning some asteroids up so fast that they break apart, perhaps leading to the formation of double asteroids. Others may be slowed down so that they take many days to complete a full turn. The YORP effect also plays an important role in changing the orbits of asteroids between Mars and Jupiter, including their delivery to planet-crossing orbits, such as those of near-Earth asteroids. Despite its importance, the effect has never been seen acting on a solar system body, until now. Using extensive optical and radar imaging from powerful Earth-based observatories, astronomers have directly observed the YORP effect in action on a small near-Earth asteroid, known as (54509) 2000 PH5. Shortly after its discovery in 2000, it was realised that asteroid 2000 PH5 would be the ideal candidate for such a YORP detection. With a diameter of just 114 metres, it is relatively small and so more susceptible to the effect. Also, it rotates very fast, with one 'day' on the asteroid lasting just over 12 Earth minutes, implying that the YORP effect may have been acting on it for some time. With this in mind, the team of astronomers undertook a long term monitoring campaign of the asteroid with the aim of detecting any tiny changes in its rotation speed. Over a 4-year time span, Stephen Lowry, Alan Fitzsimmons and colleagues took images of the asteroid at a range of telescope sites including ESO's 8.2-m Very Large Telescope array and 3.5-m New Technology Telescope in Chile, the 3.5-m telescope at Calar Alto, Spain, along with a suite of other telescopes from the Czech Republic, the Canary Islands, Hawaii, Spain and Chile. With these facilities the astronomers measured the slight brightness variations as the asteroid rotated. ESO PR Photo 11b/07 ESO PR Photo 11b/07 Radar Images of 2000 PH5 Over the same time period, the radar team led by Patrick Taylor and Jean-Luc Margot of Cornell University employed the unique capabilities of the Arecibo Observatory in Puerto Rico and the Goldstone radar facility in California to observe the asteroid by 'bouncing' a radar pulse off the asteroid and analysing its echo. "With this technique we can reconstruct a 3-D model of the asteroid's shape, with the necessary detail to allow a comparison between the observations and theory," said Taylor. After careful analysis of the optical data, the asteroid's spin rate was seen to steadily increase with time, at a rate that can be explained by the YORP theory. Critically, the effect was observed year after year, for more than 4 years. Furthermore, this number was elegantly supported via analysis of the combined radar and optical data, as it was required that the asteroid is increasing its spin rate at exactly this rate in order for a satisfactory 3-D shape model to be determined. ESO PR Video 11/07 ESO PR Video 11c/07 Watch the Asteroid Move! To predict what will happen to the asteroid in the future, Lowry and his colleagues performed detailed computer simulations using the measured strength of the YORP effect and the detailed shape model. They found that the orbit of the asteroid about the Sun could remain stable for up to the next 35 million years, allowing the rotation period to be reduced by a factor of 36, to just 20 seconds, faster than any asteroid whose rotation has been measured until now. "This exceptionally fast spin-rate could force the asteroid to reshape itself or even split apart, leading to the birth of a new double system," said Lowry.

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2017 October-December

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2018-04-01

Lightcurves for 18 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2017 October-December. All but one of the asteroids were targets of opportunity, i.e., in the field of planned targets, which demonstrates a good reason for data mining images.

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2017 July Through October

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2018-01-01

Lightcurves for 17 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2017 July through October. All but two of the asteroids were targets of opportunity, i.e., in the field of planned targets, demonstrating a good reason for data mining images.

Artist's Concept of Psyche Spacecraft with Five-Panel Array

NASA Image and Video Library

2017-05-23

This artist's-concept illustration depicts the spacecraft of NASA's Psyche mission near the mission's target, the metal asteroid Psyche. The artwork was created in May 2017 to show the five-panel solar arrays planned for the spacecraft. The spacecraft's structure will include power and propulsion systems to travel to, and orbit, the asteroid. These systems will combine solar power with electric propulsion to carry the scientific instruments used to study the asteroid through space. The mission plans launch in 2022 and arrival at Psyche, between the orbits of Mars and Jupiter, in 2026. This selected asteroid is made almost entirely of nickel-iron metal. It offers evidence about violent collisions that created Earth and other terrestrial planets. https://photojournal.jpl.nasa.gov/catalog/PIA21499

Synergistic approach of asteroid exploitation and planetary protection

NASA Astrophysics Data System (ADS)

Sanchez, J. P.; McInnes, C. R.

2012-02-01

The asteroid and cometary impact hazard has long been recognised as an important issue requiring risk assessment and contingency planning. At the same time asteroids have also been acknowledged as possible sources of raw materials for future large-scale space engineering ventures. This paper explores possible synergies between these two apparently opposed views; planetary protection and space resource exploitation. In particular, the paper assumes a 5 tonne low-thrust spacecraft as a baseline for asteroid deflection and capture (or resource transport) missions. The system is assumed to land on the asteroid and provide a continuous thrust able to modify the orbit of the asteroid according to the mission objective. The paper analyses the capability of such a near-term system to provide both planetary protection and asteroid resources to Earth. Results show that a 5 tonne spacecraft could provide a high level of protection for modest impact hazards: airburst and local damage events (caused by 15-170 m diameter objects). At the same time, the same spacecraft could also be used to transport to bound Earth orbits significant quantities of material through judicious use of orbital dynamics and passively safe aero-capture manoeuvres or low energy ballistic capture. As will be shown, a 5 tonne low-thrust spacecraft could potentially transport between 12 and 350 times its own mass of asteroid resources by means of ballistic capture or aero-capture trajectories that pose very low dynamical pressures on the object.

Building Blocks of the Terrestrial Planets: Mineralogy of Hungaria Asteroids

NASA Astrophysics Data System (ADS)

Lucas, Michael; Emery, J. P.

2013-10-01

Deciphering the mineralogy of the Hungaria asteroids has the potential to place constraints on the material from which the terrestrial planets accreted. Among asteroids with semi-major axes interior to the main-belt (e.g., Hungarias, Mars-crossers, and near-Earth asteroids), only the Hungarias are located in relatively stable orbital space. Hungaria asteroids have likely resided in this orbital space since the planets completed their migration to their current orbits. The accretion and igneous differentiation of primitive asteroids appears to be a function of chronology and heliocentric distance. However, differentiated bodies that originated in the terrestrial planet region were either accreted or scattered out of this region early in solar system history. Thus, the Hungaria asteroids represent the closest reservoir of in situ material to the terrestrial planet region from early in solar system history. We present VISNIR 0.45-2.45 µm) and NIR spectra 0.65-2.45 µm) spectra of 24 Hungaria group (objects in similar orbital space) asteroids. Our NIR data (17 objects) were acquired using the InfraRed Telescope Facility and was supplemented with available visible data. Spectra of seven objects were obtained from the MIT-UH-IRTF survey. We distinguish our sample between Hungaria family (presumed fragments of parent 434 Hungaria; 2 objects) and Hungaria background (group minus family 22 objects) asteroids using proper orbital elements. The classification of each asteroid is determined using the taxonomy of Bus-DeMeo. We find that S- and S-subtypes are prevalent among the Hungaria background population (17/22). Spectral band parameters measurements (i.e., Band I and Band II centers and depths, and Band Area Ratio) indicate that eight of these S-types are analogous with undifferentiated ordinary chondrites (SIV “boot” of S-subtypes plot). Mafic silicate mineral abundances and compositions derived for these SIV asteroids mainly correlate with L chondrites. However, one object is an SIII subtype (possible ureilite analog), while two asteroids are SVI subtypes (possible primitive achondrite analog). Family member 6447 Terrycole is a Xe-type, consistent with the taxonomic classification of the parent 434 Hungaria.

A brief visit from a red and extremely elongated interstellar asteroid.

PubMed

Meech, Karen J; Weryk, Robert; Micheli, Marco; Kleyna, Jan T; Hainaut, Olivier R; Jedicke, Robert; Wainscoat, Richard J; Chambers, Kenneth C; Keane, Jacqueline V; Petric, Andreea; Denneau, Larry; Magnier, Eugene; Berger, Travis; Huber, Mark E; Flewelling, Heather; Waters, Chris; Schunova-Lilly, Eva; Chastel, Serge

2017-12-21

None of the approximately 750,000 known asteroids and comets in the Solar System is thought to have originated outside it, despite models of the formation of planetary systems suggesting that orbital migration of giant planets ejects a large fraction of the original planetesimals into interstellar space. The high predicted number density of icy interstellar objects (2.4 × 10 -4 per cubic astronomical unit) suggests that some should have been detected, yet hitherto none has been seen. Many decades of asteroid and comet characterization have yielded formation models that explain the mass distribution, chemical abundances and planetary configuration of the Solar System today, but there has been no way of telling whether the Solar System is typical of planetary systems. Here we report observations and analysis of the object 1I/2017 U1 ('Oumuamua) that demonstrate its extrasolar trajectory, and that thus enable comparisons to be made between material from another planetary system and from our own. Our observations during the brief visit by the object to the inner Solar System reveal it to be asteroidal, with no hint of cometary activity despite an approach within 0.25 astronomical units of the Sun. Spectroscopic measurements show that the surface of the object is spectrally red, consistent with comets or organic-rich asteroids that reside within the Solar System. Light-curve observations indicate that the object has an extremely oblong shape, with a length about ten times its width, and a mean radius of about 102 metres assuming an albedo of 0.04. No known objects in the Solar System have such extreme dimensions. The presence of 'Oumuamua in the Solar System suggests that previous estimates of the number density of interstellar objects, based on the assumption that all such objects were cometary, were pessimistically low. Planned upgrades to contemporary asteroid survey instruments and improved data processing techniques are likely to result in the detection of more interstellar objects in the coming years.

Enhanced Gravity Tractor Derived from the Asteroid Redirect Mission for Deflecting Hypothetical Asteroid 2017 PDC

NASA Technical Reports Server (NTRS)

Mazanek, Daniel D.; Reeves, David M.; Abell, Paul A.; Shen, Haijun; Qu, Min

2017-01-01

The Asteroid Redirect Mission (ARM) concept would robotically visit a hazardous-size near-Earth asteroid (NEA) with a rendezvous spacecraft, collect a multi-ton boulder and regolith samples from its surface, demonstrate an innovative planetary defense technique known as the Enhanced Gravity Tractor (EGT), and return the asteroidal material to a stable orbit around the Moon, allowing astronauts to explore the returned material in the mid-2020s. Launch of the robotic vehicle to rendezvous with the ARM reference target, NEA (341843) 2008 EV5, would occur in late 2021 [1,2]. The robotic segment of the ARM concept uses a 40 kW Solar Electric Propulsion (SEP) system with a specific impulse (Isp) of 2600 s, and would provide the first ever demonstration of the EGT technique on a hazardous-size asteroid and validate one method of collecting mass in-situ. The power, propellant, and thrust capability of the ARM robotic spacecraft can be scaled from a 40 kW system to 150 kW and 300 kW, which represent a likely future power level progression. The gravity tractor technique uses the gravitational attraction of a station-keeping spacecraft with the asteroid to provide a velocity change and gradually alter the trajectory of the asteroid. EGT utilizes a spacecraft with a high-efficiency propulsion system, such as Solar Electric Propulsion (SEP), along with mass collected in-situ to augment the mass of the spacecraft, thereby increasing the gravitational force between the objects [3]. As long as the spacecraft has sufficient thrust and propellant capability, the EGT force is only limited by the amount of in-situ mass collected and can be increased several orders of magnitude compared to the traditional gravity tractor technique in which only the spacecraft mass is used to generate the gravitational attraction force. This increase in available force greatly reduces the required deflection time. The collected material can be a single boulder, multiple boulders, regolith, or a combination of different material types using a variety of collection techniques. The EGT concept assumes that the ability to efficiently collect asteroid mass in-situ from a wide variety of asteroid types and environments is a future capability that will be developed and perfected in the future by the asteroid mining community. Additionally, it is anticipated that the mass collection would likely be performed by a single or multiple separable spacecraft to allow the SEP spacecraft to operate at safe distance from the asteroid.

Asteroid Redirection Mission Evaluation Using Multiple Landers

NASA Astrophysics Data System (ADS)

Bazzocchi, Michael C. F.; Emami, M. Reza

2018-06-01

In this paper, a low-thrust tugboat redirection method is assessed using multiple spacecraft for a target range of small near-Earth asteroids. The benefits of a landed configuration of tugboat spacecraft in formation are examined for the redirection of a near-Earth asteroid. The tugboat method uses a gimballed thruster with a highly collimated ion beam to generate a thrust on the asteroid. The target asteroid range focuses on near-Earth asteroids smaller than 150 m in diameter, and carbonaceous (C-type) asteroids, due to the volatiles available for in-situ utilization. The assessment focuses primarily on the three key parameters, i.e., the asteroid mass redirected, the timeframe for redirection, and the overall system cost. An evaluation methodology for each parameter is discussed in detail, and the parameters are employed to determine the expected return and feasibility of the redirection mission. The number of spacecraft employed is optimized along with the electrical power needed for each spacecraft to ensure the highest possible return on investment. A discussion of the optimization results and the benefits of spacecraft formation for the tugboat method are presented.

Japanese Studies of Asteroids Following the Discovery of the Hirayama Families

NASA Astrophysics Data System (ADS)

Nakamura, Tsuko

This paper reviews studies relating to asteroids conducted by Japanese astronomers since the discovery of asteroid families by Kiyotsugu Hirayama in 1918. First, the situation is mentioned that it took quite some time for the concept of an `asteroid family' to be understood correctly by the astronomical community worldwide. It is no wonder that some eminent researches on the dynamics of asteroids based on secular perturbation theories appeared in Japan after WWII, as represented by the `Kozai mechanism' (1962), which probably was influenced by Hirayama's monumental discovery. As for studies of the physical nature of asteroids, we must note the pioneering work by M. Kitamura in 1959 when the observed colors of about 40 asteroids were compared with reflectance spectra of several meteorites measured in the laboratory, even though this result unfortunately was not pursued further at the time. Modern impact experiments initiated by A. Fujiwara in 1975 soon became an important means of investigating the origin of asteroid families, and of the ubiquitous craters seen on the surfaces of airless Solar System bodies.

A census of the asteroid belt

NASA Technical Reports Server (NTRS)

Tedesco, E. F.; Veeder, G. J.

1991-01-01

Observations obtained by the Infrared Astronomical Satellite (IRAS) during its ten month mission in 1983 were originally processed by the Asteroid Data Analysis System (ADAS) to search for 3453 asteroids with known orbital elements as of September 1985. A total of 1811 had one or more observations of sufficient reliability to be accepted. These results were released in October 1986. Recently IRAS data were reprocessed to increase both the number of recognized asteroid observations and their reliability. As input 7311 asteroids were used with known orbital elements as of December 1990. This processor is referred to as the IRAS Minor Planet Survey (IMPS). As of April 1991 approximately 3000 asteroids had been identified with one or more acceptable observations. These results were used to derive the total number of asteroids with diameters greater than 1 km. In addition to being an interesting piece of information in itself these size-frequency distributions produce bias-correction factors which, for example, will be used in investigations of the physical properties of asteroid dynamical families and to estimate the distribution of the taxonomic classes as a function of heliocentric distance.

Asteroid Redirection Mission Evaluation Using Multiple Landers

NASA Astrophysics Data System (ADS)

Bazzocchi, Michael C. F.; Emami, M. Reza

2018-01-01

In this paper, a low-thrust tugboat redirection method is assessed using multiple spacecraft for a target range of small near-Earth asteroids. The benefits of a landed configuration of tugboat spacecraft in formation are examined for the redirection of a near-Earth asteroid. The tugboat method uses a gimballed thruster with a highly collimated ion beam to generate a thrust on the asteroid. The target asteroid range focuses on near-Earth asteroids smaller than 150 m in diameter, and carbonaceous (C-type) asteroids, due to the volatiles available for in-situ utilization. The assessment focuses primarily on the three key parameters, i.e., the asteroid mass redirected, the timeframe for redirection, and the overall system cost. An evaluation methodology for each parameter is discussed in detail, and the parameters are employed to determine the expected return and feasibility of the redirection mission. The number of spacecraft employed is optimized along with the electrical power needed for each spacecraft to ensure the highest possible return on investment. A discussion of the optimization results and the benefits of spacecraft formation for the tugboat method are presented.

The IRAS Minor Planet Survey

NASA Technical Reports Server (NTRS)

Tedesco, Edward F.; Veeder, Glenn J.; Fowler, John W.; Chillemi, Joseph R.

1992-01-01

This report documents the program and data used to identify known asteroids observed by the Infrared Astronomical Satellite (IRAS) and to compute albedos and diameters from their IRAS fluxes. It also presents listings of the results obtained. These results supplant those in the IRAS Asteroid and Comet Survey, 1986. The present version used new and improved asteroid orbital elements for 4679 numbered asteroids and 2632 additional asteroids for which at least two-opposition elements were available as of mid-1991. It employed asteroid absolute magnitudes on the International Astronomical Union system adopted in 1991. In addition, the code was modified to increase the reliability of associating asteroids with IRAS sources and rectify several shortcomings in the final data products released in 1986. Association reliability was improved by decreasing the position difference between an IRAS source and a predicted asteroid position required for an association. The shortcomings addressed included the problem of flux overestimation for low SNR sources and the systematic difference in albedos and diameters among the three wavelength bands (12, 25, and 60 micrometers). Several minor bugs in the original code were also corrected.

Mine Planning for Asteroid Orebodies

NASA Astrophysics Data System (ADS)

Gertsch, L. S.; Gertsch, R. E.

2000-01-01

Given that an asteroid (or comet) has been determined to contain sufficient material of value to be potentially economic to exploit, a mining method must be selected and implemented. This paper discusses the engineering necessary to bring a mine online, and the opportunities and challenges inherent in asteroid mineral prospects. The very important step of orebody characterization is discussed elsewhere. The mining methods discussed here are based on enclosing the asteroid within a bag in some fashion, whether completely or partially. In general, asteroid mining methods based on bags will consist of the following steps. Not all will be required in every case, nor necessarily in this particular sequence. Some steps will be performed simultaneously. Their purpose is to extract the valuable material from the body of the asteroid in the most efficient, cost-effective manner possible. In approximate order of initiation, if not of conclusion, the steps are: 1. Tether anchoring to the asteroid. 2. Asteroid motion control. 3. Body/fragment restraint system placement. 4. Operations platform construction. 5. Bag construction. 6. Auxiliary and support equipment placement. 7. Mining operations. 8. Processing operations. 9. Product transport to markets.

Ion Beam Deflection (AKA Push-Me/Pull-You)

NASA Technical Reports Server (NTRS)

Brophy, John

2013-01-01

The Ion Beam Deflection provides the following potential advantages over other asteroid deflection systems. Like the gravity tractor, it doesn't require despinning of the asteroid. Unlike the gravity tractor, it provides a significantly higher coupling force that is independent of the asteroid size. The concept could be tested as part of the baseline Asteroid Redirect Robotic Mission. The thrust and total impulse are entirely within the design of the SEP vehicle. The total impulse is potentially competitive with kinetic impactors and eliminates the need for a second rendezvous spacecraft.?Gridded ion thrusters provide beam divergence angles of a few degrees enabling long stand-off distances from the asteroid. Mitigating control issues. Minimizing back-sputter contamination risks

The Tagish Lake meteorite: a possible sample from a D-type asteroid.

PubMed

Hiroi, T; Zolensky, M E; Pieters, C M

2001-09-21

A new type of carbonaceous chondrite, the Tagish Lake meteorite, exhibits a reflectance spectrum similar to spectra observed from the D-type asteroids, which are relatively abundant in the outer solar system beyond the main asteroid belt and have been inferred to be more primitive than any known meteorite. Until the Tagish Lake fall, these asteroids had no analog in the meteorite collections. The Tagish Lake meteorite is a carbon-rich (4 to 5 weight %), aqueously altered carbonaceous chondrite and contains high concentrations of presolar grains and carbonate minerals, which is consistent with the expectation that the D-type asteroids were originally made of primitive materials and did not experience any extensive heating.

The Size Frequency Distribution of Small Main-Belt Asteroids

NASA Technical Reports Server (NTRS)

Burt, Brian J.; Trilling, David E.; Hines, Dean C.; Stapelfeldt, Karl R.; Rebull, Luisa M.; Fuentes, Cesar I.; Hulsebus, Alan

2012-01-01

The asteroid size distribution informs us about the formation and composition of the Solar System. We build on our previous work in which we harvest serendipitously observed data of the Taurus region and measure the brightness and size distributions of Main-belt asteroids. This is accomplished with the highly sensitive MIPS 24 micron channel. We expect to catalog 104 asteroids, giving us a statistically significant data set. Results from this investigation will allow us to characterize the total population of small, Main-belt asteroids. Here we will present new results on the completeness of our study; on the presence of size distribution variations with inclination and radial distance in the belt; and early result on other archival fields.

A Photometric Study of Phocaea Group Asteroid 1584 Fuji

NASA Astrophysics Data System (ADS)

Drake, J. S.

2004-05-01

Observations of Phocaea group asteroid 1584 Fuji with the 31-inch telescope at Lowell Observatory in Arizona and the 24-inch telescope at Britton Observatory at Dickinson College in Pennsylvania from 31 January 2004 to 28 February 2004 indicate a sinusoidal lightcurve with a period of 14.89 ± 0.01 hours, in conflict with published results. Reduction of these data to a standard magnitude system indicate a V-band amplitude of 0.13 ± 0.02 magnitudes, further diverging from the accepted value. Application of the IAU Two-Parameter magnitude system for asteroids permits an estimation of the body's diameter. I compare these parameters with those published for Fuji's companions in the Phocaea group, other S-type objects in the main belt, and asteroids of similar size throughout the Solar System. I thank Dickinson College and the Arizona Space Grant Consortium for their financial support.

Asteroid Return Mission Feasibility Study

NASA Technical Reports Server (NTRS)

Brophy, John R.; Gershman, Robert; Landau, Damon; Polk, James; Porter, Chris; Yeomans, Don; Allen, Carlton; Williams, Willie; Asphaug, Erik

2011-01-01

This paper describes an investigation into the technological feasibility of finding, characterizing, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the International Space Station (ISS) for scientific investigation, evaluation of its resource potential, determination of its internal structure and other aspects important for planetary defense activities, and to serve as a testbed for human operations in the vicinity of an asteroid. Reasonable projections suggest that several dozen candidates NEAs in the size range of interest (approximately 2-m diameter) will be known before the end of the decade from which a suitable target could be selected. The conceptual mission objective is to return an approximately 10,000-kg asteroid to the ISS in a total flight time of approximately 5 years using a single Evolved Expendable Launch Vehicle. Preliminary calculations indicate that this could be accomplished using a solar electric propulsion (SEP) system with high-power Hall thrusters and a maximum power into the propulsion system of approximately 40 kW. The SEP system would be used to provide all of the post-launch delta V. The asteroid would have an unrestricted Earth return Planetary Protection categorization, and would be curated at the ISS where numerous scientific and resource utilization experiments would be conducted. Asteroid material brought to the ground would be curated at the NASA Johnson Space Center. This preliminary study identified several areas where additional work is required, but no show stoppers were identified for the approach that would return an entire 10,000-kg asteroid to the ISS in a mission that could be launched by the end of this decade.

A CubeSat Asteroid Mission: Design Study and Trade-Offs

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Oleson, Steven R.; McGuire, Melissa; Hepp, Aloysius; Stegeman, James; Bur, Mike; Burke, Laura; Martini, Michael; Fittje, James E.; Kohout, Lisa;

BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near Earth Asteroid Disruption

NASA Technical Reports Server (NTRS)

Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent W.

2015-01-01

Currently, no planetary defense demonstration mission has ever been flown. While Nuclear Explosive Devices (NEDs) have significantly more energy than a kinetic impactor launched directly from Earth, they present safety and political complications, and therefore may only be used when absolutely necessary. The Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System (BILLIARDS) is a demonstration mission for planetary defense, which is capable of delivering comparable energy to the lower range of NED capabilities in the form of a safer kinetic impactor. A small asteroid (<10m) is captured by a spacecraft, which greatly increases the mass available as a kinetic impactor, without the need to bring all of the mass out of Earth's gravity well. The small asteroid is then deflected onto a collision course with a larger (approx. 100m) asteroid. This collision will deflect or disrupt the larger asteroid. To reduce the cost and complexity, an asteroid pair which has a natural close approach is selected.

Hydrated Minerals on Asteroids: The Astronomical Record

NASA Technical Reports Server (NTRS)

Rivkin, A. S.; Howell, E. S.; Vilas, F.; Lebofsky, L. A.

2002-01-01

Knowledge of the hydrated mineral inventory on the asteroids is important for deducing the origin of Earth's water, interpreting the meteorite record, and unraveling the processes occurring during the earliest times in solar system history. Reflectance spectroscopy shows absorption features in both the 0.6-0.8 and 2.5-3.5 micrometers regions, which are diagnostic of or associated with hydrated minerals. Observations in those regions show that hydrated minerals are common in the mid-asteroid belt, and can be found in unexpected spectral groupings, as well. Asteroid groups formerly associated with mineralogies assumed to have high temperature formation, such as M- and E-class asteroids, have been observed to have hydration features in their reflectance spectra. Some asteroids have apparently been heated to several hundred degrees Celsius, enough to destroy some fraction of their phyllosilicates. Others have rotational variation suggesting that heating was uneven. We summarize this work, and present the astronomical evidence for water- and hydroxyl-bearing minerals on asteroids.

Potential Mission Scenarios Post Asteroid Crewed Mission

NASA Technical Reports Server (NTRS)

Lopez, Pedro, Jr.; McDonald, Mark A.

2015-01-01

A deep-space mission has been proposed to identify and redirect an asteroid to a distant retrograde orbit around the moon, and explore it by sending a crew using the Space Launch System and the Orion spacecraft. The Asteroid Redirect Crewed Mission (ARCM), which represents the third segment of the Asteroid Redirect Mission (ARM), could be performed on EM-3 or EM-4 depending on asteroid return date. Recent NASA studies have raised questions on how we could progress from current Human Space Flight (HSF) efforts to longer term human exploration of Mars. This paper will describe the benefits of execution of the ARM as the initial stepping stone towards Mars exploration, and how the capabilities required to send humans to Mars could be built upon those developed for the asteroid mission. A series of potential interim missions aimed at developing such capabilities will be described, and the feasibility of such mission manifest will be discussed. Options for the asteroid crewed mission will also be addressed, including crew size and mission duration.

Small D-type asteroids in the NEO population: new targets for space missions

NASA Astrophysics Data System (ADS)

Barucci, Maria Antonietta; Perna, D.; Popescu, M.; Fornasier, S.; Doressoundiram, A.; Lantz, C.; Merlin, F.; Fulchignoni, M.; Dotto, E.; Kanuchova, S.

2018-06-01

In the framework of the Near Earth Objects (NEOs) observational campaign carried out within the NEOShield-2 project, we identify nine new small D-type asteroids with estimated diameter less than 600 m. The link with meteorites for this class of asteroids is weak and the best fit obtained is with the Tagish Lake meteorite for seven of them. D-type asteroids are believed to contain the most pristine material of the Solar system and could have delivered the pre-biotic material to the Earth. Our results double the known sample of the D-types in the NEO population and triple the candidates of this class for a sample-return mission (at very low ΔV). Our finding increases considerably the number of targets for sample-return mission. A sample-return mission to a D-type asteroid will provide a major progress in understanding the early history of the Solar system and to investigate the origin of life on the Earth.

Momentum Management for the NASA Near Earth Asteroid Scout Solar Sail Mission

NASA Technical Reports Server (NTRS)

Heaton, Andrew; Diedrich, Benjamin L.; Orphee, Juan; Stiltner, Brandon; Becker, Christopher

2017-01-01

The Momentum Management (MM) system is described for the NASA Near Earth Asteroid Scout (NEA Scout) cubesat solar sail mission. Unlike many solar sail mission proposals that used solar torque as the primary or only attitude control system, NEA Scout uses small reaction wheels (RW) and a reaction control system (RCS) with cold gas thrusters, as described in the abstract "Solar Sail Attitude Control System for Near Earth Asteroid Scout Cubesat Mission." The reaction wheels allow fine pointing and higher rates with low mass actuators to meet the science, communication, and trajectory guidance requirements. The MM system keeps the speed of the wheels within their operating margins using a combination of solar torque and the RCS.

Crew Systems for Asteroid Exploration: Concepts for Lightweight & Low Volume EVA Systems

NASA Technical Reports Server (NTRS)

Mueller, Rob; Calle, Carlos; Mantovani, James

2013-01-01

This RFI response is targeting Area 5. Crew Systems for Asteroid Exploration: concepts for lightweight and low volume robotic and extra-vehicular activity (EVA) systems, such as space suits, tools, translation aids, stowage containers, and other equipment. The NASA KSC Surface Systems Office, Granular Mechanics and Regolith Operations (GMRO) Lab and the Electrostatics & Surface Physics Lab (ESPL) are dedicated to developing technologies for operating in regolith environments on target body surfaces. We have identified two technologies in our current portfolio that are highly relevant and useful for crews that will visit a re-directed asteroid in Cis-Lunar Space. Both technologies are at a high TRL of 5/6 and could be rapidly implemented in time for an ARM mission in this decade.

Observation of asteroid 2013 TV135 supports my idea that a new impaction will come in 20 years

NASA Astrophysics Data System (ADS)

Cao, Dayong

2014-03-01

Asteroid 2013 TV135 who will impact in 2023 was newly discovered by Ukrainian astronomers in 2013. It supports my idea that a new impaction will come in 20 years. http://www.nasa.gov/mission_pages/asteroids/news/asteroid20131017.html, http://meetings.aps.org/link/BAPS.2011.DFD.LA.24, http://meetings.aps.org/link/BAPS.2012.APR.K1.78, http://meetings.aps.org/link/BAPS.2013.APR.S2.14. The Sun's companion-dark hole, which is made of dark matter seasonal took its dark comets belt, dark matter, dark lives, and the pressed asteroids belt to impact near our earth. These impactions and dark matter's killers caused seasonal extinctions and produced new species. By many dark comets and asteroids impacting, the dark impaction model is a high probability impaction model; the impaction would not change the orbit of the invisible dark hole, so that it could keep accurate periodicity impactions. With the space-time center, the dark hole system is a negative Einstein's model by ``mass-energy coordinate.'' Sun and Dark hole build up the balance system. Through studying the model, the rule of the impaction can be calculated. Avoid Earth Extinction Association.

COMPASS Final Report: Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER)

NASA Technical Reports Server (NTRS)

Oleson, Steven R.; McGuire, Melissa L.

2009-01-01

In this study, the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team completed a design for a multi-asteroid (Nereus and 1996 FG3) sample return capable spacecraft for the NASA In-Space Propulsion Office. The objective of the study was to support technology development and assess the relative benefits of different electric propulsion systems on asteroid sample return design. The design uses a single, heritage Orion solar array (SA) (approx.6.5 kW at 1 AU) to power a single NASA Evolutionary Xenon Thruster ((NEXT) a spare NEXT is carried) to propel a lander to two near Earth asteroids. After landing and gathering science samples, the Solar Electric Propulsion (SEP) vehicle spirals back to Earth where it drops off the first sample s return capsule and performs an Earth flyby to assist the craft in rendezvousing with a second asteroid, which is then sampled. The second sample is returned in a similar fashion. The vehicle, dubbed Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER), easily fits in an Atlas 401 launcher and its cost estimates put the mission in the New Frontier s (NF's) class mission.

An update of the Near-Earth Asteroid Tracking/Maui Space Surveillance System (NEAT/MSSS) collaboration

NASA Technical Reports Server (NTRS)

Bambery, R. J.; Helin, E. F.; Pravdo, S. H.; Lawrence, K. J.; Hicks, M. D.

2002-01-01

Jet Propulsion Laboratory's (JPL) Near-Earth Asteroid Tracking (NEAT) program has two simultaneously-operating, autonomous search systems on two geographically-separated 1.2-m telescopes; one at the Maui Space Surveillance System (NEAT/MSSS) and the other on the Palomar Observatory's Oschin telescope (NEAT/Palomar). This paper will focus exclusively on the NEAT/MSSS system.

Resurfacing asteroids from YORP spin-up and failure

NASA Astrophysics Data System (ADS)

Graves, Kevin J.; Minton, David A.; Hirabayashi, Masatoshi; DeMeo, Francesca E.; Carry, Benoit

2018-04-01

The spectral properties of S and Q-type asteroids can change over time due to interaction with the solar wind and micrometeorite impacts in a process known as 'space weathering.' Space weathering raises the spectral slope and decreases the 1 μm absorption band depth in the spectra of S and Q-type asteroids. Over time, Q-type asteroids, which have very similar spectra to ordinary chondrite meteorites, will change into S-type asteroids. Because there are a significant number of Q-type asteroids, there must be some process which is resurfacing S-type asteroids into Q-types. In this study, we use asteroid data from the Sloan Digital Sky Survey to show a trend between the slope through the g‧, r‧, and i‧ filters, called the gri-slope, and size that holds for all populations of S and Q-type asteroids in the inner solar system, regardless of orbit. We model the evolution of a suite of asteroids in a Monte Carlo YORP rotational evolution and space weathering model. We show that spin-up and failure from YORP is one of the key resurfacing mechanisms that creates the observed weathering trends with size. By varying the non-dimensional YORP coefficient and running time of the present model over the range 475-1425 Myr, we find a range of values for the space weathering timescale, τSW ≈ 19-80 Myr at 2.2 AU. We also estimate the time to weather a newly resurfaced Q-type asteroid into an S-complex asteroid at 1 AU, τQ → S(1AU) ≈ 2-7 Myr.

Basalt or Not? Near-infrared Spectra, Surface Mineralogical Estimates, and Meteorite Analogs for 33 Vp-type Asteroids

NASA Astrophysics Data System (ADS)

Hardersen, Paul S.; Reddy, Vishnu; Cloutis, Edward; Nowinski, Matt; Dievendorf, Margaret; Genet, Russell M.; Becker, Savan; Roberts, Rachel

2018-07-01

Investigations of the main asteroid belt and efforts to constrain that population’s physical characteristics involve the daunting task of studying hundreds of thousands of small bodies. Taxonomic systems are routinely employed to study the large-scale nature of the asteroid belt because they utilize common observational parameters, but asteroid taxonomies only define broadly observable properties and are not compositionally diagnostic. This work builds upon the results of work by Hardersen et al., which has the goal of constraining the abundance and distribution of basaltic asteroids throughout the main asteroid belt. We report on the near-infrared (NIR: 0.7 to 2.5 μm) reflectance spectra, surface mineralogical characterizations, analysis of spectral band parameters, and meteorite analogs for 33 Vp asteroids. NIR reflectance spectroscopy is an effective remote sensing technique to detect most pyroxene group minerals, which are spectrally distinct with two very broad spectral absorptions at ∼0.9 and ∼1.9 μm. Combined with the results from Hardersen et al., we identify basaltic asteroids for ∼95% (39/41) of our inner-belt Vp sample, but only ∼25% (2/8) of the outer-belt Vp sample. Inner-belt basaltic asteroids are most likely associated with (4) Vesta and represent impact fragments ejected from previous collisions. Outer-belt Vp asteroids exhibit disparate spectral, mineralogical, and meteorite analog characteristics and likely originate from diverse parent bodies. The discovery of two additional likely basaltic asteroids provides additional evidence for an outer-belt basaltic asteroid population.

The Earth-Moon system as a typical binary in the Solar System

NASA Astrophysics Data System (ADS)

Ipatov, S.

2014-07-01

In recent years new arguments in favor of the formation of solid planetesimals by contraction of rarefied preplanetesimals (RPPs) have been found. It is often considered that masses of some RPPs can correspond to masses of solid bodies of diameter about 1000 km. [1] showed that in the vortices launched by the Rossby wave instability in the borders of the dead zone, the solids quickly achieve critical densities and undergo gravitational collapse into protoplanetary embryos in the mass range 0.1-0.6M_E (where M_E is the mass of the Earth). [2] and [3] supposed that transneptunian binaries were formed from RPPs. It was shown in [2] that the angular momenta acquired at collisions of RPPs moving in circular heliocentric orbits could have the same values as the angular momenta of discovered transneptunian and asteroid binaries. [4] obtained that the angular momenta used in [3] as initial data in calculations of the contraction of RPPs leading to formation of transneptunian binaries could be acquired at collisions of two RPPs moving in circular heliocentric orbits. I supposed that the fraction of RPPs collided with other RPPs during their contraction can be about the fraction of small bodies of diameter d>100 km with satellites (among all such small bodies), i.e., it can be about 0.3 for objects formed in the transneptunian belt. The model of collisions of RPPs explains negative angular momenta of some observed binaries, as about 20 percent of collisions of RPPs moving in circular heliocentric orbits lead to retrograde rotation. Note that if all RPPs got their angular momenta at their formation without mutual collisions, then the angular momenta of small bodies without satellites and those with satellites could be similar (but actually they differ considerably). Most of rarefied preasteroids could turn into solid asteroids before they collided with other preasteroids. Some present asteroids can be debris of larger solid bodies, and the formation of many binaries with primaries with d<100 km can be explained by other models (not by contraction of RPPs). [5] noted that the giant impact concept, which is a popular model of the Moon formation, has several weaknesses. In particular, they calculated formation of the Earth-Moon system from a rarefied protoplanet which mass equaled to the mass of the Earth-Moon system. Using the formulas presented in [2], we obtained that the ratio r_K=K_{EM}/K_{s2} of the angular momentum K_{EM} of the Earth-Moon system to the angular momentum K_{s2} at a typical collision of two identical RPPs - Hill spheres, which masses m_2 are equal to 0.5\\cdot1.0123M_E and heliocentric orbits are circular, is about 0.0335. As K_{s2} ∝ (m_2)^{3/5} [2], then K_{s2}=K_{EM} at 2 m_2=0.0335^{3/5}\\cdot 1.0123M_E=0.13M_E. For circular heliocentric orbits, the maximum value of K_{s2} is greater by a factor of 0.6^{-1} than the above typical value. In this case, r_K=0.02 and 0.02^{3/5}=0.096. Therefore, the angular momentum of the Earth-Moon system can be acquired at a collision of two RPPs with a total mass not smaller than the mass of Mars. We suppose that solid proto-Earth and proto-Moon (with masses m_{Eo} and m_{Mo}) could be formed from a RPP (e.g., according to the models of contraction of a RPP [3,5]). Let us consider the model of the growth of proto-Earth and proto-Moon to the present masses of the Earth and the Moon (M_E and 0.0123M_E, respectively) by accumulation of smaller planetesimals for the case when the effective radii of proto-Earth and proto-Moon are proportional to r (where r is a radius of a considered object). Such proportionality can be considered for large enough eccentricities of planetesimals. In this case, r_{Mo}=m_{Mo}/M_E = [ (0.0123)^{-2/3} - k + k \\cdot (m_{Eo}/M_E)^{-2/3})]^{-3/2}, where k=(k_d)^{-2/3}, and k_d is the ratio of the density of the growing Moon to that of the growing Earth (k_d=0.6 for the present Earth and Moon). For r_{Eo}=m_{Eo}/M_E=0.1, we have r_{Mo}=0.0094 at k=1 and r_{Mo}=0.0086 at k=0.6^{-2/3}. At these values of r_{Mo}, the ratio f_M=(0.0123-r_{Mo})/0.0123 of the mass of planetesimals that were accreted by the Moon at the stage of the solid body accumulation to the present mass of the Moon is 0.24 and 0.30, respectively. If we consider that effective radii of the objects are proportional to r^2 (the case of relatively small relative velocities of planetesimals), then at r_{Eo}=0.1 for k_d equal 1 and 0.6, we obtain f_M equal to 0.04 and 0.05, respectively. In the above model, the Moon could acquire up to 1/3 of its mass at the stage of accumulation of solid bodies, while the mass of the growing Earth increased by a factor of ten, but probably the initial mass of a solid proto-Earth exceeded 0.1M_E. Probably, the RPPs that contracted and formed the embryos of other terrestrial planets did not collide with massive RPPs, and therefore they did not get large enough angular momentum needed to form massive satellites.

Preliminary performance analysis of an interplanetary navigation system using asteroid based beacons

NASA Technical Reports Server (NTRS)

Jee, J. Rodney; Khatib, Ahmad R.; Muellerschoen, Ronald J.; Williams, Bobby G.; Vincent, Mark A.

1988-01-01

A futuristic interplanetary navigation system using transmitters placed on selected asteroids is introduced. This network of space beacons is seen as a needed alternative to the overly burdened Deep Space Network. Covariance analyses on the potential performance of these space beacons located on a candidate constellation of eight real asteroids are initiated. Simplified analytic calculations are performed to determine limiting accuracies attainable with the network for geometric positioning. More sophisticated computer simulations are also performed to determine potential accuracies using long arcs of range and Doppler data from the beacons. The results from these computations show promise for this navigation system.

Search for Water in Outer Main Belt Based on AKARI Asteroid Catalog

NASA Astrophysics Data System (ADS)

Usui, Fumihiko

2012-06-01

We propose a program to search water ice on the surface of asteroids in the outer main belt regions, which have high albedo measured with AKARI. The distribution of water in the main belt provides important information to understanding of the formation and evolution of the solar system, because water is a good indicator of temperature in the early solar nebula. The existence of water ice is a hot topic in the solar system studies today. Water ice is recently found in the outer region of the main asteroid belt and some of them are linked to the main belt comets. Brand-new albedo data brought by AKARI opens the possibility of detection of water ice on the C-type asteroids. Here we propose to make the spectroscopic observations with the Subaru telescope in the near-infrared wavelengths to detect water ice on these high-albedo C-type asteroids. Thanks to a large aperture of Subaru telescope and a high altitude of Mauna Kea, it can be only possible to observe a weak signal of the existence of water on the surface of asteroids with a certain S/N. In addition, using the imaging data taken prior to IRCS spectroscopic mode, we intend to seek any comet-like activities by investigating diffuseness of the asteroids, which can be detected by comparing the observed point-spread functions with those of field stars.

Comet nucleus and asteroid sample return missions

NASA Technical Reports Server (NTRS)

Melton, Robert G.; Thompson, Roger C.; Starchville, Thomas F., Jr.; Adams, C.; Aldo, A.; Dobson, K.; Flotta, C.; Gagliardino, J.; Lear, M.; Mcmillan, C.

1992-01-01

During the 1991-92 academic year, the Pennsylvania State University has developed three sample return missions: one to the nucleus of comet Wild 2, one to the asteroid Eros, and one to three asteroids located in the Main Belt. The primary objective of the comet nucleus sample return mission is to rendezvous with a short period comet and acquire a 10 kg sample for return to Earth. Upon rendezvous with the comet, a tethered coring and sampler drill will contact the surface and extract a two-meter core sample from the target site. Before the spacecraft returns to Earth, a monitoring penetrator containing scientific instruments will be deployed for gathering long-term data about the comet. A single asteroid sample return mission to the asteroid 433 Eros (chosen for proximity and launch opportunities) will extract a sample from the asteroid surface for return to Earth. To limit overall mission cost, most of the mission design uses current technologies, except the sampler drill design. The multiple asteroid sample return mission could best be characterized through its use of future technology including an optical communications system, a nuclear power reactor, and a low-thrust propulsion system. A low-thrust trajectory optimization code (QuickTop 2) obtained from the NASA LeRC helped in planning the size of major subsystem components, as well as the trajectory between targets.

Abodes for life in carbonaceous asteroids?

NASA Astrophysics Data System (ADS)

Abramov, Oleg; Mojzsis, Stephen J.

2011-05-01

Thermal evolution models for carbonaceous asteroids that use new data for permeability, pore volume, and water circulation as input parameters provide a window into what are arguably the earliest habitable environments in the Solar System. Plausible models of the Murchison meteorite (CM) parent body show that to first-order, conditions suitable for the stability of liquid water, and thus pre- or post-biotic chemistry, could have persisted within these asteroids for tens of Myr. In particular, our modeling results indicate that a 200-km carbonaceous asteroid with a 40% initial ice content takes almost 60 Myr to cool completely, with habitable temperatures being maintained for ˜24 Myr in the center. Yet, there are a number of indications that even with the requisite liquid water, thermal energy sources to drive chemical gradients, and abundant organic "building blocks" deemed necessary criteria for life, carbonaceous asteroids were intrinsically unfavorable sites for biopoesis. These controls include different degrees of exothermal mineral hydration reactions that boost internal warming but effectively remove liquid water from the system, rapid (1-10 mm yr -1) inward migration of internal habitable volumes in most models, and limitations imposed by low permeabilities and small pore sizes in primitive undifferentiated carbonaceous asteroids. Our results do not preclude the existence of habitable conditions on larger, possibly differentiated objects such as Ceres and the Themis family asteroids due to presumed longer, more intense heating and possible long-lived water reservoirs.

Drilling, sampling, and sample-handling system for China's asteroid exploration mission

NASA Astrophysics Data System (ADS)

Zhang, Tao; Zhang, Wenming; Wang, Kang; Gao, Sheng; Hou, Liang; Ji, Jianghui; Ding, Xilun

2017-08-01

Asteroid exploration has a significant importance in promoting our understanding of the solar system and the origin of life on Earth. A unique opportunity to study near-Earth asteroid 99942 Apophis will occur in 2029 because it will be at its perigee. In the current work, a drilling, sampling, and sample-handling system (DSSHS) is proposed to penetrate the asteroid regolith, collect regolith samples at different depths, and distribute the samples to different scientific instruments for in situ analysis. In this system, a rotary-drilling method is employed for the penetration, and an inner sampling tube is utilized to collect and discharge the regolith samples. The sampling tube can deliver samples up to a maximum volume of 84 mm3 at a maximum penetration depth of 300 mm to 17 different ovens. To activate the release of volatile substances, the samples will be heated up to a temperature of 600 °C by the ovens, and these substances will be analyzed by scientific instruments such as a mass spectrometer, an isotopic analyzer, and micro-cameras, among other instruments. The DSSHS is capable of penetrating rocks with a hardness value of six, and it can be used for China's asteroid exploration mission in the foreseeable future.

77 FR 3102 - Procedures for Implementing the National Environmental Policy Act

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-23

... from solar system bodies (such as asteroids, comets, planets, dwarf planets, and planetary moons.../program which would return samples to Earth from solar system bodies (such as asteroids, comets, planets, dwarf planets, and planetary moons), which would likely receive a Restricted Earth Return categorization...

Boulder Capture System Design Options for the Asteroid Robotic Redirect Mission Alternate Approach Trade Study

NASA Technical Reports Server (NTRS)

Belbin, Scott P.; Merrill, Raymond G.

2014-01-01

This paper presents a boulder acquisition and asteroid surface interaction electromechanical concept developed for the Asteroid Robotic Redirect Mission (ARRM) option to capture a free standing boulder on the surface of a 100 m or larger Near Earth Asteroid (NEA). It details the down select process and ranking of potential boulder capture methods, the evolution of a simple yet elegant articulating spaceframe, and ongoing risk reduction and concept refinement efforts. The capture system configuration leverages the spaceframe, heritage manipulators, and a new microspine technology to enable the ARRM boulder capture. While at the NEA it enables attenuation of terminal descent velocity, ascent to escape velocity, boulder collection and restraint. After departure from the NEA it enables, robotic inspection, sample caching, and crew Extra Vehicular Activities (EVA).

Near-Earth Asteroid Tracking with the Maui Space Surveillance System (NEAT/MSSS)

NASA Technical Reports Server (NTRS)

Helin, Eleanor F.; Pravdo, Steven H.; Lawrence, Kenneth J.; Hicks, Michael D.

2001-01-01

Over the last year the Jet Propulsion Laboratory's (JPL) Near-Earth Asteroid Tracking (NEAT) program has made significant progress and now consists of two simultaneously-operating, autonomous search systems on the 1.2-m (48") telescopes: on the Maui Space Surveillance System (NEAT/MSSS) and NEAT/Palomar on the Palomar Observatory's Oschin telescope. This paper will focus exclusively on the NEAT/MSSS system. NEAT/MSSS is operated as a partnership between NASA/JPL and the United States Air Force Research Laboratory (AFRL), utilizing the AFRL 1.2-m telescope on the 3000-m summit of Haleakala, Maui, The USAF Space Command (SPCMD) contributed financial support to build and install the 'NEAT focal reducer' on the MSSS 1.2-m telescope giving it a large field of view (2.5 square degrees), suitable for the near-earth object (NEO),both asteroids and comets, survey. This work was completed in February 2000. AFRL has made a commitment to NEAT/MSSS that allows NEAT to operate full time with the understanding that AFRL participate as partners in NEAT/MSSS and have use of the NEAT camera system for high priority satellite observations during bright time (parts of 12 nights each month). Currently, NEAT has discovered 42 NEAs including 12 larger than 1-km, 5 Potentially Hazardous Asteroids (PHAs), 6 comets, and nearly 25,000 asteroid detections since March 2000.

Dynamical configurations of celestial systems comprised of multiple irregular bodies

NASA Astrophysics Data System (ADS)

Jiang, Yu; Zhang, Yun; Baoyin, Hexi; Li, Junfeng

2016-09-01

This manuscript considers the main features of the nonlinear dynamics of multiple irregular celestial body systems. The gravitational potential, static electric potential, and magnetic potential are considered. Based on the three established potentials, we show that three conservative values exist for this system, including a Jacobi integral. The equilibrium conditions for the system are derived and their stability analyzed. The equilibrium conditions of a celestial system comprised of n irregular bodies are reduced to 12n - 9 equations. The dynamical results are applied to simulate the motion of multiple-asteroid systems. The simulation is useful for the study of the stability of multiple irregular celestial body systems and for the design of spacecraft orbits to triple-asteroid systems discovered in the solar system. The dynamical configurations of the five triple-asteroid systems 45 Eugenia, 87 Sylvia, 93 Minerva, 216 Kleopatra, and 136617 1994CC, and the six-body system 134340 Pluto are calculated and analyzed.

Asteroid-comet continuum objects in the solar system.

PubMed

Hsieh, Henry H

2017-07-13

In this review presented at the Royal Society meeting, 'Cometary science after Rosetta', I present an overview of studies of small solar system objects that exhibit properties of both asteroids and comets (with a focus on so-called active asteroids). Sometimes referred to as 'transition objects', these bodies are perhaps more appropriately described as 'continuum objects', to reflect the notion that rather than necessarily representing actual transitional evolutionary states between asteroids and comets, they simply belong to the general population of small solar system bodies that happen to exhibit a continuous range of observational, physical and dynamical properties. Continuum objects are intriguing because they possess many of the properties that make classical comets interesting to study (e.g. relatively primitive compositions, ejection of surface and subsurface material into space where it can be more easily studied, and orbital properties that allow us to sample material from distant parts of the solar system that would otherwise be inaccessible), while allowing us to study regions of the solar system that are not sampled by classical comets.This article is part of the themed issue 'Cometary science after Rosetta'. © 2017 The Author(s).

The role of "asteroid taxis" at mastering of Solar system

NASA Astrophysics Data System (ADS)

Steklov, A. F.; Vidmachenko, A. P.

2018-05-01

At the present time, two main tendencies can be considered for the solar system to be habitable: 1) to do something with the objects of the solar system in order to make them suitable for life; and 2), it is necessary to make it so that the interplanetary space of the solar system also becomes suitable for life. We believe that it is better to combine these two trends. To this end, we must develop a methodology for constructing special settlements at asteroids and cometary nuclei. And then, it is necessary to build settlements - the "technospheres" - on the most diverse bodies in the Solar system: asteroids, cometary nuclei, satellites of planets and even on some planets. And, first of all, it is highly desirable to use the own resources of the listed objects. Such "technospheres" should be long-term settlements in interplanetary space and at planetoids. To save energy resources, it is necessary to use near-Earth asteroids enriched with water ice. To successfully implement these concepts, it is necessary at least by two orders of magnitude reduce the cost of such settlements.

Stop hitting yourself: did most terrestrial impactors originate from the terrestrial planets?

NASA Astrophysics Data System (ADS)

Jackson, Alan; Asphaug, Erik; Elkins-Tanton, Linda

2014-11-01

Although the asteroid belt is the main source of impactors in the inner solar system today, it contains only 0.0006 Earth mass, or 0.05 Lunar mass. While the asteroid belt would have been more massive when it formed, it is unlikely to have had greater than 0.5 Lunar mass since the formation of Jupiter and the dissipation of the solar nebula. By comparison, giant impacts onto the terrestrial planets typically release debris equal to several per cent of the planets mass. The Moon-forming impact on Earth and the dichotomy forming impact on Mars, to consider but two of these major events, released 1.3 and 0.3 Lunar mass in debris respectively, many times the mass of the present day asteroid belt. This escaping impact debris is less long lived than the main asteroid belt, as it is injected on unstable, planet-crossing orbits, but this same factor also increases the impact probability with the terrestrial planets and asteroids. We show that as a result terrestrial ejecta played a major role in the impact history of the early inner solar system, and we expect the same is also likely to be true in other planetary systems.

A New Tool for Classifying Small Solar System Objects

NASA Astrophysics Data System (ADS)

Desfosses, Ryan; Arel, D.; Walker, M. E.; Ziffer, J.; Harvell, T.; Campins, H.; Fernandez, Y. R.

2011-05-01

An artificial intelligence program, AutoClass, which was developed by NASA's Artificial Intelligence Branch, uses Bayesian classification theory to automatically choose the most probable classification distribution to describe a dataset. To investigate its usefulness to the Planetary Science community, we tested its ability to reproduce the taxonomic classes as defined by Tholen and Barucci (1989). Of the 406 asteroids from the Eight Color Asteroid Survey (ECAS) we chose for our test, 346 were firmly classified and all but 3 (<1%) were classified by Autoclass as they had been in the previous classification system (Walker et al., 2011). We are now applying it to larger datasets to improve the taxonomy of currently unclassified objects. Having demonstrated AutoClass's ability to recreate existing classification effectively, we extended this work to investigations of albedo-based classification systems. To determine how predictive albedo can be, we used data from the Infrared Astronomical Satellite (IRAS) database in conjunction with the large Sloan Digital Sky Survey (SDSS), which contains color and position data for over 200,000 classified and unclassified asteroids (Ivesic et al., 2001). To judge our success we compared our results with a similar approach to classifying objects using IRAS albedo and asteroid color by Tedesco et al. (1989). Understanding the distribution of the taxonomic classes is important to understanding the history and evolution of our Solar System. AutoClass's success in categorizing ECAS, IRAS and SDSS asteroidal data highlights its potential to scan large domains for natural classes in small solar system objects. Based upon our AutoClass results, we intend to make testable predictions about asteroids observed with the Wide-field Infrared Survey Explorer (WISE).

Understanding asteroid collisional history through experimental and numerical studies

NASA Technical Reports Server (NTRS)

Davis, Donald R.; Ryan, Eileen V.; Weidenschilling, S. J.

1991-01-01

Asteroids can lose angular momentum due to so called splash effect, the analog to the drain effect for cratering impacts. Numerical code with the splash effect incorporated was applied to study the simultaneous evolution of asteroid sized and spins. Results are presented on the spin changes of asteroids due to various physical effects that are incorporated in the described model. The goal was to understand the interplay between the evolution of sizes and spins over a wide and plausible range of model parameters. A single starting population was used both for size distribution and the spin distribution of asteroids and the changes in the spins were calculated over solar system history for different model parameters. It is shown that there is a strong coupling between the size and spin evolution, that the observed relative spindown of asteroids approximately 100 km diameter is likely to be the result of the angular momentum splash effect.

Understanding asteroid collisional history through experimental and numerical studies

NASA Astrophysics Data System (ADS)

Davis, Donald R.; Ryan, Eileen V.; Weidenschilling, S. J.

1991-06-01

Asteroids can lose angular momentum due to so called splash effect, the analog to the drain effect for cratering impacts. Numerical code with the splash effect incorporated was applied to study the simultaneous evolution of asteroid sized and spins. Results are presented on the spin changes of asteroids due to various physical effects that are incorporated in the described model. The goal was to understand the interplay between the evolution of sizes and spins over a wide and plausible range of model parameters. A single starting population was used both for size distribution and the spin distribution of asteroids and the changes in the spins were calculated over solar system history for different model parameters. It is shown that there is a strong coupling between the size and spin evolution, that the observed relative spindown of asteroids approximately 100 km diameter is likely to be the result of the angular momentum splash effect.

UV Spectroscopy of Metallic Asteroid (16) Psyche

NASA Astrophysics Data System (ADS)

Cunningham, N. J.; Becker, T. M.; Retherford, K. D.; Roth, L.; Feaga, L. M.; Wahlund, J.-E.; Elkins-Tanton, L. T.

2017-09-01

Asteroid (16) Psyche is the largest M-type asteroid, and the planned destination of the NASA Discovery mission Psyche and the proposed ESA M5 mission Heavy Metal. Psyche is considered to be the exposed core of a differentiated asteroid, whose mantle has been stripped by collisions; but other histories have been proposed. We observed Psyche with the Space Telescope Imaging Spectrograph (STIS) and Cosmic Origins Spectrograph (COS) aboard the Hubble Space Telescope, to obtain a full ultraviolet (UV) spectrum of both of Psyche's hemispheres. We seek to test three possible scenarios for Psyche's origin: Is Psyche the exposed core of a differentiated asteroid? Is it an asteroid with high olivine content that has been space-weathered? Or did Psyche accrete as-is in a highly-reducing environment early in the history of the solar system? We will present the UV spectra and their implications for Psyche's history.

Radar observations of near-Earth asteroids from Arecibo Observatory

NASA Astrophysics Data System (ADS)

Rivera-Valentin, Edgard G.; Taylor, Patrick A.; Rodriguez-Ford, Linda A.; Zambrano Marin, Luisa Fernanda; Virkki, Anne; Aponte Hernandez, Betzaida

2016-10-01

The Arecibo S-Band (2.38 GHz, 12.6 cm, 1 MW) planetary radar system at the 305-m William E. Gordon Telescope in Arecibo, Puerto Rico is the most active and most sensitive planetary radar facility in the world. Since October 2015, we have detected 56 near-Earth asteroids, of which 17 are classified as potentially hazardous to Earth and 22 are compliant with the Near-Earth Object Human Space Flight Accessible Target Study (NHATS) as possible future robotic- or human-mission destinations. We will present a sampling of the asteroid zoo observed by the Arecibo radar since the 2015 DPS meeting. This includes press-noted asteroids 2015 TB145, the so-called "Great Pumpkin", and 2003 SD220, the so-called "Christmas Eve asteroid".

Mosaic of CCDs to Survey for Asteroids and Comets

NASA Technical Reports Server (NTRS)

McMillan, Robert S.

2002-01-01

Spacewatch searches for asteroids and comets ranging in location from near-Earth space to regions beyond the orbit of Neptune. We are studying Earth-approaching asteroids, main belt asteroids, comets, Centaurs, and TNOs, as well as the interrelationships of these classes and their bearing on the origin and evolution of the solar system. Spacewatch is described at http://www. lpl. arizona. edu/spacewatch/index.html. The Spacewatch Project has been discovering Earth-approaching asteroids (EAs) steadily and has used the results aggressively to estimate the statistical properties of the EA population. This grant funded Spacewatch to develop and implement a mosaic of CCD imaging detectors for the 0.9-m telescope, to increase that telescope's rate of coverage of sky area while preserving its limiting magnitude.

Flyght Dynamics of Artificial Satellite of the Minor Asteroid

NASA Astrophysics Data System (ADS)

Zakharov, Alexander; Eismont, Natan; Ledkov, Anton; Simonov, Alexander; Pol, Vadim

During last years the scientific interest to the asteroid is constantly growing. It may be explained by different reasons. One of the most important from them is confirmation of the fact that the asteroids present the real hazard to the Earth. The Chelyabinsk event demonstrates strong in support of this statement. Besides, the asteroids exploration promises to supply new data for understanding of the solar system origin and evolution. And the projects aimed to reach this goal have begun from the NASA NEAR mission to Eros. It was the first one when the spacecraft was landed on the surface of the asteroid. The other successive mission was fulfilled by JAXA with Hayabusa spacecraft which has returned to the Earth soil samples of Itokawa asteroid. In the nearest future the mission to RQ 36 asteroid is planned supposing landing and soil samples return. Unavoidable phase of such missions is the spacecraft flight in vicinity of the target asteroid, for example on the asteroid satellite orbit. It should be mentioned that quite visible number of asteroids has geometric form which is far from being sphere. Accordingly the gravity field of such asteroid cannot be presented as the one close to sphere. The problem is that prior to the mission to the asteroid one cannot receive good enough knowledge of its gravity field and even its gravity field constant. In the paper the flight dynamics problem of spacecraft moving along asteroid satellite orbit is explored. It is supposed that the asteroid is comparatively small with diameter (maximum size) about 300 m, like Apophis asteroid has, or less. To approximate the gravity field of asteroid the last is considered as totality of mass points. We assume such approach as more simple and effective as compared with the commonly accepted use of Legendre polynomial expansion. Different orbits near asteroid are analyzed with the sets of orbital parameters determining the size of orbit, its shape and position with respect to the Sun. The goal of this analysis is to understand what initial orbital parameters deliver stability of the orbit in terms of avoiding the collision with the asteroid surface. The orbital heights are calculated which allow to consider the asteroid gravity field as close to the spherical one de-pending on the shape of asteroid. Also maneuvers are estimated necessary for keeping the spacecraft on asteroid satellite orbit and for changing orbital parameters. Taking into account that gravity field parameters of the target asteroids may have pure accuracy it is supposed that spacecraft starts its motion in vicinity of the asteroid from the high enough orbit and then after processing of the tracking data maneuvers are executed to decrease spacecraft altitude. Methods of this procedure optimization are explored.

The OSIRIS-REx Asteroid Sample Return Mission

NASA Technical Reports Server (NTRS)

Beshore, Edward; Lauretta, Dante; Boynton, William; Shinohara, Chriss; Sutter, Brian; Everett, David; Gal-Edd, Jonathan S.; Mink, Ronald G.; Moreau, Michael; Dworkin, Jason

2015-01-01

Interpretation, Resource Identification, Security, Regolith EXplorer) spacecraft will depart for asteroid (101955) Bennu, and when it does, humanity will turn an important corner in the exploration of the Solar System. After arriving at the asteroid in the Fall of 2018, it will undertake a program of observations designed to select a site suitable for retrieving a sample that will be returned to the Earth in 2023..

Did ASAS-SN Kill the Supermassive Black Hole Binary Candidate PG1302-102?

NASA Astrophysics Data System (ADS)

Liu, Tingting; Gezari, Suvi; Miller, M. Coleman

2018-05-01

Graham et al. reported a periodically varying quasar and supermassive black hole binary candidate, PG1302-102 (hereafter PG1302), which was discovered in the Catalina Real-time Transient Survey (CRTS). Its combined Lincoln Near-Earth Asteroid Research (LINEAR) and CRTS optical light curve is well fitted to a sinusoid of an observed period of ≈1884 days and well modeled by the relativistic Doppler boosting of the secondary mini-disk. However, the LINEAR+CRTS light curve from MJD ≈52,700 to MJD ≈56,400 covers only ∼2 cycles of periodic variation, which is a short baseline that can be highly susceptible to normal, stochastic quasar variability. In this Letter, we present a reanalysis of PG1302 using the latest light curve from the All-sky Automated Survey for Supernovae (ASAS-SN), which extends the observational baseline to the present day (MJD ≈58,200), and adopting a maximum likelihood method that searches for a periodic component in addition to stochastic quasar variability. When the ASAS-SN data are combined with the previous LINEAR+CRTS data, the evidence for periodicity decreases. For genuine periodicity one would expect that additional data would strengthen the evidence, so the decrease in significance may be an indication that the binary model is disfavored.

An Overview of Advanced Concepts for Launch

DTIC Science & Technology

2012-02-09

Loads, System. --- Space Platforms Unfeasible. --- Space Elevator Materials, O, µmeteoroids, weather, vibrations.. Asteroid Mining Breakthrough...Unfeasible. --- Space Elevator Materials, O, µmeteoroids, weather, vibrations.. Asteroid Mining Breakthrough Physics No known feasible concepts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharya, B.; Helou, G.; Noriega-Crespo, A.

The Spitzer Space Telescope routinely detects asteroids in astrophysical observations near the ecliptic plane. For the galactic or extragalactic astronomer, these solar system bodies can introduce appreciable uncertainty into the source identification process. We discuss an infrared color discrimination tool that may be used to distinguish between solar system objects and extrasolar sources. We employ four Spitzer Legacy data sets, the First Look Survey-Ecliptic Plane Component (FLS-EPC), SCOSMOS, SWIRE, and GOODS. We use the Standard Thermal Model to derive FLS-EPC main belt asteroid (MBA) diameters of 1-4 km for the numbered asteroids in our sample and note that several ofmore » our solar system sources may have fainter absolute magnitude values than previously thought. A number of the MBAs are detected at flux densities as low as a few tens of {mu}Jy at 3.6 {mu}m. As the FLS-EPC provides the only 3.6-24.0 {mu}m observations of individual asteroids to date, we are able to use this data set to carry out a detailed study of asteroid color in comparison to astrophysical sources observed by SCOSMOS, SWIRE, and GOODS. Both SCOSMOS and SWIRE have identified a significant number of asteroids in their data, and we investigate the effectiveness of using relative color to distinguish between asteroids and background objects. We find a notable difference in color in the IRAC 3.6-8.0 mm and MIPS 24 {mu}m bands between the majority of MBAs, stars, galaxies, and active galactic nuclei, though this variation is less significant when comparing fluxes in individual bands. We find median colors for the FLS-EPC asteroids to be [F(5.8/3.6), F(8.0/4.5), F(24/8)] = (4.9 {+-} 1.8, 8.9 {+-} 7.4, 6.4 {+-} 2.3). Finally, we consider the utility of this technique for other mid-infrared observations that are sensitive to near-Earth objects, MBAs, and trans-Neptunian objects. We consider the potential of using color to differentiate between solar system and background sources for several space-based observatories, including Warm Spitzer, Herschel, and WISE.« less

Near Earth Asteroid redirect missions based on gravity assist maneuver

NASA Astrophysics Data System (ADS)

Ledkov, Anton; Shustov, Boris M.; Eismont, Natan; Boyarsky, Michael; Nazirov, Ravil; Fedyaev, Konstantin

During last years several events attracted world community attention to the hazards of hitting the Earth by sky objects. One of these objects is Apophis asteroid what was expected with nonzero probability to hit the Earth in 2036. Luckily after more precise measurements this event is considered as practically improbable. But the other object has really reached the Earth, entered the atmosphere in the Chelyabinsk area and caused vast damages. After this the hazardous near Earth objects problem received practical confirmation of the necessity to find the methods of its resolution. The methods to prevent collision of the dangerous sky object with the Earth proposed up to now look not practical enough if one mentions such as gravitational tractor or changing the reflectivity of the asteroid surface. Even the method supposing the targeting of the spacecraft to the hazardous object in order to deflect it from initial trajectory by impact does not work because its low mass as compared with the mass of asteroid to be deflected. For example the mass of the Apophis is estimated to be about 40 million tons but the spacecraft which can be launched to intercept the asteroid using contemporary launchers has the mass not more than 5 tons. So the question arises where to find the heavier projectile which is possible to direct to the dangerous object? The answer proposed in our paper is very simple: to search it among small near Earth asteroids. As small ones we suppose those which have the cross section size not more than 12-15 meters and mass not exceeding 1500 -1700 tons. According to contemporary estimates the number of such asteroids is not less than 100000. The other question is how to redirect such asteroid to the dangerous one. In the paper the possibilities are studied to use for that purpose gravity assist maneuvers near Earth. It is shown that even among asteroids included in contemporary catalogue there are the ones which could be directed to the trajectory of the gravity assist maneuver near Earth resulted by following impact with dangerous asteroid. As example of the last one the Apophis was chosen. The required delta-V pulse to be applied to the candidate projectile asteroid to fulfill mentioned change of initial trajectory was confirmed to be comparatively small: not exceeding 10 m/s, and the smallest is about 2 m/s. To fulfilled this maneuver it is necessary to land and to mount on the surface of the asteroid projectile the spacecraft with sufficient amount of propellant onboard. The possible trajectories and demanded maneuvers were explored and it was confirmed that for contemporary space technology it is doable for the small asteroids belonging to the determined by our studies list of candidates supposing some reservations, namely the mass of the found asteroids. This was not considered as decisive obstacle because up to now only about 1% of small enough asteroids are included in catalogue so the list of the appropriate ones is far from to be closed. The studies have been fulfilled aimed to develop the methods to reached required accuracies of asteroid projectile trajectory parameters determination. With existing methods used for the usual spacecraft the limits of achievable accuracies demand the corrections delta-V maneuvers which may exceed the nominal ones. As a result the proposed conception of hazardous asteroids deflection becomes problematic. To overcome this obstacle in the paper new method of trajectory parameters determination is proposed and explored. Practically it is radio interferometer method when one transponder is placed on the asteroid target and two others together with the asteroid projectile form tetrahedron. This system begins to operate in vicinity of target asteroid in autonomous regime and expected to allow reaching the demanded low enough correction maneuver values. Paper gives the estimations of the accuracy of these three bodies relative motion parameters and expected limit values of correction maneuvers needed for hitting the target object. As additional option of planetary defense system construction the idea to redirect small near Earth asteroids onto the orbits resonance with the Earth orbit is explored. It is shown that it is possible to reach it by the use gravity assist maneuvers as it was described above by applying small velocity impulses to the asteroids. At least 11 asteroids were found demanded small enough delta-V for transferring them on such trajectories. After executing these maneuvers one can receive the system of asteroids approaching to the Earth practically each month with a possibility to use them as projectiles or for the purposes of delivering to the Earth their soil samples.

Contextual Student Learning through Authentic Asteroid Research Projects using a Robotic Telescope Network

NASA Astrophysics Data System (ADS)

Hoette, Vivian L.; Puckett, Andrew W.; Linder, Tyler R.; Heatherly, Sue Ann; Rector, Travis A.; Haislip, Joshua B.; Meredith, Kate; Caughey, Austin L.; Brown, Johnny E.; McCarty, Cameron B.; Whitmore, Kevin T.

2015-11-01

Skynet is a worldwide robotic telescope network operated by the University of North Carolina at Chapel Hill with active observing sites on 3 continents. The queue-based observation request system is simple enough to be used by middle school students, but powerful enough to supply data for research scientists. The Skynet Junior Scholars program, funded by the NSF, has teamed up with professional astronomers to engage students from middle school to undergraduates in authentic research projects, from target selection through image analysis and publication of results. Asteroid research is a particularly fruitful area for youth collaboration that reinforces STEM education standards and can allow students to make real contributions to scientific knowledge, e.g., orbit refinement through astrometric submissions to the Minor Planet Center. We have created a set of projects for youth to: 1. Image an asteroid, make a movie, and post it to a gallery; 2. Measure the asteroid’s apparent motion using the Afterglow online image processor; and 3. Image asteroids from two or more telescopes simultaneously to demonstrate parallax. The apparent motion and parallax projects allow students to estimate the distance to their asteroid, as if they were the discoverer of a brand new object in the solar system. Older students may take on advanced projects, such as analyzing uncertainties in asteroid orbital parameters; studying impact probabilities of known objects; observing time-sensitive targets such as Near Earth Asteroids; and even discovering brand new objects in the solar system.Images are acquired from among seven Skynet telescopes in North Carolina, California, Wisconsin, Canada, Australia, and Chile, as well as collaborating observatories such as WestRock in Columbus, Georgia; Stone Edge in El Verano, California; and Astronomical Research Institute in Westfield, Illinois.

Photometry of Main Belt and Trojan asteroids with K2

NASA Astrophysics Data System (ADS)

Szabó, Gyula; Kiss, Csaba; Pal, Andras; Szabo, Robert

2016-10-01

Due to the failure of the second reaction wheel, a new mission was conceived for the otherwise healthy Kepler space telescope. In the course of the K2 Mission, the telescope is staring at the plane of the Ecliptic, hence thousands of Solar System bodies cross the K2 fields, usually causing extra noise in the highly accurate photometric data.We could measure the first continuous asteroid light curves, covering several days wthout interruption, that has been unprecedented to date. We studied the K2 superstamps covering the M35 and Neptune/Nereid fields observed in the long cadence (29.4-min sampling) mode. Asteroid light curves are generated by applying elongated apertures. We investigated the photometric precision that the K2 Mission can deliver on moving Solar System bodies, and determined the first uninterrupted optical light curves of main-belt and Trojan asteroids. We use thed Lomb-Scargle method to find periodicities due to rotation.We derived K2 light curves of 924 main-belt asteroids in the M35 field, and 96 in the path of Neptune and Nereid. Due to the faintness of the asteroids and the high density of stars in the M35 field, 4.0% of the asteroids with at least 12 data points show clear periodicities or trend signalling a long rotational period, as opposed to 15.9% in the less crowded Neptune field. We found that the duty cycle of the observations had to reach ˜ 60% in order to successfully recover rotational periods.The derived period-amplitude diagram is consistent to the known distribution of Main Belt asteroids. For Trojan asteroids, the contribution of our 56 objects with newly determined precise period and amplitude is in the order of all previously known asteroids. The comparison with earth-based determinations showed a previous bias toward short periods and has also proven that asteroid periods >20 hour can be unreliable in a few cases because of daylight time and diurnal calibrations. These biases are avoided from the space. We present an unbiased sample of rotation periods and identify a higher rate of slow rotators. We also found multiple periods of large asteroids that has not been observed earlier and still needs explanation.

Extreme AO Observations of Two Triple Asteroid Systems with SPHERE

NASA Astrophysics Data System (ADS)

Yang, B.; Wahhaj, Z.; Beauvalet, L.; Marchis, F.; Dumas, C.; Marsset, M.; Nielsen, E. L.; Vachier, F.

2016-04-01

We present the discovery of a new satellite of asteroid (130) Elektra—S/2014 (130) 1—in differential imaging and in integral field spectroscopy data over multiple epochs obtained with Spectro-Polarimetric High-contrast Exoplanet Research/Very Large Telescope. This new (second) moonlet of Elektra is about 2 km across, on an eccentric orbit, and about 500 km away from the primary. For a comparative study, we also observed another triple asteroid system, (93) Minerva. For both systems, component-resolved reflectance spectra of the satellites and primary were obtained simultaneously. No significant spectral difference was observed between the satellites and the primary for either triple system. We find that the moonlets in both systems are more likely to have been created by sub-disruptive impacts as opposed to having been captured.

The Shape, Internal Structure and Dynamics of 433 Eros from the NEAR Laser Ranging Investigation

NASA Astrophysics Data System (ADS)

Zuber, M. T.; Smith, D. E.; Cheng, A. F.; Garvin, J. B.; NLR Science Team

2000-10-01

The NEAR Laser Rangefinder, an instrument on the NEAR-Shoemaker spacecraft, has been mapping the detailed shape of asteroid 433 Eros since February 29, 2000. The instrument has a range resolution of 31 cm and a surface spot size that varies between 8 to 45 m (depending on orbital altitude), yielding along-track profiles that are often contiguous or overlapping. The NLR has so far provided over 7 million valid measurements of the range from the NEAR-Shoemaker spacecraft to the surface of 433 Eros, which are converted to mass-centered radii through solutions for the spacecraft orbit from Doppler tracking. The current spherical harmonic model, produced in a joint solution between altimetry and Doppler, is to degree and order 48 and is characterized by a spatial resolution of 470 m and a vertical accuracy of a few tens of meters. The shape model has an RMS misfit of 1000 +/- 126 m to an ellipsoid, which represents a poor fit compared to other measured asteroids. Eros' complex shape was dominated by collisions but the asteroid shows no evidence of dumbbell-like structure suggestive of a contact binary bound loosely by self-gravitation. Clustered regions of high slopes on the walls of the two largest depressions represent evidence for structural competence. The offset between the asteroid's center of mass and center of figure can be explained by a density gradient of only 4.3 kg m-3 km-1. This minor deviation of internal structure from homogeneity is likely due to variations in mechanical competence (regolith distribution and variations in internal porosity) rather than composition. Regolith thicknesses of a few tens of meters are inferred from depths of topographic benches in craters. Impact crater morphology shows evidence of influence from both gravity and structural control. Small-scale topography reveals ridges and grooves likely generated by impact-related fracturing.

Astrophysics and astronomy (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 26 January 2011)

NASA Astrophysics Data System (ADS)

2011-10-01

An Astrophysics and Astronomy scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) was held in the Conference Hall of the P N Lebedev Physical Institute, RAS, on 26 January 2011. The following reports were put on the session's agenda posted on the web site www.gpad.ac.ru of the Physical Sciences Division, RAS: (1) Cherepashchuk A M (Sternberg Astronomical Institute, Moscow State University, Moscow) "Investigation of X-ray sources"; (2) Shustov B M (Institute of Astronomy, Russian Academy of Sciences, Moscow) "Asteroid and comet hazards: physical and other aspects"; (3) Sazhin M V (Sternberg Astronomical Institute, Moscow State University, Moscow) "Search for cosmic strings"; (4) Zakharov A F (Russian Federation State Scientific Center 'A I Alikhanov Institute for Theoretical and Experimental Physics', Moscow) "Exoplanet search using gravitational microlensing". Papers written on the basis of the reports are published below. • Optical investigations of X-ray binary systems, A M Cherepashchuk Physics-Uspekhi, 2011, Volume 54, Number 10, Pages 1061-1067 • Asteroid and comet hazards: the role of physical sciences in solving the problem, B M Shustov Physics-Uspekhi, 2011, Volume 54, Number 10, Pages 1068-1071 • Search for cosmic strings using optical and radio astronomy methods, O S Sazhina, M V Sazhin, M Capaccioli, G Longo Physics-Uspekhi, 2011, Volume 54, Number 10, Pages 1072-1077 • Search for exoplanets using gravitational microlensing, A F Zakharov Physics-Uspekhi, 2011, Volume 54, Number 10, Pages 1077-1084

Numerical Simulations of Granular Physics in the Solar System

NASA Astrophysics Data System (ADS)

Ballouz, Ronald

2017-08-01

Granular physics is a sub-discipline of physics that attempts to combine principles that have been developed for both solid-state physics and engineering (such as soil mechanics) with fluid dynamics in order to formulate a coherent theory for the description of granular materials, which are found in both terrestrial (e.g., earthquakes, landslides, and pharmaceuticals) and extra-terrestrial settings (e.g., asteroids surfaces, asteroid interiors, and planetary ring systems). In the case of our solar system, the growth of this sub-discipline has been key in helping to interpret the formation, structure, and evolution of both asteroids and planetary rings. It is difficult to develop a deterministic theory for granular materials due to the fact that granular systems are composed of a large number of elements that interact through a non-linear combination of various forces (mechanical, gravitational, and electrostatic, for example) leading to a high degree of stochasticity. Hence, we study these environments using an N-body code, pkdgrav, that is able to simulate the gravitational, collisional, and cohesive interactions of grains. Using pkdgrav, I have studied the size segregation on asteroid surfaces due to seismic shaking (the Brazil-nut effect), the interaction of the OSIRIS-REx asteroid sample-return mission sampling head, TAGSAM, with the surface of the asteroid Bennu, the collisional disruptions of rubble-pile asteroids, and the formation of structure in Saturn's rings. In all of these scenarios, I have found that the evolution of a granular system depends sensitively on the intrinsic properties of the individual grains (size, shape, sand surface roughness). For example, through our simulations, we have been able to determine relationships between regolith properties and the amount of surface penetration a spacecraft achieves upon landing. Furthermore, we have demonstrated that this relationship also depends on the strength of the local gravity. By comparing our numerical results to laboratory experiments and observations by spacecraft we can begin to understand which microscopic properties (i.e., grain properties) control the macroscopic properties of the system. For example, we can compare the mechanical response of a spacecraft to landing or Cassini observations of Saturn's ring to understand how the penetration depth of a spacecraft or the complex optical depth structure of a ring system depends on the size and surface properties of the grains in those systems.

Radar Imagery of Asteroid 2014 JO25

NASA Image and Video Library

2017-04-19

This composite of 30 images of asteroid 2014 JO25 was generated with radar data collected using NASA Goldstone Solar System Radar in California Mojave Desert. https://photojournal.jpl.nasa.gov/catalog/PIA21594

Tools for Asteroid Regolith Operations

NASA Technical Reports Server (NTRS)

Mueller, Robert P.; Calle, Carlos I.; Mantovani, James G.

2013-01-01

This RFI response is targeting Area 5. Crew Systems for Asteroid Exploration: concepts for lightweight and low volume robotic and extra-vehicular activity (EVA) systems, such as space suits, tools, translation aids, stowage containers, and other equipment.The NASA KSC Surface Systems Office, Granular Mechanics and Regolith Operations (GMRO) Lab and the Electrostatics Surface Physics Lab (ESPL) are dedicated to developing technologies for operating in regolith environments on target body surfaces. We have identified two technologies in our current portfolio that are highly relevant and useful for crews that will visit a re-directed asteroid in Cis-Lunar Space. Both technologies are at a high TRL of 56 and could be rapidly implemented in time for an ARM mission in this decade.

Qualitative and quantitative behaviour of planetary systems; Proceedings of the 3rd Alexander von Humboldt Colloquium on Celestial Mechanics, Ramsau, Austria, Mar. 29-Apr. 4, 1992

NASA Astrophysics Data System (ADS)

Dvorak, R.; Henrard, J.

1993-06-01

Topics addressed include planetary theories, the Sitnikov problem, asteroids, resonance, general dynamical systems, and chaos and stability. Particular attention is given to recent progress in the theory and application of symplectic integrators, a computer-aided analysis of the Sitnikov problem, the chaotic behavior of trajectories for the asteroidal resonances, and the resonant motion in the restricted three-body problem. Also discussed are the second order long-period motion of Hyperion, meteorites from the asteroid 6 Hebe, and least squares parameter estimation in chaotic differential equations.

Power Supply for a Manned International Asteroid Mission

NASA Technical Reports Server (NTRS)

Weingartner, Stefan; Nahra, Henry K.; Kohout, Lisa L.; Larin, Max

1991-01-01

A feasibility study considering the exploitation of a near Earth asteroid was performed. The power requirements and proposed power systems for the crew vehicle, cargo vehicles, mining and processing equipment are described. A photovoltaic power system was selected to meet the 52.1 kWe and the 3.9 kWe power requirements of the crew and cargo vehicles, respectively. A nuclear power plant using a thermodynamic Rankine cycle with a total mass of 62.1 tons was chosen to provide the 7.225 MWe and the 5.5 MWth required for the mining and processing activities at the asteroid.

On the metal-rich surfaces of (16) Psyche and other M-type asteroids from interferometric observations in the thermal infrared

NASA Astrophysics Data System (ADS)

Delbo, Marco; Matter, A.; Gundlach, B.; Blum, J.

2013-10-01

Asteroids belonging to the spectroscopic M-type exhibit a quasi featureless and moderately red reflectance spectrum and a geometric visible albedo between 0.1 and 0.3. These asteroids were initially thought to be metallic cores of differentiated asteroids that were exposed to space by a catastrophic disruption by impacts. Later, this view has been challenged by the detection of silicates and hydration spectroscopic bands on these bodies. Unveiling the physical properties of the surfaces of these asteroids, and identifying their meteorite analogs is a challenge from remote-sensing observations. Nevertheless, these are crucial problems, important for estimating the number of asteroids that underwent differentiation in the early phases of the formation of our solar system. The thermal inertia is a sensitive indicator for the presence of metal in the regolith on the surfaces of asteroids. We developed a new thermophysical model that allow us to derive the value of the thermal inertia from interferometric observations in the thermal infrared. We report on our investigation of the thermal inertia of M-type asteroids, including the asteroids (16) Psyche, for which we obtained a thermal inertia value anomalously high compared to the thermal inertia values of other asteroids in the same size range. From the thermal inertia and model of heat conductivity that accounts for different values of the packing fraction (a measure of the degree of compaction of the regolith particles) the regolith grain size is derived.

VESTOIDS, PART II: THE BASALTIC NATURE AND HED METEORITE ANALOGS FOR EIGHT V{sub p}-TYPE ASTEROIDS AND THEIR ASSOCIATIONS WITH (4) VESTA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hardersen, Paul S.; Reddy, Vishnu; Roberts, Rachel, E-mail: Hardersen@space.edu

Improving the constraints on the abundance of basaltic asteroids in the main asteroid belt is necessary for better understanding the thermal and collisional environment in the early solar system, for more rigorously identifying the genetic family for (4) Vesta, for determining the effectiveness of Yarkovsky/YORP in dispersing asteroid families, and for better quantifying the population of basaltic asteroids in the outer main belt (a > 2.5 AU) that is likely unrelated to (4) Vesta. Near-infrared (NIR) spectral observations in this work were obtained for the V{sub p}-type asteroids (2011) Veteraniya, (5875) Kuga, (8149) Ruff, (9147) Kourakuen, (9553) Colas, (15237) 1988 RL{sub 6},more » (31414) Rotaryusa, and (32940) 1995 UW{sub 4} during 2014 August/September utilizing the SpeX spectrograph at the NASA Infrared Telescope Facility, Mauna Kea, Hawaii. Spectral band parameter (band centers, band area ratios) and mineralogical analysis (pyroxene chemistry) for each average asteroid NIR reflectance spectrum suggest a howardite–eucrite–diogenite meteorite analog for each asteroid. (5875) Kuga is most closely associated with the eucrite meteorites, (31414) Rotaryusa is most closely associated with the diogenites, and the remaining other six asteroids are most closely associated with the howardite meteorites. Along with their orbital locations in the inner main belt and in the vicinity of (4) Vesta, the existing evidence suggests that these eight V{sub p}-type asteroids are also likely Vestoids.« less

Application of Close Encounters in Determining the Masses of Asteroids

NASA Astrophysics Data System (ADS)

Tang, H. J.; Li, F.; Fu, Y. N.

2017-11-01

Asteroids are important part of the solar system. So far, the number of known asteroids is more than seven hundred thousand, and the total number is probably more than one million. Among many events of encounters among asteroids, those very close ones can be used to improve the precision of the masses of asteroids. To achieve this, it's necessary to search for the latter events in advance by making an accurate assessment of the effectiveness of an encounter in the mass determination. In this context, the previous dynamical models and assessing indicators are not precise enough. By using a more realistic dynamical model and introducing a properly defined Signal-to-Noise ratio, we are able to estimate the precision of the mass determination based on observations made from the Earth. Moreover, the best observation time span can be quantitatively given, which is useful in collecting observational data and planning further observations. We search systematically for the useful asteroid encounters involving one of the 773 massive asteroids with equivalent diameter larger than 50 km, for which the searched time span is from the year 2000 to 2030.

Logistics Needs for Potential Deep Space Mission Scenarios Post Asteroid Crewed Mission

NASA Technical Reports Server (NTRS)

Lopez, Pedro, Jr.

2015-01-01

A deep-space mission has been proposed to identify and redirect an asteroid to a distant retrograde orbit around the moon, and explore it by sending a crew using the Space Launch System and the Orion spacecraft. The Asteroid Redirect Crewed Mission (ARCM), which represents the third segment of the Asteroid Redirect Mission (ARM), could be performed on EM-3 or EM-4 depending on asteroid return date. Recent NASA studies have raised questions on how we could progress from current Human Space Flight (HSF) efforts to longer term human exploration of Mars. This paper will describe the benefits of execution of the ARM as the initial stepping stone towards Mars exploration, and how the capabilities required to send humans to Mars could be built upon those developed for the asteroid mission. A series of potential interim missions aimed at developing such capabilities will be described, and the feasibility of such mission manifest will be discussed. Options for the asteroid crewed mission will also be addressed, including crew size and mission duration.

Trajectory of asteroid 2017 SB20 within the CRTBP

NASA Astrophysics Data System (ADS)

Tiwary, Rishikesh Dutta; Kushvah, Badam Singh; Ishwar, Bhola

2018-06-01

Regular monitoring the trajectory of asteroids to a future time is a necessity, because the variety of known probably unsafe near-Earth asteroids are increasing. The analysis is perform to avoid any incident or whether they would have a further future threat to the Earth or not. Recently a new Near Earth Asteroid (2017 SB20) has been observed to cross the Earth orbit. In view of this we obtain the trajectory of Asteroid in the circular restricted three body problem with radiation pressure and oblateness. We examine nature of Asteroid's orbit with Lyapunov Characteristic Exponents (LCEs) over a finite intervals of time. LCE of the system confirms that the motion of asteroid is chaotic in nature. With the effect of radiation pressure and oblateness the length of curve varies in both the planes. Oblateness factor is found to be more perturbative than radiation pressure. To see the precision of result obtain from numerical integration we show the error propagation and the numerical stability is assured around the singularity by applying regularized equations of motion for precise long-term study.

Spitzer IRS Spectra of Basaltic Asteroids: Preliminary Results

NASA Technical Reports Server (NTRS)

Lim, Lucy F.; Emery, Joshua P.; Moskovitz, Nick; Stewart, Heather; Marchis, Frank

2008-01-01

We present preliminary results of a Spitzer program to observe the 5.2--38 micron spectra of small basaltic asteroids using the Spitzer IRS (Infrared Spectrograph). Our targets include members of the dynamical family of the unique large differentiated asteroid 4 Vesta ("Vestoids"), four outer-main-belt basaltic asteroids whose orbits exclude them from originating on 4 Vesta, and the basaltic near-Earth asteroid (NEA) 4055 Magellan. We will compare the compositions and thermophysical properties of the non-Vestoid objects with those of the dynamical vestoids to provide insight on the extent of metal-silicate differentiation on planetsimals during the epoch of planet formation in the early Solar System. As of this writing, spectra of asteroids 10537 (1991 RY16) and 2763 Jeans have been returned. Analysis of these data are ongolng. Observations of 956 Elisa, 2653 Principia, 4215 Kamo, 7472 Kumakiri, and 1459 Magnya have been scheduled and are expected to be available by the time of the DPS meeting. NIR spectra and lightcurves o f the target asteroids are also being observed in support of this program.

AN ASTEROID BELT INTERPRETATION FOR THE TIMING VARIATIONS OF THE MILLISECOND PULSAR B1937+21

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shannon, R. M.; Cordes, J. M.; Metcalfe, T. S.

Pulsar timing observations have revealed companions to neutron stars that include other neutron stars, white dwarfs, main-sequence stars, and planets. We demonstrate that the correlated and apparently stochastic residual times of arrival from the millisecond pulsar B1937+21 are consistent with the signature of an asteroid belt having a total mass {approx}< 0.05 M{sub Circled-Plus }. Unlike the solar system's asteroid belt, the best fit pulsar asteroid belt extends over a wide range of radii, consistent with the absence of any shepherding companions. We suggest that any pulsar that has undergone accretion-driven spin-up and subsequently evaporated its companion may harbor orbitingmore » asteroid mass objects. The resulting timing variations may fundamentally limit the timing precision of some of the other millisecond pulsars. Observational tests of the asteroid belt model include identifying periodicities from individual asteroids, which are difficult; testing for statistical stationarity, which becomes possible when observations are conducted over a longer observing span; and searching for reflected radio emission.« less

The great asteroid nomenclature controversy of 1801

NASA Technical Reports Server (NTRS)

Cunningham, Clifford J.

1992-01-01

With the almost complete neglect of 19th century asteroid research by professional historians of science, it is scarcely surprising that great gaps exist in our knowledge of that important field. This paper focuses on issue of naming the first asteroid. This seemingly innocuous issue assumed great importance because many believed the object discovered by Giuseppe Piazzi at Palermo Observatory to be the eighth primary planet of the solar system.

Near-Earth Asteroid Retrieval Mission (ARM) Study

NASA Technical Reports Server (NTRS)

Brophy, John R.; Muirhead, Brian

2013-01-01

The Asteroid Redirect Mission (ARM) concept brings together the capabilities of the science, technology, and the human exploration communities on a grand challenge combining robotic and human space exploration beyond low Earth orbit. This paper addresses the key aspects of this concept and the options studied to assess its technical feasibility. Included are evaluations of the expected number of potential targets, their expected discovery rate, the necessity to adequately characterize candidate mission targets, the process to capture a non-cooperative asteroid in deep space, and the power and propulsion technology required for transportation back to the Earth-Moon system. Viable options for spacecraft and mission designs are developed. Orbits for storing the retrieved asteroid that are stable for more than a hundred years, yet allow for human exploration and commercial utilization of a redirected asteroid, are identified. The study concludes that the key aspects of finding, capturing and redirecting an entire small, near-Earth asteroid to the Earth-Moon system by the first half of the next decade are technically feasible. The study was conducted from January 2013 through March 2013 by the Jet Propulsion Laboratory (JPL) in collaboration with Glenn Research Center (GRC), Johnson Space Center (JSC), Langley Research Center (LaRC), and Marshall Space Flight Center (MSFC).

Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results

NASA Astrophysics Data System (ADS)

Vereš, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; Chastel, Serge; Wainscoat, Richard J.; Burgett, William S.; Chambers, Kenneth C.; Flewelling, Heather; Kaiser, Nick; Magnier, Eugen A.; Morgan, Jeff S.; Price, Paul A.; Tonry, John L.; Waters, Christopher

2015-11-01

We present the results of a Monte Carlo technique to calculate the absolute magnitudes (H) and slope parameters (G) of ∼240,000 asteroids observed by the Pan-STARRS1 telescope during the first 15 months of its 3-year all-sky survey mission. The system's exquisite photometry with photometric errors ≲ 0.04mag , and well-defined filter and photometric system, allowed us to derive accurate H and G even with a limited number of observations and restricted range in phase angles. Our Monte Carlo method simulates each asteroid's rotation period, amplitude and color to derive the most-likely H and G, but its major advantage is in estimating realistic statistical + systematic uncertainties and errors on each parameter. The method was tested by comparison with the well-established and accurate results for about 500 asteroids provided by Pravec et al. (Pravec, P. et al. [2012]. Icarus 221, 365-387) and then applied to determining H and G for the Pan-STARRS1 asteroids using both the Muinonen et al. (Muinonen, K. et al. [2010]. Icarus 209, 542-555) and Bowell et al. (Bowell, E. et al. [1989]. Asteroids III, Chapter Application of Photometric Models to Asteroids. University of Arizona Press, pp. 524-555) phase functions. Our results confirm the bias in MPC photometry discovered by Jurić et al. (Jurić, M. et al. [2002]. Astrophys. J. 124, 1776-1787).

Rotational properties of the Maria asteroid family

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, M.-J.; Byun, Y.-I.; Choi, Y.-J.

2014-03-01

The Maria family is regarded as an old-type (∼3 ± 1 Gyr) asteroid family that has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids to the inner solar system. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in the observed rotation rate distribution. The one-sample Kolmogorov-Smirnov testmore » confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of light curves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a light-curve inversion method, we successfully determined the pole orientations for 13 Maria members and found an excess of prograde versus retrograde spins with a ratio (N{sub p} /N{sub r} ) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner solar system since the formation of the Maria family. We estimate that approximately 37-75 Maria family asteroids larger than 1 km have entered near-Earth space every 100 Myr.« less

The asteroid rendezvous spacecraft. An adaptation study of TIROS/DMSP technology

NASA Technical Reports Server (NTRS)

1982-01-01

The feasibility of using the TIROS/DMSP Earth orbiting meteorological satellite in application to a near Earth asteroid rendezvous mission. System and subsystems analysis was carried out to develop a configuration of the spacecraft suitable for this mission. Mission analysis studies were also done and maneuver/rendezvous scenarios developed for baseline missions to both Anteros and Eros. The fact that the Asteroid mission is the most complex of the Pioneer class missions currently under consideration notwithstanding, the basic conclusion very strongly supports the suitability of the basic TIROS bus for this mission in all systems and subsystems areas, including science accommodation. Further, the modifications which are required due to the unique mission are very low risk and can be accomplished readily. The key issue is that in virtually every key subsystem, the demands of the Asteroid mission are a subset of the basic meteorological satellite mission. This allows a relatively simple reconfiguration to be accomplished without a major system redesign.

Modeling and experimental validation of sawing based lander anchoring and sampling methods for asteroid exploration

NASA Astrophysics Data System (ADS)

Zhang, Jun; Dong, Chengcheng; Zhang, Hui; Li, Song; Song, Aiguo

2018-05-01

This paper presents a novel lander anchoring system based on sawing method for asteroid exploration. The system is composed of three robotic arms, three cutting discs, and a control system. The discs mounted at the end of the arms are able to penetrate into the rock surface of asteroids. After the discs cut into the rock surface, the self-locking function of the arms provides forces to fix the lander on the surface. Modeling, trajectory planning, simulations, mechanism design, and prototype fabrication of the anchoring system are discussed, respectively. The performances of the system are tested on different kinds of rocks, at different sawing angles, locations, and speeds. Results show that the system can cut 15 mm deep into granite rock in 180 s at sawing angle of 60°, with the average power of 58.41 W, and the "weight on bit" (WOB) of 8.637 N. The 7.8 kg anchoring system is capable of providing omni-directional anchoring forces, at least 225 N normal and 157 N tangent to the surface of the rock. The system has the advantages of low-weight, low energy consumption and balance forces, high anchoring efficiency and reliability, and could enable the lander to move and sample or assist astronauts and robots in walking and sampling on asteroids.

Distant asteroids and Chiron

NASA Technical Reports Server (NTRS)

French, Linda M.; Vilas, Faith; Hartmann, William K.; Tholen, David J.

1989-01-01

Knowledge of the physical properties of distant asteroids (a greater than 3.3 AU) has grown dramatically over the past five years, due to systematic compositional and lighcurve studies. Most of these objects have red, dark surfaces, and their spectra show a reddening in spectral slope with heliocentric distance, implying a change in surface composition. Trojans for which near-opposition phase curve information is available appear to show little or no opposition effect, unlike any other dark solar system objects. The lightcurve amplitudes of Trojan and Hilda asteroids imply significantly more elongated shapes for these groups than for main-belt asteroids of comparable size. These recent observations are reviewed in the context of their implications for the formationan and subsequent evolution of the distant asteroids, and their interrelations with the main belt, Chiron, and comets.

In-Situ Resource Utilization Experiment for the Asteroid Redirect Crewed Mission

NASA Astrophysics Data System (ADS)

Elliott, J.; Fries, M.; Love, S.; Sellar, R. G.; Voecks, G.; Wilson, D.

2015-10-01

The Asteroid Redirect Crewed Mission (ARCM) represents a unique opportunity to perform in-situ testing of concepts that could lead to full-scale exploitation of asteroids for their valuable resources [1]. This paper describes a concept for an astronautoperated "suitcase" experiment to would demonstrate asteroid volatile extraction using a solar-heated oven and integral cold trap in a configuration scalable to full-size asteroids. Conversion of liberated water into H2 and O2 products would also be demonstrated through an integral processing and storage unit. The plan also includes development of a local prospecting system consisting of a suit-mounted multi-spectral imager to aid the crew in choosing optimal samples, both for In-Situ Resource Utilization (ISRU) and for potential return to Earth.

On the Contribution of Asteroid Disruptions to the Interplanetary Dust Flux

NASA Astrophysics Data System (ADS)

Kehoe, T. J. J.; Kehoe, A. E.

2017-12-01

Recent modeling has shown the significant contribution of micron- to millimeter-sized particles released by the disruption of main-belt asteroids (MBAs) to the interplanetary dust particle (IDP) flux (e.g., Dermott et al., 2002; Nesvorný et al., 2003; Espy Kehoe et al., 2015). In this paper, we present the results of a study that indicates that the dust injected into the zodiacal cloud due to the catastrophic disruption of an asteroid is dominated by the release of its surface regolith particles. Our research suggests that disrupting a single asteroid with diameter O(100 km) will be enough to regenerate the entire zodiacal cloud. The breakup of smaller asteroids with diameters O(10 km) will likely produce more moderate, but still significant, changes in the dust environment of the inner solar system. As collisional disruptions of asteroids in this size range occur more frequently, it is important that we develop a better understanding of the injection of asteroidal material into the zodiacal cloud as a result of these type of events in order to determine the temporal evolution of the interplanetary dust flux. The results presented in this paper will lead to a better understanding of the threat to exploration activities due to the enhanced IDP flux resulting from the disruption of asteroidal regoliths. These findings can be employed to improve engineering models, for example, the NASA Meteoroid Engineering Model (MEM) that is widely utilized to assess the impact hazard to space hardware and activities in the inner solar system due to the natural meteoroid environment (McNamara et al., 2004). This is an important area of concern for current and future mission development purposes.

Comet deflection by directed energy: a finite element analysis

NASA Astrophysics Data System (ADS)

Madajian, Jonathan; Griswold, Janelle; Gandra, Anush; Hughes, Gary B.; Zhang, Qicheng; Rupert, Nic; Lubin, Philip

2016-09-01

Comets and Asteroids are viable threats to our planet; if these space rocks are smaller than 25 meters, they burn up in the atmosphere, but if they are wider than 25 meters they can cause damage to the impact area. Anything more than one to two kilometers can have worldwide effects, furthermore a mile-wide asteroid travelling at 30,000 miles per hour has the energy equal to a megaton bomb and is very likely to wipe out most of the life on Earth. Residents near Chelyabinsk, Russia experienced the detrimental effects of a collision with a Near-Earth Asteroid (NEA) on 15 February 2013 as a 20 m object penetrated the atmosphere above that city. The effective yield from this object was approximately 1/2 Megaton TNT equivalent (Mt), or that of a large strategic warhead. The 1908 Tunguska event, also over Russia, is estimated to have had a yield of approximately 15 Mt and had the potential to kill millions of people had it come down over a large city1. In the face of such danger a planetary defense system is necessary and this paper proposes a design for such a system. DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) is a phased array laser system that can be used to oblate, deflect and de-spin asteroids and comets.

Spacewatch Survey of the Solar System

NASA Technical Reports Server (NTRS)

McMillan, Robert S.

2000-01-01

The purpose of the Spacewatch project is to explore the various populations of small objects throughout the solar system. Statistics on all classes of small bodies are needed to infer their physical and dynamical evolution. More Earth Approachers need to be found to assess the impact hazard. (We have adopted the term "Earth Approacher", EA, to include all those asteroids, nuclei of extinct short period comets, and short period comets that can approach close to Earth. The adjective "near" carries potential confusion, as we have found in communicating with the media, that the objects are always near Earth, following it like a cloud.) Persistent and voluminous accumulation of astrometry of incidentally observed main belt asteroids MBAs will eventually permit the Minor Planet Center (MPQ to determine the orbits of large numbers (tens of thousands) of asteroids. Such a large body of information will ultimately allow better resolution of orbit classes and the determinations of luminosity functions of the various classes, Comet and asteroid recoveries are essential services to planetary astronomy. Statistics of objects in the outer solar system (Centaurs, scattered-disk objects, and Trans-Neptunian Objects; TNOs) ultimately will tell part of the story of solar system evolution. Spacewatch led the development of sky surveying by electronic means and has acted as a responsible interface to the media and general public on this discipline and on the issue of the hazard from impacts by asteroids and comets.

NASA's Dawn Mission to Asteroid 4 Vesta

NASA Technical Reports Server (NTRS)

McFadden, Lucyann A.

2011-01-01

NASA's Dawn Mission to asteroid 4 Vesta is part of a 13-year robotic space project designed to reveal the nature of two of the largest asteroids in the Main Asteroid Belt of our Solar System. Ceres and Vesta are two complementary terrestrial protoplanets whose accretion was probably terminated by the formation of Jupiter. They provide a bridge in our understanding between the rocky bodies of the inner solar system and the icy bodies of the outer solar system. Ceres appears to be undifferentiated Vesta has experienced significant heating and likely differentiation. Both formed very early in history of the solar system and while suffering many impacts have remained intact, thereby retaining a record of events and processes from the time of planet formation. Detailed study of the geophysics and geochemistry of these two bodies provides critical benchmarks for early solar system conditions and processes that shaped its subsequent evolution. Dawn provides the missing context for both primitive and evolved meteoritic data, thus playing a central role in understanding terrestrial planet formation and the evolution of the asteroid belt. Dawn is to he launched in 2006 arriving at Vesta in 20l0 and Ceres in 2014, stopping at each to make 11 months of orbital measurements. The spacecraft uses solar electric propulsion, both in cruise and in orbit, to make most efficient use of its xenon propellant. The spacecraft carries a framing camera, visible and infrared mapping spectrometer, gamma ray/neutron magnetometer, and radio science.

A Shared Bombardment History

NASA Image and Video Library

2013-03-25

Studying meteorites from the asteroid Vesta helps scientists understand the event known as the lunar cataclysm, when a repositioning of the gas giant planets destabilized a portion of the asteroid belt and triggered a solar-system-wide bombardment.

Solar System Science with LSST

NASA Astrophysics Data System (ADS)

Jones, R. L.; Chesley, S. R.; Connolly, A. J.; Harris, A. W.; Ivezic, Z.; Knezevic, Z.; Kubica, J.; Milani, A.; Trilling, D. E.

2008-09-01

The Large Synoptic Survey Telescope (LSST) will provide a unique tool to study moving objects throughout the solar system, creating massive catalogs of Near Earth Objects (NEOs), asteroids, Trojans, TransNeptunian Objects (TNOs), comets and planetary satellites with well-measured orbits and high quality, multi-color photometry accurate to 0.005 magnitudes for the brightest objects. In the baseline LSST observing plan, back-to-back 15-second images will reach a limiting magnitude as faint as r=24.7 in each 9.6 square degree image, twice per night; a total of approximately 15,000 square degrees of the sky will be imaged in multiple filters every 3 nights. This time sampling will continue throughout each lunation, creating a huge database of observations. Fig. 1 Sky coverage of LSST over 10 years; separate panels for each of the 6 LSST filters. Color bars indicate number of observations in filter. The catalogs will include more than 80% of the potentially hazardous asteroids larger than 140m in diameter within the first 10 years of LSST operation, millions of main-belt asteroids and perhaps 20,000 Trans-Neptunian Objects. Objects with diameters as small as 100m in the Main Belt and <100km in the Kuiper Belt can be detected in individual images. Specialized `deep drilling' observing sequences will detect KBOs down to 10s of kilometers in diameter. Long period comets will be detected at larger distances than previously possible, constrainting models of the Oort cloud. With the large number of objects expected in the catalogs, it may be possible to observe a pristine comet start outgassing on its first journey into the inner solar system. By observing fields over a wide range of ecliptic longitudes and latitudes, including large separations from the ecliptic plane, not only will these catalogs greatly increase the numbers of known objects, the characterization of the inclination distributions of these populations will be much improved. Derivation of proper elements for main belt and Trojan asteroids will allow ever more resolution of asteroid families and their size-frequency distribution, as well as the study of the long-term dynamics of the individual asteroids and the asteroid belt as a whole. Fig. 2 Orbital parameters of Main Belt Asteroids, color-coded according to ugriz colors measured by SDSS. The figure to the left shows osculating elements, the figure to the right shows proper elements - note the asteroid families visible as clumps in parameter space [1]. By obtaining multi-color ugrizy data for a substantial fraction of objects, relationships between color and dynamical history can be established. This will also enable taxonomic classification of asteroids, provide further links between diverse populations such as irregular satellites and TNOs or planetary Trojans, and enable estimates of asteroid diameter with rms uncertainty of 30%. With the addition of light-curve information, rotation periods and phase curves can be measured for large fractions of each population, leading to new insight on physical characteristics. Photometric variability information, together with sparse lightcurve inversion, will allow spin state and shape estimation for up to two orders of magnitude more objects than presently known. This will leverage physical studies of asteroids by constraining the size-strength relationship, which has important implications for the internal structure (solid, fractured, rubble pile) and in turn the collisional evolution of the asteroid belt. Similar information can be gained for other solar system bodies. [1] Parker, A., Ivezic

Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection

NASA Technical Reports Server (NTRS)

Hernandez, Sonia; Barbee, Brent W.

2011-01-01

There are currently over 8,000 known near-Earth asteroids (NEAs), and more are being discovered on a continual basis. More than 1,200 of these are classified as Potentially Hazardous Asteroids (PHAs) because their Minimum Orbit Intersection Distance (MOID) with Earth's orbit is <= 0.05 AU and their estimated diameters are >= 150 m. To date, 178 Earth impact structures have been discovered, indicating that our planet has previously been struck with devastating force by NEAs and will be struck again. Such collisions are aperiodic events and can occur at any time. A variety of techniques have been proposed to defend our planet from NEA impacts by deflecting the incoming asteroid. However, none of these techniques have been tested. Unless rigorous testing is conducted to produce reliable asteroid deflection systems, we will be forced to deploy completely untested -- and therefore unreliable -- deflection missions when a sizable asteroid on a collision course with Earth is discovered. Such missions will have a high probability of failure. We propose to address this problem with a campaign of deflection technology test missions deployed to harmless NEAs. The objective of these missions is to safely evaluate and refine the mission concepts and asteroid deflection system designs. Our current research focuses on the kinetic impactor, one of the simplest proposed asteroid deflection techniques in which a spacecraft is sent to collide with an asteroid at high relative velocity. By deploying test missions in the near future, we can characterize the performance of this deflection technique and resolve any problems inherent to its execution before needing to rely upon it during a true emergency. In this paper we present the methodology and results of our survey, including lists of NEAs for which safe and effective kinetic impactor test missions may be conducted within the next decade. Full mission designs are also presented for the NEAs which offer the best mission opportunities.

OSIRIS-REx, Returning the Asteroid Sample

NASA Technical Reports Server (NTRS)

Ajluni, Thomas, M.; Everett, David F.; Linn, Timothy; Mink, Ronald; Willcockson, William; Wood, Joshua

2015-01-01

This paper addresses the technical aspects of the sample return system for the upcoming Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission. The overall mission design and current implementation are presented as an overview to establish a context for the technical description of the reentry and landing segment of the mission.The prime objective of the OSIRIS-REx mission is to sample a primitive, carbonaceous asteroid and to return that sample to Earth in pristine condition for detailed laboratory analysis. Targeting the near-Earth asteroid Bennu, the mission launches in September 2016 with an Earth reentry date of September 24, 2023.OSIRIS-REx will thoroughly characterize asteroid Bennu providing knowledge of the nature of near-Earth asteroids that is fundamental to understanding planet formation and the origin of life. The return to Earth of pristine samples with known geologic context will enable precise analyses that cannot be duplicated by spacecraft-based instruments, revolutionizing our understanding of the early Solar System. Bennu is both the most accessible carbonaceous asteroid and one of the most potentially Earth-hazardous asteroids known. Study of Bennu addresses multiple NASA objectives to understand the origin of the Solar System and the origin of life and will provide a greater understanding of both the hazards and resources in near-Earth space, serving as a precursor to future human missions to asteroids.This paper focuses on the technical aspects of the Sample Return Capsule (SRC) design and concept of operations, including trajectory design and reentry retrieval. Highlights of the mission are included below.The OSIRIS-REx spacecraft provides the essential functions for an asteroid characterization and sample return mission: attitude control propulsion power thermal control telecommunications command and data handling structural support to ensure successful rendezvous with Bennu characterization of Bennus properties delivery of the sampler to the surface, and return of the spacecraft to the vicinity of the Earth sample collection, performed by the Touch-and-Go Sample Acquisition Mechanism (TAGSAM), to acquire a regolith sample from the surface Earth re-entry and SRC recovery. Following sample collection, OSIRIS-REx drifts away from Bennu until the Asteroid Departure Maneuver is commanded on March 4, 2021, sending OSIRIS-REx on a ballistic return cruise to Earth. No additional large deterministic maneuvers are required to return the SRC to Earth. During the cruise, tracking and trajectory correction maneuvers (TCMs) are performed as necessary to precisely target the entry corridor. As OSIRIS-REx approaches Earth, the reentry plans are reviewed starting about a year before arrival, and preparations begin. The spacecraft is targeted away from the Earth until 7 days before entry. The final two trajectory correction maneuvers bring the spacecraft on target toward the Utah Test and Training Range (UTTR), with sufficient time for contingency resolution. The SRC releases 4 hours prior to atmospheric entry interface and, using the Stardust capsule heritage design, employs a traditional drogue and main parachute descent system for a soft touchdown.

EXTREME AO OBSERVATIONS OF TWO TRIPLE ASTEROID SYSTEMS WITH SPHERE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, B.; Wahhaj, Z.; Dumas, C.

We present the discovery of a new satellite of asteroid (130) Elektra—S/2014 (130) 1—in differential imaging and in integral field spectroscopy data over multiple epochs obtained with Spectro-Polarimetric High-contrast Exoplanet Research/Very Large Telescope. This new (second) moonlet of Elektra is about 2 km across, on an eccentric orbit, and about 500 km away from the primary. For a comparative study, we also observed another triple asteroid system, (93) Minerva. For both systems, component-resolved reflectance spectra of the satellites and primary were obtained simultaneously. No significant spectral difference was observed between the satellites and the primary for either triple system. Wemore » find that the moonlets in both systems are more likely to have been created by sub-disruptive impacts as opposed to having been captured.« less

Scattering V-type asteroids during the giant planet instability: a step for Jupiter, a leap for basalt

NASA Astrophysics Data System (ADS)

Brasil, P. I. O.; Roig, F.; Nesvorný, D.; Carruba, V.

2017-06-01

V-type asteroids are a taxonomic class whose surface is associated with a basaltic composition. The only known source of V-type asteroids in the Main Asteroid Belt is (4) Vesta, which is located in the inner part of the Main Belt. However, many V-type asteroids cannot be dynamically linked to Vesta, in particular, those asteroids located in the middle and outer parts of the Main Belt. Previous works have failed to find mechanisms to transport V-type asteroids from the inner to the middle and outer belts. In this work, we propose a dynamical mechanism that could have acted on primordial asteroid families. We consider a model of the giant planet migration known as the jumping Jupiter model with five planets. Our study is focused on the period of 10 Myr that encompasses the instability phase of the giant planets. We show that, for different hypothetical Vesta-like paleo-families in the inner belt, the perturbations caused by the ice giant that is scattered into the asteroid belt before being ejected from the Solar system are able to scatter V-type asteroids to the middle and outer belts. Based on the orbital distribution of V-type candidates identified from the Sloan Digital Sky Survey and the VISTA Survey colours, we show that this mechanism is efficient enough provided that the hypothetical paleo-family originated from a 100 to 500 km crater excavated on the surface of (4) Vesta. This mechanism is able to explain the currently observed V-type asteroids in the middle and outer belts, with the exception of (1459) Magnya.

Discovery and dynamical characterization of the Amor-class asteroid 2012 XH16

NASA Astrophysics Data System (ADS)

Wlodarczyk, I.; Cernis, K.; Boyle, R. P.; Laugalys, V.

2014-03-01

The near-Earth asteroid belt is continuously replenished with material originally moving in Amor-class orbits. Here, the orbit of the dynamically interesting Amor-class asteroid 2012 XH16 is analysed. This asteroid was discovered with the Vatican Advanced Technology Telescope (VATT) at the Mt Graham International Observatory as part of an ongoing asteroid survey focused on astrometry and photometry. The orbit of the asteroid was computed using 66 observations (57 obtained with VATT and 9 from the Lunar and Planetary Laboratory-Spacewatch II project) to give a = 1.63 au, e = 0.36, i = 3.76°. The absolute magnitude of the asteroid is 22.3 which translates into a diameter in the range 104-231 m, assuming the average albedos of S-type and C-type asteroids, respectively. We have used the current orbit to study the future dynamical evolution of the asteroid under the perturbations of the planets and the Moon, relativistic effects, and the Yarkovsky force. Asteroid 2012 XH16 is locked close to the strong 1:2 mean motion resonance with the Earth. The object shows stable evolution and could survive in near-resonance for a relatively long period of time despite experiencing frequent close encounters with Mars. Moreover, results of our computations show that the asteroid 2012 XH16 can survive in the Amor region at most for about 200-400 Myr. The evolution is highly chaotic with a characteristic Lyapunov time of 245 yr. Jupiter is the main perturber but the effects of Saturn, Mars and the Earth-Moon system are also important. In particular, secular resonances with Saturn are significant.

Automated Design of Propellant-Optimal, End-to-End, Low-Thrust Trajectories for Trojan Asteroid Tours

NASA Technical Reports Server (NTRS)

Stuart, Jeffrey; Howell, Kathleen; Wilson, Roby

2013-01-01

The Sun-Jupiter Trojan asteroids are celestial bodies of great scientific interest as well as potential resources offering water and other mineral resources for longterm human exploration of the solar system. Previous investigations under this project have addressed the automated design of tours within the asteroid swarm. This investigation expands the current automation scheme by incorporating options for a complete trajectory design approach to the Trojan asteroids. Computational aspects of the design procedure are automated such that end-to-end trajectories are generated with a minimum of human interaction after key elements and constraints associated with a proposed mission concept are specified.

Hubble Witnesses an Asteroid Mysteriously Disintegrating

NASA Image and Video Library

2014-03-06

Though fragile comet nuclei have been seen falling apart as they near the Sun, nothing like the slow breakup of an asteroid has ever before been observed in the asteroid belt. A series of Hubble Space Telescope images shows that the fragments are drifting away from each other at a leisurely one mile per hour. This makes it unlikely that the asteroid is disintegrating because of a collision with another asteroid. A plausible explanation is that the asteroid is crumbling due to a subtle effect of sunlight. This causes the rotation rate to slowly increase until centrifugal force pulls the asteroid apart. The asteroid's remnant debris, weighing in at 200,000 tons, will in the future provide a rich source of meteoroids. Hubble Observation of P/2013 R3 - November 15, 2013 Credit: NASA, ESA, and D. Jewitt (University of California, Los Angeles) Read more: 1.usa.gov/1ig2E0x NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

DEEP-South: Preliminary Lightcurves of Potentially Hazardous Asteroids from the First Year Operation

NASA Astrophysics Data System (ADS)

Moon, Hong-Kyu; Kim, Myung-Jin; Choi, Young-Jun; Yim, Hong-Suh; Park, Jintae; Roh, Dong-Goo; Lee, Hee-Jae; Oh, Young-Seok; Bae, Young-Ho

2016-10-01

Deep Ecliptic Patrol of the Southern Sky (DEEP-South) observation is being made during the off-season for exoplanet search. It started in October 2015, using Korea Microlensing Telescope Network (KMTNet), a network of three identical telescopes with 1.6 m aperture equipped with 18K × 18K CCDs located in Chile (CTIO), South Africa (SAAO), and Australia (SSO). The combination of KMTNet's prime focus optics and the 340 million pixel CCD provides four square degree field of view with 0.4 arcsec/pixel plate scale.Most of the allocated time for DEEP-South is devoted to targeted photometry of PHAs and NEAs to increase the number of those objects with known physical properties. It is efficiently achieved by multiband, time series photometry. This Opposition Census (OC) mode targets objects near their opposition, with km-sized PHAs in early stage and goes down to sub-km objects. Continuous monitoring of the sky with KMTNEt is optimized for spin characterization of various kinds of asteroids, including binaries, slow/fast- and non-principal axis- rotators, and hence expected to facilitate the debiasing of previously reported lightcurve observations. We present the preliminary lightcurves of PHAs from year one of the DEEP-South Project.

The OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS): Spectral Maps of the Asteroid Bennu

NASA Astrophysics Data System (ADS)

Reuter, D. C.; Simon, A. A.; Hair, J.; Lunsford, A.; Manthripragada, S.; Bly, V.; Bos, B.; Brambora, C.; Caldwell, E.; Casto, G.; Dolch, Z.; Finneran, P.; Jennings, D.; Jhabvala, M.; Matson, E.; McLelland, M.; Roher, W.; Sullivan, T.; Weigle, E.; Wen, Y.; Wilson, D.; Lauretta, D. S.

2018-03-01

The OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) is a point spectrometer covering the spectral range of 0.4 to 4.3 microns (25,000-2300 cm-1). Its primary purpose is to map the surface composition of the asteroid Bennu, the target asteroid of the OSIRIS-REx asteroid sample return mission. The information it returns will help guide the selection of the sample site. It will also provide global context for the sample and high spatial resolution spectra that can be related to spatially unresolved terrestrial observations of asteroids. It is a compact, low-mass (17.8 kg), power efficient (8.8 W average), and robust instrument with the sensitivity needed to detect a 5% spectral absorption feature on a very dark surface (3% reflectance) in the inner solar system (0.89-1.35 AU). It, in combination with the other instruments on the OSIRIS-REx Mission, will provide an unprecedented view of an asteroid's surface.

Hydrated Minerals on Asteroids: The Astronomical Record

NASA Technical Reports Server (NTRS)

Rivkin, A. S.; Howell, E. S.; Vilas, F.; Lebofsky, L. A.

2003-01-01

Knowledge of the hydrated mineral inventory on the asteroids is important for deducing the origin of Earth's water, interpreting the meteorite record, and unraveling the processes occurring during the earliest times in solar system history. Reflectance spectroscopy shows absorption features in both the 0.6-0.8 and 2.5-3.5-micron regions, which are diagnostic of or associated with hydrated minerals. Observations in those regions show that hydrated minerals are common in the mid-asteroid belt, and can be found in unexpected spectral groupings as well. Asteroid groups formerly associated with mineralogies assumed to have high-temperature formation, such as M- and E-class steroids, have been observed to have hydration features in their reflectance spectra. Some asteroids have apparently been heated to several hundred degrees Celsius, enough to destroy some fraction of their phyllosilicates. Others have rotational variation suggesting that heating was uneven. We summarize this work, and present the astronomical evidence for water- and Hydroxl-bearing minerals on asteroids.

GPU-accelerated computational tool for studying the effectiveness of asteroid disruption techniques

NASA Astrophysics Data System (ADS)

Zimmerman, Ben J.; Wie, Bong

2016-10-01

This paper presents the development of a new Graphics Processing Unit (GPU) accelerated computational tool for asteroid disruption techniques. Numerical simulations are completed using the high-order spectral difference (SD) method. Due to the compact nature of the SD method, it is well suited for implementation with the GPU architecture, hence solutions are generated at orders of magnitude faster than the Central Processing Unit (CPU) counterpart. A multiphase model integrated with the SD method is introduced, and several asteroid disruption simulations are conducted, including kinetic-energy impactors, multi-kinetic energy impactor systems, and nuclear options. Results illustrate the benefits of using multi-kinetic energy impactor systems when compared to a single impactor system. In addition, the effectiveness of nuclear options is observed.

Meteoroid Impact Ejecta Detection by Nanosatellites for Asteroid Surface Characterization

NASA Astrophysics Data System (ADS)

Lee, N.; Close, S.; Goel, A.

2015-12-01

Asteroids are constantly bombarded by much smaller meteoroids at extremely high speeds, which results in erosion of the material on the asteroid surface. Some of this material is vaporized and ionized, forming a plasma that is ejected into the environment around the asteroid where it can be detected by a constellation of closely orbiting nanosatellites. We present a concept to leverage this natural phenomenon and to analyze this excavated material using low-power plasma sensors on nanosatellites in order to determine the composition of the asteroid surface. This concept would enable a constellation of nanosatellites to provide useful data complementing existing techniques such as spectroscopy, which require larger and more power-hungry sensors. Possible mission architectures include precursor exploratory missions using nanosatellites to survey and identify asteroid candidates worthy of further study by a large spacecraft, or simultaneous exploration by a nanosatellite constellation with a larger parent spacecraft to decrease the time required to cover the entire asteroid surface. The use of meteoroid impact plasma to analyze the surface composition of asteroids will not only produce measurements that have not been previously obtained, including the molecular composition of the surface, but will also yield a better measurement of the meteoroid flux in the vicinity of the asteroid. Current meteoroid models are poorly constrained beyond the orbit of Mars, due to scarcity of data. If this technology is used to survey asteroids in the main belt, it will offer a dramatic increase in the availability of meteoroid flux measurements in deep space, identifying previously unknown meteoroid streams and providing additional data to support models of solar system dust dynamics.

Samples from Differentiated Asteroids; Regolithic Achondrites

NASA Technical Reports Server (NTRS)

Herrin J. S.; Ross, A. J.; Cartwright, J. A.; Ross, D. K.; Zolensky, Michael E.; Jenniskens, P.

2011-01-01

Differentiated and partially differentiated asteroids preserve a glimpse of planet formation frozen in time from the early solar system and thus are attractive targets for future exploration. Samples of such asteroids arrive to Earth in the form of achondrite meteorites. Many achondrites, particularly those thought to be most representative of asteroidal regolith, contain a diverse assortment of materials both indigenous and exogenous to the original igneous parent body intermixed at microscopic scales. Remote sensing spacecraft and landers would have difficulty deciphering individual components at these spatial scales, potentially leading to confusing results. Sample return would thus be much more informative than a robotic probe. In this and a companion abstract [1] we consider two regolithic achondrite types, howardites and (polymict) ureilites, in order to evaluate what materials might occur in samples returned from surfaces of differentiated asteroids and what sampling strategies might be prudent.

The size distribution of the earth-approaching asteroids

NASA Technical Reports Server (NTRS)

Rabinowitz, D. L.

1993-01-01

The discovery circumstances of the first asteroids ever observed outside the earth's atmosphere but within the neighborhood of the earth-moon system are described. Four natural objects with diameters in the range 5-50 m were detected during a search for earth-approaching asteroids conducted each month at the 0.91-m Spacewatch Telescope at Kitt Peak. An additional 19 earth approachers with sizes in the range 50 m to 5 km were discovered. These obervations determine the cumulative flux of asteroids near earth as a function of absolute magnitude. For asteroids larger than about 100 m, a power-law dependence with exponent of about 0.9 is observed, consistent with their evolution from the main-belt population. At about 10 m, the flux is more than two orders of magnitude greater than this power-law extrapolation.

Near Earth Asteroids- Prospection, Orbit Modification and Mining

NASA Astrophysics Data System (ADS)

Grandl, W.; Bazso, A.

2014-04-01

The number of known Near Earth Asteroids (NEAs) has increased continuously during the last decades. Now we understand the role of asteroid impacts for the evolution of life on Earth. To ensure that mankind will survive in the long run, we have to face the "asteroid threat" seriously. On one hand we will have to develop methods of detection and deflection for Hazardous Asteroids, on the other hand we can use these methods to modify their orbits and exploit their resources. Rare-earth elements, rare metals like platinum group elements, etc. may be extracted more easily from NEAs than from terrestrial soil, without environmental pollution or political and social problems. In a first step NEAs, which are expected to contain resources like nickel-iron, platinum group metals or rare-earth elements, will be prospected by robotic probes. Then a number of asteroids with a minimum bulk density of 2 g/cm^3 and a diameter of 150 to 500 m will be selected for mining. Given the long duration of an individual mission time of 10-20 years, the authors propose a "pipeline" concept. While the observation of NEAs can be done in parallel, the precursor missions of the the next phase can be launched in short intervals, giving time for technical corrections and upgrades. In this way a continuous data flow is established and there are no idle times. For our purpose Potentially Hazardous Asteroids (PHAs) seem to be a favorable choice for the following reasons: They have frequent closeencounters to Earth, their minimum orbit intersection distance is less than 0.05 AU (Astronomic Units) and they have diameters exceeding 150 meters. The necessary velocity change (delta V) for a spaceship is below 12 km/s to reach the PHA. The authors propose to modify the orbits of the chosen PHAs by orbital maneuvers from solar orbits to stable Earth orbits beyond the Moon. To change the orbits of these celestial bodies it is necessary to develop advanced propulsion systems. They must be able to deliver high thrust and specific impulse to move the huge masses of the asteroids. Such a propulsion system could be the Bussard Fusion System, also known as the quiet-electricdischarge (QED) engine. It uses electrostatic fusion devices to generate electrical power. The fuel consists of Deuterium and Helium3 that are fusing to Helium4 plus protons releasing 18.3 MeV of energy per reaction. The charged protons escape from the confinement; their kinetic energy can be converted to electricity or be used directly as a plasma beam for generating thrust. For the reaction a specific energy of 3.5x1014 Joule/kg can be computed, i.e. orders-ofmagnitude higher than for any existing propulsion system. As an example we take the Asteroid with the designation 2008 EV5. It is classified as an Aten group asteroid with a mean diameter of 450 meters and belongs to spectral type S (stony asteroids). Our mass estimate (using a bulk density of 3 g/cm^3) is 1.4x1011 kg. To transfer 2008 EV5 to an Earth-like orbit the energy required is estimated to be in the order of 2.8x1018 Joule. This is the difference in Kepler energy between the NEA's current orbit and the Earth's orbit around the sun. Using the Bussard Fusion System the amount of fuel would be approx. 8000 kg of Helium3. To move an asteroid by remote control the authors propose to design unmanned space tugs which are propelled by Bussard Fusion Engines. A pair of space tugs is docked to each asteroid using drilling anchors. The fusion engines of the tugs then apply the thrust forces for the maneuvers. The first tug, which carries the main fuel quantity, applies the primary force for the orbital maneuvers. The second one adjust the flight track by short engine thrusts.

NASA's Hubble Sees Asteroid Spout Six Comet-like Tails

NASA Image and Video Library

2013-11-13

This NASA Hubble Space Telescope set of images reveals a never-before-seen set of six comet-like tails radiating from a body in the asteroid belt, designated P/2013 P5. The asteroid was discovered as an unusually fuzzy-looking object with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013. When Hubble returned to the asteroid on Sept. 23, the asteroid's appearance had totally changed. It looked as if the entire structure had swung around. One interpretation is that the asteroid's rotation rate has been increased to the point where dust is falling off the surface and escaping into space where the pressure of sunlight sweeps out fingerlike tails. According to this theory, the asteroid's spin has been accelerated by the gentle push of sunlight. The object, estimated to be no more than 1,400 feet across, has ejected dust for at least five months, based on analysis of the tail structure. These visible-light, false-color images were taken with Hubble's Wide Field Camera 3. Object Name: P/2013 P5 Image Type: Astronomical/Annotated Credit: NASA, ESA, and D. Jewitt (UCLA) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

NASA's Hubble Sees Asteroid Spout Six Comet-like Tails

NASA Image and Video Library

2013-11-13

P/2013 P5 on September 23, 2013. --- This NASA Hubble Space Telescope set of images reveals a never-before-seen set of six comet-like tails radiating from a body in the asteroid belt, designated P/2013 P5. The asteroid was discovered as an unusually fuzzy-looking object with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013. When Hubble returned to the asteroid on Sept. 23, the asteroid's appearance had totally changed. It looked as if the entire structure had swung around. One interpretation is that the asteroid's rotation rate has been increased to the point where dust is falling off the surface and escaping into space where the pressure of sunlight sweeps out fingerlike tails. According to this theory, the asteroid's spin has been accelerated by the gentle push of sunlight. The object, estimated to be no more than 1,400 feet across, has ejected dust for at least five months, based on analysis of the tail structure. These visible-light, false-color images were taken with Hubble's Wide Field Camera 3. Object Name: P/2013 P5 Image Type: Astronomical/Annotated Credit: NASA, ESA, and D. Jewitt (UCLA) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

NASA's Hubble Sees Asteroid Spout Six Comet-like Tails

NASA Image and Video Library

2013-11-13

P/2013 P5 on September 10, 2013. --- This NASA Hubble Space Telescope set of images reveals a never-before-seen set of six comet-like tails radiating from a body in the asteroid belt, designated P/2013 P5. The asteroid was discovered as an unusually fuzzy-looking object with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013. When Hubble returned to the asteroid on Sept. 23, the asteroid's appearance had totally changed. It looked as if the entire structure had swung around. One interpretation is that the asteroid's rotation rate has been increased to the point where dust is falling off the surface and escaping into space where the pressure of sunlight sweeps out fingerlike tails. According to this theory, the asteroid's spin has been accelerated by the gentle push of sunlight. The object, estimated to be no more than 1,400 feet across, has ejected dust for at least five months, based on analysis of the tail structure. These visible-light, false-color images were taken with Hubble's Wide Field Camera 3. Object Name: P/2013 P5 Image Type: Astronomical/Annotated Credit: NASA, ESA, and D. Jewitt (UCLA) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Design and validation of a GNC system for missions to asteroids: the AIM scenario

NASA Astrophysics Data System (ADS)

Pellacani, A.; Kicman, P.; Suatoni, M.; Casasco, M.; Gil, J.; Carnelli, I.

2017-12-01

Deep space missions, and in particular missions to asteroids, impose a certain level of autonomy that depends on the mission objectives. If the mission requires the spacecraft to perform close approaches to the target body (the extreme case being a landing scenario), the autonomy level must be increased to guarantee the fast and reactive response which is required in both nominal and contingency operations. The GNC system must be designed in accordance with the required level of autonomy. The GNC system designed and tested in the frame of ESA's Asteroid Impact Mission (AIM) system studies (Phase A/B1 and Consolidation Phase) is an example of an autonomous GNC system that meets the challenging objectives of AIM. The paper reports the design of such GNC system and its validation through a DDVV plan that includes Model-in-the-Loop and Hardware-in-the-Loop testing. Main focus is the translational navigation, which is able to provide online the relative state estimation with respect to the target body using exclusively cameras as relative navigation sensors. The relative navigation outputs are meant to be used for nominal spacecraft trajectory corrections as well as to estimate the collision risk with the asteroid and, if needed, to command the execution of a collision avoidance manoeuvre to guarantee spacecraft safety

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mainzer, A.; Masiero, J.; Bauer, J.

We have combined the NEOWISE and Sloan Digital Sky Survey data to study the albedos of 24,353 asteroids with candidate taxonomic classifications derived using Sloan photometry. We find a wide range of moderate to high albedos for candidate S-type asteroids that are analogous to the S complex defined by previous spectrophotometrically based taxonomic systems. The candidate C-type asteroids, while generally very dark, have a tail of higher albedos that overlaps the S types. The albedo distribution for asteroids with a photometrically derived Q classification is extremely similar to those of the S types. Asteroids with similar colors to (4) Vestamore » have higher albedos than the S types, and most have orbital elements similar to known Vesta family members. Finally, we show that the relative reflectance at 3.4 and 4.6 {mu}m is higher for D-type asteroids and suggest that their red visible and near-infrared spectral slope extends out to these wavelengths. Understanding the relationship between size, albedo, and taxonomic classification is complicated by the fact that the objects with classifications were selected from the visible/near-infrared Sloan Moving Object Catalog, which is biased against fainter asteroids, including those with lower albedos.« less

Spatial Mapping of NEO 2008 EV5 Using Small Satellite Formation Flying and Steresoscopic Technology

NASA Astrophysics Data System (ADS)

Gonzalez, Juan; Singh Derewa, Chrishma

2016-10-01

NASA is currently developing the first-ever robotic Asteroid Redirect Robotic Mission (ARRM) to the near-Earth asteroid 2008 EV5 with the objective to capture a multi-ton boulder from the asteroids surface and use its mass to redirect its parent into a CIS lunar orbit where astronauts will study its physical and chemical composition.A critical step towards achieving this mission is to effectively map the target asteroid, identify the candidate boulder for retrieval and characterize its critical parameters. Currently, ARRM utilizes a laser altimeter to characterize the height of the boulders and mapping for final autonomous control of the capture. The proposed Lava-Kusha mission provides the increased of stereoscopic imaging and mapping, not only the Earthward side of the asteroid which has been observed for possible landing sites, but mapping the whole asteroid. LKM will enhance the fidelity of the data collected by the laser altimeter and gather improved topographic data for future Orion missions to 2008 EV5 once in cis lunar space.LKM consists of two low cost small satellites (6U) as a part of the ARRM. They will launch with ARRM as an integrated part of the system. Once at the target, this formation of pathfinder satellites will image the mission critical boulder to ensure the system design can support its removal. LKM will conduct a series of flybys prior to ARRM's rendezvous. LKMs stereoscopic cameras will provide detailed surveys of the boulder's terrain and environment to ensure ARRM can operate safely, reach the location and interface with the boulder. The LKM attitude control and cold gas propulsion system will enable formation maintenance maneuvers for global mapping of asteroid 2008 EV5 at an altitude of 100 km to a high-spatial resolution imaging altitude of 5 km.LKM will demonstrate formation flying in deep space and the reliability of stereoscopic cameras to precisely identify a specific target and provide physical characterization of an asteroid. An assessment of the off-the-shelf technology used at JPL will be provided also with technology readiness descriptions, mission architecture, cost analysis and future work required to make the proposed LKM mission a partner to ARRM.

Asteroid Deflection Mission Design Considering On-Ground Risks

NASA Astrophysics Data System (ADS)

Rumpf, Clemens; Lewis, Hugh G.; Atkinson, Peter

The deflection of an Earth-threatening asteroid requires high transparency of the mission design process. The goal of such a mission is to move the projected point of impact over the face of Earth until the asteroid is on a miss trajectory. During the course of deflection operations, the projected point of impact will match regions that were less affected before alteration of the asteroid’s trajectory. These regions are at risk of sustaining considerable damage if the deflecting spacecraft becomes non-operational. The projected impact point would remain where the deflection mission put it at the time of mission failure. Hence, all regions that are potentially affected by the deflection campaign need to be informed about this risk and should be involved in the mission design process. A mission design compromise will have to be found that is acceptable to all affected parties (Schweickart, 2004). A software tool that assesses the on-ground risk due to deflection missions is under development. It will allow to study the accumulated on-ground risk along the path of the projected impact point. The tool will help determine a deflection mission design that minimizes the on-ground casualty and damage risk due to deflection operations. Currently, the tool is capable of simulating asteroid trajectories through the solar system and considers gravitational forces between solar system bodies. A virtual asteroid may be placed at an arbitrary point in the simulation for analysis and manipulation. Furthermore, the tool determines the asteroid’s point of impact and provides an estimate of the population at risk. Validation has been conducted against the solar system ephemeris catalogue HORIZONS by NASA’s Jet Propulsion Laboratory (JPL). Asteroids that are propagated over a period of 15 years show typical position discrepancies of 0.05 Earth radii relative to HORIZONS’ output. Ultimately, results from this research will aid in the identification of requirements for deflection missions that enable effective, minimum risk asteroid deflection. Schweickart, R. L. (2004). THE REAL DEFLECTION DILEMMA. In 2004 Planetary Defense Conference: Protecting Earth from Asteroids (pp. 1-6). Orange County, California. Retrieved from http://b612foundation.org/wp-content/uploads/2013/02/Real_Deflection_Dilemma.pdf

The Gaia Investigation of the Solar System

NASA Astrophysics Data System (ADS)

Delbo, Marco; Tanga, Paolo; Mignard, Francois; Cellino, Alberto; Hestroffer, Daniel

2015-08-01

The space mission Gaia of the European Space Agency (ESA) has begun its scientific whole-sky survey of all astrophysical sources with V<=20 in July 2014. The high precision astrometry is the main science driver for the mission, but Gaia will also obtain visible photometry and low-resolution spectroscopy of the observed sources, including solar system small bodies. Preliminary results show a good quality of the data, in general, in line with the expected pre-flight specifications. These data will consist a mine of information for a remote-sensing exploration of the small worlds of our Solar System. Indeed, ~250,000 asteroids will be observed by Gaia throughout its 5-years-long mission. After an update about the status of the mission and the on-going data analysis, including some preliminary results, we are going to present the plans for the data releases, the first foreseen at the end of 2016, and the general data treatment.We will show how Gaia spectroscopy will allow up to map the composition of about 100,000 asteroids throughout the Main Belt, with high signal to noise ratio. Given its advantage position outside the Earth's atmosphere, the blue part of the spectrum (roughly below 0.5 micron) will be observed for an unprecedented number of asteroids.Additionally, precise photometry and astrometry will also be important to reveal the physical nature of these small bodies. In particular, it is estimated that three-dimensional shapes, rotation, period and pole orientation will be derived for 10,000 asteroids. The masses of about 150 of the largest asteroids, will be determined from measurements of the orbital gravitational perturbations that these bodies will exert on small asteroids during mutual close approaches.Moreover, the combination of Gaia data (delivering masses and shapes) with infrared radiometric observations, e.g. from the NASA WISE mission (informing us about the size of the bodies), will allow precise asteroid bulk densities to be determined. The bulk density and the internal structure are among the most important characteristics of asteroids, that are currently some of the least constrained.

Compositional studies of primitive asteroids

NASA Technical Reports Server (NTRS)

Vilas, Faith

1991-01-01

The aqueous alteration history in the solar system are studied through acquiring additional CCD reflectance spectra in the blue-UV through near-IR spectral region and analyzing these spectra for information about iron oxides in phyllosilicates identified in the CM and CI carbonaceous chondrites. Emphasis is on the main-belt and Cybele primitive asteroids, as these asteroids show spectral diversity and are also spectral analogues for known meteorite samples. The porphyrin bands found in organics near 0.4 micron is also sought.

Characteristics and large bulk density of the C-type main-belt triple asteroid (93) Minerva

NASA Astrophysics Data System (ADS)

Marchis, F.; Vachier, F.; Ďurech, J.; Enriquez, J. E.; Harris, A. W.; Dalba, P. A.; Berthier, J.; Emery, J. P.; Bouy, H.; Melbourne, J.; Stockton, A.; Fassnacht, C. D.; Dupuy, T. J.; Strajnic, J.

2013-05-01

From a set of adaptive optics (AO) observations collected with the W.M. Keck telescope between August and September 2009, we derived the orbital parameters of the most recently discovered satellites of the large C-type asteroid (93) Minerva. The satellites of Minerva, which are approximately 3 and 4 km in diameter, orbit very close to the primary (˜5 and ˜8 × Rp and ˜1% and ˜2% × RHill) in a circular manner, sharing common characteristics with most of the triple asteroid systems in the main-belt. Combining these AO observations with lightcurve data collected since 1980 and two stellar occultations in 2010 and 2011, we removed the ambiguity of the pole solution of Minerva's primary and showed that it has an almost regular shape with an equivalent diameter Deq = 154 ± 6 km in agreement with IRAS observations. The surprisingly high bulk density of 1.75 ± 0.30 g/cm3 for this C-type asteroid, suggests that this taxonomic class is composed of asteroids with different compositions, For instance, Minerva could be made of the same material as dry CR, CO, and CV meteorites. We discuss possible scenarios on the origin of the system and conclude that future observations may shine light on the nature and composition of this fifth known triple main-belt asteroid.

Three dimensional modelling for the target asteroid of HAYABUSA

NASA Astrophysics Data System (ADS)

Demura, H.; Kobayashi, S.; Asada, N.; Hashimoto, T.; Saito, J.

Hayabusa program is the first sample return mission of Japan. This was launched at May 9 2003, and will arrive at the target asteroid 25143 Itokawa on June 2005. The spacecraft has three optical navigation cameras, which are two wide angle ones and a telescopic one. The telescope with a filter wheel was named AMICA (Asteroid Multiband Imaging CAmera). We are going to model a shape of the target asteroid by this telescope; expected resolution: 1m/pixel at 10 km in distanc, field of view: 5.7 squared degrees, MPP-type CCD with 1024 x 1000 pixels. Because size of the Hayabusa is about 1x1x1 m, our goal is shape modeling with about 1m in precision on the basis of a camera system with scanning by rotation of the asteroid. This image-based modeling requires sequential images via AMICA and a history of distance between the asteroid and Hayabusa provided by a Laser Range Finder. We established a system of hierarchically recursive search with sub-pixel matching of Ground Control Points, which are picked up with Susan Operator. The matched dataset is restored with a restriction of epipolar geometry, and the obtained a group of three dimensional points are converted to a polygon model with Delaunay Triangulation. The current status of our development for the shape modeling is displayed.

Incorporating Uncertainty into Spacecraft Mission and Trajectory Design

NASA Astrophysics Data System (ADS)

Juliana D., Feldhacker

The complex nature of many astrodynamic systems often leads to high computational costs or degraded accuracy in the analysis and design of spacecraft missions, and the incorporation of uncertainty into the trajectory optimization process often becomes intractable. This research applies mathematical modeling techniques to reduce computational cost and improve tractability for design, optimization, uncertainty quantication (UQ) and sensitivity analysis (SA) in astrodynamic systems and develops a method for trajectory optimization under uncertainty (OUU). This thesis demonstrates the use of surrogate regression models and polynomial chaos expansions for the purpose of design and UQ in the complex three-body system. Results are presented for the application of the models to the design of mid-eld rendezvous maneuvers for spacecraft in three-body orbits. The models are shown to provide high accuracy with no a priori knowledge on the sample size required for convergence. Additionally, a method is developed for the direct incorporation of system uncertainties into the design process for the purpose of OUU and robust design; these methods are also applied to the rendezvous problem. It is shown that the models can be used for constrained optimization with orders of magnitude fewer samples than is required for a Monte Carlo approach to the same problem. Finally, this research considers an application for which regression models are not well-suited, namely UQ for the kinetic de ection of potentially hazardous asteroids under the assumptions of real asteroid shape models and uncertainties in the impact trajectory and the surface material properties of the asteroid, which produce a non-smooth system response. An alternate set of models is presented that enables analytic computation of the uncertainties in the imparted momentum from impact. Use of these models for a survey of asteroids allows conclusions to be drawn on the eects of an asteroid's shape on the ability to successfully divert the asteroid via kinetic impactor.