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Sample records for earth-trailing heliocentric orbit

  1. Lifetimes of Small Bodies in Planetocentric (or Heliocentric) Orbits

    NASA Astrophysics Data System (ADS)

    Dobrovolskis, A. R.; Alvarellos, J. L.; Lissauer, J. J.

    2005-08-01

    Small bodies left over from the formation of the planets and satellites litter the Solar System, along with the debris from more recent collisions. These bodies are removed by expulsion from heliocentric or planetocentric orbit, as well as by collisions with planets, moons, and the Sun, with characteristic lifetimes depending on their orbits. However, the rate at which a given population of objects declines cannot be described by the simple exponential law used to describe radioactive decay. On the contrary, the removal of comets and remnant planetesimals has sometimes been described as ``logarithmic decay". Our work on the fate of ejecta from Hyperion (Dobrovolskis and Lissauer 2004, Icarus 169, 462-473) as well as our recent results from other satellites suggests instead that ejecta removal is best described by a ``stretched exponential" decay law, where the particle lifetimes increase as a fractional power of the elapsed time, suggestive of a diffusion process. Statistical analysis suports this conclusion, and enables us to determine the decay parameters. The results should be valuable in several contexts, including the delivery of meteorites to Earth and the bombardment history of the planets and their moons. NASA's PGG grant RTOP 344-30-50-01 supported this research.

  2. Lifetimes of Small Bodiesin Planetocentric (or Heliocentric) Orbits

    NASA Astrophysics Data System (ADS)

    Dobrovolskis, Anthony R.; Alvarellos, J. L.; Lissauer, J. J.

    2006-06-01

    Small bodies left over from the formation of the planets and satellites litter the Solar System, along with the debris from more recent collisions. These bodies are removed by expulsion from heliocentric or planetocentric orbit, as well as by collisions with planets, moons, and the Sun, with characteristic lifetimes depending on their orbits. However, the rate at which a given population of objects declines cannot be described by the simple exponential law used to describe radioactive decay. On the contrary, the removal of comets and remnant planetesimals has sometimes been described as "logarithmic decay''. Our work on the fate of ejecta from Hyperion (Dobrovolskis and Lissauer 2004, Icarus 169, 462--473), as well as recent results from other satellites, suggests instead that ejecta removal is best described by a "stretched exponential'' decay law, where the particle lifetimes increase as a fractional power of the elapsed time, suggestive of a diffusion process. Statistical analysis supports this conclusion, and enables us to determine the decay parameters. The results should be valuable in several contexts, including the delivery of meteorites to Earth and the bombardment history of the planets and their moons.

  3. Modeling atmospheric drag effect on Mangalyaan Mars orbiter during geocentric, heliocentric and areocentric trajectories

    NASA Astrophysics Data System (ADS)

    Nwankwo, Victor U. J.; Chakrabarti, Sandip Kumar

    2016-07-01

    Interplanetary missions are susceptible to gravitational and non-gravitational perturbing forces at every trajectory phase, assuming that the man made rockets and thrusters work as expected. These forces are mainly due to planetary and solar-forcing-induced perturbations during geocentric, heliocentric and Martian trajectories, and before orbit insertion. In this study, we analyzed perturbing forces and their possible effects on interplanetary and/or Mars mission satellites, before Orbit Insertion. We also model the significance of atmospheric drag force on Mangalyaan Mars orbiter mission, as a function of appropriate space environmental parameters during its 28 days in Earth's orbit (around and during perigee passage), 300 days of heliocentric and 100 days of Martian trajectory based on Earth-Mars atmosphere density ratio.

  4. Lessons Learned from Natural Space Debris in Heliocentric Orbit: An Analogue for Hazardous Debris in Earth Orbit

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Wei, Hanying; Connors, Martin; Lai, Hairong; Delzanno, Gian Luca

    Interplanetary Field Enhancements (IFEs) were discovered almost 30 years ago in the PVO magnetic-field records. Our current understanding is that IFEs result from interactions between solar wind and clouds of nanometer-scale charged dust released in interplanetary collisions. These charged dust clouds are then accelerated by the solar wind and moving away from the Sun at near solar wind speed and detected by spacecraft in heliocentric orbit. The dynamics of the debris in heliocentric orbit is analogous to that mankind has placed into Earth orbit. There are lessons here that are worth exploring. The IFE formation hypothesis was supported by the discovery of co-orbiting materials associated with asteroid 2201 Oljato: IFE rate peaked when Oljato was close and IFE occurrence clustered in the longitudes near which the orbit of Oljato intersects the orbital plane of Venus. A followed up study with Venus Express observations suggested that the co-orbiting materials dissipated in 30 years. An important aspect of this evolution is that at collisional speeds of 20 km/s, a small body can destroy one 106 times more massive. This destruction of large debris by small debris could also be important in the evolution of the terrestrial debris. At 1AU, based on ACE and Wind observations, IFEs have a significant cluster in the longitude range between 195° and 225°. Thus we use the same IFE technique to identify the ‘parent’ Near-Earth Objects of co-orbiting materials which should be responsible for those IFEs. There are more than 5000 JPL documented NEOs whose ecliptic plane crossings are near to or inside the Earth’s orbit and whose orbital periods are less than five years. By comparing their trajectories, we find that the asteroid 138175 is a good candidate for the ‘parent’ body. This asteroid orbits the Sun in a 5.24° inclined elliptical orbit with a period of 367.96 days. Its descending node is at about 206°, where the IFE occurrence rate peaks. We also find that

  5. Coupled Attitude-Orbit Dynamics and Control for an Electric Sail in a Heliocentric Transfer Mission

    PubMed Central

    Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

    2015-01-01

    The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail. PMID:25950179

  6. Coupled attitude-orbit dynamics and control for an electric sail in a heliocentric transfer mission.

    PubMed

    Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

    2015-01-01

    The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail.

  7. Secular influence of change in the heliocentric gravitation constant GM ⊙ on evolution of orbits of Meteor Streams

    NASA Astrophysics Data System (ADS)

    Li, Lin-Sen

    2016-06-01

    The Secular influence of the change in the heliocentric gravitational constant on the evolution of orbits of Meteor Streams is examined by using the method of celestial mechanics with variable mass and variable gravitational constant. The change in the heliocentric gravitational constant includes the combined changes in the sun's mass and gravitational constant obtained from the modern observation of planets and spacecraft. The perturbation equations are solved by expanding series with mean anomaly. The solutions of the secular and periodic variation of orbital elements are derived. The theoretical results for the secular variables of the semi-major axes, solar distances at perihelion and orbital periods are given for three Meteor Streams: Dracorids, Quadrantids, and Ursids. The numerical results are shown in Table 2. The discussion and conclusion are drawn.

  8. Probes to the inferior planets—A new dawn for NEO and IEO detection technology demonstration from heliocentric orbits interior to the earth's?

    NASA Astrophysics Data System (ADS)

    Grundmann, Jan Thimo; Mottola, Stefano; Drentschew, Maximilian; Drobczyk, Martin; Kahle, Ralph; Maiwald, Volker; Quantius, Dominik; Zabel, Paul; van Zoest, Tim

    2013-09-01

    Recent years have seen a renewed interest in exploration of the interior of the solar system. A number of missions are currently under way, in planning as well as in space, with the primary goal to expand our knowledge on the planets Mercury and Venus. Chemical propulsion missions to Mercury in particular require an extended cruise phase prior to arrival at their destination, usually involving multiple planetary fly-by manoeuvres and many revolutions in heliocentric orbit. The difficulties in discovering and tracking small objects interior to Earth's orbit, mainly due to unfavourable viewing geometry as well as atmospheric interference, have long been noted by the solar system science and planetary defence communities. Space probes in the interior of the solar system are in a position to observe objects near or interior to Earth's orbit in favourable opposition geometry. They are also usually free from planet-related interference, at least while in cruise, and often can be while in planetary eclipse. Dedicated search and survey missions to look for Near and Inner Earth Objects (NEO, IEO) from the vicinity of Earth or low Earth orbit are being planned. In this article, the ad-hoc available as well as near-term planned in-situ capabilities of the optical instrument payloads of space probes to Venus and Mercury are compiled from publications by the respective instrument teams. The small-object detection capabilities of cameras and spectrographs in opposition geometry are estimated by a common method, using data from comparable instruments to supplement missing information where necessary. The on-board cameras are classified according to their small-object detection potential in a technology demonstration of asteroid detection from a heliocentric orbit substantially interior to Earth's.

  9. Probes to the Inferior Planets - A New Dawn for NEO and IEO Detection Technology Demonstration from Heliocentric Orbits Interior to the Earth's?

    NASA Astrophysics Data System (ADS)

    Grundmann, J. T.; Mottola, S.; Drentschew, M.; Drobczyk, M.; Kahle, R.; Maiwald, V.; Quantius, D.; Zabel, P.; Van Zoest, T.

    2011-11-01

    With the launch of MESSENGER and VENUS EXPRESS, a new wave of exploration of the inner solar system has begun. Noting the growing number of probes to the inner solar system, it is proposed to connect the expertise of the respective spacecraft teams and the NEO and IEO survey community to best utilize the extended cruise phases and to provide additional data return in support of pure science as well as planetary defence. Several missions to Venus and Mercury are planned to follow in this decade. Increased interest in the inferior planets is accompanied by several missions designed to study the Sun and the interplanetary medium (IPM) from a position near or in Earth orbit, such as the STEREO probes and SDO. These augment established solar observation capabilities at the Sun-Earth L1 Lagrangian point such as the SOHO spacecraft. Thus, three distinct classes of spacecraft operate or observe interior to Earth's orbit. All these spacecraft carry powerful multispectral cameras optimized for their respective primary targets. MESSENGER is scheduled to end its six-year interplanetary cruise in March 2011 to enter Mercury orbit, but a similarly extended cruise with several gravity-assists awaits the European Mercury mission BEPICOLOMBO. Unfortunately, the automatic abort of the orbit insertion manoeuvre has also left AKATSUKI (a.k.a. Venus Climate Orbiter (VCO), Planet-C) stranded in heliocentric orbit. After an unintended fly-by, the probe will catch up with Venus in approximately six years. Meanwhile, it stays mostly interior to Venus in a planet-leading orbit. In addition to the study of comets and their interaction with the IPM, observations of small bodies akin to those carried out by outer solar system probes are occasionally attempted with the equipment available. The study of structures in the interplanetary dust (IPD) cloud has been a science objective during the cruise phase of the Japanese Venus probe AKATSUKI from Earth to Venus. IPD observations in the

  10. The Case for a Geocentric rather than Heliocentric Origin of the Late Stage Heavy Bombardment (LHB) of the Moon and Tidal Evolution of its Orbit

    NASA Astrophysics Data System (ADS)

    Davis, P. M.; Stacey, F. D.

    2009-12-01

    Melt breccia samples returned from the Apollo mission have dates that suggest that the impacts that formed major basins on the Moon occurred between 3.8 and 4.0 Ga i.e., about 0.6 G years after Lunar formation. Three models have been proposed to explain the LHB. Heliocentric models including (1) The period marked the end of large-scale impacts associated with planetary formation and (2) It corresponded to a spike in impacts associated with major reorientation of the solar system (the ‘Nice model’), when the orbits Jupiter and Saturn became resonant, causing the orbits of Uranus and Neptune to become unstable and grow, scattering cometary and asteroidal fragments into Earth-Moon crossing orbits, and a geocentric model (3) It was due to collision with the last of a series of moonlets formed during Earth accretion which were swept up by tidal regression of a large Moon that had been formed near the Earth by a giant impact. While there is no smoking gun for any of these scenarios we will discuss a possible scenario for (3). Numerical calculations show that tidal regression of a large inner Moon sequentially traps exterior smaller moonlets into 2:1 resonance. Resonant trapping rapidly increases the eccentricity of their orbits causing them to become Moon-crossing. If the orbital radii of the moonlets had a resonance or Bode's law-type distribution, for the last collision to take place at 0.6 Gy, the Moon would have been at ~40 RE when it took place. One of the implications is that the associated LHB impacts would have significantly less relative velocity than those derived from asteroidal or cometary distances associated with (1) or (2). This may explain the low content of vapor condensate in the Lunar breccias. The tidal evolution from ~40 RE at 0.6 Gy requires a lower tidal friction than at present, but this has been evident for many years from tidal rhythmite data.

  11. Heliocentric phasing performance of electric sail spacecraft

    NASA Astrophysics Data System (ADS)

    Mengali, Giovanni; Quarta, Alessandro A.; Aliasi, Generoso

    2016-10-01

    We investigate the heliocentric in-orbit repositioning problem of a spacecraft propelled by an Electric Solar Wind Sail. Given an initial circular parking orbit, we look for the heliocentric trajectory that minimizes the time required for the spacecraft to change its azimuthal position, along the initial orbit, of a (prescribed) phasing angle. The in-orbit repositioning problem can be solved using either a drift ahead or a drift behind maneuver and, in general, the flight times for the two cases are different for a given value of the phasing angle. However, there exists a critical azimuthal position, whose value is numerically found, which univocally establishes whether a drift ahead or behind trajectory is superior in terms of flight time it requires for the maneuver to be completed. We solve the optimization problem using an indirect approach for different values of both the spacecraft maximum propulsive acceleration and the phasing angle, and the solution is then specialized to a repositioning problem along the Earth's heliocentric orbit. Finally, we use the simulation results to obtain a first order estimate of the minimum flight times for a scientific mission towards triangular Lagrangian points of the Sun-[Earth+Moon] system.

  12. Orbital motions of astronomical bodies and their centre of mass from different reference frames: a conceptual step between the geocentric and heliocentric models

    NASA Astrophysics Data System (ADS)

    Guerra, André G. C.; Simeão Carvalho, Paulo

    2016-09-01

    The motion of astronomical bodies and the centre of mass of the system is not always well perceived by students. One of the struggles is the conceptual change of reference frame, which is the same that held back the acceptance of the Heliocentric model over the Geocentric one. To address the question, the notion of centre of mass, motion equations (and their numerical solution for a system of multiple bodies), and change of frame of reference is introduced. The discussion is done based on conceptual and real world examples, using the solar system. Consequently, through the use of simple ‘do it yourself’ methods and basic equations, students can debate complex motions, and have a wider and potentially effective understanding of physics.

  13. Kepler's winding Path to true Heliocentrism

    NASA Astrophysics Data System (ADS)

    Bialas, Volker

    The paper concerns the evolution of concepts by Johannes Kepler from Aristotelian conception of the Universe to Heliocentrism. Already as young Magister in Tubingen Kepler has taken an active part in Physical disputations of the candidates and has defended the doctrines of Copernik (1). In the Mysterium Cosmographicum he refers the planetary distances no longer to the center of the earth's orbit, but to the center of the true sun. But just by working out his Astronomia Nova Kepler succeeds in creating a strictly heliocentric astronomy as his handwriting Manuscripts give detailed information (2). Notes: 1) fragmentum orations de motu terrae. In Keppler Gesammelte werke Vol. 20.1, Munich 1988, p. 147-149 2) Commentaria in Theoriam Martis. Edition in: Kepler Gessamelete Werke Vol. 20.2 (in preparation)

  14. Simulations of the Solar Orbiter spacecraft interactions with the Solar wind at different heliocentric distances: effects on SWA-EAS measurements

    NASA Astrophysics Data System (ADS)

    Guillemant, S.; Genot, V. N.; Matéo Vélez, J.; Sarrailh, P.; Louarn, P.; Maksimovic, M.; Owen, C. J.; Hilgers, A. M.

    2013-12-01

    This presentation focuses on numerical simulations of the Solar Orbiter spacecraft/plasma interactions performed with the Spacecraft Plasma Interaction System (SPIS) software (http://dev.spis.org/projects/spine/home/spis/). This toolkit aims at modelling spacecraft-plasma interactions, based on an electrostatic 3-D unstructured particle-in-cell plasma model. New powerful SPIS functionalities were recently delivered within the extension of the software: SPIS-Science (ESA contract). This version revolutionizes spacecraft/plasma interactions as users are now able to model and configure plasma instrument such as Langmuir probes or particle detectors taking into account instrument characteristics like geometry, materials, energy ranges and resolution, output frequency, field of view ... In the validation context of SPIS-Science functionalities, a simulation campaign was carried out, including several cases of the ESA Solar Orbiter mission. The results presented here specifically focus on particle measurements through the modelling of the Solar Wind Analyzer - Electron Analyzer System instrument (SWA-EAS). Simulations of the spacecraft in different environments have been performed and extensively analysed. A detailed analysis will be presented concerning 1/ the satellite charging and, in particular, differential potentials on the dielectric surfaces of the Solar panels and the High Gain Antenna, which may severely affect low energy EAS measurements, 2/ the surrounding plasma behaviour : potential barriers for secondary and photoelectrons of about -5 V around the vehicle are indeed observed at the mission perihelion of 0.28 AU from the Sun and 3/ a quantification of biases on EAS measurements due to the combined effects of surface potentials, ion wake, and potential barriers. This work proposes a general framework to prepare the analysis of the future Solar Orbiter measurements.

  15. Solar Sail Optimal Orbit Transfers to Synchronous Orbits

    NASA Technical Reports Server (NTRS)

    Powers, Robert B.; Coverstone, Victoria; Prussing, John E.; Lunney, Bryan C. (Technical Monitor)

    1999-01-01

    A constant outward radial thrust acceleration can be used to reduce the radius of a circular orbit of specified period. Heliocentric circular orbits are designed to match the orbital period of Earth or Mars for various radial thrust accelerations and are defined as synchronous orbits. Minimum-time solar sail orbit transfers to these synchronous heliocentric orbits are presented.

  16. Comprehensive investigation of the dynamics of micron and submicron lunar ejecta in heliocentric space

    SciTech Connect

    Hargrave, A.D.

    1984-01-01

    The forces which act on micron and submicron dust particles in interplanetary space are studied in detail. Particular attention is given to Mie scattering theory as it applies to the calculation of the force due to radiation pressure. All of the forces are integrated into a computer model to study the heliocentric orbits of lunar ejecta. It is shown that lunar ejecta contribute to a geocentric dust cloud, as well as to a heliocentric dust belt.

  17. Ancient Greek Heliocentric Views Hidden from Prevailing Beliefs?

    NASA Astrophysics Data System (ADS)

    Liritzis, Ioannis; Coucouzeli, Alexandra

    2008-03-01

    We put forward the working hypothesis that the heliocentric, rather than the geocentric view, of the Solar System was the essential belief of the early Greek philosophers and astronomers. Although most of them referred to the geocentric view, it is plausible that the prevalent religious beliefs about the sacred character of the Earth as well as the fear of prosecution for impiety (asebeia) prevented them from expressing the heliocentric view, even though they were fully aware of it. Moreover, putting the geocentric view forward, instead, would have facilitated the reception of the surrounding world and the understanding of everyday celestial phenomena, much like the modern presentation of the celestial sphere and the zodiac, where the Earth is at the centre and the Sun makes an apparent orbit on the ecliptic. Such an ingenious stance would have set these early astronomers in harmony with the dominant religious beliefs and, at the same time, would have helped them to 'save the appearances', without sacrificing the essence of their ideas. In Hellenistic and Roman times, the prevailing view was still the geocentric one. The brilliant heliocentric theory advanced by Aristarchos in the early third century B.C. was never established, because it met with hostility in Athens - Aristarchos was accused of impiety and faced the death penalty. The textual evidence suggests that the tight connection which existed between religion and the city-state (polis) in ancient Greece, and which led to a series of impiety trials against philosophers in Athens during the fifth and fourth centuries B.C., would have made any contrary opinion expressed by the astronomers seem almost a high treason against the state.

  18. Analytical control laws of the heliocentric motion of the solar sail spacecraft

    NASA Astrophysics Data System (ADS)

    Gorbunova, Irina; Starinova, Olga

    2014-12-01

    The heliocentric motion of the solar sail spacecraft is described in classical Keplerian elements. The flat of solar sail with an ideal reflection coefficient is considered. The spacecraft performs a noncoplanar motion with the sun gravity and the light pressure. Disturbances of other celestial bodies gravity are not considered. We have received analytical terms for laws to control a solar sail, which ensure constancy or maximum rate of change of the Keplerian elements. To confirm the results correctness, we simulated the solar sail spacecraft. The spacecraft's initial orbit coincides with the average Earth orbit relative to the Sun. Authors developed a program complex to simulated the planar heliocentric movement and obtained results for motion simulation of flights to Mars and Venus. The results were compared with the simulation results obtained using the Pontryagin maximum principle.

  19. The Heliocentric Variation of the Properties of Interplanetary Field Enhancement

    NASA Astrophysics Data System (ADS)

    Lai, H.; Russell, C. T.; Wei, H.; Zhang, T.

    2013-05-01

    Interplanetary Field Enhancements (IFEs) are increases of the interplanetary magnetic field usually to a sharp maximum and containing a current sheet near the center of the event. They have been observed at Helios and MESSENGER as close as 0.3 AU to the Sun, at VEX and PVO at 0.72 AU; at STEREO, ACE, Wind, Geotail, ARTEMIS at 1 AU and Ulysses from 1 to 5 AU. Our model for the physical mechanism for creating these disturbances is that collisions of bodies in the size range 10 - 1000m are catastrophically disrupted by a collision with a fast moving smaller object. The rate of detection of IFEs is dependent on heliocentric range increasing closer to the Sun. There are several possible reasons for this increase which we explore. The mass of the dust cloud that is picked up is significant about 108kg. The magnetic gradient force of the IFE is large enough to lift this mass through the Sun's gravitational potential wall. The momentum transfer that enables this outward transport is a small fraction of the solar wind momentum flux but this transfer can be detected using superposed epoch studies of the solar wind, and is consistent with the hypothesis. We note that the rate of IFE observations in the Helios and MESSENGER data at 0.3 AU is less than expected from extrapolating the observations at and beyond 0.7 AU. This result can soon be extended closer to the Sun with Solar Orbiter and Solar Probe Plus.

  20. Heliocentric zoning of the asteroid belt by aluminum-26 heating

    NASA Technical Reports Server (NTRS)

    Grimm, R. E.; Mcsween, H. Y., Jr.

    1993-01-01

    Variations in petrology among meteorites attest to a strong heating event early in solar system history, but the heat source has remained unresolved. Aluminum-26 has been considered the most likely high-energy, short-lived radionuclide (half-life 0.72 million years) since the discovery of its decay product - excess Mg-26 - in Allende CAI's. Furthermore, observation of relict Mg-26 in an achondritic clast and in feldspars within ordinary chondrites (3,4) provided strong evidence for live Al-26 in meteorite parent bodies and not just in refractory nebular condensates. The inferred amount of Al-26 is consistent with constraints on the thermal evolution of both ordinary and carbonaceous chondrite parent objects up to a few hundred kilometers in diameter. Meteorites can constrain the early thermal evolution of their parent body locations, provided that a link can be established between asteroid spectrophotometric signature and meteorite class. Asteroid compositions are heliocentrically distributed: objects thought to have experienced high metamorphic or even melting temperatures are located closer to the sun, whereas apparently unaltered or mildly heated asteroids are located farther away. Heliocentric zoning could be the result of Al-26 heating if the initial amount of the radionuclide incorporated into planetesimals was controlled by accretion time, which in turn varies with semimajor axis. Analytic expressions for planetary accretion may be integrated to given the time, tau, required for a planetesimal to grow to a specified radius: tau varies as a(sup n), where n = 1.5 to 3 depending on the assumptions about variations in the surface density of the planetesimal swarm. Numerical simulations of planetesimal accretion at fixed semimajor axis demonstrate that variations in accretion time among small planetesimals can be strongly nonlinear depending on the initial conditions and model assumptions. The general relationship with semimajor axis remains valid because it

  1. Proof-of-Concept Trajectory Designs for a Multi-Spacecraft, Low-Thrust Heliocentric Solar Weather Buoy Mission

    NASA Technical Reports Server (NTRS)

    Muller, Ronald; Franz, Heather; Roberts, Craig; Folta, Dave

    2005-01-01

    A new solar weather mission has been proposed, involving a dozen or more small spacecraft spaced at regular, constant intervals in a mutual heliocentric circular orbit between the orbits of Earth and Venus. These solar weather buoys (SWBs) would carry instrumentation to detect and measure the material in solar flares, solar energetic particle events, and coronal mass ejections as they flowed past the buoys, serving both as science probes and as a radiation early warning system for the Earth and interplanetary travelers to Mars. The baseline concept involves placing a mothercraft carrying the SWBs into a staging orbit at the Sun-Earth L1 libration point. The mothercraft departs the L1 orbit at the proper time to execute a trailing-edge lunar flyby near New Moon, injecting it into a heliocentric orbit with its perihelion interior to Earth s orbit. An alternative approach would involve the use of a Double Lunar Swingby (DLS) orbit, rather than the L1 orbit, for staging prior to this flyby. After injection into heliocentric orbit, the mothercraft releases the SWBs-all equipped with low-thrust pulsed plasma thrusters (PPTs)-whereupon each SWB executes a multi-day low-thrust finite bum around perihelion, lowering aphelion such that each achieves an elliptical phasing orbit of different orbital period from its companions. The resulting differences in angular rates of motion cause the spacecraft to separate. While the lead SWB achieves the mission orbit following an insertion burn at its second perihelion passage, the remaining SWBs must complete several revolutions in their respective phasing orbits to establish them in the mission orbit with the desired longitudinal spacing. The complete configuration for a 14 SWB scenario using a single mothercraft is achieved in about 8 years, and the spacing remains stable for at least a further 6 years. Flight operations can be simplified, and mission risk reduced, by employing two mothercraft instead of one. In this scenario: the

  2. Microlensing Parallax for Observers in Heliocentric Motion

    NASA Astrophysics Data System (ADS)

    Calchi Novati, S.; Scarpetta, G.

    2016-06-01

    Motivated by the ongoing Spitzer observational campaign, and the forthcoming K2 one, we revisit, working in an heliocentric reference frame, the geometrical foundation for the analysis of the microlensing parallax, as measured with the simultaneous observation of the same microlensing event from two observers with relative distance of order au. For the case of observers at rest, we discuss the well-known fourfold microlensing parallax degeneracy and determine an equation for the degenerate directions of the lens trajectory. For the case of observers in motion, we write down an extension of the Gould relationship between the microlensing parallax and the observable quantities and, at the same time, highlight the functional dependence of these same quantities from the timescale of the underlying microlensing event. Furthermore, through a series of examples, we show the importance of taking into account themotion of the observers to correctly recover the parameters of the underlying microlensing event. In particular, we discuss the cases of the amplitude of the microlensing parallax and that of the difference of the timescales between the observed microlensing events, which are key to understand the breaking of the microlensing parallax degeneracy. Finally, we consider the case of the simultaneous observation of the same microlensing event from the ground and two satellites, a case relevant for the expected joint K2 and Spitzer observational programs in 2016.

  3. Orbital

    NASA Astrophysics Data System (ADS)

    Hanson, Robert M.

    2003-06-01

    ORBITAL requires the following software, which is available for free download from the Internet: Netscape Navigator, version 4.75 or higher, or Microsoft Internet Explorer, version 5.0 or higher; Chime Plug-in, version compatible with your OS and browser (available from MDL).

  4. Variations of Chondrite Properties with Heliocentric Distance

    NASA Astrophysics Data System (ADS)

    Rubin, A. E.; Wasson, J. T.

    1995-09-01

    There are 12 well-established chondrite groups distinguishable by significant compositional hiatus among their compositional and petrographic characteristics. Because each group represents a different parent asteroid, formed in a distinct nebular region (and/or at a particular time), it is plausible that chondrite properties varied in a smooth fashion with heliocentric distance (HD). Oxidation state. Thermodynamic calculations indicate that the equilibrium FeO/(FeO+MgO) ratio increases with decreasing nebular temperature. Because the nebular temperature gradient decreased with HD, at all times inner nebular regions had a lower oxidation state than more distant regions. If the time of agglomeration increased with HD, outer-solar-system materials generally would have acquired more ferroan compositions. By these criteria we infer that enstatite chondrites formed closer to the Sun, OC at intermediate HD, and R chondrites and carbonaceous chondrites still farther from the Sun. Oxygen isotopic composition. The nearer the Sun, the higher the nebular temperature and the larger the fraction of infalling interstellar material that evaporated; this resulted in greater equilibration with nebular gas and greater isotopic homogeneity. Because the Earth, Moon and EH-EL chondrites lie on the terrestrial fractionation (TF) line on the standard three O-isotope diagram, and martian meteorites (Delta^(17)O=0.36 per mil) and eucrites (Delta^(17)O=-0.40 per mil) lie close to this line, we infer that the mean nebular (i.e., solar) O-isotopic composition was on or near the TF line. At >1 AU the absolute value of Delta^(17)O increased. We infer that EH and EL chondrites formed at a HD <1 AU; H, L and LL chondrites (mean Delta^(17)O = 0.73, 1.07 and 1.26 per mil) formed appreciably beyond Mars' distance of 1.5 AU (probably near 2.5 AU at the 3:1 Jupiter-period resonance); R chondrites (Delta^(17)O ~2.9 per mil) and CR, CM, CO, CV and CK chondrites (Delta^(17)O ~ -1.6, -2.3, -4.5, -3.4 and

  5. A Review of Cometary Outbursts at Large Heliocentric Distances

    NASA Astrophysics Data System (ADS)

    Gronkowski, P.; Wesołowski, M.

    2016-11-01

    The outbursts of comets, sudden large increases in their luminosity, are still very interesting and mysterious signs of activity of this celestial bodies. Most of the cometary outbursts are taking place at heliocentric distances where sublimation of water ice plays an important role in the activity of comets. However, the phenomenon is also observed far away from the Sun (i.e. ≃5-20 au) where the sublimation of water ice is negligible and the activity of comets is dominated by more volatile chemicals. Not only typical comets show `cometary-like' activity but also Centaurs. In addition to the long-term changes in brightness related to heliocentric distances and short-periodic variations connected with the rotation of the nucleus, they also exhibit a random variations in luminosity which are similar to the cometary outbursts. Paper presents an overview of the most likely hypotheses and models which try to explain this phenomenon.

  6. CCD-photometry of comets at large heliocentric distances

    NASA Technical Reports Server (NTRS)

    Mueller, Beatrice E. A.

    1992-01-01

    CCD imaging and time series photometry are used to determine the state of activity, nuclear properties and eventually the rotational motion of cometary nuclei. Cometary activity at large heliocentric distances and mantle evolution are not yet fully understood. Results of observations carried out at the 2.1 telescope on Kitt Peak April 10-12 and May 15-16, 1991 are discussed. Color values and color-color diagrams are presented for several comets and asteroids. Estimations of nuclear radii and shapes are given.

  7. Modeling the Dynamics of Comet Hale-Bopp's Dust at Large Heliocentric Distances

    NASA Astrophysics Data System (ADS)

    Kramer, Emily A.; Fernandez, Y. R.; Kelley, M. S.; Woodney, L. M.; Lisse, C. M.

    2010-10-01

    Comet Hale-Bopp has provided an unprecedented opportunity to observe a bright comet over a wide range of heliocentric distances. We present here Spitzer Space Telescope observations of Hale-Bopp from 2005 and 2008 that show a distinct coma and tail, which is uncommon given its heliocentric distance -- 21.6 AU and 27.2 AU, respectively. These 24 um images (obtained with MIPS, the Multiband Imaging Photometer for Spitzer) show thermal emission from the dust, and are being studied using dynamical models [1, 2] to explain the dust morphology and constrain the dust's properties. Preliminary work suggests that the motion of the dust cannot be solely due to the effects of gravity and radiation pressure. We investigate the role of other possible driving forces, including the so-called rocket force [3]. Our initial analysis also shows that: (1) there is no trail lying along the orbit plane, as Spitzer saw for many other comets [4]; (2) the position angle of the tail changed by about 50º between 2005 and 2008; (3) the faintness and shape of the tail in 2008 compared to 2005 cannot solely be due to the change in observing geometry. These points suggest that even though Hale-Bopp is far from the Sun its tail is made of relatively recently-released grains. Our science goals are to understand the comet's activity mechanism, constrain the age of the dust, find the size of the grains, and compare properties of the dust seen now to those of the dust seen in the 1990s. We acknowledge support from the NSF, NASA and the Spitzer Science Center for this work. References: [1] Kelley, M.S., et al.  2008, Icarus 193, 572, [2] Lisse, C.M., et al. 1998, ApJ 496, 971, [3] Reach, W.T., et al. 2009, Icarus 203, 571, [4] Reach, W.T., et al. 2007, Icarus 191, 298.

  8. Heliocentric distance dependence of the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Behannon, K. W.

    1977-01-01

    Recent and ongoing planetary missions have provided extensive observations of the variations of the Interplanetary Magnetic Field (IMF) both in time and with heliocentric distance from the sun. Large time variations in both the IMF and its fluctuations were observed. These are produced predominantly by dynamical processes in the interplanetary medium associated with stream interactions. Magnetic field variations near the sun are propagated to greater heliocentric distances, also contributing to the observed variablity of the IMF. Temporal variations on a time-scale comparable to or less than the corotation period complicate attempts to deduce radial gradients of the field and its fluctuations from the various observations. However, recent measurements inward to 0.46 AU and outward to 5 AU suggest that the radial component of the field on average decreases approximately as r to the minus second power, while the azimuthal component decreases more rapidly than the r to the minum first power dependence predicted by simple theory. This, and other observations, are discussed.

  9. The Structure of the Solar Wind at Large Heliocentric Distances: CIRs and their Successors

    NASA Technical Reports Server (NTRS)

    Gazis, P. R.

    1997-01-01

    Co-rotating interaction regions (CIRs) and their associated shock pairs are dominant structures in the solar wind between the heliocentric distances of 2 and 8 AU. At larger heliocentric distances, these structures undergo a qualitative change. Shocks decay to a point where they are often difficult to detect, and may have little influence on the dynamics of the solar wind. Interaction regions spread and merge, though they appear to retain their identity to surprisingly large distances from the Sun. Solar wind and IMF data from the Pioneer 10, Pioneer 11, and Voyager 2 spacecraft were used to conduct a comprehensive survey of CIRs and their successors between heliocentric distances of 1 and 55 AU over the last two solar cycles. The structure of the solar wind varied in a consistent fashion with heliocentric distance. Similar structures were observed at similar heliocentric distances by all three spacecraft during different portions of the solar cycle.

  10. The Structure of the Solar Wind at Large Heliocentric Distances: CIRs and their Successors

    NASA Technical Reports Server (NTRS)

    Gazis, P. R.

    1999-01-01

    Co-rotating interaction regions (CIRs) and their associated shock pairs are dominant structures in the solar wind between the heliocentric distances of 2 and 8 AU. At larger heliocentric distances, these structures undergo a qualitative change. Shocks decay to a point where they are often difficult to detect, and may have little influence on the dynamics of the solar wind. Interaction regions spread and merge, though they appear to retain their identity to surprisingly large distances from the Sun. Solar wind and IMF data from the Pioneer 10, Pioneer 11, and Voyager 2 spacecraft were used to conduct a comprehensive survey of CIRs and their successors between heliocentric distances of 1 and 55 AU over the last two solar cycles. The structure of the solar wind varied in a consistent fashion with heliocentric distance. Similar structures were observed at similar heliocentric distances by all three spacecraft during different portions of the solar cycle.

  11. Heliocentric trajectory analysis of Sun-pointing smart dust with electrochromic control

    NASA Astrophysics Data System (ADS)

    Mengali, Giovanni; Quarta, Alessandro A.

    2016-02-01

    A smart dust is a micro spacecraft, with a characteristic side length on the order of a few millimeters, whose surface is coated with electrochromic material. Its orbital dynamics is controlled by exploiting the differential force due to the solar radiation pressure, which is obtained by modulating the reflectivity coefficient of the electrochromic material within a range of admissible values. A significant thrust level can be reached due to the high values of area-to-mass ratio of such a spacecraft configuration. Assuming that the smart dust is designed to achieve a passive Sun-pointing attitude, the propulsive acceleration due to the solar radiation pressure lies along the Sun-spacecraft direction. The aim of this paper is to study the smart dust heliocentric dynamics in order to find a closed form, analytical solution of its trajectory when the reflectivity coefficient of the electrochromic material can assume two values only. The problem is addressed by introducing a suitable transformation that regularizes the spacecraft motion and translates the smart-dust dynamics into that of a linear harmonic oscillator with unitary frequency, whose forcing input is a boxcar function. The solution is found using the Laplace transform method, and afterwards the problem is generalized by accounting for the degradation of the electrochromic material due to its exposition to the solar radiation. Three spacecraft configurations, corresponding to low, medium and high performance smart dusts, are finally used to quantify the potentialities of these advanced devices in an interplanetary mission scenario.

  12. Pioneer 10 observation of the solar wind proton temperature heliocentric gradient

    NASA Technical Reports Server (NTRS)

    Mihalov, J. D.; Wolfe, J. H.

    1978-01-01

    Solar wind isotropic proton temperatures as measured out to 12.2 AU heliocentric distance by the Ames plasma analyzer aboard Pioneer 10 are presented as consecutive averages over three Carrington solar rotations and discussed. The weighted least-squares fit of average temperature to heliocentric radial distance, R, yields the power law R sup -.52. These average proton temperatures are not correlated as well with Pioneer 10's heliocentric radial distance (-.85) as are the corresponding average Zurich sunspot numbers R sub z (-.95). Consequently, it is difficult to isolate the spatial gradient in the Pioneer 10 solar wind proton temperatures using that data alone.

  13. The heliocentric system from the Orphic Hymns and the Pythagoreans to emperor Julian

    NASA Astrophysics Data System (ADS)

    Theodossiou, Efstratios; Dacanalis, Aris; Dimitrijević, Milan, S.; Mantarakis, Petros

    The evolution of the heliocentric theory in the antiquity has been analyzed, from the first seeds in the Orphic Hymns to the emperor Julian, also called "the Apostate" in the 4th century A.D. In particular the Orphic Hymns, views of Pythagoreans, as well as the heliocentric ideas of Philolaus of Croton, Icetas, Ecphantus, Heraclides of Pontos, Anaximander, Seleucus of Seleucia, Aristarchus of Samos and Emperor Julian were analyzed.

  14. An analytical description of three-dimensional heliocentric solar sail orbits

    NASA Astrophysics Data System (ADS)

    Stewart, Brian; Palmer, Phil; Roberts, Mark

    2016-12-01

    When gravitational aggregates are spun to fission they can undergo complex dynamical evolution, including escape and reconfiguration. Previous work has shown that a simple analysis of the full 2-body problem provides physically relevant insights for whether a fissioned system can lead to escape of the components and the creation of asteroid pairs. In this paper we extend the analysis to the full 3-body problem, utilizing recent advances in the understanding of fission mechanics of these systems. Specifically, we find that the full 3-body problem can eject a body with as much as 0.31 of the total system mass, significantly larger than the 0.17 mass limit previously calculated for the full 2-body problem. This paper derives rigorous limits on a fissioned 3-body system with regards to whether fissioned system components can physically escape from each other and what other stable relative equilibria they could settle in. We explore this question with a narrow focus on the Spherical Full Three Body Problem studied in detail earlier.

  15. No evidence for a decrease of nuclear decay rates with increasing heliocentric distance based on radiochronology of meteorites

    NASA Astrophysics Data System (ADS)

    Meier, Matthias M. M.; Wieler, Rainer

    2014-03-01

    It has been argued that the decay rates of several radioactive nuclides are slightly lower at Earth's aphelion than at perihelion, and that this effect might depend on heliocentric distance. It might then be expected that nuclear decay rates be considerably lower at larger distances from the sun, e.g., in the asteroid belt at 2-3 AU from where most meteorites originate. If so, ages of meteorites obtained by analyses of radioactive nuclides and their stable daughter isotopes might be in error, since these ages are based on decay rates determined on Earth. Here we evaluate whether the large data base on nuclear cosmochronology offers any hint for discrepancies which might be due to radially variable decay rates. Chlorine-36 (t1/2 = 301,000 a) is produced in meteorites by interactions with cosmic rays and is the nuclide for which a decay rate dependence from heliocentric distance has been proposed, which, in principle, can be tested with our approach and the current data base. We show that compilations of 36Cl concentrations measured in meteorites offer no support for a spatially variable 36Cl decay rate. For very short-lived cosmic-ray produced radionuclides (half-lives < 10-100 days), the concentration should be different for meteorites hitting the Earth on the incoming vs. outgoing part of their orbit. However, the current data base of very short-lived radionuclides in freshly fallen meteorites is far from sufficient to deduce solid constraints. Constraints on the age of the Earth and the oldest meteorite phases obtained by the U-Pb dating technique give no hints for radially variable decay rates of the α-decaying nuclides 235U or 238U. Similarly, some of the oldest phases in meteorites have U-Pb ages whose differences agree almost perfectly with respective age differences obtained with "short-lived" radionuclides present in the early solar system, again indicating no variability of uranium decay rates in different meteorite parent bodies in the asteroid belt

  16. New estimate of the micrometeoroids flux at the heliocentric distance of Mercury

    NASA Astrophysics Data System (ADS)

    Borin, Patrizia; Cremonese, Gabriele; Marzari, Francesco

    This work shows preliminary results of a study of the orbital evolution of dust particles originating from the Main Belt in order to obtain a statistical analysis, then to provide an estimate of the flux of particles hitting the Mercury's surface. Meteoritic flux on Mercury really depends on the particle size, because meteoroids of different size follow different dynamical evolution. In this work we consider meteoritic sizes smaller than 1 cm that are particles with a dynamical evolution dominated by the Poynting-Robertson effect. The meteoroid impact mechanism seems to be an important source of neutral atoms contributing to the exosphere and, according to recent papers, mostly due to particles smaller than 1 cm. Unfortunately the dynamical studies and statistics of meteoroids smaller than 1 cm are based on quite old papers and always extrapolated from calculations made for the Earth. This is the reason why we are working on a dynamical model following small dust particles that may hit the surface of Mercury. Up to now we have taken into account only particles coming from the Main Belt. The main effects that determine the distribution of dust in the Solar System are the gravitational attractions of the Sun and planets, Poynting-Robertson drag, solar radiation pressure, solar wind pressure and the effects of different magnetic fields. In order to determine the meteoritic flux at the heliocentric distance of Mercury we utilize the dynamical evolution model of dust particles of Marzari and Vanzani (1994) that numerically solves a (N+1)+M body problem (Sun + N planets + M body with zero mass) with the high-precision integrator RA15 (Everhart 1985). The solar radiation pressure and Poynting-Robertson drag, together with the gravitational interactions of the planets, are taken as major perturbing forces affecting the orbital evolution of the dust particles. We have performed numerical simulations with different initial conditions for the dust particles, depending on the

  17. Ludwik Antoni Birkenmajer and Curtis Wilson on the Origin of Nicholas Copernicus's Heliocentrism.

    PubMed

    Goddu, André

    2016-06-01

    What moved Copernicus to switch from the time-honored geocentric to a heliocentric setup for the planetary system? He himself did not explain this momentous move in any detail--his only comments about it suggest that Ptolemy's complete solution to the problem of nonuniform motion, the equant model, led him to propose. Earth's annual motion around the Sun. The most widely accepted accounts of the origin of Copernicus's theory dismiss or dispute any direct relation between the principle of uniform motion and the heliocentric theory. Two scholars, the Polish expert on Copernicus Ludwik Antoni Birkenmajer (1855-1929) and the American historian of astronomy Curtis Wilson (1921-2012), constructed detailed arguments about how Copernicus's rejection of Ptolemy's solution led him to his theory. The principal aim of this essay is to reintroduce Birkenmajer's and Wilson's voices to the discussion of the origin of Copernicus's heliocentrism.

  18. On the Distribution of Quiet-Sun Magnetic Fields at Different Heliocentric Angles

    NASA Astrophysics Data System (ADS)

    Orozco Suárez, D.; Katsukawa, Y.

    2012-02-01

    This paper presents results from the analysis of high signal-to-noise ratio spectropolarimetric data taken at four heliocentric angles in quiet-Sun internetwork regions with the Hinode satellite. First, we find that the total circular and total linear polarization signals vary with heliocentric angle, at least for fields with large polarization signals. We also report changes on the Stokes V amplitude asymmetry histograms with viewing angle for fields weaker than 200 G. Then, we subject the data to a Milne-Eddington inversion and analyze the variation of the field vector probability density functions with heliocentric angle. Weak, highly inclined fields permeate the internetwork at all heliocentric distances. For fields weaker than 200 G, the distributions of field inclinations peak at 90° and do not vary with viewing angle. The inclination distributions change for fields stronger than 200 G. We argue that the shape of the inclination distribution for weak fields partly results from the presence of coherent, loop-like magnetic features at all heliocentric distances and not from tangled fields within the field of view. We also find that the average magnetic field strength is about 180 G (for 75% of the pixels) and is constant with heliocentric angle. The average vertical and horizontal magnetic field components are 70 and 150 G. The latter (former) is slightly greater (smaller) near the limb. Finally, the ratio between the horizontal and vertical components of the fields ranges from ~1 for strong fields to ~3.5 for weak fields, suggesting that the magnetic field vector is not isotropically distributed within the field of view.

  19. From Pythagoreans to Kepler: the dispute between the geocentric and the heliocentric systems

    NASA Astrophysics Data System (ADS)

    Theodossiou, E.; Danezis, E.; Manimanis, V. N.; Kalyva, E.-M.

    2002-06-01

    Some ancient Greek philosophers and thinkers questioned the geocentric system and proposed instead a heliocentric system. The main proponents of this view - which was seen as heretical at the time - are believed to have been the Pythagoreans Philolaos, Heraclides, Hicetas, and Ecphantos, but mainly Aristarchos of Samos, who placed the Sun in the position of the "central fire" of the Pythagoreans. The geocentric system, reworked by Claudius Ptolemaeus (Ptolemy), was the dominant one for centuries, and it was only during the sixteenth century that the Polish monk-astronomer, Copernicus, revisited the ancient Greek heliocentric views and became the new champion of the theory that we all accept today.

  20. Heliocentric distance and temporal dependence of the interplanetary density-magnetic field magnitude correlation

    NASA Technical Reports Server (NTRS)

    Roberts, D. A.

    1990-01-01

    The Helios, IMP 8, ISEE 3, ad Voyager 2 spacecraft are used to examine the solar cycle and heliocentric distance dependence of the correlation between density n and magnetic field magnitude B in the solar wind. Previous work had suggested that this correlation becomes progressively more negative with heliocentric distance out to 9.5 AU. Here it is shown that this evolution is not a solar cycle effect, and that the correlations become even more strongly negative at heliocentric distance larger than 9.5 AU. There is considerable variability in the distributions of the correlations at a given heliocentric distance, but this is not simply related to the solar cycle. Examination of the evolution of correlations between density and speed suggest that most of the structures responsible for evolution in the anticorrelation between n and B are not slow-mode waves, but rather pressure balance structures. The latter consist of both coherent structures such as tangential discontinuities and the more generally pervasive 'pseudosound' which may include the coherent structures as a subset.

  1. The trend of production rates with heliocentric distance for comet P/Halley

    NASA Astrophysics Data System (ADS)

    Fink, U.

    1994-03-01

    Comet P/Halley was observed spectroscopically in the wavelength range 5200-10,400 A during 10 observing runs, roughly a month apart from 1985 August 28 to 1986 June 6. The observations span a heliocentric distance from 0.73 to 2.52 AU. This data set is analyzed to determine the course of the production rate with heliocentric distance for C2, NH2, CN, and the continuum. The effect of changing the Haser scale lengths and their heliocentric distance dependence is examined. The production rate ratios to water change only in a minor way, but the absolute values of the production rates are more severely affected. Fluorescent efficiencies, or g-factors for the CN red system are calculated, and band intensity ratios for NH2 and CN are presented. Using presently available fluorescence efficiencies and Haser scale lengths, mixing ratios for the parents of C2, CN, and NH2 with respect to water are: 0.34 +/- 0.07%, 0.15 +/- 0.04%, and 0.13 +/- 0.05%. It is found that these mixing ratios are essentially constant over the heliocentric distance range of the observations, implying a rather uniform nucleus and uniform outgassing characteristics, although there are indications of smaller scale day-to-day variations. The results provide strong observational confirmation that water evaporation controls the activity of the comet over the distance range studied. Continuum values Af rho are determined, and their ratios to QH2O are found to have a clear dependence with heliocentric distance approximately r-1.0 with a post-perihelion enhancement. No correlation of the production rate ratios with light curve of P/Halley were found, nor was there any correlation of the C2 or CN production with the dust.

  2. MESSENGER's special delivery: Comets 2P/Encke and C/2012 S1 (ISON) at small heliocentric distances

    NASA Astrophysics Data System (ADS)

    Fernandez, Yanga R.; Vervack, Ronald J., Jr.; Knight, Matthew M.; McCandliss, Stephan R.; Dello Russo, Neil; Feldman, Paul D.; Lisse, Casey M.; Tamblyn, Peter

    2016-10-01

    Observations of comets when they are close to the Sun can potentially reveal interesting aspects of their behavior thanks to the rapid change of both seasons on the nucleus and the local insolation environment. However this is typically the most difficult time to make observations from Earth because the solar elongation is small, so studies of comets that are near the Sun generally require special facilities. In autumn 2013, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft observed comets 2P/Encke and C/2012 S1 (ISON) from its orbital perch around Mercury when both comets were poorly located for most Earth-based telescopes. The observations included visible-wavelength, multi-filter imaging as well as ultraviolet spectroscopy. Both comets were observed down to about 0.3 AU from the Sun; in Encke's case it was followed through perihelion, which has rarely been done before. The data provide us with a look at the behavior of the dust and gas (e.g., OH, CO, OI, CI, SI, HI) production rates over several weeks, and we can investigate how the rates change with time, rotational phase, and heliocentric distance. In this poster we will present preliminary analyses of the time-series photometry and spectroscopy of these MESSENGER-observed comets, and place their behaviors into context.

  3. On the Provability of Heliocentrism. II. Leon Foucault and the Rotation of the Earth

    NASA Astrophysics Data System (ADS)

    Sterken, Christiaan

    2007-10-01

    This paper deals with the experimental provability of heliocentrism from the scientific Renaissance in the beginning of the 17th century, till the Industrial Revolution of the 1850s. Foucault's famous pendulum demonstration is documented. We underline the importance of high accuracy of observations, the interdependence of hypotheses and theories, the impact of technological breakthroughs, the role of serendipity, the importance of fast and accurate publishing, and the need for precise science communication and teaching.

  4. Orbital stability zones about asteroids. II - The destabilizing effects of eccentric orbits and of solar radiation

    NASA Astrophysics Data System (ADS)

    Hamilton, Douglas P.; Burns, Joseph A.

    1992-03-01

    Recently, Hamilton and Burns (1991) characterized the size and shape of a stability zone around an asteroid on a circular heliocentric orbit within which asteroid material could remain bound for an extended period of time. The present paper considers two additional effects: the asteroid's nonzero heliocentric eccentricity and solar radiation pressure. Results of numerical analyses show that, for an asteroid on an eccentric orbit, the stability zone scales roughly as the size of the Hill sphere calculated at the asteroid's pericenter. It was also found that solar radiation pressure is a very efficient mechanism for removing small (on the order of 0.1 mm) particles from circular asteroidal zone. Particles larger than a few centimeters are only slightly affected by radiation pressure. The results are applied to the Gaspra 951 asteroid.

  5. CONSTRAINING THE DUST COMA PROPERTIES OF COMET C/SIDING SPRING (2013 A1) AT LARGE HELIOCENTRIC DISTANCES

    SciTech Connect

    Li, Jian-Yang; Samarasinha, Nalin H.; Kelley, Michael S. P.; Farnham, Tony L.; A'Hearn, Michael F.; Mutchler, Max J.; Lisse, Carey M.; Delamere, W. Alan E-mail: nalin@psi.edu E-mail: farnham@astro.umd.edu E-mail: mutchler@stsci.edu E-mail: alan@delamere.biz

    2014-12-10

    The close encounter of comet C/2013 A1 (Siding Spring) with Mars on 2014 October 19 presented an extremely rare opportunity to obtain the first flyby quality data of the nucleus and inner coma of a dynamically new comet. However, the comet's dust tail potentially posed an impact hazard to those spacecraft orbiting Mars. To characterize the comet at large heliocentric distances, study its long-term evolution, and provide critical inputs to hazard modeling, we imaged C/Siding Spring with the Hubble Space Telescope when the comet was at 4.58, 3.77, and 3.28 AU from the Sun. The dust production rate, parameterized by the quantity Afρ, was 2500, 2100, and 1700 cm (5000 km radius aperture) for the three epochs, respectively. The color of the dust coma is (5.0 ± 0.3)%/100 nm for the first two epochs, and (9.0 ± 0.3)%/100 nm for the last epoch, and reddens with increasing cometocentric distance out to ∼3000 km from the nucleus. The spatial distribution and the temporal evolution of the dust color are most consistent with the existence of icy grains in the coma. Two jet-like dust features appear in the northwest and south-southeast directions projected in the sky plane. Within each epoch of 1-2 hr, no temporal variations were observed for either feature, but the position angle of the south-southeastern feature varied between the three epochs by ∼30°. The dust feature morphology suggests two possible orientations for the rotational pole of the nucleus, (R.A., decl.) = (295° ± 5°, +43° ± 2°) and (190° ± 10°, +50° ± 5°), or their diametrically opposite orientations.

  6. Sublimation rates of carbon monoxide and carbon dioxide from comets at large heliocentric distances

    NASA Technical Reports Server (NTRS)

    Sekanina, Zdenek

    1992-01-01

    Using a simple model for outgassing from a small flat surface area, the sublimation rates of carbon monoxide and carbon dioxide, two species more volatile than water ice that are known to be present in comets, are calculated for a suddenly activated discrete source on the rotating nucleus. The instantaneous sublimation rate depends upon the comet's heliocentric distance and the Sun's zenith angle at the location of the source. The values are derived for the constants of CO and CO2 in an expression that yields the local rotation-averaged sublimation rate as a function of the comet's spin parameters and the source's cometocentric latitude.

  7. Possible Periodic Orbit Control Maneuvers for an eLISA Mission

    NASA Technical Reports Server (NTRS)

    Bender, Peter L.; Welter, Gary L.

    2012-01-01

    This paper investigates the possible application of periodic orbit control maneuvers for so-called evolved-LISA (eLISA) missions, i.e., missions for which the constellation arm lengths and mean distance from the Earth are substantially reduced. We find that for missions with arm lengths of 106 km and Earth-trailing distance ranging from approx. 12deg to 20deg over the science lifetime, the occasional use of the spacecraft micro-Newton thrusters for constellation configuration maintenance should be able to essentially eliminate constellation distortion caused by Earth-induced tidal forces at a cost to science time of only a few percent. With interior angle variation kept to approx. +/-0:1deg, the required changes in the angles between the laser beam pointing directions for the two arms from any spacecraft could be kept quite small. This would considerably simplify the apparatus necessary for changing the transmitted beam directions.

  8. Orbit Determination and Navigation of the Solar Terrestrial Relations Observatory (STEREO)

    NASA Technical Reports Server (NTRS)

    Mesarch, Michael; Robertson, Mika; Ottenstein, Neil; Nicholson, Ann; Nicholson, Mark; Ward, Douglas T.; Cosgrove, Jennifer; German, Darla; Hendry, Stephen; Shaw, James

    2007-01-01

    This paper provides an overview of the required upgrades necessary for navigation of NASA's twin heliocentric science missions, Solar TErestrial RElations Observatory (STEREO) Ahead and Behind. The orbit determination of the STEREO spacecraft was provided by the NASA Goddard Space Flight Center's (GSFC) Flight Dynamics Facility (FDF) in support of the mission operations activities performed by the Johns Hopkins University Applied Physics Laboratory (APL). The changes to FDF s orbit determination software included modeling upgrades as well as modifications required to process the Deep Space Network X-band tracking data used for STEREO. Orbit results as well as comparisons to independently computed solutions are also included. The successful orbit determination support aided in maneuvering the STEREO spacecraft, launched on October 26, 2006 (00:52 Z), to target the lunar gravity assists required to place the spacecraft into their final heliocentric drift-away orbits where they are providing stereo imaging of the Sun.

  9. Orbit Determination and Navigation of the Solar Terrestrial Relations Observatory (STEREO)

    NASA Technical Reports Server (NTRS)

    Mesarch, Michael A.; Robertson, Mika; Ottenstein, Neil; Nicholson, Ann; Nicholson, Mark; Ward, Douglas T.; Cosgrove, Jennifer; German, Darla; Hendry, Stephen; Shaw, James

    2007-01-01

    This paper provides an overview of the required upgrades necessary for navigation of NASA's twin heliocentric science missions, Solar TErestrial RElations Observatory (STEREO) Ahead and Behind. The orbit determination of the STEREO spacecraft was provided by the NASA Goddard Space Flight Center's (GSFC) Flight Dynamics Facility (FDF) in support of the mission operations activities performed by the Johns Hopkins University Applied Physics Laboratory (APL). The changes to FDF's orbit determination software included modeling upgrades as well as modifications required to process the Deep Space Network X-band tracking data used for STEREO. Orbit results as well as comparisons to independently computed solutions are also included. The successful orbit determination support aided in maneuvering the STEREO spacecraft, launched on October 26, 2006 (00:52 Z), to target the lunar gravity assists required to place the spacecraft into their final heliocentric drift-away orbits where they are providing stereo imaging of the Sun.

  10. The heliocentric evolution of cometary infrared spectra - Results from an organic grain model

    NASA Technical Reports Server (NTRS)

    Chyba, Christopher F.; Sagan, Carl; Mumma, Michael J.

    1989-01-01

    An emission feature peaking near 3.4 microns that is typical of C-H stretching in hydrocarbons and which fits a simple, two-component thermal emission model for dust in the cometary coma, has been noted in observations of Comets Halley and Wilson. A noteworthy consequence of this modeling is that, at about 1 AU, emission features at wavelengths longer than 3.4 microns come to be 'diluted' by continuum emission. A quantitative development of the model shows it to agree with observational data for Comet Halley for certain, plausible values of the optical constants; the observed heliocentric evolution of the 3.4-micron feature thereby furnishes information on the composition of the comet's organic grains.

  11. Video Orbits of the Geminids

    NASA Astrophysics Data System (ADS)

    Hajdukova, M.

    2014-07-01

    Geminid meteoroids, observed by the video technique, were analysed with the aim of determining the actual dispersion of their reciprocal semimajor axes 1/a within the stream. Orbits were selected from the European Video Meteor Network Database, EDMOND, (Kornos et al., 2013), from the SonotaCo Shower Catalogue (SonotaCo, 2009), and from the Czech Catalogue of Video Meteor Orbits (Koten et al., 2003). The observed orbital dispersion, including the measurement errors, was compared with that obtained from the precisely-reduced photographic orbits of Geminids from the IAU Meteor Data Center (Lindblad et al., 2003). In this paper, we concentrate on the influence of errors on the orbital dispersion. The size and distribution of observational errors determined from the long-period meteoroid streams (Hajdukova 2013), were applied to determine the real dispersion within this short-period meteoroid stream. The observed dispersions, described by the median absolute deviation in terms of 1/a, range from 0.041 to 0.050 1/au. The deviation of the median reciprocal semimajor axis from the parent (3200) Phaethon, obtained from Japanese video orbits, is 0.009 1/au, and that from the EDMOND data 0.01 1/au. This deviation obtained from the photographic orbits of the IAU Meteor Data Center was significantly greater (Hajdukova 2009). Similar results were obtained from the Czech Video Orbits Catalogue, where the value is 0.05 1/au. The investigation showed that semimajor axes of meteor orbits in both the SonotaCo and EDMOND datasets are systematically biased as a consequence of the method used for the video orbit determination, probably because corrections for atmospheric deceleration were either incorrectly made or were not done at all. Thus, the determined heliocentric velocities are underestimated, and the semimajor axes medians shifted towards smaller values. The observed distributions in 1/a from these video data become biased towards higher values of 1/a. The orbits of the Geminid

  12. Telemetry coding study for the international magnetosphere explorers, mother/daughter and heliocentric missions. Volume 2: Final report

    NASA Technical Reports Server (NTRS)

    Cartier, D. E.

    1973-01-01

    A convolutional coding theory is given for the IME and the Heliocentric spacecraft. The amount of coding gain needed by the mission is determined. Recommendations are given for an encoder/decoder system to provide the gain along with an evaluation of the impact of the system on the space network in terms of costs and complexity.

  13. A Synoptic Analysis of the Change from the Geocentric to the Heliocentric Conception of the Solar System.

    ERIC Educational Resources Information Center

    Wilson, Roosevelt L.

    The changes which occurred in man's view of the solar system from the time of Ptolemy to that of Galileo are presented. Contained is a brief review of the chain of events which resulted in the acceptance of a heliocentric system. Ptolomy's theory is described and a diagram illustrates the paths of the epicycle of Mars according to his geocentric…

  14. Reconstruction of the 1801 Discovery Orbit of Ceres via Contemporary Angles-Only Algorithms

    NASA Astrophysics Data System (ADS)

    Mansfield, R.; Der, G.

    2016-09-01

    This paper employs contemporary angles-only methods of initial orbit determination (IOD) and differential correction (DC) to revisit how Gauss solved for the orbit of Ceres using observations taken more than two centuries ago. The solutions obtained with these angles-only algorithms are verified by accurate numerically-integrated ephemerides and published U.S. Naval Observatory (USNO) values. These angles-only IOD and DC algorithms are fully applicable to today's space situational awareness for both geocentric and heliocentric objects.

  15. Kepler Stars with Multiple Transiting Planet Candidates

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2012-01-01

    NASA's Kepler spacecraft was launched into an Earth-trailing heliocentric orbit in March of 2009. Kepler is designed to conduct a statistical census of planetary system properties using transit photometry. Among the most exciting early results from Kepler are target stars found to have photometric signatures that suggest the presence of more than one transiting planet. Individual transiting planets provide information on the size and orbital period distributions of exoplanets. Multiple transiting planets provide additional information on the spacing and flatness distributions of planetary systems. Results to d ate and plans for future analysis will be presented.

  16. Orbital cellulitis

    MedlinePlus

    ... hemolytic streptococci may also cause orbital cellulitis. Orbital cellulitis infections in children may get worse very quickly and ... in the space around the eye. An orbital cellulitis infection can get worse very quickly. A person with ...

  17. The Orbital Design of Alpha Centauri Exoplanet Satellite (ACESat)

    NASA Technical Reports Server (NTRS)

    Weston, Sasha; Belikov, Rus; Bendek, Eduardo

    2015-01-01

    Exoplanet candidates discovered by Kepler are too distant for biomarkers to be detected with foreseeable technology. Alpha Centauri has high separation from other stars and is of close proximity to Earth, which makes the binary star system 'low hanging fruit' for scientists. Alpha Centauri Exoplanet Satellite (ACESat) is a mission proposed to Small Explorer Program (SMEX) that will use a coronagraph to search for an orbiting planet around one of the stars of Alpha Centauri. The trajectory design for this mission is presented here where three different trajectories are considered: Low Earth Orbit (LEO), Geosynchronous Orbit (GEO) and a Heliocentric Orbit. Uninterrupted stare time to Alpha Centauri is desirable for meeting science requirements, or an orbit that provides 90% stare time to the science target. The instrument thermal stability also has stringent requirements for proper function, influencing trajectory design.

  18. Heliocentric Potential (HCP) Prediction Model for Nowscast of Aviation Radiation Dose

    NASA Astrophysics Data System (ADS)

    Hwang, Junga; Kim, Kyung-Chan; Dokgo, Kyunghwan; Choi, Enjin; Kim, Hang-Pyo

    2015-03-01

    It is well known that the space radiation dose over the polar route should be carefully considered especially when the space weather shows sudden disturbances such as CME and flares. The National Meteorological Satellite Center (NMSC) and Korea Astronomy and Space Science Institute (KASI) recently established a basis for a space radiation service for the public by developing a space radiation prediction model and heliocentric potential (HCP) prediction model. The HCP value is used as a critical input value of the CARI-6 and CARI-6M programs, which estimate the aviation route dose. The CARI-6/6M is the most widely used and confidential program that is officially provided by the U.S. Federal Aviation Administration (FAA). The HCP value is given one month late in the FAA official webpage, making it difficult to obtain real-time information on the aviation route dose. In order to overcome this limitation regarding time delay, we developed a HCP prediction model based on the sunspot number variation. In this paper, we focus on the purpose and process of our HCP prediction model development. Finally, we find the highest correlation coefficient of 0.9 between the monthly sunspot number and the HCP value with an eight month time shift.

  19. Contingency Trajectory Design for a Lunar Orbit Insertion Maneuver Failure by the Lunar Atmosphere Dust Environment Explorer (LADEE) Spacecraft

    NASA Technical Reports Server (NTRS)

    Genova, Anthony L.; Loucks, Michael; Carrico, John

    2014-01-01

    The purpose of this extended abstract is to present results from a failed lunar-orbit insertion (LOI) maneuver contingency analysis for the Lunar Atmosphere Dust Environment Explorer (LADEE) mission, managed and operated by NASA Ames Research Center in Moffett Field, CA. The LADEE spacecrafts nominal trajectory implemented multiple sub-lunar phasing orbits centered at Earth before eventually reaching the Moon (Fig. 1) where a critical LOI maneuver was to be performed [1,2,3]. If this LOI was missed, the LADEE spacecraft would be on an Earth-escape trajectory, bound for heliocentric space. Although a partial mission recovery is possible from a heliocentric orbit (to be discussed in the full paper), it was found that an escape-prevention maneuver could be performed several days after a hypothetical LOI-miss, allowing a return to the desired science orbit around the Moon without leaving the Earths sphere-of-influence (SOI).

  20. Data catalog series for space science and applications flight missions. Volume 1A: Brief descriptions of planetary and heliocentric spacecraft and investigations

    NASA Technical Reports Server (NTRS)

    Cameron, W. S. (Editor); Vostreys, R. W. (Editor)

    1982-01-01

    Planetary and heliocentric spacecraft, including planetary flybys and probes, are described. Imaging, particles and fields, ultraviolet, infrared, radio science and celestial mechanics, atmospheres, surface chemistry, biology, and polarization are discussed.

  1. Improving the Accuracy of a Heliocentric Potential (HCP) Prediction Model for the Aviation Radiation Dose

    NASA Astrophysics Data System (ADS)

    Hwang, Junga; Yoon, Kyoung-Won; Jo, Gyeongbok; Noh, Sung-Jun

    2016-12-01

    The space radiation dose over air routes including polar routes should be carefully considered, especially when space weather shows sudden disturbances such as coronal mass ejections (CMEs), flares, and accompanying solar energetic particle events. We recently established a heliocentric potential (HCP) prediction model for real-time operation of the CARI-6 and CARI-6M programs. Specifically, the HCP value is used as a critical input value in the CARI-6/6M programs, which estimate the aviation route dose based on the effective dose rate. The CARI-6/6M approach is the most widely used technique, and the programs can be obtained from the U.S. Federal Aviation Administration (FAA). However, HCP values are given at a one month delay on the FAA official webpage, which makes it difficult to obtain real-time information on the aviation route dose. In order to overcome this critical limitation regarding the time delay for space weather customers, we developed a HCP prediction model based on sunspot number variations (Hwang et al. 2015). In this paper, we focus on improvements to our HCP prediction model and update it with neutron monitoring data. We found that the most accurate method to derive the HCP value involves (1) real-time daily sunspot assessments, (2) predictions of the daily HCP by our prediction algorithm, and (3) calculations of the resultant daily effective dose rate. Additionally, we also derived the HCP prediction algorithm in this paper by using ground neutron counts. With the compensation stemming from the use of ground neutron count data, the newly developed HCP prediction model was improved.

  2. Extrasolar Planetary Imaging Coronagraph (EPIC)

    NASA Technical Reports Server (NTRS)

    Clampin, Mark

    2009-01-01

    EPIC is a NASA mission being studied to detect and characterize Jovian and superEarth planets, and, the dust/debris disks surrounding the parent star. It will be launched into a heliocentric Earth trailing orbit and operate for 5 years. EPIC would operate over the wavelength range of 480 - 960 nm with spectral resolutions of R < 50 and employs a visible nulling coronagraph (VNC) to suppress the starlight, yielding contrast ratios of greater than 9 orders of magnitude. We will discuss the science mission, and its role in the search for habitable planets.

  3. Kepler's Orbit

    NASA Video Gallery

    Kepler does not orbit the Earth, rather it orbits the Sun in concert with the Earth, slowly drifting away from Earth. Every 61 Earth years, Kepler and Earth will pass by each other. Throughout the ...

  4. The spectral behavior of P/Halley at large heliocentric distance in light of the Giotto/Vega results

    NASA Technical Reports Server (NTRS)

    Belton, M. J. S.; Spinrad, H.; Wehinger, P. A.; Wyckoff, S.; Yeomans, D. K.

    1987-01-01

    This paper presents the results of the preperihelion spectroscopic observations of the P/Halley comet, conducted with the Mayall 4 m telescope/CRYOCAM combination on Kitt Peak when the comet was between 8.8 and 5.6 AU from the sun. The V magnitudes and the (g - r) and (V - R) color indices, derived from the five spectra obtained between October 10, 1983, and February 4, 1984, showed a trend to increasing redness with decreasing heliocentric distance. However, the (V - R) color of the comet while near 8 AU was anomalous in that it was significantly bluer than the sun. Tentative interpretation of this phenomenon is presented.

  5. Spitzer Space Telescope in-orbit checkout and science verification operations

    NASA Technical Reports Server (NTRS)

    Linick, Sue H.; Miles, John W.; Gilbert, John B.; Boyles, Carol A.

    2004-01-01

    Spitzer Space Telescope, the fourth and final of NASA's great observatories, and the first mission in NASA's Origins Program was launched 25 August 2003 into an Earth-trailing solar orbit. The observatory was designed to probe and explore the universe in the infrared. Before science data could be acquired, however, the observatory had to be initialized, characterized, calibrated, and commissioned. A two phased operations approach was defined to complete this work. These phases were identified as In-Orbit Checkout (IOC) and Science Verification (SV). Because the observatory lifetime is cryogen-limited these operations had to be highly efficient. The IOC/SV operations design accommodated a pre-defined distributed organizational structure and a complex, cryogenic flight system. Many checkout activities were inter-dependent, and therefore the operations concept and ground data system had to provide the flexibility required for a 'short turn-around' environment. This paper describes the adaptive operations system design and evolution, implementation, and lessons-learned from the completion of IOC/SV.

  6. Antarctic polar plateau vertical electric field variations across heliocentric current sheet crossings

    NASA Astrophysics Data System (ADS)

    Burns, G. B.; Tinsley, B. A.; Klekociuk, A. R.; Troshichev, O. A.; Frank-Kamenetsky, A. V.; Duldig, M. L.; Bering, E. A.; Clem, J. M.

    2006-03-01

    A superposed epoch analysis of variations of the vertical electric field measured at Vostok (78.5°S, 107°E; magnetic latitude 83.6°S) during 1998 2002 heliocentric current sheet (HCS) crossings yields no significant variation other than an association imposed by polar-cap potential differences above the site. This result contradicts published reports of a reduction ˜15% in electric field 1 3 days after HCS crossings, an observation initially made ˜30 years ago. If such a reduction had been caused by reductions in stratospheric ionising radiation, the presence of polar stratospheric clouds (PSC) would seem necessary for the occurrence of this effect. PSCs would increase the resistance of the stratosphere thus making ionisation in that region significant in the context of the ionosphere ground current flow, in a manner analogous to the role of volcanic aerosols in the stratosphere in the explanation of the weakening of northern hemisphere winter cyclones associated with HCS crossings, the so-called ‘Wilcox effect’. However, separating the present data to correspond to the likely presence of PSC above Vostok also does not yield the reported reduction. Significant increases or decreases of the vertical electric field emerge from the observations when the HCS crossings are separated into sets depending on whether the solar wind magnetic field changes from ‘toward-to-away’ (increase of ˜11%) and ‘away-to-toward’ (decrease of ˜8%). Polar-cap potential changes above the site, inferred from solar wind parameters using the Weimer model, also show such step functions that reverse with the sign of HCS transition and are broadly consistent with the measured electric field increases or decreases. Remaining differences between the measurements and the model are consistent with a somewhat stronger solar wind speed and/or magnetic activity influence on polar-cap convection above Vostok than is predicted by the model. Variations in ground-level neutron counts, a

  7. Low cost transfer into useful sun-synchronous orbits at Mars

    NASA Technical Reports Server (NTRS)

    Glickman, R. E.; Stuart, J. R.

    1981-01-01

    Mars oblateness has been found to provide sun-synchronous orbits, including orbits with stationary apsides, similar to those used at earth. A low mass and low data rate complement of scientific instruments placed in such orbits can provide exciting planetary investigations such as the Mars Orbiter Water Mission described herein. Use of a modest Shuttle kickstage (PAM-A) and existing spacecraft hardware makes this mission low-cost. A preliminary mission and spacecraft design is described. The major emphasis of the paper is on the mechanics of heliocentric transfer for the 1986 and 1988 launch opportunities, Martian sun-synchronous orbit geometries, injectable mass capabilities, and methods of achieving these scientifically useful orbits.

  8. In-Flight Operation of the Dawn Ion Propulsion System Through Orbit Capture at Vesta

    NASA Technical Reports Server (NTRS)

    Garner, Charles E.; Rayman, Marc D.; Brophy, John R.; Mikes, Steven C.

    2011-01-01

    The Dawn mission, part of NASA's Discovery Program, has as its goal the scientific exploration of the two most massive main-belt asteroids, Vesta and Ceres. The Dawn spacecraft was launched from Cape Canaveral Air Force Station on September 27, 2007 on a Delta -II 7925H-9.5 (Delta-II Heavy) rocket that placed the 1218 kg spacecraft into an Earth-escape trajectory. Onboard the spacecraft is an ion propulsion system (IPS) developed at the Jet Propulsion Laboratory which will provide most of the ?V needed for heliocentric transfer to Vesta, orbit capture at Vesta, transfer among Vesta science orbits, departure and escape from Vesta, heliocentric transfer to Ceres, orbit capture at Ceres, and transfer among Ceres science orbits. The first 80 days after launch were dedicated to the initial checkout of the spacecraft which was followed by about ten months of full-power thrusting leading to a Mars gravity assist in February 2009 that provided 1 km/s of heliocentric energy increase and is the only part of the mission following launch in which a needed velocity change is not accomplished by the IPS. Deterministic thrusting for heliocentric transfer to Vesta resumed in June 2009 and was concluded with orbit capture at Vesta in July 2011. IPS was operated for approximately 23,400 hours, consumed approximately 250 kg of xenon, and provided a delta-V of approximately 6.7 km/s to achieve orbit capture at Vesta. IPS performance characteristics are very close to the expected performance characteristics based on analysis performed pre-launch. The only significant problem to have occurred over the almost four years of IPS operations in flight was the temporary failure of a valve driver board in DCIU-1, resulting in a loss of thrust of approximately 29 hours. Thrusting operations resumed after switching to DCIU-2, and power cycling conducted after orbit capture indicates DCIU-1 is completely operational. After about three weeks of survey operations IPS will be used to maneuver the

  9. Spitzer Space Telescope mission design

    NASA Technical Reports Server (NTRS)

    Kwok, Johnny H.; Garcia, Mark D.; Bonfiglio, Eugene; Long, Stacia M.

    2004-01-01

    This paper gives a description of the mission design, launch, orbit, and navigation results for the Spitzer space telescope mission. The Spitzer telescope was launched by the Delta II Heavy launch vehicle into a heliocentric Earth trailing orbit. This orbit is flown for the first time and will be used by several future astronomical missions such as Kepler, SIM, and LISA. This paper describes the launch strategy for a winter versus a summer launch and how it affects communications. It also describes how the solar orbit affects the design and operations of the Observatory. It describes the actual launch timeline, launch vehicle flight performance, and the long term behavior of the as flown orbit. It also provides the orbit knowledge from in-flight navigation data.

  10. Effects of non-gravitational forces on orbital evolution of active Centaurs

    NASA Astrophysics Data System (ADS)

    Churyumov, Klim; Kovalenko, Nataliya

    2016-07-01

    Currently there are 26 active Centaurs known among 121 discovered .In the present study we have investigated the influence of cometary activity on their orbital evolution by using orbital evolution integrators. Since there is no information on exact values of non-gravitational forces for these cometary Centaurs, because of their large heliocentric distances, we assumed their non-gravitational forces as the one for comet Halley with coefficient of 1/r^{2}, where r is perihelion distance. As a result we got the differences in perihelion passage dates for active Centaurs and differences in their perihelion distances during one period around the Sun and longer time-span.

  11. THE PLASMA ENVIRONMENT IN COMETS OVER A WIDE RANGE OF HELIOCENTRIC DISTANCES: APPLICATION TO COMET C/2006 P1 (MCNAUGHT)

    SciTech Connect

    Shou, Y.; Combi, M.; Gombosi, T.; Toth, G.; Jia, Y.-D.; Rubin, M.

    2015-08-20

    On 2007 January 12, comet C/2006 P1 (McNaught) passed its perihelion at 0.17 AU. Abundant remote observations offer plenty of information on the neutral composition and neutral velocities within 1 million kilometers of the comet nucleus. In early February, the Ulysses spacecraft made an in situ measurement of the ion composition, plasma velocity, and magnetic field when passing through the distant ion tail and the ambient solar wind. The measurement by Ulysses was made when the comet was at around 0.8 AU. With the constraints provided by remote and in situ observations, we simulated the plasma environment of Comet C/2006 P1 (McNaught) using a multi-species comet MHD model over a wide range of heliocentric distances from 0.17 to 1.75 AU. The solar wind interaction of the comet at various locations is characterized and typical subsolar standoff distances of the bow shock and contact surface are presented and compared to analytic solutions. We find the variation in the bow shock standoff distances at different heliocentric distances is smaller than the contact surface. In addition, we modified the multi-species model for the case when the comet was at 0.7 AU and achieved comparable water group ion abundances, proton densities, plasma velocities, and plasma temperatures to the Ulysses/SWICS and SWOOPS observations. We discuss the dominating chemical reactions throughout the comet-solar wind interaction region and demonstrate the link between the ion composition near the comet and in the distant tail as measured by Ulysses.

  12. Orbiter's Skeleton

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The structure of NASA's Mars Reconnaissance Orbiter spacecraft is constructed from composite panels of carbon layers over aluminum honeycomb, lightweight yet strong. This forms a basic structure or skeleton on which the instruments, electronics, propulsion and power systems can be mounted. The propellant tank is contained in the center of the orbiter's structure. This photo was taken at Lockheed Martin Space Systems, Denver, during construction of the spacecraft.

  13. Program manual for HILTOP, a heliocentric interplanetary low thrust trajectory optimization program. Part 1: User's guide

    NASA Technical Reports Server (NTRS)

    Mann, F. I.; Horsewood, J. L.

    1974-01-01

    A performance-analysis computer program, that was developed explicitly to generate optimum electric propulsion trajectory data for missions of interest in the exploration of the solar system is presented. The program was primarily designed to evaluate the performance capabilities of electric propulsion systems, and in the simulation of a wide variety of interplanetary missions. A numerical integration of the two-body, three-dimensional equations of motion and the Euler-Lagrange equations was used in the program. Transversality conditions which permit the rapid generation of converged maximum-payload trajectory data, and the optimization of numerous other performance indices for which no transversality conditions exist are included. The ability to simulate constrained optimum solutions, including trajectories having specified propulsion time and constant thrust cone angle, is also in the program. The program was designed to handle multiple-target missions with various types of encounters, such as rendezvous, stopover, orbital capture, and flyby. Performance requirements for a variety of launch vehicles can be determined.

  14. Orbital Debris

    NASA Technical Reports Server (NTRS)

    Kessler, D. J. (Compiler); Su, S. Y. (Compiler)

    1985-01-01

    Earth orbital debris issues and recommended future activities are discussed. The workshop addressed the areas of environment definition, hazards to spacecraft, and space object management. It concluded that orbital debris is a potential problem for future space operations. However, before recommending any major efforts to control the environment, more data are required. The most significant required data are on the population of debris smaller than 4 cm in diameter. New damage criteria are also required. When these data are obtained, they can be combined with hypervelocity data to evaluate the hazards to future spacecraft. After these hazards are understood, then techniques to control the environment can be evaluated.

  15. Orbit Determination Accuracy for Comets on Earth-Impacting Trajectories

    NASA Technical Reports Server (NTRS)

    Kay-Bunnell, Linda

    2004-01-01

    The results presented show the level of orbit determination accuracy obtainable for long-period comets discovered approximately one year before collision with Earth. Preliminary orbits are determined from simulated observations using Gauss' method. Additional measurements are incorporated to improve the solution through the use of a Kalman filter, and include non-gravitational perturbations due to outgassing. Comparisons between observatories in several different circular heliocentric orbits show that observatories in orbits with radii less than 1 AU result in increased orbit determination accuracy for short tracking durations due to increased parallax per unit time. However, an observatory at 1 AU will perform similarly if the tracking duration is increased, and accuracy is significantly improved if additional observatories are positioned at the Sun-Earth Lagrange points L3, L4, or L5. A single observatory at 1 AU capable of both optical and range measurements yields the highest orbit determination accuracy in the shortest amount of time when compared to other systems of observatories.

  16. Nuclear reactor power for an electrically powered orbital transfer vehicle

    NASA Technical Reports Server (NTRS)

    Jaffe, L.; Beatty, R.; Bhandari, P.; Chow, E.; Deininger, W.; Ewell, R.; Fujita, T.; Grossman, M.; Kia, T.; Nesmith, B.

    1987-01-01

    To help determine the systems requirements for a 300-kWe space nuclear reactor power system, a mission and spacecraft have been examined which utilize electric propulsion and this nuclear reactor power for multiple transfers of cargo between low earth orbit (LEO) and geosynchronous earth orbit (GEO). A propulsion system employing ion thrusters and xenon propellant was selected. Propellant and thrusters are replaced after each sortie to GEO. The mass of the Orbital Transfer Vehicle (OTV), empty and dry, is 11,000 kg; nominal propellant load is 5000 kg. The OTV operates between a circular orbit at 925 km altitude, 28.5 deg inclination, and GEO. Cargo is brought to the OTV by Shuttle and an Orbital Maneuvering Vehicle (OMV); the OTV then takes it to GEO. The OTV can also bring cargo back from GEO, for transfer by OMV to the Shuttle. OTV propellant is resupplied and the ion thrusters are replaced by the OMV before each trip to GEO. At the end of mission life, the OTV's electric propulsion is used to place it in a heliocentric orbit so that the reactor will not return to earth. The nominal cargo capability to GEO is 6000 kg with a transit time of 120 days; 1350 kg can be transferred in 90 days, and 14,300 kg in 240 days. These capabilities can be considerably increased by using separate Shuttle launches to bring up propellant and cargo, or by changing to mercury propellant.

  17. Solar orbiter - Close-up view of the sun

    NASA Astrophysics Data System (ADS)

    Marsden, Richard G.; Müller, Daniel; StCyr, O. Chris

    2013-06-01

    Solar Orbiter, the first Medium-class mission of ESA's Cosmic Vision 2015-2025 programme, is designed to study the Sun and inner heliosphere in greater detail than ever before. At the closest point on its heliocentric orbit, the Solar Orbiter spacecraft will be about 0.28 AU from the Sun, closer than any other satellite to date. In addition to providing high-resolution images of the solar surface, perihelion passes at these distances allow the instruments to track features on the solar surface for significantly longer than from Earth orbit. The mission profile also includes a latitude cranking phase that will enable observations from up to 34° above the solar equator. The combination of near-Sun and out-of-ecliptic observations by a suite of complementary remote-sensing and in-situ instruments makes Solar Orbiter a unique platform for studying the links between the Sun and inner heliosphere. Planned for launch in January 2017, the mission will be carried out in collaboration with NASA. In this paper we present a brief overview of the mission and its scientific objectives, and examine those areas where Solar Orbiter is expected to make major contributions with emphasis on close-up and high-latitude observations.

  18. Nuclear orbiting

    SciTech Connect

    Shapira, D.

    1988-01-01

    Nuclear orbiting following collisions between sd and p shell nuclei is discussed. The dependence of this process on the real and imaginary parts of the nucleus-nucleus potential is discussed, as well as the evolution of the dinucleus toward a fully equilibrated fused system. 26 refs., 15 figs.

  19. Preliminary Optimal Orbit Design for the Laser Interferometer Space Antenna (LISA)

    NASA Technical Reports Server (NTRS)

    Hughes, Steven P.; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    In this paper we present a preliminary optimal orbit analysis for the Laser Interferometer Space Antenna (LISA). LISA is a NASA/ESA mission to study gravitational waves and test predictions of general relativity. The nominal formation consists of three spacecraft in heliocentric orbits at 1 AU and trailing the Earth by twenty degrees. This configuration was chosen as a trade off to reduce the noise sources that will affect the instrument and to reduce the fuel to achieve the final orbit. We present equations for the nominal orbit design and discuss several different measures of performance for the LISA formation. All of the measures directly relate the formation dynamics to science performance. Also, constraints on the formation dynamics due to spacecraft and instrument limitations are discussed. Using the nominal solution as an initial guess, the formation is optimized using Sequential Quadratic Programming to maximize the performance while satisfying a set of nonlinear constraints. Results are presented for each of the performance measures.

  20. Changes in the Physical Environment of the Inner Coma of 67P/Churyumov-Gerasimenko with Decreasing Heliocentric Distance

    NASA Astrophysics Data System (ADS)

    Bodewits, D.; Lara, L. M.; A'Hearn, M. F.; La Forgia, F.; Gicquel, A.; Kovacs, G.; Knollenberg, J.; Lazzarin, M.; Lin, Z.-Y.; Shi, X.; Snodgrass, C.; Tubiana, C.; Sierks, H.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; Keller, H. U.; Barucci, M. A.; Bertaux, J.-L.; Bertini, I.; Boudreault, S.; Cremonese, G.; Da Deppo, V.; Davidsson, B.; Debei, S.; De Cecco, M.; Fornasier, S.; Fulle, M.; Groussin, O.; Gutiérrez, P. J.; Güttler, C.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Kramm, J.-R.; Kührt, E.; Küppers, M.; López-Moreno, J. J.; Marzari, F.; Naletto, G.; Oklay, N.; Thomas, N.; Toth, I.; Vincent, J.-B.

    2016-11-01

    The Wide Angle Camera of the OSIRIS instrument on board the Rosetta spacecraft is equipped with several narrow-band filters that are centered on the emission lines and bands of various fragment species. These are used to determine the evolution of the production and spatial distribution of the gas in the inner coma of comet 67P with time and heliocentric distance, here between 2.6 and 1.3 au pre-perihelion. Our observations indicate that the emission observed in the OH, O i, CN, NH, and NH2 filters is mostly produced by dissociative electron impact excitation of different parent species. We conclude that CO2 rather than H2O is a significant source of the [O i] 630 nm emission. A strong plume-like feature observed in the CN and O i filters is present throughout our observations. This plume is not present in OH emission and indicates a local enhancement of the CO2/H2O ratio by as much as a factor of 3. We observed a sudden decrease in intensity levels after 2015 March, which we attribute to decreased electron temperatures in the first few kilometers above the surface of the nucleus.

  1. Eye and orbit ultrasound

    MedlinePlus

    Echography - eye orbit; Ultrasound - eye orbit; Ocular ultrasonography; Orbital ultrasonography ... ophthalmology department of a hospital or clinic. Your eye is numbed with medicine (anesthetic drops). The ultrasound ...

  2. Orbital evolution of impact ejecta from Mars

    NASA Astrophysics Data System (ADS)

    Wetherill, G. W.

    1984-03-01

    The orbital evolution of material ejected from Mars into heliocentric orbits is investigated, with emphasis on the origin of the shergottite, nakhlite, and chassignite achondrites. Two models are considered. In the first, meteorite-size bodies are ejected directly from Mars. In the second, the ejecta are approximately 15 m diameter bodies, that are subsequently fragmented by collisions in space. In both cases about 35 percent of the objects that will ever reach earth do so within 10 m y. For the small body model, it is found that about 0.03 percent of the Mars crater ejecta must be accelerated to the Mars escape velocity; the large body model requires an efficiency of 0.4 percent. The results indicate that meteorites originating as small bodies should dominate the terrestrial flux of Mars ejecta. This is in general agreement with data from SNC meteorites. The yield of meteorites from Mercury is found to be at least a factor of 100 lower than from Mars.

  3. Orbital Effects on Mercury's Escaping Sodium Exosphere

    NASA Technical Reports Server (NTRS)

    Schmidt, Carl A.; Wilson, Jody K.; Baumgardner, Jeffrey; Mendillo, Michael

    2009-01-01

    We present results from coronagraphic imaging of Mercury's sodium tail over a 7 deg field of view. Several sets of observations made at the McDonald Observatory since May 2007 show a tail of neutral sodium atoms stretching more than 1000 Mercury radii (R(sub m)) in length, or a full degree of sky. However, no tail was observed extending beyond 120 R(sub m) during the January 2008 MESSENGER Fly-by period, or during a similar orbital phase of Mercury in July 2008. Large changes in Mercury's heliocentric radial velocity cause Doppler shifts about the Fraunhofer absorption features; the resultant change in solar flux and radiation pressure is the primary cause of the observed variation in tail brightness. Smaller fluctuations in brightness may exist due to changing source rates at the surface, but we have no explicit evidence for such changes in this data set. The effects of radiation pressure on Mercury's escaping atmosphere are investigated using seven observations spanning different orbital phases. Total escape rates of atmospheric sodium are estimated to be between 5 and 13 x 10(exp 23) atoms/s and show a correlation to radiation pressure. Candidate sources of Mercury's sodium exosphere include desorption by UV sunlight, thermal desorption, solar wind channeled along Mercury's magnetic field lines, and micro-meteor impacts. Wide-angle observations of the full extent of Mercury's sodium tail offer opportunities to enhance our understanding of the time histories of these source rates.

  4. Analysis and interpretation of CCD data on P/Halley and physical parameters and activity status of cometary nuclei at large heliocentric distance

    NASA Technical Reports Server (NTRS)

    Belton, Michael J. S.; Mueller, Beatrice

    1991-01-01

    The scientific objectives were as follows: (1) to construct a well sampled photometric time series of comet Halley extending to large heliocentric distances both post and pre-perihelion passage and derive a precise ephemeris for the nuclear spin so that the physical and chemical characteristics of individual regions of activity on the nucleus can be determined; and (2) to extend the techniques in the study of Comet Halley to the study of other cometary nuclei and to obtain new observational data.

  5. A STUDY OF THE HELIOCENTRIC DEPENDENCE OF SHOCK STANDOFF DISTANCE AND GEOMETRY USING 2.5D MAGNETOHYDRODYNAMIC SIMULATIONS OF CORONAL MASS EJECTION DRIVEN SHOCKS

    SciTech Connect

    Savani, N. P.; Shiota, D.; Kusano, K.; Vourlidas, A.; Lugaz, N.

    2012-11-10

    We perform four numerical magnetohydrodynamic simulations in 2.5 dimensions (2.5D) of fast coronal mass ejections (CMEs) and their associated shock fronts between 10 Rs and 300 Rs. We investigate the relative change in the shock standoff distance, {Delta}, as a fraction of the CME radial half-width, D {sub OB} (i.e., {Delta}/D {sub OB}). Previous hydrodynamic studies have related the shock standoff distance for Earth's magnetosphere to the density compression ratio (DR; {rho} {sub u}/{rho} {sub d}) measured across the bow shock. The DR coefficient, k {sub dr}, which is the proportionality constant between the relative standoff distance ({Delta}/D {sub OB}) and the compression ratio, was semi-empirically estimated as 1.1. For CMEs, we show that this value varies linearly as a function of heliocentric distance and changes significantly for different radii of curvature of the CME's leading edge. We find that a value of 0.8 {+-} 0.1 is more appropriate for small heliocentric distances (<30 Rs) which corresponds to the spherical geometry of a magnetosphere presented by Seiff. As the CME propagates its cross section becomes more oblate and the k {sub dr} value increases linearly with heliocentric distance, such that k {sub dr} = 1.1 is most appropriate at a heliocentric distance of about 80 Rs. For terrestrial distances (215 Rs) we estimate k {sub dr} = 1.8 {+-} 0.3, which also indicates that the CME cross-sectional structure is generally more oblate than that of Earth's magnetosphere. These alterations to the proportionality coefficients may serve to improve investigations into the estimates of the magnetic field in the corona upstream of a CME as well as the aspect ratio of CMEs as measured in situ.

  6. The improvement of the Pluto orbit using additional new data

    NASA Astrophysics Data System (ADS)

    Girdiuk, A.

    2015-08-01

    Observational series of the Pluto dwarf planet have started since 1913. At this moment observations have covered only a third of the Pluto orbit, therefore, the Pluto orbital elements are defined with insufficient accuracy. A growing number of observations leads to the improvement of the accuracy of the orbit determination. The database of the Pluto's observations was expanded with the help of about 350 observations during 1930-1996 obtained at the Pulkovo Observatory, and about 5500 observations (1995-2013) including occultation data from Brazilian colleagues obtained at the European Southern Observatory and the Pico dos Dias Observatory, and the new analyzed 469 historical photographic observations archived at Lowell Observatory. The new cross-platform software ERA-8 has been developed in IAA RAS and has been used for implementation of all mathematical procedures for constructing Pluto orbit. The modern ephemerides (EPM2011, EPM2013, DE430, DE432, INPOP13c) are chosen for comparison of the ephemeris positions: equatorial coordinates and heliocentric distance. The main result of the work - construction of ephemerides EPM2014a is a significant improvement of the Pluto's orbit using additional observations.

  7. Orbit analysis

    SciTech Connect

    Michelotti, L.

    1995-01-01

    The past fifteen years have witnessed a remarkable development of methods for analyzing single particle orbit dynamics in accelerators. Unlike their more classic counterparts, which act upon differential equations, these methods proceed by manipulating Poincare maps directly. This attribute makes them well matched for studying accelerators whose physics is most naturally modelled in terms of maps, an observation that has been championed most vigorously by Forest. In the following sections the author sketchs a little background, explains some of the physics underlying these techniques, and discusses the best computing strategy for implementing them in conjunction with modeling accelerators.

  8. Life and Death Near Zero: The distribution and evolution of NEA orbits of near-zero MOID, (e, i), and q

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Morbidelli, Alessandro; Granvik, Mikael

    2016-10-01

    Modeling the distribution of orbits with near-zero orbital parameters requires special attention to the dimensionality of the parameters in question. This is even more true since orbits of near-zero MOID, (e, i), or q are especially interesting as sources or sinks of NEAs. An essentially zero value of MOID (Minimum Orbital Intersection Distance) with respect to the Earth's orbit is a requirement for an impact trajectory, and initially also for ejecta from lunar impacts into heliocentric orbits. The collision cross section of the Earth goes up greatly with decreasing relative encounter velocity, venc, thus the impact flux onto the Earth is enhanced in such low-venc objects, which correspond to near-zero (e,i) orbits. And lunar ejecta that escapes from the Earth-moon system mostly does so at only barely greater than minimum velocity for escape (Gladman, et al., 1995, Icarus 118, 302-321), so the Earth-moon system is both a source and a sink of such low-venc orbits, and understanding the evolution of these populations requires accurately modeling the orbit distributions. Lastly, orbits of very low heliocentric perihelion distance, q, are particularly interesting as a "sink" in the NEA population as asteroids "fall into the sun" (Farinella, et al., 1994, Nature 371, 314-317). Understanding this process, and especially the role of disintegration of small asteroids as they evolve into low-q orbits (Granvik et al., 2016, Nature 530, 303-306), requires accurate modeling of the q distribution that would exist in the absence of a "sink" in the distribution. In this paper, we derive analytical expressions for the expected steady-state distributions near zero of MOID, (e,i), and q in the absence of sources or sinks, compare those to numerical simulations of orbit distributions, and lastly evaluate the distributions of discovered NEAs to try to understand the sources and sinks of NEAs "near zero" of these orbital parameters.

  9. Orbital Winch

    NASA Technical Reports Server (NTRS)

    Hoyt, Robert (Inventor); Slostad, Jeffrey T. (Inventor); Frank, Scott (Inventor); Barnes, Ian M. (Inventor)

    2016-01-01

    Orbital winch having: lower and upper frames; spool having upper and lower flanges with lower flange attached to lower frame; axial tether guide mounted to upper frame; secondary slewing ring coaxial with spool and rotatably mounted to upper frame, wherein secondary slewing ring's outer surface has gearing; upper tether guide mounted to inner surface of secondary slewing ring; linear translation means having upper end mounted to upper frame and lower end mounted on lower frame; primary slewing ring rotatably mounted within linear translation means allowing translation axially between flanges, wherein primary slewing ring's outer surface has gearing; lower tether guide mounted on primary slewing ring's inner surface; pinion rod having upper end mounted to upper frame and lower end mounted to lower frame, wherein pinion rod's teeth engage primary and secondary slewing rings' outer surface teeth; and tether passing through axial, upper, and lower tether guides and winding around spool.

  10. Mission Steering Profiles of Outer Planetary Orbiters Using Radioisotope Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Fiehler, Douglas; Oleson, Steven

    2004-01-01

    Radioisotope Electric Propulsion (REP) has the potential to enable small spacecraft to orbit outer planetary targets with trip times comparable to flyby missions. The ability to transition from a flyby to an orbiter mission lies in the availability of continuous low power electric propulsion along the entire trajectory. The electric propulsion system s role is to add and remove energy from the spacecraft s trajectory to bring it in and out of a heliocentric hyperbolic escape trajectory for the outermost target bodies. Energy is added and the trajectory is reshaped to rendezvous with the closer-in target bodies. Sample REP trajectories will be presented for missions ranging for distances from Jupiter orbit to the Pluto-Kuiper Belt.

  11. The Southern Argentina Agile MEteor Radar Orbital System (SAAMER-OS): An Initial Sporadic Meteoroid Orbital Survey in the Southern Sky

    NASA Astrophysics Data System (ADS)

    Janches, D.; Close, S.; Hormaechea, J. L.; Swarnalingam, N.; Murphy, A.; O'Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C.

    2015-08-01

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER’s location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  12. The Southern Argentina Agile Meteor Radar Orbital System (SAAMER-OS): An Initial Sporadic Meteoroid Orbital Survey in the Southern Sky

    NASA Technical Reports Server (NTRS)

    Janches, D.; Close, S.; Hormaechea, J. L.; Swarnalingam, N.; Murphy, A.; O'Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C.

    2015-01-01

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteoroid applications. The outcomes of this work show that, given SAAMERs location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  13. THE SOUTHERN ARGENTINA AGILE METEOR RADAR ORBITAL SYSTEM (SAAMER-OS): AN INITIAL SPORADIC METEOROID ORBITAL SURVEY IN THE SOUTHERN SKY

    SciTech Connect

    Janches, D.; Swarnalingam, N.; Close, S.; Hormaechea, J. L.; Murphy, A.; O’Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C. E-mail: nimalan.swarnalingam@nasa.gov E-mail: jlhormaechea@untdf.edu.ar E-mail: doconnor@gsoft.com.au E-mail: bfuller@gsoft.com.au E-mail: claudiobrunini@yahoo.com

    2015-08-10

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER’s location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  14. Pupils Produce their Own Narratives Inspired by the History of Science: Animation Movies Concerning the Geocentric-Heliocentric Debate

    NASA Astrophysics Data System (ADS)

    Piliouras, Panagiotis; Siakas, Spyros; Seroglou, Fanny

    2011-07-01

    In this paper, we present the design and application of a teaching scenario appropriate for 12-years-old pupils in the primary school aiming to a better understanding of scientific concepts and scientific methods, linking the development of individual thinking with the development of scientific ideas and facilitating a better understanding of the nature of science. The design of the instructional material supporting this scenario has been based on the study of the history of astronomy and especially on: (a) The various theories concerning the movement of Earth, our solar system and the universe. (b) Key-stories highlighting the evolutionary character of scientific knowledge as well as the cultural interrelations of science and society. The design of the teaching scenario has focused on the participation of pupils in gradually evolving discourses and practices encouraging an appreciation of aspects of the nature of science (e.g. the role of observation and hypothesis, the use of evidence, the creation and modification of models). In this case, pupils are asked to produce their own narratives: animation movies concerning the geocentric-heliocentric debate inspired by the history of science, as the animation technique presents strong expressional potential and currently has many applications in the field of educational multimedia. The research design of this current case study has been based on the SHINE research model, while data coming from pupils' animation movies, questionnaires, interviews, worksheets, story-boards and drawings have been studied and analyzed using the GNOSIS research model. Elaborated data coming from our analysis approach reveal the appearance, transformation and evolution of aspects of nature of science appreciated by pupils and presented in their movies. Data analysis shows that during the application pupils gradually consider more and more the existence of multiple answers in scientific questions, appreciate the effect of culture on the way

  15. Heliocentric Distance of Coronal Mass Ejections at the Time of Energetic Particle Release: Revisiting the Ground Level Enhancement Events of Solar Cycle 23

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Natchimuthuk

    2011-01-01

    Using the kinematics of coronal mass ejections (CMEs), onset time of soft X-ray flares, and the finite size of the pre-eruption CME structure, we derive the heliocentric distane at which the energetic particles during the ground level enhancement (GLE) events of Solar Cycle 23. We find that the GLE particles are released when the CMEs reach an average heliocentric distance of approx.3.25 solar radii (Rs). From this we infer that the shocks accelerating the particles are located at similar heights. Type II radio burst observations indicate that the CMEs are at much lower distances (average approx.1.4 Rs) when the CME-driven shock first forms. The shock seems to travel approx.1.8 Rs over a period of approox.30 min on the average before releasing the GLE particles. In deriving these results, we made three assumptions that have observational support: (i) the CME lift off occurs from an initial distance of about 1.25 Rs; (ii) the flare onset and CME onset are one and the same because these are two different manifestations of the same eruption; and (iii) the CME has positive acceleration from the onset to the first appearance in the coronagraphic field of view (2.5 to 6 Rs). Observations of coronal cavities in eclipse pictures and in coronagraphic images justify the assumption (i). The close relationship between the flare reconnection magnetic flux and the azimuthal flux of interplanetary magnetic clouds justify assumption (ii) consistent with the standard model (CSHKP) of solar eruption. Coronagraphic observations made close to the solar surface indicate a large positive acceleration of CMEs to a heliocentric distance of approx.3 Rs before they start slowing down due to the drag force. The inferred acceleration (approx.1.5 km/s/s) is consistent with reported values in the literature.

  16. Materials co-orbiting with known NEO asteroids: Properties inferred from collision-produced dust clouds

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Wei, Hanying; Connors, Martin; Lai, Hairong; Delzanno, Gian Luca

    Materials co-orbiting with Near-Earth Objects (NEOs) can be potentially hazardous when their diameters are of tens of meters. Such co-orbiting material is produced when small meteoroids about several meters in diameter collide with parent bodies of much larger diameters. These materials will be dispersed in orbits around the associated NEOs, and therefore could enter the terrestrial atmosphere even when their ‘parent’ NEOs miss the Earth. However, due to the small dimensions of these materials, they are hard to discover by traditional surveys. The co-orbiting materials collide regularly with smaller interplanetary objects, since the smaller objects are quite numerous. The dust cloud released in the collisions, containing fine-sized particles, becomes charged and can perturb the ambient solar wind. The resultant interplanetary magnetic field structure is called interplanetary field enhancement (IFE) and can be detected by magnetometers carried by interplanetary spacecraft as the dust cloud is swept outward by the solar wind. We use the records of IFE occurrence to trace interplanetary collisions and thus identify co-orbiting materials of well-known NEOs with ecliptic plane crossing near to or inside the Earth’s orbit. We suggest that co-orbiting materials of asteroid 138175, whose descending node is inside Earth’s orbit at heliocentric ecliptic longitude of 206 ̊, should be responsible for at least some IFEs detected in the longitude range between 195 ̊ and 225 ̊. The mass and spatial distributions of the potentially associated IFEs indicate that these co-orbiting materials had diameters of tens of meters before the collisions and had significant dispersion about the asteroid’s orbit. We can apply this technique to inventory the co-orbiting materials of other known NEOs and obtain the number density, orbits and sizes distributions of the materials. Thus we can estimate their impact probability and issue alerts when the Earth approaches the orbits of the

  17. Data catalog series for space science and applications flight missions. Volume 1A: Descriptions of planetary and heliocentric spacecraft and investigations, second edition

    NASA Technical Reports Server (NTRS)

    Cameron, Winifred Sawtell (Editor); Vostreys, Robert W. (Editor)

    1988-01-01

    The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA and other U.S. government agencies. This volume contains narrative descriptions of planetary and heliocentric spacecraft and associated experiments. The following spacecraft series are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also included.

  18. Data catalog series for space science and applications flight missions. Volume 1B: Descriptions of data sets from planetary and heliocentric spacecraft and investigations

    NASA Technical Reports Server (NTRS)

    Horowitz, Richard (Compiler); Jackson, John E. (Compiler); Cameron, Winifred S. (Compiler)

    1987-01-01

    The main purpose of the data catalog series is to provide descriptive references to data generated by space science flight missions. The data sets described include all of the actual holdings of the Space Science Data Center (NSSDC), all data sets for which direct contact information is available, and some data collections held and serviced by foreign investigators, NASA and other U.S. government agencies. This volume contains narrative descriptions of planetary and heliocentric spacecraft and associated experiments. The following spacecraft series are included: Mariner, Pioneer, Pioneer Venus, Venera, Viking, Voyager, and Helios. Separate indexes to the planetary and interplanetary missions are also provided.

  19. Observing Solar Hard X-rays from Heliospheric Orbits

    NASA Astrophysics Data System (ADS)

    Hurford, Gordon J.; Benz, A.; Dennis, B.; Krucker, S.; Limousin, O.; Lin, R.; Vilmer, N.

    2010-05-01

    The coming decade provides two opportunities to acquire a different observational perspective on solar hard x-ray emission. Both ESA's Solar Orbiter and NASA's Solar Probe Plus missions will be in heliocentric orbits with perihelia of 0.28 au and 0.05 au respectively. This poster indicates the unique scientific advantages of hard x-ray imaging/spectroscopy observations from such platforms. These advantages stem from three factors: First, in combination with other payload elements, the hard x-rays provide the ability to observationally link accelerated electrons at the Sun to radio observations of the propagating electrons and to direct observations of in situ electrons. Second, the substantial gain in sensitivity afforded by close-in vantage points enables exploration of the origin of non-flare associated SEP events to be studied and the character of quiescent active-region heating and electron acceleration to be evaluated. Third, the different observational perspectives provided by the heliocentric orbits compared to low-Earth orbits enable improved separation of coronal and footpoint sources as well as measurements of the isotropy of the x-ray emission. Despite the limited payload resources (mass, power, telemetry) afforded by such missions, scientifically effective hard x-ray imaging spectroscopy from 5 keV to 150 keV is still feasible. The Spectrometer/Telescope for Imaging X-rays (STIX), accepted as part of the Solar Orbiter payload, combines high spectral resolution ( 1 keV FWHM at 10 keV) with spatial resolution as good as 1500 km, and can efficiently encode the data for several hundred optimized images per hour within a modest telemetry allocation and 4 kg / 4 watt budget. The X-ray Imaging Spectrometer (XIS) proposed for Solar Probe Plus, views the Sun through its thermal shield. It also features high spectral resolution from 6 to 150 keV and spatial resolution of 1500 km at perihelion. The poster describes the imaging principles and current configurations

  20. On the Milankovitch orbital elements for perturbed Keplerian motion

    NASA Astrophysics Data System (ADS)

    Rosengren, Aaron J.; Scheeres, Daniel J.

    2014-03-01

    We consider sets of natural vectorial orbital elements of the Milankovitch type for perturbed Keplerian motion. These elements are closely related to the two vectorial first integrals of the unperturbed two-body problem; namely, the angular momentum vector and the Laplace-Runge-Lenz vector. After a detailed historical discussion of the origin and development of such elements, nonsingular equations for the time variations of these sets of elements under perturbations are established, both in Lagrangian and Gaussian form. After averaging, a compact, elegant, and symmetrical form of secular Milankovitch-like equations is obtained, which reminds of the structure of canonical systems of equations in Hamiltonian mechanics. As an application of this vectorial formulation, we analyze the motion of an object orbiting about a planet (idealized as a point mass moving in a heliocentric elliptical orbit) and subject to solar radiation pressure acceleration (obeying an inverse-square law). We show that the corresponding secular problem is integrable and we give an explicit closed-form solution.

  1. On the co-orbital motion in the planar restricted three-body problem: the quasi-satellite motion revisited

    NASA Astrophysics Data System (ADS)

    Pousse, Alexandre; Robutel, Philippe; Vienne, Alain

    2017-02-01

    In the framework of the planar and circular restricted three-body problem, we consider an asteroid that orbits the Sun in quasi-satellite motion with a planet. A quasi-satellite trajectory is a heliocentric orbit in co-orbital resonance with the planet, characterized by a nonzero eccentricity and a resonant angle that librates around zero. Likewise, in the rotating frame with the planet, it describes the same trajectory as the one of a retrograde satellite even though the planet acts as a perturbator. In the last few years, the discoveries of asteroids in this type of motion made the term "quasi-satellite" more and more present in the literature. However, some authors rather use the term "retrograde satellite" when referring to this kind of motion in the studies of the restricted problem in the rotating frame. In this paper, we intend to clarify the terminology to use, in order to bridge the gap between the perturbative co-orbital point of view and the more general approach in the rotating frame. Through a numerical exploration of the co-orbital phase space, we describe the quasi-satellite domain and highlight that it is not reachable by low eccentricities by averaging process. We will show that the quasi-satellite domain is effectively included in the domain of the retrograde satellites and neatly defined in terms of frequencies. Eventually, we highlight a remarkable high eccentric quasi-satellite orbit corresponding to a frozen ellipse in the heliocentric frame. We extend this result to the eccentric case (planet on an eccentric motion) and show that two families of frozen ellipses originate from this remarkable orbit.

  2. Orbital dystopia due to orbital roof defect.

    PubMed

    Rha, Eun Young; Joo, Hong Sil; Byeon, Jun Hee

    2013-01-01

    We performed a retrospective review of patients who presented with delayed dystopia as a consequence of an orbital roof defect due to fractures and nontraumatic causes to search for a correlation between orbital roof defect size and surgical indications for the treatment thereof. Retrospective analyses were performed in 7 patients, all of whom presented with delayed dystopia due to orbital roof defects, between January 2001 and June 2011. The causes of orbital roof defects were displaced orbital roof fractures (5 cases), tumor (1 case), and congenital sphenoid dysplasia (1 case). All 7 patients had initially been treated conservatively and later presented with significant dystopia. The sizes of the defects were calculated on computed tomographic scans. Among the 7 patients, aspiration of cerebrospinal fluid, which caused ocular symptoms, in 1 patient with minimal displaced orbital roof and reconstruction with calvarial bone, titanium micromesh, or Medpor in 6 other patients were performed. The minimal size of the orbital roof in patients who underwent orbital roof reconstruction was 1.2 cm (defect height) x 1.0 cm (defect length), 0.94 cm(2). For all patients with orbital dystopia, displacement of the globe was corrected without any complications, regardless of whether the patient was evaluated grossly or by radiology. In this retrospective study, continuous monitoring of clinical signs and active surgical management should be considered for cases in which an orbital roof defect is detected, even if no definite symptoms are noted, to prevent delayed sequelae.

  3. Sclerosing idiopathic orbital inflammation.

    PubMed

    Brannan, Paul A; Kersten, Robert C; Kulwin, Dwight R

    2006-01-01

    A 5-year-old girl referred for orbital cellulitis was found to have a right orbital mass. Computed tomography revealed a mass occupying the inferotemporal orbit, extending into the maxillary sinus. Biopsy yielded a diagnosis of sclerosing idiopathic orbital inflammation. She was successfully treated with prednisone.

  4. Orbital fractures: a review

    PubMed Central

    Joseph, Jeffrey M; Glavas, Ioannis P

    2011-01-01

    This review of orbital fractures has three goals: 1) to understand the clinically relevant orbital anatomy with regard to periorbital trauma and orbital fractures, 2) to explain how to assess and examine a patient after periorbital trauma, and 3) to understand the medical and surgical management of orbital fractures. The article aims to summarize the evaluation and management of commonly encountered orbital fractures from the ophthalmologic perspective and to provide an overview for all practicing ophthalmologists and ophthalmologists in training. PMID:21339801

  5. Contingency Trajectory Design for a Lunar Orbit Insertion Maneuver Failure by the LADEE Spacecraft

    NASA Technical Reports Server (NTRS)

    Genova, A. L.

    2014-01-01

    This paper presents results from a contingency trajectory analysis performed for the Lunar Atmosphere & Dust Environment Explorer (LADEE) mission in the event of a missed lunar-orbit insertion (LOI) maneuver by the LADEE spacecraft. The effects of varying solar perturbations in the vicinity of the weak stability boundary (WSB) in the Sun-Earth system on the trajectory design are analyzed and discussed. It is shown that geocentric recovery trajectory options existed for the LADEE spacecraft, depending on the spacecraft's recovery time to perform an Earth escape-prevention maneuver after the hypothetical LOI maneuver failure and subsequent path traveled through the Sun-Earth WSB. If Earth-escape occurred, a heliocentric recovery option existed, but with reduced science capacapability for the spacecraft in an eccentric, not circular near-equatorial retrograde lunar orbit.

  6. The BioSentinel Bioanalytical Microsystem: Characterizing DNA Radiation Damage in Living Organisms Beyond Earth Orbit

    NASA Technical Reports Server (NTRS)

    Ricco, A. J.; Hanel, R.; Bhattacharya, S.; Boone, T.; Tan, M.; Mousavi, A.; Rademacher, A.; Schooley, A.; Klamm, B.; Benton, J.; Padgen, M.; Gentry, D.; Friedericks, C.; Defouw, G.; Parra, M.; Santa Maria, S.; Marina, D.; Swan, B. G.; Wheeler, S.; Gavalas, S.; Lewis, B.; Sanchez, H.; Chartres, J.; Lusby, T.

    2016-01-01

    We will present details and initial lab test results from an integrated bioanalytical microsystem designed to conduct the first biology experiments beyond low Earth orbit (LEO) since Apollo 17 (1972). The 14-kg, 12x24x37-cm BioSentinel spacecraft (Figure 1) assays radiation-responsive yeast in its science payload by measuring DNA double-strand breaks (DSBs) repaired via homologous recombination, a mechanism common to all eukaryotes including humans. S. cerevisiae (brewer's yeast) in 288 microwells are provided with nutrient and optically assayed for growth and metabolism via 3-color absorptimetry monthly during the 18-month mission. BioSentinel is one of several secondary payloads to be deployed by NASA's Exploration Mission 1 (EM-1) launch vehicle into approximately 0.95 AU heliocentric orbit in July 2018; it will communicate with Earth from up to 100 million km.

  7. A continuum model for the orbit evolution of self-propelled `smart dust' swarms

    NASA Astrophysics Data System (ADS)

    McInnes, Colin R.

    2016-06-01

    A continuity equation is developed to model the evolution of a swarm of self-propelled `smart dust' devices in heliocentric orbit driven by solar radiation pressure. These devices are assumed to be MEMs-scale (micro-electromechanical systems) with a large area-to-mass ratio. For large numbers of devices it will be assumed that a continuum approximation can be used to model their orbit evolution. The families of closed-form solutions to the resulting swarm continuity equation then represent the evolution of the number density of devices as a function of both position and time from a set of initial data. Forcing terms are also considered which model swarm sources and sinks (device deposition and device failure). The closed-form solutions presented for the swarm number density provide insights into the behaviour of swarms of self-propelled `smart dust' devices an can form the basis of more complex mission design methodologies.

  8. Lunar Reconnaissance Orbiter Orbit Determination Accuracy Analysis

    NASA Technical Reports Server (NTRS)

    Slojkowski, Steven E.

    2014-01-01

    Results from operational OD produced by the NASA Goddard Flight Dynamics Facility for the LRO nominal and extended mission are presented. During the LRO nominal mission, when LRO flew in a low circular orbit, orbit determination requirements were met nearly 100% of the time. When the extended mission began, LRO returned to a more elliptical frozen orbit where gravity and other modeling errors caused numerous violations of mission accuracy requirements. Prediction accuracy is particularly challenged during periods when LRO is in full-Sun. A series of improvements to LRO orbit determination are presented, including implementation of new lunar gravity models, improved spacecraft solar radiation pressure modeling using a dynamic multi-plate area model, a shorter orbit determination arc length, and a constrained plane method for estimation. The analysis presented in this paper shows that updated lunar gravity models improved accuracy in the frozen orbit, and a multiplate dynamic area model improves prediction accuracy during full-Sun orbit periods. Implementation of a 36-hour tracking data arc and plane constraints during edge-on orbit geometry also provide benefits. A comparison of the operational solutions to precision orbit determination solutions shows agreement on a 100- to 250-meter level in definitive accuracy.

  9. Manned Venus Orbiting Mission

    NASA Technical Reports Server (NTRS)

    Willis, E. A., Jr.

    1967-01-01

    Manned orbiting stopover round trips to Venus are studied for departure dates between 1975 and 1986 over a range of trip times and stay times. The use of highly elliptic parking orbits at Venus leads to low initial weights in Earth orbit compared with circular orbits. For the elliptic parking orbit, the effect of constraints on the low altitude observation time on the initial weight is shown. The mission can be accomplished with the Apollo level of chemical propulsion, but advanced chemical or nuclear propulsion can give large weight reductions. The Venus orbiting mission weights than the corresponding Mars mission.

  10. The dust environment of comet 67P/Churyumov-Gerasimenko from Rosetta OSIRIS and VLT observations in the 4.5 to 2.9 AU heliocentric distance range inbound

    NASA Astrophysics Data System (ADS)

    Moreno, F.; Snodgrass, C.; Hainaut, O.; Tubiana, C.; Sierks, H.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; Keller, H. U.; Agarwal, J.; A'Hearn, M. F.; Barucci, M. A.; Bertaux, J.-L.; Bertini, I.; Besse, S.; Bodewits, D.; Cremonese, G.; Da Deppo, V.; Davidsson, B.; Debei, S.; De Cecco, M.; Ferri, F.; Fornasier, S.; Fulle, M.; Groussin, O.; Gutiérrez, P. J.; Gutiérrez-Marques, P.; Güttler, C.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Knollenberg, J.; Kovacs, G.; Kramm, J.-R.; Kührt, E.; Küppers, M.; Lara, L. M.; Lazzarin, M.; López-Moreno, J. J.; Marzari, F.; Mottola, S.; Naletto, G.; Oklay, N.; Pajola, M.; Thomas, N.; Vincent, J. B.; Della Corte, V.; Fitzsimmons, A.; Faggi, S.; Jehin, E.; Opitom, C.; Tozzi, G.-P.

    2016-03-01

    Context. The ESA Rosetta spacecraft, currently orbiting around comet 67P/Churyumov-Gerasimenko, has already provided in situ measurements of the dust grain properties from several instruments,particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the overall, time-dependent dust-production rate and size distribution. Aims: To constrain the dust grain properties, we take Rosetta OSIRIS and GIADA results into account, and combine OSIRIS data during the approach phase (from late April to early June 2014) with a large data set of ground-based images that were acquired with the ESO Very Large Telescope (VLT) from February to November 2014. Methods: A Monte Carlo dust tail code, which has already been used to characterise the dust environments of several comets and active asteroids, has been applied to retrieve the dust parameters. Key properties of the grains (density, velocity, and size distribution) were obtained from Rosetta observations: these parameters were used as input of the code to considerably reduce the number of free parameters. In this way, the overall dust mass-loss rate and its dependence on the heliocentric distance could be obtained accurately. Results: The dust parameters derived from the inner coma measurements by OSIRIS and GIADA and from distant imaging using VLT data are consistent, except for the power index of the size-distribution function, which is α = -3, instead of α = -2, for grains smaller than 1 mm. This is possibly linked to the presence of fluffy aggregates in the coma. The onset of cometary activity occurs at approximately 4.3 AU, with a dust production rate of 0.5 kg/s, increasing up to 15 kg/s at 2.9 AU. This implies a dust-to-gas mass ratio varying between 3.8 and 6.5 for the best-fit model when combined with water-production rates from the MIRO experiment.

  11. NASA's Spitzer Space Telescope's Operational Mission Experience

    NASA Technical Reports Server (NTRS)

    Wilson, Robert K.; Scott, Charles P.

    2006-01-01

    New Generation of Detector Arrays(100 to 10,000 Gain in Capability over Previous Infrared Space Missions). IRAC: 256 x 256 pixel arrays operating at 3.6 microns, 4.5 microns, 5.8 microns, 8.0 microns. MIPS: Photometer with 3 sets of arrays operating at 24 microns, 70 microns and 160 microns. 128 x 128; 32 x 32 and 2 x 20 arrays. Spectrometer with 50-100 micron capabilities. IRS: 4 Array (128x128 pixel) Spectrograph, 4 -40 microns. Warm Launch Architecture: All other Infrared Missions launched with both the telescope and scientific instrument payload within the cryostat or Dewar. Passive cooling used to cool outer shell to approx.40 K. Cryogenic Boil-off then cools telescope to required 5.5K. Earth Trailing Heliocentric Orbit: Increased observing efficiency, simplification of observation planning, removes earth as heat source.

  12. Lunar orbiting prospector

    NASA Technical Reports Server (NTRS)

    1988-01-01

    One of the prime reasons for establishing a manned lunar presence is the possibility of using the potential lunar resources. The Lunar Orbital Prospector (LOP) is a lunar orbiting platform whose mission is to prospect and explore the Moon from orbit in support of early lunar colonization and exploitation efforts. The LOP mission is divided into three primary phases: transport from Earth to low lunar orbit (LLO), operation in lunar orbit, and platform servicing in lunar orbit. The platform alters its orbit to obtain the desired surface viewing, and the orbit can be changed periodically as needed. After completion of the inital remote sensing mission, more ambitious and/or complicated prospecting and exploration missions can be contemplated. A refueled propulsion module, updated instruments, or additional remote sensing packages can be flown up from the lunar base to the platform.

  13. Analysis of planetary and solar-induced perturbations on trans-Martian trajectory of Mars missions before and after Mars orbit insertion

    NASA Astrophysics Data System (ADS)

    Nwankwo, V. U. J.; Chakrabarti, S. K.

    2015-12-01

    Interplanetary missions are susceptible to gravitational and nongravitational perturbing forces at every trajectory phase, assuming, of course, that the man made rockets and thrusters work as expected. These forces are mainly due to planetary and solar-forcing-induced perturbations during geocentric, heliocentric and Martian trajectories, and before orbit insertion. In this study, we review and/or analyze Mars orbiters mission associated perturbing forces and their possible impacts before Mars Orbit Insertion viz Earth's oblateness, Third body (solar and lunar), solar radiation pressure, solar energetic radiation environment and atmospheric drag forces. We also model the significance of atmospheric drag force on Mangalyaan Mars orbiter mission, as a function of appropriate space environmental parameters during its 28 days in Earth's orbit (around and during perigee passage), 300 days of heliocentric and 100 days of Martian trajectory. We have found that for a total perigee height boost of about 250 km, the cumulative orbit decay can be approximately 720 m. The approximate altitude variation could be up to 158 m with respect to the sun during 300 days of interplanetary journey toward Mars. After Mars orbit insertion, the total decay experienced by the spacecraft could be up to 701 m with decay rate of up to 9 m/day during 100 days of Martian trajectory, based on Mars-Earth atmosphere density ratio. In principle, resulting deviations due to perturbing forces are usually corrected before Earth departure (and/or Mars orbit insertion) and are beyond the scope of this work. However, the knowledge is important for mission planning, design, implementation and situational awareness. We find that the deviations are small enough and should be correctable.

  14. Introducing Earth's Orbital Eccentricity

    ERIC Educational Resources Information Center

    Oostra, Benjamin

    2015-01-01

    Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…

  15. Five Equivalent d Orbitals

    ERIC Educational Resources Information Center

    Pauling, Linus; McClure, Vance

    1970-01-01

    Amplifies and clarifies a previous paper on pyramidal d orbitals. Discusses two sets of pyramid d orbitals with respect to their maximum bond strength and their symmetry. Authors described the oblate and prolate pentagonal antiprisms arising from the two sets of five equivalent d orbitals. (RR)

  16. Nozomi Cis-Lunar Phase Orbit Determination

    NASA Technical Reports Server (NTRS)

    Ryne, Mark; Criddle, Kevin

    2000-01-01

    Japan's Institute of Space and Astronautical Science (ISAS) launched Nozomi, its first mission to the planet Mars using the newly developed M-V launch vehicle on July 3, 1998. Scientific objectives of the mission are to study the structure and dynamics of the Martian upper atmosphere and its interaction with the solar wind. Nozomi is a cooperative mission between ISAS and the National Aeronautics and Space Administration (NASA). The NASA contribution includes navigation and tracking services provided by the Jet Propulsion Laboratory (JPL). The spacecraft also serves as an engineering demonstration of basic technology for planetary exploration. One of the new technologies was a unique trajectory, developed by ISAS, which used solar gravitational perturbations at the weak stability boundary as an aid to achieve an Earth-Mars transfer orbit. This trajectory saves approximately 120 m/s of Delta V compared to direct hyperbolic insertion and is considered an enabling technology for the mission. Nozomi was the first spacecraft to employ this trajectory and provided on-orbit validation of the technique. The trajectory was achieved by initially placing the spacecraft in a highly elliptical cis-lunar phasing orbit. Six maneuvers were performed during this period to correct injection errors and target an outbound lunar swingby in September 1998. The gravity assist from the lunar swingby raised apogee to the vicinity of the weak stability boundary. After three more targeting maneuvers, Nozomi performed an inbound lunar swingby followed immediately by a powered Earth swingby in late December 1998. A 420 m/s Trans Mars Insertion (TMI) burn at the final Earth periapsis was intended to place the spacecraft on a heliocentric trajectory leading to Mars orbit insertion in October 1999. Orbit determination for Nozomi is performed in parallel by both ISAS and the Multi-Mission Navigation (MMNAV) group at JPL. This was an advantage for the mission because each group would generate

  17. Orbit Software Suite

    NASA Technical Reports Server (NTRS)

    Osgood, Cathy; Williams, Kevin; Gentry, Philip; Brownfield, Dana; Hallstrom, John; Stuit, Tim

    2012-01-01

    Orbit Software Suite is used to support a variety of NASA/DM (Dependable Multiprocessor) mission planning and analysis activities on the IPS (Intrusion Prevention System) platform. The suite of Orbit software tools (Orbit Design and Orbit Dynamics) resides on IPS/Linux workstations, and is used to perform mission design and analysis tasks corresponding to trajectory/ launch window, rendezvous, and proximity operations flight segments. A list of tools in Orbit Software Suite represents tool versions established during/after the Equipment Rehost-3 Project.

  18. Painless orbital myositis.

    PubMed

    Chakor, Rahul T; Santhosh, N S

    2012-07-01

    Idiopathic orbital inflammation is the third most common orbital disease, following Graves orbitopathy and lymphoproliferative diseases. We present a 11 year old girl with 15 days history of painless diplopia. There was no history of fluctuation of symptoms, drooping of eye lids or diminished vision. She had near total restricted extra-ocular movements and mild proptosis of the right eye. There was no conjunctival injection, chemosis, or bulb pain. There was no eyelid retraction or lid lag. Rest of the neurological examination was unremarkable.Erythrocyte sedimentation rate was raised with eosinophilia. Antinuclear antibodies were positive. Liver, renal and thyroid functions were normal. Antithyroid, double stranded deoxyribonucleic acid and acetylcholine receptor antibodies were negative. Repetitive nerve stimulation was negative. Magnetic resonance imaging (MRI) of the orbit was typical of orbital myositis. The patient responded to oral steroids. Orbital myositis can present as painless diplopia. MRI of orbit is diagnostic in orbital myositis.

  19. Orbit Determination of the Lunar Reconnaissance Orbiter

    NASA Technical Reports Server (NTRS)

    Mazarico, Erwan; Rowlands, D. D.; Neumann, G. A.; Smith, D. E.; Torrence, M. H.; Lemoine, F. G.; Zuber, M. T.

    2011-01-01

    We present the results on precision orbit determination from the radio science investigation of the Lunar Reconnaissance Orbiter (LRO) spacecraft. We describe the data, modeling and methods used to achieve position knowledge several times better than the required 50-100m (in total position), over the period from 13 July 2009 to 31 January 2011. In addition to the near-continuous radiometric tracking data, we include altimetric data from the Lunar Orbiter Laser Altimeter (LOLA) in the form of crossover measurements, and show that they strongly improve the accuracy of the orbit reconstruction (total position overlap differences decrease from approx.70m to approx.23 m). To refine the spacecraft trajectory further, we develop a lunar gravity field by combining the newly acquired LRO data with the historical data. The reprocessing of the spacecraft trajectory with that model shows significantly increased accuracy (approx.20m with only the radiometric data, and approx.14m with the addition of the altimetric crossovers). LOLA topographic maps and calibration data from the Lunar Reconnaissance Orbiter Camera were used to supplement the results of the overlap analysis and demonstrate the trajectory accuracy.

  20. Orbital Debris: A Chronology

    NASA Technical Reports Server (NTRS)

    Portree, Davis S. F. (Editor); Loftus, Joseph P., Jr. (Editor)

    1999-01-01

    This chronology covers the 37-year history of orbital debris concerns. It tracks orbital debris hazard creation, research, observation, experimentation, management, mitigation, protection, and policy. Included are debris-producing, events; U.N. orbital debris treaties, Space Shuttle and space station orbital debris issues; ASAT tests; milestones in theory and modeling; uncontrolled reentries; detection system development; shielding development; geosynchronous debris issues, including reboost policies: returned surfaces studies, seminar papers reports, conferences, and studies; the increasing effect of space activities on astronomy; and growing international awareness of the near-Earth environment.

  1. Introducing Earth's Orbital Eccentricity

    NASA Astrophysics Data System (ADS)

    Oostra, Benjamin

    2015-12-01

    Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is small, and its only effect on the seasons is their unequal durations. Here I show a pleasant way to guide students to the actual value of Earth's orbital eccentricity, starting from the durations of the four seasons. The date of perihelion is also found.

  2. Magnetospheric Multiscale (MMS) Orbit

    NASA Video Gallery

    This animation shows the orbits of Magnetospheric Multiscale (MMS) mission, a Solar-Terrestrial Probe mission comprising of four identically instrumented spacecraft that will study the Earth's magn...

  3. Family of Orbiters

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image shows the paths of three spacecraft currently in orbit around Mars, as well as the path by which NASA's Phoenix Mars Lander will approach and land on the planet. The t-shaped crosses show where the orbiters will be when Phoenix enters the atmosphere, while the x-shaped crosses show their location at landing time.

    All three orbiters, NASA's Mars Reconnaissance Orbiter, NASA's Mars Odyssey and the European Space Agency's Mars Express, will be monitoring Phoenix during the final steps of its journey to the Red Planet.

    Phoenix will land just south of Mars's north polar ice cap.

  4. Orbital granulocytic sarcoma

    PubMed Central

    Stockl, F.; Dolmetsch, A.; Saornil, M; Font, R.; Burnier, M.

    1997-01-01

    AIM—Orbital granulocytic sarcoma is a localised tumour composed of cells of myeloid origin. Histological diagnosis can be difficult in patients with poorly differentiated orbital tumours and no evidence of systemic leukaemia. The naphthol AS-D chloracetate esterase (Leder stain) and immunohistochemical stains for lysozyme and MAC387 were used to determine the staining characteristics of these tumours. A case series of seven patients with orbital granulocytic sarcoma is presented.
METHODS—Seven patients with orbital granulocytic sarcoma were studied. Haematoxylin and eosin, Leder, and lysozyme stained sections were available in seven cases. Unstained formalin fixed paraffin embedded sections of seven cases were available for immunohistochemical evaluation using the avidin-biotin-complex technique for MAC387.
RESULTS—The mean age of presentation of the orbital tumour was 8.8 years. Four patients presented with an orbital tumour before any systemic manifestations of leukaemia. In two cases the diagnosis of the orbital tumour and systemic leukaemia was made simultaneously. There was one case of established systemic myeloid leukaemia in remission with the subsequent development of orbital granulocytic sarcoma. Six of seven cases (86%) were positive for the Leder stain. Five of seven cases (71%) showed positive immunoreactivity with lysozyme. The immunohistochemical stain for MAC387 was positive in all seven cases (100%) including one case that was negative for both lysozyme and Leder stains.
CONCLUSIONS—Orbital granulocytic sarcoma is a tumour that affects children and can present with rapidly progressive proptosis. This tumour may develop before, during, or after the occurrence of systemic leukaemia. The combination of Leder and lysozyme stains is useful in the diagnosis of orbital granulocytic sarcoma. MAC387 may be a more reliable marker for orbital granulocytic sarcoma.

 PMID:9497470

  5. Congenital orbital encephalocele, orbital dystopia, and exophthalmos.

    PubMed

    Hwang, Kun; Kim, Han Joon

    2012-07-01

    We present here an exceedingly rare variant of a nonmidline basal encephalocele of the spheno-orbital type, and this was accompanied with orbital dystopia in a 56-year-old man. On examination, his left eye was located more inferolaterally than his right eye, and the patient said this had been this way since his birth. The protrusion of his left eye was aggravated when he is tired. His naked visual acuity was 0.7/0.3, and the ocular pressure was 14/12 mm Hg. The exophthalmometry was 10/14 to 16 mm. His eyeball motion was not restricted, yet diplopia was present in all directions. The distance from the midline to the medial canthus was 20/15 mm. The distance from the midline to the midpupillary line was 35/22 mm. The vertical dimension of the palpebral fissure was 12/9 mm. The height difference of the upper eyelid margin was 11 mm, and the height difference of the lower eyelid margin was 8 mm. Facial computed tomography and magnetic resonance imaging showed left sphenoid wing hypoplasia and herniation of the left anterior temporal pole and dura mater into the orbit, and this resulted into left exophthalmos and encephalomalacia in the left anterior temporal pole. To the best of our knowledge, our case is the second case of basal encephalocele and orbital dystopia.

  6. Reticulohistiocytoma of the Orbit

    PubMed Central

    Weissman, Heather M.; Hayek, Brent R.; Grossniklaus, Hans E.

    2015-01-01

    Reticulohistiocytoma is a rare, benign histiocytic proliferation of the skin or soft tissue. While ocular involvement has been documented in the past, there have been no previously reported cases of reticulohistiocytoma of the orbit. In this report, the authors describe a reticulohistiocytoma of the orbit in a middle-aged woman. PMID:24807799

  7. Statistical initial orbit determination

    SciTech Connect

    Taff, L.G.; Belkin, B.; Schweiter, G.A.; Sommar, K. D.H. Wagner Associates, Inc., Paoli, PA )

    1992-02-01

    For the ballistic missile initial orbit determination problem in particular, the concept of 'launch folders' is extended. This allows to decouple the observational data from the initial orbit determination problem per se. The observational data is only used to select among the possible orbital element sets in the group of folders. Monte Carlo simulations using up to 7200 orbital element sets are described. The results are compared to the true orbital element set and the one a good radar would have been able to produce if collocated with the optical sensor. The simplest version of the new method routinely outperforms the radar initial orbital element set by a factor of two in future miss distance. In addition, not only can a differentially corrected orbital element set be produced via this approach - after only two measurements of direction - but also an updated, meaningful, six-dimensional covariance array for it can be calculated. This technique represents a significant advance in initial orbit determination for this problem, and the concept can easily be extended to minor planets and artificial satellites. 9 refs.

  8. Orbital Shape Representations.

    ERIC Educational Resources Information Center

    Kikuchi, Osamu; Suzuki, Keizo

    1985-01-01

    Discusses the use of orbital shapes for instructional purposes, emphasizing that differences between polar, contour, and three-dimensional plots must be made clear to students or misconceptions will occur. Also presents three-dimensional contour surfaces for the seven 4f atomic orbitals of hydrogen and discusses their computer generation. (JN)

  9. Orbital endoscopic surgery.

    PubMed

    Prabhakaran, Venkatesh C; Selva, Dinesh

    2008-01-01

    Minimally invasive "keyhole" surgery performed using endoscopic visualization is increasing in popularity and is being used by almost all surgical subspecialties. Within ophthalmology, however, endoscopic surgery is not commonly performed and there is little literature on the use of the endoscope in orbital surgery. Transorbital use of the endoscope can greatly aid in visualizing orbital roof lesions and minimizing the need for bone removal. The endoscope is also useful during decompression procedures and as a teaching aid to train orbital surgeons. In this article, we review the history of endoscopic orbital surgery and provide an overview of the technique and describe situations where the endoscope can act as a useful adjunct to orbital surgery.

  10. Orbital Plots Using Gnuplot

    NASA Astrophysics Data System (ADS)

    Moore, Brian G.

    2000-06-01

    The plotting program Gnuplot is freely available, general purpose, easy to use, and available on a variety of platforms. Complex three-dimensional surfaces, including the familiar angular parts of the hydrogen atom orbitals, are easily represented using Gnuplot. Contour plots allow viewing the radial and angular variation of the probability density in an orbital. Examples are given of how Gnuplot is used in an undergraduate physical chemistry class to view familiar atomic orbitals in new ways or to generate views of orbital functions that the student may have not seen before. Gnuplot may also be easily integrated into the environment of a Web page; an example of this is discussed (and is available at http://onsager.bd.psu.edu/~moore/orbitals_gnuplot). The plotting commands are entered with a form and a CGI script is used to run Gnuplot and display the result back to the browser.

  11. Congenital Orbital Teratoma

    PubMed Central

    Pellerano, Fernando; Guillermo, Elvis; Garrido, Gloreley; Berges, Pedro

    2017-01-01

    We report a case of congenital orbital teratoma. A 3-day-old male, born at 39 weeks’ gestation without relevant prenatal history, presented with a large vascularized proptotic mass distorting the left midface. Laboratory studies showed elevated serum alpha-fetoprotein (12,910 ng/ml). Computed tomography showed a multiloculated heterogeneous lesion composed of hypodense and hyperdense calcified areas encompassing the whole orbital cavity with expansion of the bony walls, as well as forward displacement and compression of the eyeball without extension to surrounding structures. Clinical, imaging and laboratory features were consistent with congenital orbital teratoma. Due to pronounced proptosis with exposure keratopathy and corneal perforation, no motility of the globe and no vision in the affected eye in a resource-limited setting, the patient underwent orbital exenteration. Histopathological examination confirmed the diagnosis of mature cystic teratoma. We describe the clinical course, radiographic and histopathological findings of this rare orbital tumor. PMID:28275597

  12. Mars Climate Orbiter

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The purpose of this mission is to study the climate history and the water distribution of Mars. Beautiful panoramic views of the shuttle on the launch pad, engine ignition, Rocket launch, and the separation and burnout of the Solid Rocket Boosters are shown. The footage also includes an animation of the mission. Detailed views of the path that the Orbiter traversed were shown. Once the Orbiter lands on the surface of Mars, it will dig a six to eight inch hole and collect samples from the planets' surface. The animation also included the prospective return of the Orbiter to Earth over the desert of Utah. The remote sensor on the Orbiter helps in finding the exact location of the Orbiter so that scientists may collect the sample and analyze it.

  13. Congenital Orbital Teratoma.

    PubMed

    Pellerano, Fernando; Guillermo, Elvis; Garrido, Gloreley; Berges, Pedro

    2017-01-01

    We report a case of congenital orbital teratoma. A 3-day-old male, born at 39 weeks' gestation without relevant prenatal history, presented with a large vascularized proptotic mass distorting the left midface. Laboratory studies showed elevated serum alpha-fetoprotein (12,910 ng/ml). Computed tomography showed a multiloculated heterogeneous lesion composed of hypodense and hyperdense calcified areas encompassing the whole orbital cavity with expansion of the bony walls, as well as forward displacement and compression of the eyeball without extension to surrounding structures. Clinical, imaging and laboratory features were consistent with congenital orbital teratoma. Due to pronounced proptosis with exposure keratopathy and corneal perforation, no motility of the globe and no vision in the affected eye in a resource-limited setting, the patient underwent orbital exenteration. Histopathological examination confirmed the diagnosis of mature cystic teratoma. We describe the clinical course, radiographic and histopathological findings of this rare orbital tumor.

  14. Remote Controlled Orbiter Capability

    NASA Technical Reports Server (NTRS)

    Garske, Michael; delaTorre, Rafael

    2007-01-01

    The Remote Control Orbiter (RCO) capability allows a Space Shuttle Orbiter to perform an unmanned re-entry and landing. This low-cost capability employs existing and newly added functions to perform key activities typically performed by flight crews and controllers during manned re-entries. During an RCO landing attempt, these functions are triggered by automation resident in the on-board computers or uplinked commands from flight controllers on the ground. In order to properly route certain commands to the appropriate hardware, an In-Flight Maintenance (IFM) cable was developed. Currently, the RCO capability is reserved for the scenario where a safe return of the crew from orbit may not be possible. The flight crew would remain in orbit and await a rescue mission. After the crew is rescued, the RCO capability would be used on the unmanned Orbiter in an attempt to salvage this national asset.

  15. Orbit determination based on meteor observations using numerical integration of equations of motion

    NASA Astrophysics Data System (ADS)

    Dmitriev, V.; Lupovka, V.; Gritsevich, M.

    2014-07-01

    We review the definitions and approaches to orbital-characteristics analysis applied to photographic or video ground-based observations of meteors. A number of camera networks dedicated to meteors registration were established all over the word, including USA, Canada, Central Europe, Australia, Spain, Finland and Poland. Many of these networks are currently operational. The meteor observations are conducted from different locations hosting the network stations. Each station is equipped with at least one camera for continuous monitoring of the firmament (except possible weather restrictions). For registered multi-station meteors, it is possible to accurately determine the direction and absolute value for the meteor velocity and thus obtain the topocentric radiant. Based on topocentric radiant one further determines the heliocentric meteor orbit. We aim to reduce total uncertainty in our orbit-determination technique, keeping it even less than the accuracy of observations. The additional corrections for the zenith attraction are widely in use and are implemented, for example, here [1]. We propose a technique for meteor-orbit determination with higher accuracy. We transform the topocentric radiant in inertial (J2000) coordinate system using the model recommended by IAU [2]. The main difference if compared to the existing orbit-determination techniques is integration of ordinary differential equations of motion instead of addition correction in visible velocity for zenith attraction. The attraction of the central body (the Sun), the perturbations by Earth, Moon and other planets of the Solar System, the Earth's flattening (important in the initial moment of integration, i.e. at the moment when a meteoroid enters the atmosphere), atmospheric drag may be optionally included in the equations. In addition, reverse integration of the same equations can be performed to analyze orbital evolution preceding to meteoroid's collision with Earth. To demonstrate the developed

  16. Orbital Causes of Incomitant Strabismus

    PubMed Central

    Lueder, Gregg T.

    2015-01-01

    Strabismus may result from abnormal innervation, structure, or function of the extraocular muscles. Abnormalities of the orbital bones or masses within the orbit may also cause strabismus due to indirect effects on the extraocular muscles. This paper reviews some disorders of the orbit that are associated with strabismus, including craniofacial malformations, orbital masses, trauma, and anomalous orbital structures. PMID:26180465

  17. Harmonically excited orbital variations

    SciTech Connect

    Morgan, T.

    1985-08-06

    Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs.

  18. Orbit Stabilization of Nanosat

    SciTech Connect

    JOHNSON,DAVID J.

    1999-12-01

    An algorithm is developed to control a pulsed {Delta}V thruster on a small satellite to allow it to fly in formation with a host satellite undergoing time dependent atmospheric drag deceleration. The algorithm uses four short thrusts per orbit to correct for differences in the average radii of the satellites due to differences in drag and one thrust to symmetrize the orbits. The radial difference between the orbits is the only input to the algorithm. The algorithm automatically stabilizes the orbits after ejection and includes provisions to allow azimuthal positional changes by modifying the drag compensation pulses. The algorithm gives radial and azimuthal deadbands of 50 cm and 3 m for a radial measurement accuracy of {+-} 5 cm and {+-} 60% period variation in the drag coefficient of the host. Approaches to further reduce the deadbands are described. The methodology of establishing a stable orbit after ejection is illustrated in an appendix. The results show the optimum ejection angle to minimize stabilization thrust is upward at 86{sup o} from the orbital velocity. At this angle the stabilization velocity that must be supplied by the thruster is half the ejection velocity. An ejection velocity of 0.02 m/sat 86{sup o} gives an azimuthal separation after ejection and orbit stabilization of 187 m. A description of liquid based gas thrusters suitable for the satellite control is included in an appendix.

  19. OL- ORBITAL LIFETIME PROGRAM

    NASA Technical Reports Server (NTRS)

    Orr, L. H.

    1994-01-01

    The Orbital Lifetime (OL) program analyzes the long-term motion of Earth-orbiting spacecraft at altitudes of up to 2500 kilometers. It models perturbations to the orbit caused by solar radiation pressure, atmospheric drag, and gravitational effects due to the sun, the moon, and Earth oblateness. OL can be used to predict the orbital lifetime and decay rate of a satellite. The atmospheric density models used in OL are the U.S. Standard Atmosphere for altitudes below 90 km and the Jacchia model for altitudes above 90 km. The Jacchia model requires solar flux and geomagnetic index for the date of orbit. An input file containing these values for 1984 to 1998 is supplied with the OL package. The solar radiation pressure calculations in OL will predict the amount of time a spacecraft is subjected to the Earth's shadow. Input to OL includes spacecraft physical characteristics, initial orbit parameters, and launch date/time. OL calculates time histories of the orbital elements, total lifetime, and decay rates. A spacecraft is considered 'down' at an altitude of 64 km. OL also generates a file of plot data which can be input to a user-supplied graphics program for lifetime plots of altitude against time. OL is written in FORTRAN 77 for interactive or batch execution and has been implemented on a DEC VAX series computer operating under VMS. This program was developed in 1985.

  20. How well do we really know short--arc KBO orbital elements?

    NASA Astrophysics Data System (ADS)

    Wasserman, L. H.

    2001-11-01

    Orbital elements for KBOs are published by the Minor Planet Center once an object has been observed twice in a single apparition. Such orbits are typically derived from an observational arc that may only be one month long and can be as short as a day or two. Such a relatively short arc requires that at least some assumptions be made to obtain the elements -- typically that the orbit is circular or that the object was observed at perihelion or aphelion (the Väisälä assumption). Later observations will refine the elements and improve the accuracy of the orbital elements. But, some objects are never followed up, and are effectively lost -- their orbits are never improved. The MPC publishes orbits without any indication of the uncertainties in the elements. As a result, orbital elements for all KBOs have been included in published graphs and statistics as though they had zero error, even though some of the objects may have large but unknown errors in their elements. We have investigated how our knowledge of KBO orbital elements: the semi-major axis, the eccentricity, and the inclination; as well as a derived quantity: the heliocentric distance at the time of discovery, improve with increasing observational arc using a monte--carlo method. KBO ``observations'' are generated using random KBO--like orbits. Orbital elements from these ``observations'' (with added noise) are calculated using both the ``traditional'' Väisälä method and the formalism of Bernstein and Khushalani (2000). The derived elements can then be compared with the known input elements to see how well the starting orbital parameters are recovered. Results derived from 400 ``test particles'' with orbital arcs of 2 hours, 30 days, 60 days, and 1 year will be presented. As a sanity check, we have also performed the same test on real KBO observations and find similar results. This work is supported by NASA grants NAG5-8990 and NAG5-11058. Reference: Bernstein, G. and Khushalani, B. 2000, AJ, 120, 3323.

  1. Removal of orbital debris

    NASA Technical Reports Server (NTRS)

    Petro, Andrew J.; Talent, David L.

    1989-01-01

    The several methods presently identified for the reduction of orbital debris populations are broadly classifiable as either preventive or remedial, and fall within distinctive operational regimes. For all particles, (1) in the 250-2000-km altitude band, intelligent sweepers may be used; (2) for large objects, in the 80-250-km altitude band, orbital decay renders removal impractical; (3) for the 250-750-km altitude band, deorbit devices should be used; (4) for 750-2500-km altitude, OMV rendezvous for propulsive deorbit package attachment is foreseeable; and beyond 2500 km, (5) propulsive escape from earth orbit is required.

  2. Orbit Determination Issues for Libration Point Orbits

    NASA Technical Reports Server (NTRS)

    Beckman, Mark; Bauer, Frank (Technical Monitor)

    2002-01-01

    Libration point mission designers require knowledge of orbital accuracy for a variety of analyses including station keeping control strategies, transfer trajectory design, and formation and constellation control. Past publications have detailed orbit determination (OD) results from individual libration point missions. This paper collects both published and unpublished results from four previous libration point missions (ISEE (International Sun-Earth Explorer) -3, SOHO (Solar and Heliospheric Observatory), ACE (Advanced Composition Explorer) and MAP (Microwave Anisotropy Probe)) supported by Goddard Space Flight Center's Guidance, Navigation & Control Center. The results of those missions are presented along with OD issues specific to each mission. All past missions have been limited to ground based tracking through NASA ground sites using standard range and Doppler measurement types. Advanced technology is enabling other OD options including onboard navigation using seaboard attitude sensors and the use of the Very Long Baseline Interferometry (VLBI) measurement Delta Differenced One-Way Range (DDOR). Both options potentially enable missions to reduce coherent dedicated tracking passes while maintaining orbital accuracy. With the increased projected loading of the DSN (Deep Space Network), missions must find alternatives to the standard OD scenario.

  3. ARTEMIS Orbits Magnetic Moon

    NASA Video Gallery

    NASA's THEMIS spacecraft have completed their mission and are still working perfectly, so NASA is re-directing the outermost two spacecraft to special orbits around the Moon. Now called ARTEMIS, th...

  4. Space Shuttle Orbiter ECLSS.

    NASA Technical Reports Server (NTRS)

    Stoll, O. T.; Laubach, G. E.; Gibb, J. W.

    1973-01-01

    The Orbiter Environmental Control and Life Support System (ECLSS) provides the functions of atmosphere revitalization, crew life support, active thermal conditioning, and airlock support for EVA and docking activities. The ECLSS must satisfy the requirements of orbital missions with four to ten crewmembers and mission duration of a few hours to 30 days and the requirements associated with an atmospheric horizontal flight test program and ferry flight missions. The ECLSS development plan utilizes an ECLSS ground test article and thermal/vacuum testing to support the first horizontal flight test at the end of 1976. The ground testing and horizontal flight test program certify the Orbiter ECLSS for the first orbital flight in early 1978.

  5. MMS Orbit Animation

    NASA Video Gallery

    This animation shows the orbits of Magnetospheric Multiscale (MMS)mission, a Solar Terrestrial Probes mission comprising of fouridentically instrumented spacecraft that will study the Earth’sm...

  6. Optical orbital debris spotter

    NASA Astrophysics Data System (ADS)

    Englert, Christoph R.; Bays, J. Timothy; Marr, Kenneth D.; Brown, Charles M.; Nicholas, Andrew C.; Finne, Theodore T.

    2014-11-01

    The number of man-made debris objects orbiting the Earth, or orbital debris, is alarmingly increasing, resulting in the increased probability of degradation, damage, or destruction of operating spacecraft. In part, small objects (<10 cm) in Low Earth Orbit (LEO) are of concern because they are abundant and difficult to track or even to detect on a routine basis. Due to the increasing debris population it is reasonable to assume that improved capabilities for on-orbit damage attribution, in addition to increased capabilities to detect and track small objects are needed. Here we present a sensor concept to detect small debris with sizes between approximately 1.0 and 0.01 cm in the vicinity of a host spacecraft for near real time damage attribution and characterization of dense debris fields and potentially to provide additional data to existing debris models.

  7. Orbiter entry aerothermodynamics

    NASA Technical Reports Server (NTRS)

    Ried, R. C.

    1985-01-01

    The challenge in the definition of the entry aerothermodynamic environment arising from the challenge of a reliable and reusable Orbiter is reviewed in light of the existing technology. Select problems pertinent to the orbiter development are discussed with reference to comprehensive treatments. These problems include boundary layer transition, leeward-side heating, shock/shock interaction scaling, tile gap heating, and nonequilibrium effects such as surface catalysis. Sample measurements obtained from test flights of the Orbiter are presented with comparison to preflight expectations. Numerical and wind tunnel simulations gave efficient information for defining the entry environment and an adequate level of preflight confidence. The high quality flight data provide an opportunity to refine the operational capability of the orbiter and serve as a benchmark both for the development of aerothermodynamic technology and for use in meeting future entry heating challenges.

  8. Report on orbital debris

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The success of space endeavors depends upon a space environment sufficiently free of debris to enable the safe and dependable operation of spacecraft. An environment overly cluttered with debris would threaten the ability to utilize space for a wide variety of scientific, technological, military, and commercial purposes. Man made space debris (orbital debris) differs from natural meteoroids because it remains in earth orbit during its lifetime and is not transient through the space around the Earth. The orbital debris environment is considered. The space environment is described along with sources of orbital debris. The current national space policy is examined, along with ways to minimize debris generation and ways to survive the debris environment. International efforts, legal issues and commercial regulations are also examined.

  9. Altimetry, Orbits and Tides

    NASA Technical Reports Server (NTRS)

    Colombo, O. L.

    1984-01-01

    The nature of the orbit error and its effect on the sea surface heights calculated with satellite altimetry are explained. The elementary concepts of celestial mechanics required to follow a general discussion of the problem are included. Consideration of errors in the orbits of satellites with precisely repeating ground tracks (SEASAT, TOPEX, ERS-1, POSEIDON, amongst past and future altimeter satellites) are detailed. The theoretical conclusions are illustrated with the numerical results of computer simulations. The nature of the errors in this type of orbits is such that this error can be filtered out by using height differences along repeating (overlapping) passes. This makes them particularly valuable for the study and monitoring of changes in the sea surface, such as tides. Elements of tidal theory, showing how these principles can be combined with those pertinent to the orbit error to make direct maps of the tides using altimetry are presented.

  10. Habitability study shuttle orbiter

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Habitability design concepts for the Shuttle Orbiter Program are provided for MSC. A variety of creative solutions for the stated tasks are presented. Sketches, mock-ups, mechanicals and models are included for establishing a foundation for future development.

  11. Tethered orbital refueling study

    NASA Technical Reports Server (NTRS)

    Fester, Dale A.; Rudolph, L. Kevin; Kiefel, Erlinda R.; Abbott, Peter W.; Grossrode, Pat

    1986-01-01

    One of the major applications of the space station will be to act as a refueling depot for cryogenic-fueled space-based orbital transfer vehicles (OTV), Earth-storable fueled orbit maneuvering vehicles, and refurbishable satellite spacecraft using hydrazine. One alternative for fuel storage at the space station is a tethered orbital refueling facility (TORF), separated from the space station by a sufficient distance to induce a gravity gradient force that settles the stored fuels. The technical feasibility was examined with the primary focus on the refueling of LO2/LH2 orbital transfer vehicles. Also examined was the tethered facility on the space station. It was compared to a zero-gravity facility. A tethered refueling facility should be considered as a viable alternative to a zero-gravity facility if the zero-gravity fluid transfer technology, such as the propellant management device and no vent fill, proves to be difficult to develop with the required performance.

  12. Orbiter thermal protection system

    NASA Technical Reports Server (NTRS)

    Dotts, R. L.; Curry, D. M.; Tillian, D. J.

    1985-01-01

    The major material and design challenges associated with the orbiter thermal protection system (TPS), the various TPS materials that are used, the different design approaches associated with each of the materials, and the performance during the flight test program are described. The first five flights of the Orbiter Columbia and the initial flight of the Orbiter Challenger provided the data necessary to verify the TPS thermal performance, structural integrity, and reusability. The flight performance characteristics of each TPS material are discussed, based on postflight inspections and postflight interpretation of the flight instrumentation data. Flights to date indicate that the thermal and structural design requirements for the orbiter TPS are met and that the overall performance is outstanding.

  13. Photographic observations of Neuschwanstein, a second meteorite from the orbit of the Príbram chondrite.

    PubMed

    Spurný, Pavel; Oberst, Jürgen; Heinlein, Dieter

    2003-05-08

    Photographic observations of meteoroids passing through the atmosphere provide information about the population of interplanetary bodies in the Earth's vicinity in the size range from 0.1 m to several metres. It is extremely rare that any of these meteoroids survives atmospheric entry to be recovered as a meteorite on the ground. Príbram was the first meteorite (an ordinary chondrite) with a photographically determined orbit; it fell on 7 April 1959 (ref. 1). Here we report the fourth meteorite fall to be captured by camera networks. We determined the atmospheric trajectory and pre-atmospheric orbit of the object from the photographic records. One 1.75-kg meteorite--named Neuschwanstein and classified as an enstatite chondrite--was recovered within the predicted impact area. The bolide's heliocentric orbit is exceptional as it is almost identical to the orbit of Príbram, suggesting that we have discovered a 'stream' of meteoritic objects in an Earth-crossing orbit. The chemical classifications and cosmic-ray exposure ages of the two meteorites are quite different, however, which implies a heterogeneous stream.

  14. A tapestry of orbits

    SciTech Connect

    King-Hele, D.

    1992-01-01

    In this book, the author describes how orbital research developed to yield a rich harvest of knowledge about the earth and its atmosphere. King-Hele relates a personal account of this research based on analysis of satellite orbits between 1957 and 1990 conducted from the Royal Aircraft Establishment in Farnborough England. The early research methods used before the launch of Sputnik in 1957 are discussed.

  15. The Lunar Orbital Prospector

    NASA Technical Reports Server (NTRS)

    Redd, Frank J.; Cantrell, James N.; Mccurdy, Greg

    1992-01-01

    The establishment of lunar bases will not end the need for remote sensing of the lunar surface by orbiting platforms. Human and robotic surface exploration will necessarily be limited to some proximate distance from the support base. Near real-time, high-resolution, global characterization of the lunar surface by orbiting sensing systems will continue to be essential to the understanding of the Moon's geophysical structure and the location of exploitable minerals and deposits of raw materials. The Lunar Orbital Prospector (LOP) is an orbiting sensing platform capable of supporting a variety of modular sensing packages. Serviced by a lunar-based shuttle, the LOP will permit the exchange of instrument packages to meet evolving mission needs. The ability to recover, modify, and rotate sensing packages allows their reuse in varying combinations. Combining this flexibility with robust orbit modification capabilities and near real-time telemetry links provides considerable system responsiveness. Maintenance and modification of the LOP orbit are accomplished through use of an onboard propulsion system that burns lunar-supplied oxygen and aluminum. The relatively low performance of such a system is more than compensated for by the elimination of the need for Earth-supplied propellants. The LOP concept envisions a continuous expansion of capability through the incorporation of new instrument technologies and the addition of platforms.

  16. The Exoplanet Orbit Database

    NASA Astrophysics Data System (ADS)

    Wright, J. T.; Fakhouri, O.; Marcy, G. W.; Han, E.; Feng, Y.; Johnson, John Asher; Howard, A. W.; Fischer, D. A.; Valenti, J. A.; Anderson, J.; Piskunov, N.

    2011-04-01

    We present a database of well-determined orbital parameters of exoplanets, and their host stars’ properties. This database comprises spectroscopic orbital elements measured for 427 planets orbiting 363 stars from radial velocity and transit measurements as reported in the literature. We have also compiled fundamental transit parameters, stellar parameters, and the method used for the planets discovery. This Exoplanet Orbit Database includes all planets with robust, well measured orbital parameters reported in peer-reviewed articles. The database is available in a searchable, filterable, and sortable form online through the Exoplanets Data Explorer table, and the data can be plotted and explored through the Exoplanet Data Explorer plotter. We use the Data Explorer to generate publication-ready plots, giving three examples of the signatures of exoplanet migration and dynamical evolution: We illustrate the character of the apparent correlation between mass and period in exoplanet orbits, the different selection biases between radial velocity and transit surveys, and that the multiplanet systems show a distinct semimajor-axis distribution from apparently singleton systems.

  17. New Heteroclinic Orbits Coined

    NASA Astrophysics Data System (ADS)

    Wang, Haijun; Li, Chang; Li, Xianyi

    We devote to studying the problem for the existence of homoclinic and heteroclinic orbits of Unified Lorenz-Type System (ULTS). Other than the known results that the ULTS has two homoclinic orbits to E0 = (0, 0, 0) for b = -2a1, d = -a1, a12 + a 2c > 0, e < 0 and two heteroclinic orbits to E1,2 = (±-2(a1 2+a2 c) e ,∓a1 a2 -2(a1 2+a2 c) e ,-a12+a2c a2e ) for b = -2a1, d = -a1, a12 + a 2c < 0, e > 0 on its invariant algebraic surface Q(x,y,z) = z - x2 2a2 = 0, formulated in the literature by Yang and Chen [2014], we seize two new heteroclinic orbits of this Unified Lorenz-Type System. Namely, we rigorously prove that this system has another two heteroclinic orbits to E0 and E± = (±b(a2 c-a1 d) a1e ,∓a1 a2 b(a2 c-a1 d) a1e , a1d-a2c a2e ) while no homoclinic orbit when a1 < 0, e < 0, a1 + d < 0, a2≠0, a2c - a1d > 0, b + 2a1 ≥ 0.

  18. Overall view of the Orbiter Servicing Structure within the Orbiter ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Overall view of the Orbiter Servicing Structure within the Orbiter Processing Facility at Kennedy Space Center. Can you see any hint of the Orbiter Discovery? It is in there. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  19. [Orbital complications of sinusitis].

    PubMed

    Šuchaň, M; Horňák, M; Kaliarik, L; Krempaská, S; Koštialová, T; Kovaľ, J

    2014-12-01

    Orbital complications categorised by Chandler are emergency. They need early diagnosis and agresive treatment. Stage and origin of orbital complications are identified by rhinoendoscopy, ophtalmologic examination and CT of orbite and paranasal sinuses. Periorbital cellulitis and early stage of orbital cellulitis can be treated conservatively with i. v. antibiotics. Monitoring of laboratory parameters and ophtalmologic symptoms is mandatory. Lack of improvement or worsening of symptoms within 24-48 hours and advanced stages of orbital complications are indicated for surgery. The purpose of the study is to evaluate epidemiology, clinical features and management of sinogenic orbital complications. Retrospective data of 8 patients with suspicion of orbital complication admited to hospital from 2008 to 2013 were evaluated. Patients were analyzed in terms of gender, age, CT findings, microbiology, clinical features, stage and treatment. Male and female were afected in rate 1,66:1. Most of patients were young adult in 3rd. and 4th. decade of life (62,5 %). Acute and chronic sinusitis were cause of orbital complication in the same rate. The most common origin of orbital complication was ethmoiditis (62,5 %), than maxillary (25 %) and frontal (12,5 %) sinusitis. Polysinusitis with affection of ethmoidal, maxillary and frontal sinuses (75 %) was usual CT finding. Staphylococcus epidermidis and Staphylococcus aureus were etiological agens in half of cases. Periorbital oedema (100 %), proptosis, chemosis (50 %), diplopia and glaucoma (12,5 %) were observed. Based on examinations, diagnosis of periorbital oedema/preseptal cellulitis was made in 3 (37,5 %), orbital cellulitis in 3 (37,5 %) and subperiosteal abscess in 2 cases (25 %). All patients underwent combined therapy - i. v. antibiotics and surgery within 24 hours. Eradication of disease from ostiomeatal complex (OMC), drainage of affected sinuses and drainage of subperiosteal abscess were done via fuctional endonasal

  20. Interplanetary Coronal Mass Ejections from MESSENGER Orbital Observations at Mercury

    NASA Astrophysics Data System (ADS)

    Winslow, R. M.; Lugaz, N.; Philpott, L. C.; Schwadron, N.; Farrugia, C. J.; Anderson, B. J.; Smith, C. W.

    2015-12-01

    We use observations from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, in orbit around Mercury, to investigate interplanetary coronal mass ejections (ICMEs) near 0.3 AU. MESSENGER, the first spacecraft since the 1980s to make in-situ measurements at distances < 0.5 AU, presents a unique opportunity for observing the innermost heliosphere. It also allows studies of ICME evolution as they expand and propagate outward, interacting with the solar wind. In order to catalog ICME events observed by MESSENGER, we design a strict set of selection criteria to identify them based on magnetic field observations only, since reliable solar wind plasma observations are not available from MESSENGER. We identify 61 ICME events observed by the MESSENGER Magnetometer between 2011 and 2014, and present statistical analyses of ICME properties at Mercury. In addition, using existing datasets of ICMEs at 1 AU we investigate key ICME property changes from Mercury to 1 AU. We find good agreement with previous studies for the magnetic field strength dependence on heliospheric distance, r. We have also established three different lines of evidence that ICME deceleration continues beyond the orbit of Mercury: 1) we find a shallow decrease with distance of ˜r-0.45 for the ICME shock speed from Mercury to 1 AU, 2) the average transit speed from the Sun to Mercury for ICMEs in our catalog is ˜20% faster than the average speed from the Sun to 1 AU, 3) the ICME transit time to 1 AU has a weaker dependence on the CME initial coronagraphic speed, as compared to what we predict based on our MESSENGER ICME catalog. Based on our results, future ICME propagation studies should account for ICME speed changes beyond Mercury's heliocentric distances to improve ICME arrival time forecasting. Our ICME database will also prove particularly useful for multipoint spacecraft studies of recent ICMEs, as well as for model validation of ICME properties.

  1. The Trajectory, Orbit and Preliminary Fall Data of the JUNE BOOTID Superbolide of July 23, 2008

    NASA Technical Reports Server (NTRS)

    Konovalova, N. A.; Madiedo, J. M.; Trigo-Rodriguez, J. M.

    2011-01-01

    The results of the atmospheric trajectory, radiant, orbit and preliminary fall data calculations of an extremely bright slow-moving fireball are presented. The fireball had a -20.7 maximum absolute magnitude and the spectacular long-persistence dust trail (Fig 1 and 2) was observed in a widespread region of Tajikistan twenty eight minutes after sunset, precisely at 14h 45m 25s UT on July 23, 2008. The bolide was first recorded at a height of 38.2 km, and attained its maximum brightness at a height of 35.0 km and finished at a height of 19.6 km. These values are very much in line with other well-known fireballs producing meteorites. The first break-up must have occurred under an aerodynamic pressure Pdyn of about 1.5 MPa, similar to those derived from the study of atmospheric break-ups of previously reported meteorite-dropping bolides. Our trajectory, and dynamic results suggest that one might well expect to find meteorites on the ground in this case. The heliocentric orbit of the meteoroid determined from the observations is very similar to the mean orbit of the June Bootid meteor shower, whose parental comet is 7P/Pons-Winnecke (Lindblad et al. 2003). If the parent was indeed a comet, this has implications for the internal structure of comets, and for the survivability of cometary meteorites.

  2. Mars Geoscience Orbiter and Lunar Geoscience Orbiter

    NASA Technical Reports Server (NTRS)

    Fuldner, W. V.; Kaskiewicz, P. F.

    1983-01-01

    The feasibility of using the AE/DE Earth orbiting spacecraft design for the LGO and/or MGO missions was determined. Configurations were developed and subsystems analysis was carried out to optimize the suitability of the spacecraft to the missions. The primary conclusion is that the basic AE/DE spacecraft can readily be applied to the LGO mission with relatively minor, low risk modifications. The MGO mission poses a somewhat more complex problem, primarily due to the overall maneuvering hydrazine budget and power requirements of the sensors and their desired duty cycle. These considerations dictate a modification (scaling up) of the structure to support mission requirements.

  3. Sedna Orbit Comparisons

    NASA Technical Reports Server (NTRS)

    2004-01-01

    These four panels show the location of the newly discovered planet-like object, dubbed 'Sedna,' which lies in the farthest reaches of our solar system. Each panel, moving counterclockwise from the upper left, successively zooms out to place Sedna in context. The first panel shows the orbits of the inner planets, including Earth, and the asteroid belt that lies between Mars and Jupiter. In the second panel, Sedna is shown well outside the orbits of the outer planets and the more distant Kuiper Belt objects. Sedna's full orbit is illustrated in the third panel along with the object's current location. Sedna is nearing its closest approach to the Sun; its 10,000 year orbit typically takes it to far greater distances. The final panel zooms out much farther, showing that even this large elliptical orbit falls inside what was previously thought to be the inner edge of the Oort cloud. The Oort cloud is a spherical distribution of cold, icy bodies lying at the limits of the Sun's gravitational pull. Sedna's presence suggests that this Oort cloud is much closer than scientists believed.

  4. Orbital spacecraft resupply technology

    NASA Technical Reports Server (NTRS)

    Eberhardt, R. N.; Tracey, T. R.; Bailey, W. J.

    1986-01-01

    The resupplying of orbital spacecraft using the Space Shuttle, Orbital Maneuvering Vehicle, Orbital Transfer Vehicle or a depot supply at a Space Station is studied. The governing factor in fluid resupply designs is the system size with respect to fluid resupply quantities. Spacecraft propellant management for tankage via diaphragm or surface tension configurations is examined. The capabilities, operation, and application of adiabatic ullage compression, ullage exchange, vent/fill/repressurize, and drain/vent/no-vent fill/repressurize, which are proposed transfer methods for spacecraft utilizing tankage configurations, are described. Selection of the appropriate resupply method is dependent on the spacecraft design features. Hydrazine adiabatic compression/detonation, liquid-free vapor venting to prevent freezing, and a method for no-vent liquid filling are analyzed. Various procedures for accurate measurements of propellant mass in low gravity are evaluated; a system of flowmeters with a PVT system was selected as the pressurant solubility and quantity gaging technique. Monopropellant and bipropellant orbital spacecraft consumable resupply system tanks which resupply 3000 lb of hydrazine and 7000 lb of MMH/NTO to spacecraft on orbit are presented.

  5. Orbits For Sixteen Binaries

    NASA Astrophysics Data System (ADS)

    Cvetkovic, Z.; Novakovic, B.

    2006-12-01

    In this paper orbits for 13 binaries are recalculated and presented. The reason is that recent observations show higher residuals than the corresponding ephemerides calculated by using the orbital elements given in the Sixth Catalog of Orbits of Visual Binary Stars. The binaries studied were: WDS 00182+7257 = A 803, WDS 00335+4006 = HO 3, WDS 00583+2124 = BU 302, WDS 01011+6022 = A 926, WDS 01014+1155 = BU 867, WDS 01112+4113 = A 655, WDS 01361-2954 + HJ 3447, WDS 02333+5219 = STT 42 AB, WDS 04362+0814 = A 1840 AB, WDS 08017-0836 = A 1580, WDS 08277-0425 = A 550, WDS 17471+1742 = STF 2215 and WDS 18025+4414 = BU 1127 Aa-B. In addition, for three binaries - WDS 01532+1526 = BU 260, WDS 02563+7253 =STF 312 AB and WDS 05003+3924 = STT 92 AB - the orbital elements are calculated for the first time. In this paper the authors present not only the orbital elements, but the masses, dynamical parallaxes, absolute magnitudes and ephemerides for the next five years, as well.

  6. Orbital Fluid Resupply Assessment

    NASA Technical Reports Server (NTRS)

    Eberhardt, Ralph N.

    1989-01-01

    Orbital fluid resupply can significantly increase the cost-effectiveness and operational flexibility of spacecraft, satellites, and orbiting platforms and observatories. Reusable tankers are currently being designed for transporting fluids to space. A number of options exist for transporting the fluids and propellant to the space-based user systems. The fluids can be transported to space either in the Shuttle cargo bay or using expendable launch vehicles (ELVs). Resupply can thus be accomplished either from the Shuttle bay, or the tanker can be removed from the Shuttle bay or launched on an ELV and attached to a carrier such as the Orbital Maneuvering Vehicle (OMV) or Orbital Transfer Vehicle (OTV) for transport to the user to be serviced. A third option involves locating the tanker at the space station or an unmanned platform as a quasi-permanent servicing facility or depot which returns to the ground for recycling once its tanks are depleted. Current modular tanker designs for monopropellants, bipropellants, and water for space station propulsion are discussed. Superfluid helium tankers are addressed, including trade-offs in tanker sizes, shapes to fit the range of ELVs currently available, and boil-off losses associated with longer-term (greater than 6-month) space-basing. It is concluded that the mixed fleet approach to on-orbit consumables resupply offers significant advantages to the overall logistics requirements.

  7. GOCE Precise Science Orbits

    NASA Astrophysics Data System (ADS)

    Bock, Heike; Jäggi, Adrian; Meyer, Ulrich; Beutler, Gerhard; Heinze, Markus; Hugentobler, Urs

    GOCE (Gravity field and steady-state Ocean Circulation Explorer), as the first ESA (European Space Agency) Earth Explorer Core Mission, is dedicated for gravity field recovery of unprece-dented accuracy using data from the gradiometer, its primary science instrument. Data from the secondary instrument, the 12-channel dual-frequency GPS (Global Positioning System) receiver, is used for precise orbit determination of the satellite. These orbits are used to accu-rately geolocate the gradiometer observations and to provide complementary information for the long-wavelength part of the gravity field. A precise science orbit (PSO) product is provided by the GOCE High-Level Processing Facility (HPF) with a precision of about 2 cm and a 1-week latency. The reduced-dynamic and kinematic orbit determination strategies for the PSO product are presented together with results of about one year of data. The focus is on the improvement achieved by the use of empirically derived azimuth-and elevation-dependent variations of the phase center of the GOCE GPS antenna. The orbits are validated with satellite laser ranging (SLR) measurements.

  8. Mars Telecommunications Orbiter, Artist's Concept

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This illustration depicts a concept for NASA's Mars Telecommunications Orbiter in flight around Mars. The orbiter is in development to be the first spacecraft with a primary function of providing communication links while orbiting a foreign planet. The project's plans call for launch in September 2009, arrival at Mars in August 2010 and a mission of six to 10 years while in orbit. Mars Telecommunication Orbiter would serve as the Mars hub for an interplanetery Internet, greatly increasing the information payoff from other future Mars missions. The mission is designed to orbit Mars more than 10 times farther from the planet than orbiters dedicated primarily to science. The high-orbit design minimizes the time that Mars itself blocks the orbiter from communicating with Earth and maximizes the time that the orbiter is above the horizon -- thus capable of communications relay -- for rovers and stationary landers on Mars' surface.

  9. On the asteroid belt's orbital and size distribution

    NASA Astrophysics Data System (ADS)

    Gladman, Brett J.; Davis, Donald R.; Neese, Carol; Jedicke, Robert; Williams, Gareth; Kavelaars, J. J.; Petit, Jean-Marc; Scholl, Hans; Holman, Matthew; Warrington, Ben; Esquerdo, Gil; Tricarico, Pasquale

    2009-07-01

    For absolute magnitudes greater than the current completeness limit of H-magnitude ∼15 the main asteroid belt's size distribution is imperfectly known. We have acquired good-quality orbital and absolute H-magnitude determinations for a sample of small main-belt asteroids in order to study the orbital and size distribution beyond H = 15, down to sub-kilometer sizes (H > 18). Based on six observing nights over a 11-night baseline we have detected, measured photometry for, and linked observations of 1087 asteroids which have one-week time baselines or more. The linkages allow the computation of full heliocentric orbits (as opposed to statistical distances determined by some past surveys). Judged by known asteroids in the field the typical uncertainty in the (a / e / i) orbital elements is less than 0.03 AU/0.03/0.5°. The distances to the objects are sufficiently well known that photometric uncertainties (of 0.3 magnitudes or better) dominate the error budget of their derived H-magnitudes. The detected asteroids range from HR = 12- 22 and provide a set of objects down to sizes below 1 km in diameter. We find an on-sky surface density of 210 asteroids per square degree in the ecliptic with opposition magnitudes brighter than mR = 23, with the cumulative number of asteroids increasing by a factor of 100.27/mag from mR = 18 down to the mR ≃ 23.5 limit of our survey. In terms of absolute H magnitudes, we find that beyond H = 15 the belt exhibits a constant power-law slope with the number increasing proportional to 100.30H from H ≃ 15 to 18, after which incompleteness begins in the survey. Examining only the subset of detections inside 2.5 AU, we find weak evidence for a mildly shallower slope for H = 15- 19.5. We provide the information necessary such that anyone wishing to model the main asteroid belt can compare a detailed model to our detected sample.

  10. Vertical orbital dystopia.

    PubMed

    Tan, S T; Ashworth, G; Czypionka, S; Poole, M D; Briggs, M

    1996-06-01

    Many pathologic processes may lead to vertical orbital dystopia. We reviewed 47 consecutive cases seen over a 13-year period. Twenty-nine patients underwent eye leveling procedures to improve cosmesis, 2 of these by camouflage procedures and 27 by orbital translocation. Ten patients had 16 secondary operations. There was one death, serious complications occurred in 3 patients, and nuisance complications occurred in 20 others. Seven patients developed diplopia postoperatively, and in 6 patients it was troublesome. In these, it resolved fully in 2 patients, improved to be of no consequence in 2, and in the remaining 2 troublesome symptoms persisted requiring inferior oblique muscle recession in 1. Binocular vision was never restored when not present preoperatively, and in 3 patients temporary loss occurred. There was an overall modest but significant improvement in appearance after surgery. It is concluded that vertical orbital translocation is rewarding and worthwhile.

  11. Deceleration Orbit Improvements

    SciTech Connect

    Church, M.

    1991-04-26

    During the accelerator studies period of 12/90-1/91 much study time was dedicated to improving the E760 deceleration ramps. 4 general goals were in mind: (1) Reduce the relative orbit deviations from the nominal reference orbit as much as possible. This reduces the potential error in the orbit length calculation - which is the primary source of error in the beam energy calculation. (2) Maximize the transverse apertures. This minimizes beam loss during deceleration and during accidental beam blow-ups. (3) Measure and correct lattice parameters. Knowledge of {gamma}{sub T}, {eta}, Q{sub h}, Q{sub v}, and the dispersion in the straight sections allows for a more accurate energy calculation and reliable SYNCH calculations. (4) Minimize the coupling. This allows one to discern between horizontal and vertical tunes.

  12. Spiral Orbit Tribometer

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.; Jones, William R., Jr.; Kingsbury, Edward; Jansen, Mark J.

    2007-01-01

    The spiral orbit tribometer (SOT) bridges the gap between full-scale life testing and typically unrealistic accelerated life testing of ball-bearing lubricants in conjunction with bearing ball and race materials. The SOT operates under realistic conditions and quickly produces results, thereby providing information that can guide the selection of lubricant, ball, and race materials early in a design process. The SOT is based upon a simplified, retainerless thrust bearing comprising one ball between flat races (see figure). The SOT measures lubricant consumption and degradation rates and friction coefficients in boundary lubricated rolling and pivoting contacts. The ball is pressed between the lower and upper races with a controlled force and the lower plate is rotated. The combination of load and rotation causes the ball to move in a nearly circular orbit that is, more precisely, an opening spiral. The spiral s pitch is directly related to the friction coefficient. At the end of the orbit, the ball contacts the guide plate, restoring the orbit to its original radius. The orbit is repeatable throughout the entire test. A force transducer, mounted in-line with the guide plate, measures the force between the ball and the guide plate, which directly relates to the friction coefficient. The SOT, shown in the figure, can operate in under ultra-high vacuum (10(exp -9) Torr) or in a variety of gases at atmospheric pressure. The load force can be adjusted between 45 and 450 N. By varying the load force and ball diameter, mean Hertzian stresses between 0.5 and 5.0 GPa can be obtained. The ball s orbital speed range is between 1 and 100 rpm.

  13. Optical orbital angular momentum.

    PubMed

    Barnett, Stephen M; Babiker, Mohamed; Padgett, Miles J

    2017-02-28

    We present a brief introduction to the orbital angular momentum of light, the subject of our theme issue and, in particular, to the developments in the 13 years following the founding paper by Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)). The papers by our invited authors serve to bring the field up to date and suggest where developments may take us next.This article is part of the themed issue 'Optical orbital angular momentum'.

  14. Optical orbital angular momentum

    NASA Astrophysics Data System (ADS)

    Barnett, Stephen M.; Babiker, Mohamed; Padgett, Miles J.

    2017-02-01

    We present a brief introduction to the orbital angular momentum of light, the subject of our theme issue and, in particular, to the developments in the 13 years following the founding paper by Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)). The papers by our invited authors serve to bring the field up to date and suggest where developments may take us next. This article is part of the themed issue 'Optical orbital angular momentum'.

  15. Optical orbital angular momentum

    PubMed Central

    Barnett, Stephen M.; Babiker, Mohamed; Padgett, Miles J.

    2017-01-01

    We present a brief introduction to the orbital angular momentum of light, the subject of our theme issue and, in particular, to the developments in the 13 years following the founding paper by Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)). The papers by our invited authors serve to bring the field up to date and suggest where developments may take us next. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069775

  16. Satellite orbit predictor

    NASA Technical Reports Server (NTRS)

    Friedman, Morton l.; Garrett, James, Major

    An analog aid to determine satellite coverage of Emergency Locator Transmitters Emergency Position Indicating Radio Beacon (ELT/EPIRB) distress incidence is discussed. The satellite orbit predictor is a graphical aid for determining the relationship between the satellite orbit, antenna coverage of the spacecraft and coverage of the Local User Terminal. The predictor allows the user to quickly visualize if a selected position will probably be detected and is composed of a base map and a satellite track overlay for each satellite.A table of equator crossings for each satellite is included.

  17. DASTCOM5: A Portable and Current Database of Asteroid and Comet Orbit Solutions

    NASA Astrophysics Data System (ADS)

    Giorgini, Jon D.; Chamberlin, Alan B.

    2014-11-01

    A portable direct-access database containing all NASA/JPL asteroid and comet orbit solutions, with the software to access it, is available for download (ftp://ssd.jpl.nasa.gov/pub/xfr/dastcom5.zip; unzip -ao dastcom5.zip). DASTCOM5 contains the latest heliocentric IAU76/J2000 ecliptic osculating orbital elements for all known asteroids and comets as determined by a least-squares best-fit to ground-based optical, spacecraft, and radar astrometric measurements. Other physical, dynamical, and covariance parameters are included when known. A total of 142 parameters per object are supported within DASTCOM5. This information is suitable for initializing high-precision numerical integrations, assessing orbit geometry, computing trajectory uncertainties, visual magnitude, and summarizing physical characteristics of the body. The DASTCOM5 distribution is updated as often as hourly to include newly discovered objects or orbit solution updates. It includes an ASCII index of objects that supports look-ups based on name, current or past designation, SPK ID, MPC packed-designations, or record number. DASTCOM5 is the database used by the NASA/JPL Horizons ephemeris system. It is a subset exported from a larger MySQL-based relational Small-Body Database ("SBDB") maintained at JPL. The DASTCOM5 distribution is intended for programmers comfortable with UNIX/LINUX/MacOSX command-line usage who need to develop stand-alone applications. The goal of the implementation is to provide small, fast, portable, and flexibly programmatic access to JPL comet and asteroid orbit solutions. The supplied software library, examples, and application programs have been verified under gfortran, Lahey, Intel, and Sun 32/64-bit Linux/UNIX FORTRAN compilers. A command-line tool ("dxlook") is provided to enable database access from shell or script environments.

  18. ARTEMIS Lunar Orbit Insertion and Science Orbit Design Through 2013

    NASA Technical Reports Server (NTRS)

    Broschart, Stephen B.; Sweetser, Theodore H.; Angelopoulos, Vassilis; Folta, David; Woodard, Mark

    2015-01-01

    As of late-July 2011, the ARTEMIS mission is transferring two spacecraft from Lissajous orbits around Earth-Moon Lagrange Point #1 into highly-eccentric lunar science orbits. This paper presents the trajectory design for the transfer from Lissajous orbit to lunar orbit insertion, the period reduction maneuvers, and the science orbits through 2013. The design accommodates large perturbations from Earth's gravity and restrictive spacecraft capabilities to enable opportunities for a range of heliophysics and planetary science measurements. The process used to design the highly-eccentric ARTEMIS science orbits is outlined. The approach may inform the design of future planetary moon missions.

  19. Design of low-energy transfer from lunar orbit to asteroid in the Sun-Earth-Moon system

    NASA Astrophysics Data System (ADS)

    Wang, Ya-Min; Qiao, Dong; Cui, Ping-Yuan

    2014-12-01

    Asteroid exploration trajectories which start from a lunar orbit are investigated in this work. It is assumed that the probe departs from lunar orbit and returns to the vicinity of Earth, then escapes from the Earth by performing a perigee maneuver. A low-energy transfer in Sun-Earth-Moon system is adopted. First, the feasible region of low-energy transfer from lunar orbit to perigee within 5 000km height above the Earth surface in Sun-Earth-Moon system is calculated and analyzed. Three transfer types are found, i.e., large maneuver and fast transfers, small maneuver and fast transfers, and disordered and slow transfers. Most of feasibility trajectories belong to the first two types. Then, the low-energy trajectory leg from lunar orbit to perigee and a heliocentric trajectory leg from perigee to asteroid are patched by a perigee maneuver. The optimal full-transfer trajectory is obtained by exploiting the differential evolution algorithm. Finally, taking 4179 Toutatis asteroid as the target, some low-energy transfer trajectories are obtained and analyzed.

  20. Sedna Orbit Animation

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This animation shows the location of the newly discovered planet-like object, dubbed 'Sedna,' in relation to the rest of the solar system. Starting at the inner solar system, which includes the orbits of Mercury, Venus, Earth, and Mars (all in yellow), the view pulls away through the asteroid belt and the orbits of the outer planets beyond (green). Pluto and the distant Kuiper Belt objects are seen next until finally Sedna comes into view. As the field widens the full orbit of Sedna can be seen along with its current location. Sedna is nearing its closest approach to the Sun; its 10,000 year orbit typically takes it to far greater distances. Moving past Sedna, what was previously thought to be the inner edge of the Oort cloud appears. The Oort cloud is a spherical distribution of cold, icy bodies lying at the limits of the Sun's gravitational pull. Sedna's presence suggests that this Oort cloud is much closer than scientists believed.

  1. A Neptune Orbiter Mission

    NASA Technical Reports Server (NTRS)

    Wallace, R. A.; Spilker, T. R.

    1998-01-01

    This paper describes the results of new analyses and mission/system designs for a low cost Neptune Orbiter mission. Science and measurement objectives, instrumentation, and mission/system design options are described and reflect an aggressive approach to the application of new advanced technologies expected to be available and developed over the next five to ten years.

  2. [Orbital neoplasms in children].

    PubMed

    Küchle, H J

    1989-04-01

    The incidence, diagnosis and clinical picture of the orbital tumors in children are discussed on the basis of 49 personal cases. Discovered was the preponderance of primary non-malignant tumors. The most frequently encountered tumors were angiomas (27 p.c.), dermatomas (19 p.c.) lymphomas (8 p.c.) and among the malignant tumors--rhabdomyosarcoma (6 p.c.).

  3. Electrostatic drops in orbit

    NASA Astrophysics Data System (ADS)

    Rodriguez, Isabel J.; Schmidt, Erin; Weislogel, Mark M.; Pettit, Donald

    2016-11-01

    We present what we think are the first intentional electrostatic orbits in the near-weightless environment of a drop tower. Classical physics problems involving Coulombic forces in orbital mechanics have traditionally been confined to thought experiments due to practical terrestrial experimental limitations, namely, the preponderance of gravity. However, the use of a drop tower as an experimental platform can overcome this challenge for brief periods. We demonstrate methanol-water droplets in orbit around a variety of charged objects- some of which can be used to validate special cases of N-body systems. Footage collected via a high-speed camera is analyzed and orbital trajectories are compared with existing theoretical predictions. Droplets of diameters 0.5 to 2mm in a variety of obits are observed. Due to the repeatability of drop tower initial conditions and effective low-g environment, such experiments may be used to construct empirical analogues and confirm analyses toward the benefit of other fields including space and planetary science. NASA Cooperative Agreement NNX12A047A, Portland State LSAMP, Robert E. McNair Scholars Program.

  4. Mars Climate Orbiter

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Mars Surveyor '98 Climate Orbiter is shown here during acoustic tests that simulate launch conditions. The orbiter was to conduct a two year primary mission to profile the Martian atmosphere and map the surface. To carry out these scientific objectives, the spacecraft carried a rebuilt version of the pressure modulated infrared radiometer, lost with the Mars Observer spacecraft, and a miniaturized dual camera system the size of a pair of binoculars, provided by Malin Space Science Systems, Inc., San Diego, California. During its primary mission, the orbiter was to monitor Mars atmosphere and surface globally on a daily basis for one Martian year (two Earth years), observing the appearance and movement of atmospheric dust and water vapor, as well as characterizing seasonal changes of the planet's surface. Imaging of the surface morphology would also provide important clues about the planet's climate in its early history. The mission was part of NASA's Mars Surveyor program, a sustained program of robotic exploration of the red planet, managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, DC. Lockheed Martin Astronautics was NASA's industrial partner in the mission. Unfortunately, Mars Climate Orbiter burned up in the Martian atmosphere on September 23, 1999, due to a metric conversion error that caused the spacecraft to be off course.

  5. Orbital Fluid Transfer System

    NASA Technical Reports Server (NTRS)

    Johnston, A. S., (Nick); Ryder, Mel; Tyler, Tony R.

    1998-01-01

    An automated fluid and power interface system needs to be developed for future space missions which require on orbit consumable replenishment. Current method of fluid transfer require manned vehicles and extravehicular activity. Currently the US does not have an automated capability for consumable transfer on-orbit. This technology would benefit both Space Station and long duration satellites. In order to provide this technology the Automated Fluid Interface System (AFIS) was developed. The AFIS project was an advanced development program aimed at developing a prototype satellite servicer for future space operations. This mechanism could transfer propellants, cryogens, fluids, gasses, electrical power, and communications from a tanker unit to the orbiting satellite. The development of this unit was a cooperative effort between Marshall Space Flight Center in Huntsville, Alabama, and Moog, Inc. in East Aurora, New York. An engineering model was built and underwent substantial development testing at Marshall Space Flight Center (MSFC). While the AFIS is not suitable for spaceflight, testing and evaluation of the AFIS provided significant experience which would be beneficial in building a flight unit. The lessons learned from testing the AFIS provided the foundation for the next generation fluid transfer mechanism, the Orbital Fluid Transfer System (OFTS). The OFTS project was a study contract with MSFC and Moog, Inc. The OFTS was designed for the International Space Station (ISS), but its flexible design could used for long duration satellite missions and other applications. The OFTS was designed to be used after docking. The primary function was to transfer bipropellants and high pressure gases. The other items addressed by this task included propellant storage, hardware integration, safety and control system issues. A new concept for high pressure couplings was also developed. The results of the AFIS testing provided an excellent basis for the OFTS design. The OFTS

  6. Shuttle on-orbit rendezvous targeting: Circular orbits

    NASA Technical Reports Server (NTRS)

    Bentley, E. L.

    1972-01-01

    The strategy and logic used in a space shuttle on-orbit rendezvous targeting program are described. The program generates ascent targeting conditions for boost to insertion into an intermediate parking orbit, and generates on-orbit targeting and timeline bases for each maneuver to effect rendezvous with a space station. Time of launch is determined so as to eliminate any plane change, and all work was performed for a near-circular space station orbit.

  7. Comparison of Low Earth Orbit and Geosynchronous Earth Orbits

    NASA Technical Reports Server (NTRS)

    Drummond, J. E.

    1980-01-01

    The technological, environmental, social, and political ramifications of low Earth orbits as compared to geosynchronous Earth orbits for the solar power satellite (SPS) are assessed. The capital cost of the transmitting facilities is dependent on the areas of the antenna and rectenna relative to the requirement of high efficiency power transmission. The salient features of a low orbit Earth orbits are discussed in terms of cost reduction efforts.

  8. Close up view of the Orbiter Discovery in the Orbiter ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Close up view of the Orbiter Discovery in the Orbiter Processing Facility at Kennedy Space Center. The view is a detail of the aft, starboard landing gear and a general view of the Thermal Protection System tiles around the landing-gear housing. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  9. Helioseismology with Solar Orbiter

    NASA Astrophysics Data System (ADS)

    Löptien, Björn; Birch, Aaron C.; Gizon, Laurent; Schou, Jesper; Appourchaux, Thierry; Blanco Rodríguez, Julián; Cally, Paul S.; Dominguez-Tagle, Carlos; Gandorfer, Achim; Hill, Frank; Hirzberger, Johann; Scherrer, Philip H.; Solanki, Sami K.

    2015-12-01

    The Solar Orbiter mission, to be launched in July 2017, will carry a suite of remote sensing and in-situ instruments, including the Polarimetric and Helioseismic Imager (PHI). PHI will deliver high-cadence images of the Sun in intensity and Doppler velocity suitable for carrying out novel helioseismic studies. The orbit of the Solar Orbiter spacecraft will reach a solar latitude of up to 21∘ (up to 34∘ by the end of the extended mission) and thus will enable the first local helioseismology studies of the polar regions. Here we consider an array of science objectives to be addressed by helioseismology within the baseline telemetry allocation (51 Gbit per orbit, current baseline) and within the science observing windows (baseline 3×10 days per orbit). A particularly important objective is the measurement of large-scale flows at high latitudes (rotation and meridional flow), which are largely unknown but play an important role in flux transport dynamos. For both helioseismology and feature tracking methods convection is a source of noise in the measurement of longitudinally averaged large-scale flows, which decreases as T -1/2 where T is the total duration of the observations. Therefore, the detection of small amplitude signals (e.g., meridional circulation, flows in the deep solar interior) requires long observation times. As an example, one hundred days of observations at lower spatial resolution would provide a noise level of about three m/s on the meridional flow at 80∘ latitude. Longer time-series are also needed to study temporal variations with the solar cycle. The full range of Earth-Sun-spacecraft angles provided by the orbit will enable helioseismology from two vantage points by combining PHI with another instrument: stereoscopic helioseismology will allow the study of the deep solar interior and a better understanding of the physics of solar oscillations in both quiet Sun and sunspots. We have used a model of the PHI instrument to study its

  10. SPECS: Orbital debris removal

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The debris problem has reached a stage at which the risk to satellites and spacecraft has become substantial in low Earth orbit (LEO). This research discovered that small particles posed little threat to spacecraft because shielding can effectively prevent these particles from damaging the spacecraft. The research also showed that, even though collision with a large piece of debris could destroy the spacecraft, the large pieces of debris pose little danger because they can be tracked and the spacecraft can be maneuvered away from these pieces. Additionally, there are many current designs to capture and remove large debris particles from the space environment. From this analysis, it was decided to concentrate on the removal of medium-sized orbital debris, that is, those pieces ranging from 1 cm to 50 cm in size. The current design incorporates a transfer vehicle and a netting vehicle to capture the medium-sized debris. The system is based near an operational space station located at 28.5 deg inclination and 400 km altitude. The system uses ground-based tracking to determine the location of a satellite breakup or debris cloud. These data are uploaded to the transfer vehicle, which proceeds to rendezvous with the debris at a lower altitude parking orbit. Next, the netting vehicle is deployed, tracks the targeted debris, and captures it. After expending the available nets, the netting vehicle returns to the transfer vehicle for a new netting module and continues to capture more debris in the target area. Once all the netting modules are expended, the transfer vehicle returns to the space station's orbit where it is resupplied with new netting modules from a space shuttle load. The new modules are launched by the shuttle from the ground and the expended modules are taken back to Earth for removal of the captured debris, refueling, and repacking of the nets. Once the netting modules are refurbished, they are taken back into orbit for reuse. In a typical mission, the

  11. Lunar Reconnaissance Orbiter Mission Highlights

    NASA Video Gallery

    Since launch on June 18, 2009 as a precursor mission, the Lunar Reconnaissance Orbiter (LRO) has remained in orbit around the moon, collecting vast amounts of science data in support of NASA's expl...

  12. The Orbital Acceleration Research Experiment

    NASA Technical Reports Server (NTRS)

    Blanchard, R. C.; Hendrix, M. K.; Fox, J. C.; Thomas, D. J.; Nicholson, J.

    1986-01-01

    The hardware and software of NASA's proposed Orbital Acceleration Research Experiment (OARE) are described. The OARE is to provide aerodynamic acceleration measurements along the Orbiter's principal axis in the free-molecular flow-flight regime at orbital attitude and in the transition regime during reentry. Models considering the effects of electromagnetic effects, solar radiation pressure, orbiter mass attraction, gravity gradient, orbital centripetal acceleration, out-of-orbital-plane effects, orbiter angular velocity, structural noise, mass expulsion signal sources, crew motion, and bias on acceleration are examined. The experiment contains an electrostatically balanced cylindrical proofmass accelerometer sensor with three orthogonal sensing axis outputs. The components and functions of the experimental calibration system and signal processor and control subsystem are analyzed. The development of the OARE software is discussed. The experimental equipment will be enclosed in a cover assembly that will be mounted in the Orbiter close to the center of gravity.

  13. Orbitals and orbital energies in DFT and TDDFT

    NASA Astrophysics Data System (ADS)

    Baerends, Evert Jan

    The status and meaning of orbitals and orbital energies in the Kohn-Sham one-electron model of DFT has been controversial, in contrast to Hartree-Fock orbitals and orbital energies. We will argue the opposite: the exact Kohn-Sham orbitals of DFT are ''better'' than HF orbitals and their orbital energies are much closer to ionization energies than HF orbital energies are. This follows from the relation between the KS potential and the wavefunction, which can be cast in the form vs =vc , kin +vH +vxchole +vresp, where each term depends on the KS orbitals and the wavefunction (the one- or two-particle density matrices). The response potential vresp (r) = ∑ j ∞|/dj(r) | 2 ρ (r) Ij - ∑ i H|/ψs , i(r) | 2 ρ (r) (-ɛi) (dj is the Dyson orbital corresponding to ion state ΨjN - 1 , ψs , i is a Kohn-Sham orbital) enables the connection between ionization energies Ii and orbital energies ɛi to be made. For virtual orbitals and orbital energies similar statements can be made: the shapes and energies of the (exact) KS orbitals are much more realistic than those of the Hartree-Fock model or hybrid functionals. The HOMO-LUMO gap in molecules is very close to the optical gap, and very different from the fundamental gap. In solids the situation is very different, which is the well-known ''KS gap problem''. Again the response potential vresp (a good approximation to it) helps to solve this problem, affording a straigtforward correction method of the KS gap to the fundamental gap.

  14. Spectrophotovoltaic orbital power generation

    NASA Technical Reports Server (NTRS)

    Onffroy, J. R.

    1980-01-01

    The feasibilty of a spectrophotovoltaic orbital power generation system that optically concentrates solar energy is demonstrated. A dichroic beam-splitting mirror is used to divide the solar spectrum into two wavebands. Absorption of these wavebands by GaAs and Si solar cell arrays with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat that must be rejected. The projected cost per peak watt if this system is $2.50/W sub p.

  15. 'Spider' in Earth Orbit

    NASA Technical Reports Server (NTRS)

    1969-01-01

    View of the Apollo 9 Lunar Module 'Spider' in a lunar landing configuration photographed by Command Module pilot David Scott inside the Command/Service Module 'Gumdrop' on the fifth day of the Apollo 9 earth-orbital mission. The landing gear on 'Spider' has been deployed. lunar surface probes (sensors) extend out from the landing gear foot pads. Inside the 'Spider' were astronauts James A. McDivitt, Apollo 9 Commander; and Russell L. Schweickart, Lunar Module pilot.

  16. Orbital Debris Modeling

    NASA Technical Reports Server (NTRS)

    Liou, J. C.

    2012-01-01

    Presentation outlne: (1) The NASA Orbital Debris (OD) Engineering Model -- A mathematical model capable of predicting OD impact risks for the ISS and other critical space assets (2) The NASA OD Evolutionary Model -- A physical model capable of predicting future debris environment based on user-specified scenarios (3) The NASA Standard Satellite Breakup Model -- A model describing the outcome of a satellite breakup (explosion or collision)

  17. Small Mercury Relativity Orbiter

    NASA Technical Reports Server (NTRS)

    Bender, Peter L.; Vincent, Mark A.

    1989-01-01

    The accuracy of solar system tests of gravitational theory could be very much improved by range and Doppler measurements to a Small Mercury Relativity Orbiter. A nearly circular orbit at roughly 2400 km altitude is assumed in order to minimize problems with orbit determination and thermal radiation from the surface. The spacecraft is spin-stabilized and has a 30 cm diameter de-spun antenna. With K-band and X-band ranging systems using a 50 MHz offset sidetone at K-band, a range accuracy of 3 cm appears to be realistically achievable. The estimated spacecraft mass is 50 kg. A consider-covariance analysis was performed to determine how well the Earth-Mercury distance as a function of time could be determined with such a Relativity Orbiter. The minimum data set is assumed to be 40 independent 8-hour arcs of tracking data at selected times during a two year period. The gravity field of Mercury up through degree and order 10 is solved for, along with the initial conditions for each arc and the Earth-Mercury distance at the center of each arc. The considered parameters include the gravity field parameters of degree 11 and 12 plus the tracking station coordinates, the tropospheric delay, and two parameters in a crude radiation pressure model. The conclusion is that the Earth-Mercury distance can be determined to 6 cm accuracy or better. From a modified worst-case analysis, this would lead to roughly 2 orders of magnitude improvement in the knowledge of the precession of perihelion, the relativistic time delay, and the possible change in the gravitational constant with time.

  18. An Orbit Plan toward AKATSUKI Venus Reencounter and Orbit Injection

    NASA Technical Reports Server (NTRS)

    Kawakatsu, Yasuhiro; Campagnola, Stefano; Hirose, Chikako; Ishii, Nobuaki

    2012-01-01

    On December 7, 2010, AKATSUKI, the Japanese Venus explorer reached its destination and tried to inject itself into Venus orbit. However, due to a malfunction of the propulsion system, the maneuver was interrupted and AKATSUKI again escaped out from the Venus into an interplanetary orbit. Telemetry data from AKATSUKI suggests the possibility to perform orbit maneuvers to reencounter the Venus and retry Venus orbit injection. Reported in this paper is an orbit plan investigated under this situation. The latest results reflecting the maneuvers conducted in the autumn 2011 is introduced as well.

  19. Circular-Orbit Maintenance Strategies for Primitive Body Orbiters

    NASA Technical Reports Server (NTRS)

    Wallace, Mark S.; Broschart, Stephen

    2013-01-01

    For missions to smaller primitive bodies, solar radiation pressure (SRP) is a significant perturbation to Keplerian dynamics. For most orbits, SRP drives large oscillations in orbit eccentricity, which leads to large perturbations from the irregular gravity field at periapsis. Ultimately, chaotic motion results that often escapes or impacts that body. This paper presents an orbit maintenance strategy to keep the orbit eccentricity small, thus avoiding the destabilizing secondary interaction with the gravity field. An estimate of the frequency and magnitude of the required maneuvers as a function of the orbit and body parameters is derived from the analytic perturbation equations.

  20. Orbiter Autoland reliability analysis

    NASA Technical Reports Server (NTRS)

    Welch, D. Phillip

    1993-01-01

    The Space Shuttle Orbiter is the only space reentry vehicle in which the crew is seated upright. This position presents some physiological effects requiring countermeasures to prevent a crewmember from becoming incapacitated. This also introduces a potential need for automated vehicle landing capability. Autoland is a primary procedure that was identified as a requirement for landing following and extended duration orbiter mission. This report documents the results of the reliability analysis performed on the hardware required for an automated landing. A reliability block diagram was used to evaluate system reliability. The analysis considers the manual and automated landing modes currently available on the Orbiter. (Autoland is presently a backup system only.) Results of this study indicate a +/- 36 percent probability of successfully extending a nominal mission to 30 days. Enough variations were evaluated to verify that the reliability could be altered with missions planning and procedures. If the crew is modeled as being fully capable after 30 days, the probability of a successful manual landing is comparable to that of Autoland because much of the hardware is used for both manual and automated landing modes. The analysis indicates that the reliability for the manual mode is limited by the hardware and depends greatly on crew capability. Crew capability for a successful landing after 30 days has not been determined yet.

  1. Global Orbit Feedback in RHIC

    SciTech Connect

    Minty, M.; Hulsart, R.; Marusic, A.; Michnoff, R.; Ptitsyn, V.; Robert-Demolaize, G.; Satogata, T.

    2010-05-23

    For improved reproducibility of good operating conditions and ramp commissioning efficiency, new dual-plane slow orbit feedback during the energy ramp was implemented during run-10 in the Relativistic Heavy Ion Collider (RHIC). The orbit feedback is based on steering the measured orbit, after subtraction of the dispersive component, to either a design orbit or to a previously saved reference orbit. Using multiple correctors and beam position monitors, an SVD-based algorithm is used for determination of the applied corrections. The online model is used as a basis for matrix computations. In this report we describe the feedback design, review the changes made to realize its implementation, and assess system performance.

  2. Orbital maneuvers and space rendezvous

    NASA Astrophysics Data System (ADS)

    Butikov, Eugene I.

    2015-12-01

    Several possibilities of launching a space vehicle from the orbital station are considered and compared. Orbital maneuvers discussed in the paper can be useful in designing a trajectory for a specific space mission. The relative motion of orbiting bodies is investigated on examples of spacecraft rendezvous with the space station that stays in a circular orbit around the Earth. An elementary approach is illustrated by an accompanying simulation computer program and supported by a mathematical treatment based on fundamental laws of physics and conservation laws. Material is appropriate for engineers and other personnel involved in space exploration, undergraduate and graduate students studying classical physics and orbital mechanics.

  3. Lunar Prospector Orbit Determination Results

    NASA Technical Reports Server (NTRS)

    Beckman, Mark; Concha, Marco

    1998-01-01

    The orbit support for Lunar Prospector (LP) consists of three main areas: (1) cislunar orbit determination, (2) rapid maneuver assessment using Doppler residuals, and (3) routine mapping orbit determination. The cislunar phase consisted of two trajectory correction maneuvers during the translunar cruise followed by three lunar orbit insertion burns. This paper will detail the cislunar orbit determination accuracy and the real-time assessment of the cislunar trajectory correction and lunar orbit insertion maneuvers. The non-spherical gravity model of the Moon is the primary influence on the mapping orbit determination accuracy. During the first two months of the mission, the GLGM-2 lunar potential model was used. After one month in the mapping orbit, a new potential model was developed that incorporated LP Doppler data. This paper will compare and contrast the mapping orbit determination accuracy using these two models. LP orbit support also includes a new enhancement - a web page to disseminate all definitive and predictive trajectory and mission planning information. The web site provides definitive mapping orbit ephemerides including moon latitude and longitude, and four week predictive products including: ephemeris, moon latitude/longitude, earth shadow, moon shadow, and ground station view periods. This paper will discuss the specifics of this web site.

  4. Orbital Debris: A Policy Perspective

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2007-01-01

    A viewgraph presentation describing orbital debris from a policy perspective is shown. The contents include: 1) Voyage through near-Earth Space-animation; 2) What is Orbital Debris?; 3) Orbital Debris Detectors and Damage Potential; 4) Hubble Space Telescope; 5) Mir Space Station Solar Array; 6) International Space Station; 7) Space Shuttle; 8) Satellite Explosions; 9) Satellite Collisions; 10) NASA Orbital Debris Mitigation Guidelines; 11) International Space Station Jettison Policy; 12) Controlled/Uncontrolled Satellite Reentries; 13) Return of Space Objects; 14) Orbital Debris and U.S. National Space Policy; 15) U.S Government Policy Strategy; 16) Bankruptcy of the Iridium Satellite System; 17) Inter-Agency Space Debris Coordination Committee (IADC); 18) Orbital Debris at the United Nations; 19) Chinese Anti-satellite System; 20) Future Evolution of Satellite Population; and 21) Challenge of Orbital Debris

  5. Orbiter door closure tools

    NASA Technical Reports Server (NTRS)

    Acres, W. R.

    1980-01-01

    Safe reentry of the shuttle orbiter requires that the payload bay doors be closed and securely latched. Since a malfunction in the door drive or bulkhead latch systems could make safe reentry impossible, the requirement to provide tools to manually close and secure the doors was implemented. The tools would disconnect a disabled door or latch closure system and close and secure the doors if the normal system failed. The tools required to perform these tasks have evolved into a set that consists of a tubing cutter, a winch, a latching tool, and a bolt extractor. The design, fabrication, and performance tests of each tool are described.

  6. Hypervelocity Orbital Intercept Guidance

    DTIC Science & Technology

    1988-04-14

    Professor Charles E. Fosha, Jr. Terminal guidance of a hypervelocity exo-atmospheric orbital interceptor with free end-time is examined. The pursuer is...stochastic nonlinear systems with free end-time was developed by Tse and 29 Bar-Shalom [5]. This method differs from the optimal control formulation...Vol. AC-18, No. 2, April 1973, pp. 98-108. 5. Tse, E., and Y. Bar-Shalom, "Adaptive Dual Control For Stochastic Nonlinear Systems with Free End- Time

  7. Lunar Exploration Orbiter (LEO)

    NASA Astrophysics Data System (ADS)

    Jaumann, R.; Spohn, T.; Hiesinger, H.; Jessberger, E. K.; Neukum, G.; Oberst, J.; Helbert, J.; Christensen, U.; Keller, H. U.; Mall, U.; Böhnhardt, H.; Hartogh, P.; Glassmeier, K.-H.; Auster, H.-U.; Moreira, A.; Werner, M.; Pätzold, M.; Palme, H.; Wimmer-Schweingruber, R.; Mandea, M.; Lesur, V.; Häusler, B.; Hördt, A.; Eichentopf, K.; Hauber, E.; Hoffmann, H.; Köhler, U.; Kührt, E.; Michaelis, H.; Pauer, M.; Sohl, F.; Denk, T.; van Gasselt, S.

    2007-08-01

    The Moon is an integral part of the Earth-Moon system, it is a witness to more than 4.5 b. y. of solar system history, and it is the only planetary body except Earth for which we have samples from known locations. The Moon is our closest companion and can easily be reached from Earth at any time, even with a relatively modest financial budget. Consequently, the Moon was the first logical step in the exploration of our solar system before we pursued more distant targets such as Mars and beyond. The vast amount of knowledge gained from the Apollo and other lunar missions of the late 1960's and early 1970's demonstrates how valuable the Moon is for the understanding of our planetary system. Even today, the Moon remains an extremely interesting target scientifically and technologically, as ever since, new data have helped to address some of our questions about the Earth-Moon system, many questions remained. Therefore, returning to the Moon is the critical stepping-stone to further exploring our immediate planetary neighborhood. In this concept study, we present scientific and technological arguments for a national German lunar mission, the Lunar Explorations Orbiter (LEO). Numerous space-faring nations have realized and identified the unique opportunities related to lunar exploration and have planned missions to the Moon within the next few years. Among these missions, LEO will be unique, because it will globally explore the Moon in unprecedented spatial and spectral resolution. LEO will significantly improve our understanding of the lunar surface composition, surface ages, mineralogy, physical properties, interior, thermal history, gravity field, regolith structure, and magnetic field. The Lunar Explorations Orbiter will carry an entire suite of innovative, complementary technologies, including high-resolution camera systems, several spectrometers that cover previously unexplored parts of the electromagnetic spectrum over a broad range of wavelengths, microwave and

  8. Numerical simulations of rotational bursting of F-coronal dust in eccentric orbits due to coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Misconi, Nebil Y.

    2004-08-01

    Model calculations were carried out to determine the extent of the effects on the rotational bursting of F-coronal dust in eccentric orbits due to their interaction with the flow of coronal mass ejections (CMEs). The model included an initial limiting perihelion distance of 8 solar radii ( RS) for all particles used. The parameters of the CMEs (velocity and proton number density) along with the various parameters of the dust particles (size and median density) were taken into consideration. By keeping these parameters the same and varying one of them, it was found that the velocity of the CMEs protons plays a major role in determining at which heliocentric distance the particle bursts. To a lesser degree, the median density of the particle also had a similar effect. Depending on the values of the dust particles orbital eccentricity, limiting sizes of the dust particles were found beyond which the particles do not burst. More particles bursted in regions close to their perihelion passage, however very few particles bursted near 8 RS from which we conclude that the majority of the fragmented particles were outside the F-corona region. The results show that rotational bursting of the dust in eccentric orbits inside the F-corona forces the particles to fragment outside 8 RS.

  9. Periodic orbits for three and four co-orbital bodies

    NASA Astrophysics Data System (ADS)

    Verrier, P. E.; McInnes, C. R.

    2014-08-01

    We investigate the natural families of periodic orbits associated with the equilibrium configurations of the planar-restricted 1 + n-body problem for the case 2 ≤ n ≤ 4 equal-mass satellites. Such periodic orbits can be used to model both trojan exoplanetary systems and parking orbits for captured asteroids within the Solar system. For n = 2, there are two families of periodic orbits associated with the equilibria of the system: the well-known horseshoe and tadpole orbits. For n = 3, there are three families that emanate from the equilibrium configurations of the satellites, while for n = 4, there are six such families as well as numerous additional connecting families. The families of periodic orbits are all of the horseshoe or tadpole type, and several have regions of neutral linear stability.

  10. Resonant and secular orbital interactions

    NASA Astrophysics Data System (ADS)

    Zhang, Ke

    In stable solar systems, planets remain in nearly elliptical orbits around their stars. Over longer timescales, however, their orbital shapes and sizes change due to mutual gravitational perturbations. Orbits of satellites around a planet vary for the same reason. Because of their interactions, the orbits of planets and satellites today are different from what they were earlier. In order to determine their original orbits, which are critical constraints on formation theories, it is crucial to understand how orbits evolve over the age of the Solar System. Depending on their timescale, we classify orbital interactions as either short-term (orbital resonances) or long-term (secular evolution). My work involves examples of both interaction types. Resonant history of the small Neptunian satellites. In satellite systems, tidal migration brings satellite orbits in and out of resonances. During a resonance passage, satellite orbits change dramatically in a very short period of time. We investigate the resonant history of the six small Neptunian moons. In this unique system, the exotic orbit of the large captured Triton (with a circular, retrograde, and highly tilted orbit) influences the resonances among the small satellites very strongly. We derive an analytical framework which can be applied to Neptune's satellites and to similar systems. Our numerical simulations explain the current orbital tilts of the small satellites as well as constrain key physical parameters of both Neptune and its moons. Secular orbital interactions during eccentricity damping. Long-term periodic changes of orbital shape and orientation occur when two or more planets orbit the same star. The variations of orbital elements are superpositions of the same number of fundamental modes as the number of planets in the system. We investigate how this effect interacts with other perturbations imposed by external disturbances, such as the tides and relativistic effects. Through analytical studies of a

  11. [Endoscopic approaches to the orbit].

    PubMed

    Cebula, H; Lahlou, A; De Battista, J C; Debry, C; Froelich, S

    2010-01-01

    During the last decade, the use of endoscopic endonasal approaches to the pituitary has increased considerably. The endoscopic endonasal and transantral approaches offer a minimally invasive alternative to the classic transcranial or transconjunctival approaches to the medial aspect of the orbit. The medial wall of the orbit, the orbital apex, and the optic canal can be exposed through a middle meatal antrostomy, an anterior and posterior ethmoidectomy, and a sphenoidotomy. The inferomedial wall of the orbit can be also perfectly visualized through a sublabial antrostomy or an inferior meatal antrostomy. Several reports have described the use of an endoscopic approach for the resection or the biopsy of lesions located on the medial extraconal aspect of the orbit and orbital apex. However, the resection of intraconal lesions is still limited by inadequate instrumentation. Other indications for the endoscopic approach to the orbit are the decompression of the orbit for Graves' ophthalmopathy and traumatic optic neuropathy. However, the optimal management of traumatic optic neuropathy remains very controversial. Endoscopic endonasal decompression of the optic nerve in case of tumor compression could be a more valid indication in combination with radiation therapy. Finally, the endoscopic transantral treatment of blowout fracture of the floor of the orbit is an interesting option that avoids the eyelid or conjunctive incision of traditional approaches. The collaboration between the neurosurgeon and the ENT surgeon is mandatory and reduces the morbidity of the approach. Progress in instrumentation and optical devices will certainly make this approach promising for intraconal tumor of the orbit.

  12. Optimal Continuous Thrust Orbital Evasive Maneuvers from Geosynchronous Orbit

    DTIC Science & Technology

    1986-12-01

    control thrusters, if its warning time and orbital parameters were appropriate. A model is developed using optimal control theory and is solved numericaly...Maneuvers of a Spacecraft Relative to a Point in Circular Orbit ,’ Journal of Guidance, Control . and Dynamics. 9(l): 27-31 (January -February 1966). 10... Elliptical Orbit ," Joursal of Guidance. Control . and Drjsmakjs1 (4: 271-275 (July- August 1979). 22. Meirovitch, Leonard. Methods of Anakytical Dynamics

  13. Orbital debris issues

    NASA Astrophysics Data System (ADS)

    Kessler, D. J.

    Orbital debris issues fall into three major topics: Environment Definition, Spacecraft Hazard, and Space Object Management. The major issue under Environment Definition is defining the debris flux for sizes smaller (10 cm in diameter) than those tracked by the North American Aerospace Defense Command (NORAD). Sources for this size debris are fragmentation of larger objects, either by explosion or collision, and solid rocket motor products. Modeling of these sources can predict fluxes in low Earth orbit which are greater than the meteoroid environment. Techniques to measure the environment in the size interval between 1 mm and 10 cm are being developed, including the use of telescopes and radar both on the ground and in space. Some impact sensors designed to detect meteoroids may have detected solid rocket motor products. Once the environment is defined, it can be combined with hypervelocity impact data and damage criteria to evaluate the Spacecraft Hazard. Shielding may be required to obtain an acceptable damage level. Space Object Management includes techniques to control the environment and the desired policy to effectively minimize the hazard to spacecraft. One control technique - reducing the likelihood of future explosions in space - has already been implemented by NASA. The effectiveness of other techniques has yet to be evaluated.

  14. Orbital construction demonstration study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A conceptual design and program plan for an Orbital Construction Demonstration Article (OCDA) was developed that can be used for evaluating and establishing practical large structural assembly operations. A flight plan for initial placement and continued utility is presented as a basic for an entirely new shuttle payload line-item having great future potential benefit for space applications. The OCDA is a three-axis stabilized platform in low-earth orbit with many structural nodals for mounting large construction and fabrication equipments. This equipment would be used to explore methods for constructing the large structures for future missions. The OCDA would be supported at regular intervals by the shuttle. Construction experiments and consumables resupply are performed during shuttle visit periods. A 250 kw solar array provides sufficient power to support the shuttle while attached to the OCDA and to run construction experiments at the same time. Wide band communications with a Telemetry and Data Relay Satellite compatible high gain antenna can be used between shuttle revisits to perform remote controlled, TV assisted construction experiments.

  15. General view of the Orbiter Discovery in the Orbiter Processing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of the Orbiter Discovery in the Orbiter Processing Facility at Kennedy Space Center showing the payload bay doors open exposing the heat-dissipating radiator panels located on the inside of the payload bay doors. Also in the view is the boom portion of the boom sensor system deployed as part of the return to flight procedures after STS-107 to inspect the orbiter's thermal protection system. The Remote Manipulator System, the "Canadarm", and the airlock are seen in the background of the image. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  16. Orbital Evolution and Impact Hazard of Asteroids on Retrograde Orbits

    NASA Astrophysics Data System (ADS)

    Kankiewicz, P.; Włodarczyk, I.

    2014-07-01

    We present the past evolutional scenarios of known group of asteroids in retrograde orbits. Applying the latest observational data, we determined their nominal and averaged orbital elements. Next, we studied the behaviour of their orbital motion 1~My in the past (100~My in the future for two NEAs) taking into account the limitations of observational errors. It has been shown that the influence of outer planets perturbations in many cases can import small bodies on high inclination or retrograde orbits into the inner Solar System.

  17. The orbit properties of colliding co-orbiting bodies

    NASA Technical Reports Server (NTRS)

    Freeman, John W.

    1987-01-01

    It is generally assumed that an ensemble of small bodies located in similar Keplarian orbits will, because of collisions, tend to disperse into more and more dissimilar orbits. This theory was challenged. Alfven maintains that for the case where the time between collisions is longer than the orbit period and the collisions are essentially inelastic the orbits and velocities will become more similar. This gives rise to the concepts of negative diffusion and jet streams. It is proposed that this question might be investigated experimentally using the space station. The proposed experiment is briefly described.

  18. Precise Orbit Determination for ALOS

    NASA Technical Reports Server (NTRS)

    Nakamura, Ryo; Nakamura, Shinichi; Kudo, Nobuo; Katagiri, Seiji

    2007-01-01

    The Advanced Land Observing Satellite (ALOS) has been developed to contribute to the fields of mapping, precise regional land coverage observation, disaster monitoring, and resource surveying. Because the mounted sensors need high geometrical accuracy, precise orbit determination for ALOS is essential for satisfying the mission objectives. So ALOS mounts a GPS receiver and a Laser Reflector (LR) for Satellite Laser Ranging (SLR). This paper deals with the precise orbit determination experiments for ALOS using Global and High Accuracy Trajectory determination System (GUTS) and the evaluation of the orbit determination accuracy by SLR data. The results show that, even though the GPS receiver loses lock of GPS signals more frequently than expected, GPS-based orbit is consistent with SLR-based orbit. And considering the 1 sigma error, orbit determination accuracy of a few decimeters (peak-to-peak) was achieved.

  19. Energy Ordering of Molecular Orbitals

    PubMed Central

    2016-01-01

    Orbitals are invaluable in providing a model of bonding in molecules or between molecules and surfaces. Most present-day methods in computational chemistry begin by calculating the molecular orbitals of the system. To what extent have these mathematical objects analogues in the real world? To shed light on this intriguing question, we employ a photoemission tomography study on monolayers of 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) grown on three Ag surfaces. The characteristic photoelectron angular distribution enables us to assign individual molecular orbitals to the emission features. When comparing the resulting energy positions to density functional calculations, we observe deviations in the energy ordering. By performing complete active space calculations (CASSCF), we can explain the experimentally observed orbital ordering, suggesting the importance of static electron correlation beyond a (semi)local approximation. On the other hand, our results also show reality and robustness of the orbital concept, thereby making molecular orbitals accessible to experimental observations. PMID:27935313

  20. Adaptive interplanetary orbit determination

    NASA Astrophysics Data System (ADS)

    Crain, Timothy Price

    This work documents the development of a real-time interplanetary orbit determination monitoring algorithm for detecting and identifying changes in the spacecraft dynamic and measurement environments. The algorithm may either be utilized in a stand-alone fashion as a spacecraft monitor and hypothesis tester by navigators or may serve as a component in an autonomous adaptive orbit determination architecture. In either application, the monitoring algorithm serves to identify the orbit determination filter parameters to be modified by an offline process to restore the operational model accuracy when the spacecraft environment changes unexpectedly. The monitoring algorithm utilizes a hierarchical mixture-of-experts to regulate a multilevel bank organization of extended Kalman filters. Banks of filters operate on the hierarchy top-level and are composed of filters with configurations representative of a specific environment change called a macromode. Fine differences, or micromodes, within the macromodes are represented by individual filter configurations. Regulation is provided by two levels of single-layer neural networks called gating networks. A single top-level gating network regulates the weighting among macromodes and each bank uses a gating network to regulate member filters internally. Experiments are conducted on the Mars Pathfinder cruise trajectory environment using range and Doppler data from the Deep Space Network. The experiments investigate the ability of the hierarchical mixture-of-experts to identify three environment macromodes: (1) unmodeled impulsive maneuvers, (2) changes in the solar radiation pressure dynamics, and (3) changes in the measurement noise strength. Two methods of initializing the gating networks are examined in each experiment. One method gives the neurons associated with all filters equivalent synaptic weight. The other method places greater weight on the operational filter initially believed to model the spacecraft environment. The

  1. 'Columbia Hills' from Orbit

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This view of the 'Columbia Hills' in Gusev Crater was made by draping an image from the Mars Orbiter Camera on NASA's Mars Global Surveyor orbiter (image E0300012 from that camera) over a digital elevation model that was derived from two Mars Orbiter Camera images (E0300012 and R0200357).

    This unique view is helpful to the rover team members as they plan the journey of NASA's Mars Exploration Rover Spirit to the base of the Columbia Hills and beyond. Spirit successfully completed a three-month primary mission, and so far remains healthy in an extended mission of bonus exploration. As of sol 135 (on May 21, 2004), Spirit sits approximately 680 meters (0.4 miles) away from its first target at the western base of the hills, a spot informally called 'West Spur.' The team estimates that Spirit will reach West Spur by sol 146 (June 1, 2004). Spirit will most likely remain there for about a week to study the outcrops and rocks associated with this location.

    When done there, Spirit will head approximately 620 meters (0.38 miles) to a higher-elevation location informally called 'Lookout Point.' Spirit might reach Lookout Point by around sol 165 (June 20, 2004). On the way, the rover will pass by and study ripple-shaped wind deposits that may reveal more information about wind processes on Mars.

    Lookout Point will provide a great vantage point for scientists to remotely study the inner basin area of the Columbia Hills. This basin contains a broad range of interesting geological targets including the informally named 'Home Plate' and other possible layered outcrops. These features suggest that the hills contain rock layers. Spirit might investigate the layers to determine whether they are water-deposited sedimentary rock.

    Once at Lookout Point, Spirit will acquire 360-degree panoramic images of the entire area to help define the rover's next steps. Assuming the rover stays healthy, Spirit will eventually drive down into the basin to get an up

  2. Orbital State Uncertainty Realism

    NASA Astrophysics Data System (ADS)

    Horwood, J.; Poore, A. B.

    2012-09-01

    Fundamental to the success of the space situational awareness (SSA) mission is the rigorous inclusion of uncertainty in the space surveillance network. The *proper characterization of uncertainty* in the orbital state of a space object is a common requirement to many SSA functions including tracking and data association, resolution of uncorrelated tracks (UCTs), conjunction analysis and probability of collision, sensor resource management, and anomaly detection. While tracking environments, such as air and missile defense, make extensive use of Gaussian and local linearity assumptions within algorithms for uncertainty management, space surveillance is inherently different due to long time gaps between updates, high misdetection rates, nonlinear and non-conservative dynamics, and non-Gaussian phenomena. The latter implies that "covariance realism" is not always sufficient. SSA also requires "uncertainty realism"; the proper characterization of both the state and covariance and all non-zero higher-order cumulants. In other words, a proper characterization of a space object's full state *probability density function (PDF)* is required. In order to provide a more statistically rigorous treatment of uncertainty in the space surveillance tracking environment and to better support the aforementioned SSA functions, a new class of multivariate PDFs are formulated which more accurately characterize the uncertainty of a space object's state or orbit. The new distribution contains a parameter set controlling the higher-order cumulants which gives the level sets a distinctive "banana" or "boomerang" shape and degenerates to a Gaussian in a suitable limit. Using the new class of PDFs within the general Bayesian nonlinear filter, the resulting filter prediction step (i.e., uncertainty propagation) is shown to have the *same computational cost as the traditional unscented Kalman filter* with the former able to maintain a proper characterization of the uncertainty for up to *ten

  3. Cassini ISS Satellite Orbit Results

    NASA Astrophysics Data System (ADS)

    Spitale, J. N.; Jacobson, R. A.; Porco, C. C.; Owen, W. M.; Charnoz, S.; Murray, C. D.; Brahic, A.; Evans, M. W.; Beurle, K.; Cooper, N.; Cassini Imaging

    2004-11-01

    We report on the orbits of several small Saturnian satellites, either recovered or newly-discovered in recent Cassini imaging observations. The mean motions of Pan and Atlas have been corrected based on recent Cassini imaging combined with Voyager observations. Two small satellites, S/2004 S 1 and S/2004 S 2, have been discovered between the orbits of Mimas and Enceladus on orbits that are nearly circular and uninclined. Both bodies were observed for a fraction of one orbit on June 1, 2004 and S/2004 S 1 was subsequently detected in images shuttered three weeks earlier. Those bodies may be recovered in late October in imaging sequences designed for that purpose. A third new object was detected in images from June 21, 2004, orbiting just outside the F ring. However, a search for additional detections revealed something orbiting interior to the F ring near the longitude at which the new object would be expected 5 hours later. A low-residual orbit that crosses the F ring has been found to explain all of the observations, but it is not yet clear whether the two sequences imaged the same object or two different objects that coincidentally were found orbiting at the same longitude but at different orbital semimajor axes. These issues make its nature -- solid satellite or F ring clump -- unclear. The data, fitting procedures, and results will be discussed.

  4. OSO-6 Orbiting Solar Observatory

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The description, development history, test history, and orbital performance analysis of the OSO-6 Orbiting Solar Observatory are presented. The OSO-6 Orbiting Solar Observatory was the sixth flight model of a series of scientific spacecraft designed to provide a stable platform for experiments engaged in the collection of solar and celestial radiation data. The design objective was 180 days of orbital operation. The OSO-6 has telemetered an enormous amount of very useful experiment and housekeeping data to GSFC ground stations. Observatory operation during the two-year reporting period was very successful except for some experiment instrument problems.

  5. Orbiter utilization as an ACRV

    NASA Technical Reports Server (NTRS)

    Cruz, Jonathan N.; Heck, Michael L.; Kumar, Renjith R.; Mazanek, Daniel D.; Troutman, Patrick A.

    1990-01-01

    Assuming that a Shuttle Orbiter could be qualified to serve long duration missions attached to Space Station Freedom in the capacity as an Assured Crew Return Vehicle (ACRV), a study was conducted to identify and examine candidate attach locations. Baseline, modified hardware, and new hardware design configurations were considered. Dual simultaneous Orbiter docking accommodation were required. Resulting flight characteristics analyzed included torque equilibrium attitude (TEA), microgravity environment, attitude controllability, and reboost fuel requirements. The baseline Station could not accommodate two Orbiters. Modified hardware configurations analyzed had large TEA's. The utilization of an oblique docking mechanism best accommodated an Orbiter as an ACRV.

  6. Imaging of the Postoperative Orbit.

    PubMed

    Learned, Kim O; Nasseri, Farbod; Mohan, Suyash

    2015-08-01

    Imaging evaluation of the postoperative orbit remains challenging even for the expert neuroradiologist. This article provides a simplified framework for understanding the complex postoperative appearances of the orbit, in an attempt to enhance the diagnostic accuracy of postoperative computed tomography and MR imaging of the orbit. Readers are familiarized with the normal appearances of common eye procedures and orbit reconstructions to help avoid interpretative pitfalls. Also reviewed are imaging features of common surgical complications, and evaluation of residual/recurrent neoplasm in the setting of oncologic imaging surveillance.

  7. Skylab Orbiter Workshop Illustration

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This cutaway illustration shows the characteristics and basic elements of the Skylab Orbiter Workshop (OWS). The OWS was divided into two major compartments. The lower level provided crew accommodations for sleeping, food preparation and consumption, hygiene, waste processing and disposal, and performance of certain experiments. The upper level consisted of a large work area and housed water storage tanks, a food freezer, storage vaults for film, scientific airlocks, mobility and stability experiment equipment, and other experimental equipment. The compartment below the crew quarters was a container for liquid and solid waste and trash accumulated throughout the mission. A solar array, consisting of two wings covered on one side with solar cells, was mounted outside the workshop to generate electrical power to augment the power generated by another solar array mounted on the solar observatory. Thrusters were provided at one end of the workshop for short-term control of the attitude of the space station.

  8. Orbital Eccrine Hidrocystoma

    PubMed Central

    Marangoz, Deniz; Doğan Ekici, Işın; Çiftçi, Ferda

    2016-01-01

    A 29-year-old female patient presented with a painless mass on her upper eyelid medially. She noticed the mass 4 years earlier and it had increased in size over time. She had no diplopia, eyelid swelling, skin lesion overlying the mass, or visual disturbances. On ocular examination, eye movements and funduscopy were normal. The mass was movable and painless with palpation. Magnetic resonance imaging with contrast showed a 12x8x7 mm well-circumscribed cystic lesion with no contrast dye appearance. Surgical removal was performed delicately and no capsular rupture occured. Pathological examination revealed an eccrine hidrocystoma. Our aim is to underline that eccrine hidrocystoma should be included in differential diagnosis of orbital masses. PMID:28058171

  9. TOPEX orbital radiation study

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Barth, J. M.

    1984-01-01

    The space radiation environment of the TOPEX spacecraft is investigated. A single trajectory was considered. The external (surface incident) charged particle radiation, predicted for the satellite, is determined by orbital flux integration for the specified trajectory. The latest standard models of the environment are used in the calculations. The evaluation is performed for solar maximum conditions. The spacecraft exposure to cosmic rays of galactic origin is evaluated over its flight path through the magnetosphere in terms of geomagnetic shielding effects, both for surface incident heavy ions and for particles emerging behind different material thickness. Limited shielding and dose evaluations are performed for simple infinite slab and spherical geometries. Results, given in graphical and tabular form, are analyzed, explained, and discussed. Conclusions are presented and commented on.

  10. Geology orbiter comparison study

    NASA Technical Reports Server (NTRS)

    Cutts, J. A. J.; Blasius, K. R.; Davis, D. R.; Pang, K. D.; Shreve, D. C.

    1977-01-01

    Instrument requirements of planetary geology orbiters were examined with the objective of determining the feasibility of applying standard instrument designs to a host of terrestrial targets. Within the basic discipline area of geochemistry, gamma-ray, X-ray fluorescence, and atomic spectroscopy remote sensing techniques were considered. Within the discipline area of geophysics, the complementary techniques of gravimetry and radar were studied. Experiments using these techniques were analyzed for comparison at the Moon, Mercury, Mars and the Galilean satellites. On the basis of these comparative assessments, the adaptability of each sensing technique was judged as a basic technique for many targets, as a single instrument applied to many targets, as a single instrument used in different mission modes, and as an instrument capability for nongeoscience objectives.

  11. Orbital angular momentum microlaser

    NASA Astrophysics Data System (ADS)

    Miao, Pei; Zhang, Zhifeng; Sun, Jingbo; Walasik, Wiktor; Longhi, Stefano; Litchinitser, Natalia M.; Feng, Liang

    2016-07-01

    Structured light provides an additional degree of freedom for modern optics and practical applications. The effective generation of orbital angular momentum (OAM) lasing, especially at a micro- and nanoscale, could address the growing demand for information capacity. By exploiting the emerging non-Hermitian photonics design at an exceptional point, we demonstrate a microring laser producing a single-mode OAM vortex lasing with the ability to precisely define the topological charge of the OAM mode. The polarization associated with OAM lasing can be further manipulated on demand, creating a radially polarized vortex emission. Our OAM microlaser could find applications in the next generation of integrated optoelectronic devices for optical communications in both quantum and classical regimes.

  12. Theory of Orbits

    NASA Astrophysics Data System (ADS)

    Boccaletti, Dino; Pucacco, Giuseppe

    This textbook treats Celestial Mechanics as well as Stellar Dynamics from the common point of view of orbit theory making use of the concepts and techniques from modern geometric mechanics. It starts with elementary Newtonian Mechanics and ends with the dynamics of chaotic motions. The book is meant for students in astronomy and physics alike. Prerequisite is a physicist's knowledge of calculus and differential geometry. Volume 1 begins with classical mechanics and a thorough treatment of the 2-body problem, including regularization, followed by an introduction to the N-body problem with particular attention given to the virial theorem. Then the authors discuss all important non-perturbative aspects of the 3-body problem. A final chapter deals with integrability of Hamilton-Jacobi-systems.

  13. Calculating Trajectories And Orbits

    NASA Technical Reports Server (NTRS)

    Alderson, Daniel J.; Brady, Franklyn H.; Breckheimer, Peter J.; Campbell, James K.; Christensen, Carl S.; Collier, James B.; Ekelund, John E.; Ellis, Jordan; Goltz, Gene L.; Hintz, Gerarld R.; Legerton, Victor N.; Mccreary, Faith A.; Mitchell, Robert T.; Mottinger, Neil A.; Moultrie, Benjamin A.; Moyer, Theodore D.; Rinker, Sheryl L.; Ryne, Mark S.; Stavert, L. Robert; Sunseri, Richard F.

    1989-01-01

    Double-Precision Trajectory Analysis Program, DPTRAJ, and Orbit Determination Program, ODP, developed and improved over years to provide highly reliable and accurate navigation capability for deep-space missions like Voyager. Each collection of programs working together to provide desired computational results. DPTRAJ, ODP, and supporting utility programs capable of handling massive amounts of data and performing various numerical calculations required for solving navigation problems associated with planetary fly-by and lander missions. Used extensively in support of NASA's Voyager project. DPTRAJ-ODP available in two machine versions. UNIVAC version, NPO-15586, written in FORTRAN V, SFTRAN, and ASSEMBLER. VAX/VMS version, NPO-17201, written in FORTRAN V, SFTRAN, PL/1 and ASSEMBLER.

  14. Orbital science's 'Bermuda Triangle'

    NASA Astrophysics Data System (ADS)

    Sherrill, Thomas J.

    1991-02-01

    The effects of a part of the inner Van Allen belt lying closest to the earth, known as the South Atlantic Anomaly (SAA) upon spacecraft including the Hubble Space Telescope (HST), are discussed. The area consists of positively charged ions and electrons from the Van Allen Belt which become trapped in the earth's dipole field. Contor maps representing the number of protons per square centimeter per second having energies greater than 10 million electron volts are presented. It is noted that the HST orbit causes it to spend about 15 percent of its time in the SAA, but that, unlike the experience with earlier spacecraft, the satellite's skin, internal structure, and normal electronic's packaging provides sufficient protection against eletrons, although some higher energy protons still get through. Various charged particle effects which can arise within scientific instruments including fluorescence, Cerenkov radiation, and induced radioactivity are described.

  15. Orbiting Carbon Observatory

    NASA Technical Reports Server (NTRS)

    Miller, Charles E.

    2005-01-01

    Human impact on the environment has produced measurable changes in the geological record since the late 1700s. Anthropogenic emissions of CO2 today may cause the global climate to depart for its natural behavior for many millenia. CO2 is the primary anthropogenic driver of climate change. The Orbiting Carbon Observatory goals are to help collect measurements of atmospheric CO2, answering questions such as why the atmospheric CO2 buildup varies annually, the roles of the oceans and land ecosystems in absorbing CO2, the roles of North American and Eurasian sinks and how these carbon sinks respond to climate change. The present carbon cycle, CO2 variability, and climate uncertainties due atmospheric CO2 uncertainties are highlighted in this presentation.

  16. Orbit Determination Toolbox

    NASA Technical Reports Server (NTRS)

    Carpenter, James R.; Berry, Kevin; Gregpru. Late; Speckman, Keith; Hur-Diaz, Sun; Surka, Derek; Gaylor, Dave

    2010-01-01

    The Orbit Determination Toolbox is an orbit determination (OD) analysis tool based on MATLAB and Java that provides a flexible way to do early mission analysis. The toolbox is primarily intended for advanced mission analysis such as might be performed in concept exploration, proposal, early design phase, or rapid design center environments. The emphasis is on flexibility, but it has enough fidelity to produce credible results. Insight into all flight dynamics source code is provided. MATLAB is the primary user interface and is used for piecing together measurement and dynamic models. The Java Astrodynamics Toolbox is used as an engine for things that might be slow or inefficient in MATLAB, such as high-fidelity trajectory propagation, lunar and planetary ephemeris look-ups, precession, nutation, polar motion calculations, ephemeris file parsing, and the like. The primary analysis functions are sequential filter/smoother and batch least-squares commands that incorporate Monte-Carlo data simulation, linear covariance analysis, measurement processing, and plotting capabilities at the generic level. These functions have a user interface that is based on that of the MATLAB ODE suite. To perform a specific analysis, users write MATLAB functions that implement truth and design system models. The user provides his or her models as inputs to the filter commands. The software provides a capability to publish and subscribe to a software bus that is compliant with the NASA Goddard Mission Services Evolution Center (GMSEC) standards, to exchange data with other flight dynamics tools to simplify the flight dynamics design cycle. Using the publish and subscribe approach allows for analysts in a rapid design center environment to seamlessly incorporate changes in spacecraft and mission design into navigation analysis and vice versa.

  17. Photometry of 2006 RH{120}: an asteroid temporary captured into a geocentric orbit

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, T.; Kryszczyńska, A.; Polińska, M.; Buckley, D. A. H.; O'Donoghue, D.; Charles, P. A.; Crause, L.; Crawford, S.; Hashimoto, Y.; Kniazev, A.; Loaring, N.; Romero Colmenero, E.; Sefako, R.; Still, M.; Vaisanen, P.

    2009-03-01

    Aims: From July 2006 to July 2007 a very small asteroid orbited the Earth within its Hill sphere. We used this opportunity to study its rotation and estimate its diameter and shape. Methods: Due to its faintness, 2006 RH{120} was observed photometrically with the new 10-m SALT telescope at the SAAO (South Africa). We obtained data on four nights: 11, 15, 16, and 17 March 2007 when the solar phase angle remained almost constant at 74°. The observations lasted about an hour each night and the object was exposed for 7-10 s through the “clear” filter. Results: From the lightcurves obtained on three nights we derived two solutions for a synodical period of rotation: P1 = 1.375 ± 0.001 min and P2 = 2.750 ± 0.002 min. The available data are not sufficient to choose between them. The absolute magnitude of the object was found to be H = 29.9 ± 0.3 mag (with the assumed slope parameter G = 0.25) and its effective diameter D = 2-7 m, depending on the geometric albedo pV (with the most typical near-Earth asteroids albedo pV = 0.18 its diameter would be D = 3.3 ± 0.4 m). The body has an elongated shape with the a/b ratio greater than 1.4. It probably originates in low-eccentricity Amor or Apollo orbits. There is still a possibility, which needs further investigation, that it is a typical near-Earth asteroid that survived the aerobraking in the Earth's atmosphere and returned to a heliocentric orbit similar to that of the Earth. Based on observations made with the Southern African Large Telescope (SALT).

  18. PyORBIT: A Python Shell For ORBIT

    SciTech Connect

    Jean-Francois Ostiguy; Jeffrey Holmes

    2003-07-01

    ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. We also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability.

  19. Orbital Chondroma: A rare mesenchymal tumor of orbit

    PubMed Central

    Kabra, Ruchi S; Patel, Sonal B; Shanbhag, Swapna S

    2015-01-01

    While relatively common in the skeletal system, cartilaginous tumors are rarely seen originating from the orbit. Here, we report a rare case of an orbital chondroma. A 27-year-old male patient presented with a painless hard mass in the superonasal quadrant (SNQ) of left orbit since 3 months. On examination, best-corrected visual acuity of both eyes was 20/20, with normal anterior and posterior segment with full movements of eyeballs and normal intraocular pressure. Computerized tomography scan revealed well defined soft tissue density lesion in SNQ of left orbit. Patient was operated for anteromedial orbitotomy under general anesthesia. Mass was excised intact and sent for histopathological examination (HPE). HPE report showed lobular aggregates of benign cartilaginous cells with mild atypia suggesting of benign cartilaginous tumor - chondroma. Very few cases of orbital chondroma have been reported in literature so far. PMID:26265654

  20. Orbital fluctuations and orbital flipping in RVO3 perovskites.

    PubMed

    Yan, J-Q; Zhou, J-S; Goodenough, J B; Ren, Y; Cheng, J G; Chang, S; Zarestky, J; Garlea, O; Llobet, A; Liobet, A; Zhou, H D; Sui, Y; Su, W H; McQueeney, R J

    2007-11-09

    The effect of the average R-site ionic radius IR and variance on the orbital and magnetic order in R3+-doped YVO3 was studied in Y1-xLaxVO3 and Y1-x(La0.2337Lu0.7663)xVO3 with fixed IR. The orbital flipping temperature T{CG} increases nonlinearly with increasing R-site variance, indicating that the V-O-V bond angle is not the primary driving force stabilizing the C-type orbitally ordered phase. The suppressed thermal conductivity in the G-type orbitally ordered phase signals some remaining orbital randomness that is enhanced by t{2} and et hybridization in {3}T{1g} site symmetry.

  1. Orbital Fluctuations and Orbital Flipping in RVO3 Perovskites

    SciTech Connect

    Yan, J.-Q.; Zhou, J.-S.; Goodenough, J. B.; Ren, Y.; Cheng, J. G.; Zarestky, Jerel L; Garlea, Vasile O; Liobet, A.; Zhou, H. D.; Sui, Y.; Su, W. H.; McQueeney, R. J.

    2007-01-01

    The effect of the average A-site ionic radius hIRi and variance on the orbital and magnetic order in R3+-doped YVO3 was studied in Y1-xLaxVO3 and Y1-x(La0.2337Lu0.7663)xVO3 with fixed . The orbital flipping temperature T_CG increases nonlinearly with increasing R-site variance, indicating that the V-O-V bond angle is not the primary driving force stabilizing the C-type orbitally ordered phase. The suppressed thermal conductivity in the G-type orbitally ordered phase signals some remaining orbital randomness that is enhanced by t2 and et hybridization in 3T_1g site symmetry.

  2. New orbit correction method uniting global and local orbit corrections

    NASA Astrophysics Data System (ADS)

    Nakamura, N.; Takaki, H.; Sakai, H.; Satoh, M.; Harada, K.; Kamiya, Y.

    2006-01-01

    A new orbit correction method, called the eigenvector method with constraints (EVC), is proposed and formulated to unite global and local orbit corrections for ring accelerators, especially synchrotron radiation(SR) sources. The EVC can exactly correct the beam positions at arbitrarily selected ring positions such as light source points, simultaneously reducing closed orbit distortion (COD) around the whole ring. Computer simulations clearly demonstrate these features of the EVC for both cases of the Super-SOR light source and the Advanced Light Source (ALS) that have typical structures of high-brilliance SR sources. In addition, the effects of errors in beam position monitor (BPM) reading and steering magnet setting on the orbit correction are analytically expressed and also compared with the computer simulations. Simulation results show that the EVC is very effective and useful for orbit correction and beam position stabilization in SR sources.

  3. Visible Nulling Coronagraph Testbed Results

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Melnick, Gary; Tolls, Volker; Woodruff, Robert; Vasudevan, Gopal; Rizzo, Maxime; Thompson, Patrick

    2009-01-01

    The Extrasolar Planetary Imaging Coronagraph (EPIC) is a NASA Astrophysics Strategic Mission Concept study and a proposed NASA Discovery mission to image and characterize extrasolar giant planets in orbits with semi-major axes between 2 and 10 AU. EPIC would provide insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. It will detect and characterize the atmospheres of planets identified by radial velocity surveys, determine orbital inclinations and masses, characterize the atmospheres around A and F stars, observed the inner spatial structure and colors of inner Spitzer selected debris disks. EPIC would be launched to heliocentric Earth trailing drift-away orbit, with a 5-year mission lifetime. The starlight suppression approach consists of a visible nulling coronagraph (VNC) that enables starlight suppression in broadband light from 480-960 nm. To demonstrate the VNC approach and advance it's technology readiness we have developed a laboratory VNC and have demonstrated white light nulling. We will discuss our ongoing VNC work and show the latest results from the VNC testbed.

  4. Extrasolar Planetary Imaging Coronagraph: Visible Nulling Coronagraph Testbed Results

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.

    2008-01-01

    The Extrasolar Planetary Imaging Coronagraph (EPIC) is a proposed NASA Discovery mission to image and characterize extrasolar giant planets in orbits with semi-major axes between 2 and 10 AU. EPIC will provide insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. It will detect and characterize the atmospheres of planets identified by radial velocity surveys, determine orbital inclinations and masses, characterize the atmospheres around A and F stars, observed the inner spatial structure and colors of inner Spitzer selected debris disks. EPIC would be launched to heliocentric Earth trailing drift-away orbit, with a 3-year mission lifetime ( 5 year goal) and will revisit planets at least three times at intervals of 9 months. The starlight suppression approach consists of a visible nulling coronagraph (VNC) that enables high order starlight suppression in broadband light. To demonstrate the VNC approach and advance it's technology readiness the NASA Goddard Space Flight Center and Lockheed-Martin have developed a laboratory VNC and have demonstrated white light nulling. We will discuss our ongoing VNC work and show the latest results from the VNC testbed,

  5. Sclerosing Orbital Inflammation Caused by Leishmania braziliensis.

    PubMed

    Cruz, Antonio Augusto V; Alves-Ferreira, Eliza V C; Milbratz-Moré, Gherusa; Chahud, Fernando; Ruy, Patricia C; Duarte, Maria Irma Seixas; Cruz, Angela Kaysel

    2017-01-11

    Orbital biopsy of nonspecific orbital inflammation, commonly referred to as "orbital pseudotumor," typically shows a combination of polyclonal lymphocytes, plasmocytes, leukocytes, macrophages, and variable degrees of collagen deposition. Herein, we report a patient with a positive history of mucocutaneous leishmaniasis who presented with an orbital mass with a histological profile of idiopathic orbital inflammation. Immunohistochemical and molecular analysis of the orbital specimens demonstrated that the orbital inflammation was associated with the presence of antigens of Leishmania braziliensis and DNA from the parasite.

  6. Dynamic behavior of solar wind as revealed by a correlation study of magnetic fields observed at the Venus and Earth orbits

    NASA Technical Reports Server (NTRS)

    Marubashi, K.

    1995-01-01

    Correlations between interplanetary magnetic fields (IMFs) at 0.72 AU and 1.0 AU have been examined using data sets obtained from the Pioneer Venus orbiter and Earth-orbiting spacecraft. While the two-sector structures are evident in long-term variations at these two heliocentric distances, the corresponding auto-correlation coefficients are consistently smaller at 1.0 AU than at 0.72 AU. This suggests that the IMF structures become less persistent at 1.0 AU due to the effects of changing solar wind dynamics between the Venus and Earth orbits. Short-term variations exhibit generally poor correlations between IMFs near Venus and those near Earth, though good correlations are sometimes obtained for well-defined structures when the Sun, Venus, and Earth are closely aligned. The rather poor correlations in the background streams indicate that the IMFs are still changing between the Venus and Earth orbits under the strong influence of solar wind dynamics.

  7. What is a MISR orbit?

    Atmospheric Science Data Center

    2014-12-08

    ... reasons, the orbit number is explicitly included in the name of many MISR data and product files. The sun-synchronous orbit of ... (each with 9 cameras and 4 spectral bands) of a particular site in 2 days (Poles) to 9 days (Equator), depending on its latitude, but of ...

  8. Antibiotic Prophylaxis in Orbital Fractures

    PubMed Central

    Reiss, Benjamin; Rajjoub, Lamise; Mansour, Tamer; Chen, Tony; Mumtaz, Aisha

    2017-01-01

    Purpose: To determine whether prophylactic antibiotic use in patients with orbital fracture prevent orbital infection. Design: Retrospective cohort study. Participants: All patients diagnosed with orbital fracture between January 1, 2008 and March 1, 2014 at The George Washington University Hospital and Clinics. Main Outcome Measures: Development of orbital infection. Results: One hundred seventy-two patients with orbital fracture met our inclusion and exclusion criteria. No orbital infections were documented. Twenty subjects (12%) received no prophylactic antibiotic, and two (1%) received only one dose of antibiotics pre-operatively for surgery. For primary antibiotic, 136 subjects (79%) received oral antibiotics, and 14 (8%) received intravenous (IV) antibiotics (excluding cefazolin). Cephalexin and amoxicillin-clavulanate were the most prescribed oral antibiotics that are equally effective. Five-to-seven day courses of antibiotics had no increased infections compared to ten-to-fourteen day courses. Calculated boundaries for effectiveness of prophylactic antibiotics ranged from a Number Needed to Treat (NNT) of 75 to a Number Needed to Harm (NNH) of 198. Conclusion: Antibiotics for prevention of orbital infection in patients with orbital fractures have become widely used. Coordination between trauma teams and specialists is needed to prevent patient overmedication and antibiotic resistance. Should antibiotics be used, shorter courses and avoidance of broad spectrum agents are recommended. Additional studies are needed.

  9. Diffractive molecular-orbital tomography

    NASA Astrophysics Data System (ADS)

    Zhai, Chunyang; Zhu, Xiaosong; Lan, Pengfei; Wang, Feng; He, Lixin; Shi, Wenjing; Li, Yang; Li, Min; Zhang, Qingbin; Lu, Peixiang

    2017-03-01

    High-order-harmonic generation in the interaction of femtosecond lasers with atoms and molecules opens the path to molecular-orbital tomography and to probe the electronic dynamics with attosecond-Ångström resolutions. Molecular-orbital tomography requires both the amplitude and phase of the high-order harmonics. Yet the measurement of phases requires sophisticated techniques and represents formidable challenges at present. Here we report a scheme, called diffractive molecular-orbital tomography, to retrieve the molecular orbital solely from the amplitude of high-order harmonics without measuring any phase information. We have applied this method to image the molecular orbitals of N2, CO2, and C2H2 . The retrieved orbital is further improved by taking account the correction of Coulomb potential. The diffractive molecular-orbital tomography scheme, removing the roadblock of phase measurement, significantly simplifies the molecular-orbital tomography procedure and paves an efficient and robust way to the imaging of more complex molecules.

  10. Unilateral orbital emphysema after sneezing.

    PubMed

    Koçak, Nilüfer; Oztürk, Taylan; Zengin, Mehmet Ozgür; Kaynak, Süleyman; Men, Süleyman

    2009-01-01

    We report a case who developed unilateral orbital emphysema after sneezing in a 30-year-old man presented with left crepitant eyelid swelling and progressive ptosis. Sneezing may cause orbital emphysema in cases with a history of minor periorbital trauma. While periodical followup without any medication is considered satisfactory, needle decompression may provide early cure.

  11. Orbital Analysis of Macron Propulsion

    DTIC Science & Technology

    2010-07-28

    effects on the orbital debris environment as well as to formulate possible implementations of this technology. Ultimately, the direction, velocity...and altitude at which these macrons are fired determine the macron’s trajectory and dictate the level of impact upon the orbital debris environment

  12. Orbital anatomy for the surgeon.

    PubMed

    Turvey, Timothy A; Golden, Brent A

    2012-11-01

    An anatomic description of the orbit and its contents and the eyelids directed toward surgeons is the focus of this article. The bone and soft tissue anatomic nuances for surgery are highlighted, including a section on osteology, muscles, and the orbital suspensory system. Innervation and vascular anatomy are also addressed.

  13. [Enophthalmos in an orbital tumor].

    PubMed

    Szabo, Bianca; Szabo, I; Nicula, Cristina; Popescu, Livia Adriana

    2013-01-01

    Enophtalmus is an unusual sign of the orbital tumors often represented by proptosis. One patient with enophtalmus and intraorbital tumor and aplasy is presented. The treatment of choice of orbital tumor is complete surgical excision and careful follow-up. Considering the more aggressive course followed by recurrent tumor, correct diagnosis and management is essential.

  14. General relativity and satellite orbits

    NASA Technical Reports Server (NTRS)

    Rubincam, D. P.

    1975-01-01

    The general relativistic correction to the position of a satellite is found by retaining Newtonian physics for an observer on the satellite and introducing a potential. The potential is expanded in terms of the Keplerian elements of the orbit and substituted in Lagrange's equations. Integration of the equations shows that a typical earth satellite with small orbital eccentricity is displaced by about 17 cm. from its unperturbed position after a single orbit, while the periodic displacement over the orbit reaches a maximum of about 3 cm. The moon is displaced by about the same amounts. Application of the equations to Mercury gives a total displacement of about 58 km. after one orbit and a maximum periodic displacement of about 12 km.

  15. Floating orbital molecular dynamics simulations.

    PubMed

    Perlt, Eva; Brüssel, Marc; Kirchner, Barbara

    2014-04-21

    We introduce an alternative ab initio molecular dynamics simulation as a unification of Hartree-Fock molecular dynamics and the floating orbital approach. The general scheme of the floating orbital molecular dynamics method is presented. Moreover, a simple but sophisticated guess for the orbital centers is provided to reduce the number of electronic structure optimization steps at each molecular dynamics step. The conservation of total energy and angular momentum is investigated in order to validate the floating orbital molecular dynamics approach with and without application of the initial guess. Finally, a water monomer and a water dimer are simulated, and the influence of the orbital floating on certain properties like the dipole moment is investigated.

  16. Low Earth Orbiter: Terminal

    NASA Technical Reports Server (NTRS)

    Kremer, Steven E.; Bundick, Steven N.

    1999-01-01

    In response to the current government budgetary environment that requires the National Aeronautics and Space Administration (NASA) to do more with less, NASA/Goddard Space Flight Center's Wallops Flight Facility has developed and implemented a class of ground stations known as a Low Earth Orbiter-Terminal (LEO-T). This development thus provides a low-cost autonomous ground tracking service for NASA's customers. More importantly, this accomplishment provides a commercial source to spacecraft customers around the world to purchase directly from the company awarded the NASA contract to build these systems. A few years ago, NASA was driven to provide more ground station capacity for spacecraft telemetry, tracking, and command (TT&C) services with a decreasing budget. NASA also made a decision to develop many smaller, cheaper satellites rather than a few large spacecraft as done in the past. In addition, university class missions were being driven to provide their own TT&C services due to the increasing load on the NASA ground-tracking network. NASA's solution for this ever increasing load was to use the existing large aperture systems to support those missions requiring that level of performance and to support the remainder of the missions with the autonomous LEO-T systems. The LEO-T antenna system is a smaller, cheaper, and fully autonomous unstaffed system that can operate without the existing NASA support infrastructure. The LEO-T provides a low-cost, reliable space communications service to the expanding number of low-earth orbiting missions around the world. The system is also fostering developments that improve cost-effectiveness of autonomous-class capabilities for NASA and commercial space use. NASA has installed three LEO-T systems. One station is at the University of Puerto Rico, the second system is installed at the Poker Flat Research Range near Fairbanks, Alaska, and the third system is installed at NASA's Wallops Flight Facility in Virginia. This paper

  17. HEO space debris orbit predictions.

    NASA Astrophysics Data System (ADS)

    Gregorowicz, Dorota; Pospieszynski, Remigiusz; Golembiewska, Justyna; Wnuk, Edwin

    2012-07-01

    HEO (Highly Elliptical Orbit) satellites are objects with an elliptic orbit with a low-altitude perigee and a high-altitude apogee. Perigee mainly cross the LEO orbits and apogee reaches regions above GEO orbits. Number of satellites on the orbits are old racket bodies and other space debris. Most of HEO objects has the eccentricity more than 0.7. Many trackable objects are included in the NORAD TLE Catalogue but much more small debris exist which we could not track. Objects on as highly elliptical orbit are very danger for satellites in LEO region because of increasing velocity near the perigee. In order to calculate the trajectory of space debris we have to take into account force model consisting of geopotential, luni-solar effects, solar radiation pressure and for objects with low-altitude of perigee, atmospheric drag. This last perturbation is very important to calculate orbits with high accuracy but also one of the hardest to predict. Many atmospheric space debris objects parameters should be taken into account in this case, but we do not have sufficient data from observations, in particular S/M (area-to-mass) ratio. Fortunately we have some archival data for some debris included in TLE Catalogue, which are very helpful to estimate the approximate value of the parameter. In this paper we present the results of calculations of orbit predictions for short and medium time span (up to several weeks). We tried to designate the S/M parameter for some HEO objects from archival data from the TLE Catalogue and predict its orbital elements for several weeks. With better knowledge about approximate mean value of the S/M parameter we are able to improve the accuracy of predicted orbits.

  18. Orbital angular momentum entanglement

    NASA Astrophysics Data System (ADS)

    Romero, Mary Jacquiline Romero

    Entanglement in higher dimensions is an attractive concept that is a challenge to realise experimentally. To this end, the entanglement of the orbital angular momentum (OAM) of photons holds promise. The OAM state-space is discrete and theoretically unbounded. In the work that follows, we investigate various aspects of OAM entanglement. We show how the correlations in OAM and its conjugate variable, angular position, are determined by phase- matching and the shape of the pump beam in spontaneous parametric down- conversion. We implement tests of quantum mechanics which have been previously done for other variables. We show the Einstein-Podolsky-Rosen paradox for OAM and angle, supporting the incompatibility of quantum mechanics with locality and realism. We demonstrate violations of Bell-type inequalities, thereby discounting local hidden variables for describing the correlations we observe. We show the Hardy paradox using OAM, again highlighting the nonlocal nature of quantum mechanics. We demonstrate violations of Leggett-type inequalities, thereby discounting nonlocal hidden variables for describing correlations. Lastly, we have looked into the entanglement of topological vortex structures formed from a special superposition of OAM modes and show violations of Bell-type inequalities confined to a finite, isolated volume.

  19. Orbiter Camera Payload System

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Components for an orbiting camera payload system (OCPS) include the large format camera (LFC), a gas supply assembly, and ground test, handling, and calibration hardware. The LFC, a high resolution large format photogrammetric camera for use in the cargo bay of the space transport system, is also adaptable to use on an RB-57 aircraft or on a free flyer satellite. Carrying 4000 feet of film, the LFC is usable over the visible to near IR, at V/h rates of from 11 to 41 milliradians per second, overlap of 10, 60, 70 or 80 percent and exposure times of from 4 to 32 milliseconds. With a 12 inch focal length it produces a 9 by 18 inch format (long dimension in line of flight) with full format low contrast resolution of 88 lines per millimeter (AWAR), full format distortion of less than 14 microns and a complement of 45 Reseau marks and 12 fiducial marks. Weight of the OCPS as supplied, fully loaded is 944 pounds and power dissipation is 273 watts average when in operation, 95 watts in standby. The LFC contains an internal exposure sensor, or will respond to external command. It is able to photograph starfields for inflight calibration upon command.

  20. Solid Propulsion De-Orbiting and Re-Orbiting

    NASA Astrophysics Data System (ADS)

    Schonenborg, R. A. C.; Schoyer, H. F. R.

    2009-03-01

    With many "innovative" de-orbit systems (e.g. tethers, aero breaking, etc.) and with natural de-orbit, the place of impact of unburned spacecraft debris on Earth can not be determined accurately. The idea that satellites burn up completely upon re-entry is a common misunderstanding. To the best of our knowledge only rocket motors are capable of delivering an impulse that is high enough, to conduct a de-orbit procedure swiftly, hence to de-orbit at a specific moment that allows to predict the impact point of unburned spacecraft debris accurately in remote areas. In addition, swift de-orbiting will reduce the on-orbit time of the 'dead' satellite, which reduces the chance of the dead satellite being hit by other dead or active satellites, while spiralling down to Earth during a slow, 25 year, or more, natural de-orbit process. Furthermore the reduced on-orbit time reduces the chance that spacecraft batteries, propellant tanks or other components blow up and also reduces the time that the object requires tracking from Earth.The use of solid propellant for the de-orbiting of spacecraft is feasible. The main advantages of a solid propellant based system are the relatively high thrust and the facts that the system can be made autonomous quite easily and that the system can be very reliable. The latter is especially desirable when one wants to de-orbit old or 'dead' satellites that might not be able to rely anymore on their primary systems. The disadvantage however, is the addition of an extra system to the spacecraft as well as a (small) mass penalty. [1]This paper describes the above mentioned system and shows as well, why such a system can also be used to re-orbit spacecraft in GEO, at the end of their life to a graveyard orbit.Additionally the system is theoretically compared to an existing system, of which performance data is available.A swift market analysis is performed as well.

  1. Orbit Determination System for Low Earth Orbit Satellites

    NASA Technical Reports Server (NTRS)

    Elisha, Yossi; Shyldkrot, Haim; Hankin, Maxim

    2007-01-01

    The IAI/MBT Precise Orbit Determination system for Low Earth Orbit satellites is presented. The system is based on GPS pesudorange and carrier phase measurements and implements the Reduced Dynamics method. The GPS measurements model, the dynamic model, and the least squares orbit determination are discussed. Results are shown for data from the CHAMP satellite and for simulated data from the ROKAR GPS receiver. In both cases the one sigma 3D position and velocity accuracy is about 0.2 m and 0.5 mm/sec respectively.

  2. Radiation therapy for orbital lymphoma

    SciTech Connect

    Zhou Ping . E-mail: pzhou@partners.org; Ng, Andrea K.; Silver, Barbara; Li Sigui; Hua Ling; Mauch, Peter M.

    2005-11-01

    Purpose: To describe radiation techniques and evaluate outcomes for orbital lymphoma. Methods and Materials: Forty-six patients (and 62 eyes) with orbital lymphoma treated with radiotherapy between 1987 and 2003 were included. The majority had mucosa-associated lymphoid tissue (48%) or follicular (30%) lymphoma. Seventeen patients had prior lymphoma at other sites, and 29 had primary orbital lymphoma. Median follow-up was 46 months. Results: The median dose was 30.6 Gy; one-third received <30 Gy. Electrons were used in 9 eyes with disease confined to the conjunctiva or eyelid, and photons in 53 eyes with involvement of intraorbital tissues to cover entire orbit. Local control rate was 98% for all patients and 100% for those with indolent lymphoma. Three of the 26 patients with localized primary lymphoma failed distantly, resulting in a 5-year freedom-from-distant-relapse rate of 89%. The 5-year disease-specific and overall survival rates were 95% and 88%, respectively. Late toxicity was mainly cataract formation in patients who received radiation without lens block. Conclusions A dose of 30 Gy is sufficient for indolent orbital lymphoma. Distant relapse rate in patients with localized orbital lymphoma was lower than that reported for low-grade lymphoma presenting in other sites. Orbital radiotherapy can be used for salvage of recurrent indolent lymphoma.

  3. Space Telescopes and Orbital Debris

    NASA Astrophysics Data System (ADS)

    Seitzer, Patrick

    2009-01-01

    Almost 12,000 artificial objects orbiting the Earth are currently in the public catalog of orbital elements maintained by the USAF. Only a small fraction of them are operational satellites. The remainder is satellites whose missions have ended, rocket bodies, and parts and debris from larger parent objects. And the catalog only contains the biggest and brightest of the objects in orbit. The Low Earth Orbit (LEO) regime where most of this population concentrates is also a regime of incredible interest to astronomers, since it is where flagship missions such as the Hubble Space Telescope and other Great Observatories operate. I'll review the current state of knowledge of the orbital debris population, how it has grown with time, and how this environment could affect current and future space telescopes. There are mitigation measures which many spacecraft operators have adopted which can control the growth of the debris population. Orbital debris research at the University of Michigan is funded by NASA's Orbital Debris Program Office, Johnson Space Center, Houston, Texas.

  4. Lifetimes of lunar satellite orbits

    NASA Technical Reports Server (NTRS)

    Meyer, Kurt W.; Buglia, James J.; Desai, Prasun N.

    1994-01-01

    The Space Exploration Initiative has generated a renewed interest in lunar mission planning. The lunar missions currently under study, unlike the Apollo missions, involve long stay times. Several lunar gravity models have been formulated, but mission planners do not have enough confidence in the proposed models to conduct detailed studies of missions with long stay times. In this report, a particular lunar gravitational model, the Ferrari 5 x 5 model, was chosen to determine the lifetimes for 100-km and 300-km perilune altitude, near-circular parking orbits. The need to analyze orbital lifetimes for a large number of initial orbital parameters was the motivation for the formulation of a simplified gravitational model from the original model. Using this model, orbital lifetimes were found to be heavily dependent on the initial conditions of the nearly circular orbits, particularly the initial inclination and argument of perilune. This selected model yielded lifetime predictions of less than 40 days for some orbits, and other orbits had lifetimes exceeding a year. Although inconsistencies and limitations are inherent in all existing lunar gravity models, primarily because of a lack of information about the far side of the moon, the methods presented in this analysis are suitable for incorporating the moon's nonspherical gravitational effects on the preliminary design level for future lunar mission planning.

  5. Orbital Infarction due to Sickle Cell Disease without Orbital Pain

    PubMed Central

    Mai, Kim-Binh T.

    2016-01-01

    Sickle cell disease is a hemoglobinopathy that results in paroxysmal arteriolar occlusion and tissue infarction that can manifest in a plurality of tissues. Rarely, these infarcted crises manifest in the bony orbit. Orbital infarction usually presents with acute onset of periorbital tenderness, swelling, erythema, and pain. Soft tissue swelling can result in proptosis and attenuation of extraocular movements. Expedient diagnosis of sickle cell orbital infarction is crucial because this is a potentially sight-threatening entity. Diagnosis can be delayed since the presentation has physical and radiographic findings mimicking various infectious and traumatic processes. We describe a patient who presented with sickle cell orbital crisis without pain. This case highlights the importance of maintaining a high index of suspicion in patients with known sickle cell disease or of African descent born outside the United States in a region where screening for hemoglobinopathy is not routine, even when the presentation is not classic. PMID:27891273

  6. Mab's orbital motion explained

    NASA Astrophysics Data System (ADS)

    Kumar, K.; de Pater, I.; Showalter, M. R.

    2015-07-01

    We explored the hypothesis that Mab's anomalous orbital motion, as deduced from Hubble Space Telescope (HST) data (Showalter, M.R., Lissauer, J.J. [2006]. Science (New York, NY) 311, 973-977), is the result of gravitational interactions with a putative suite of large bodies in the μ-ring. We conducted simulations to compute the gravitational effect of Mab (a recently discovered Uranian moon) on a cloud of test particles. Subsequently, by employing the data extracted from the test particle simulations, we executed random walk simulations to compute the back-reaction of nearby perturbers on Mab. By generating simulated observation metrics, we compared our results to the data retrieved from the HST. Our results indicate that the longitude residual change noted in the HST data (Δλr,Mab ≈ 1 deg) is well matched by our simulations. The eccentricity variations (ΔeMab ≈10-3) are however typically two orders of magnitude too small. We present a variety of reasons that could account for this discrepancy. The nominal scenario that we investigated assumes a perturber ring mass (mring) of 1 mMab (Mab's mass) and a perturber ring number density (ρn,ring) of 10 perturbers per 3 RHill,Mab (Mab's Hill radius). This effectively translates to a few tens of perturbers with radii of approximately 2-3 km, depending on the albedo assumed. The results obtained also include an interesting litmus test: variations of Mab's inclination on the order of the eccentricity changes should be observable. Our work provides clues for further investigation into the tantalizing prospect that the Mab/μ-ring system is undergoing re-accretion after a recent catastrophic disruption.

  7. Orbiter Crew Compartment Integration-Stowage

    NASA Technical Reports Server (NTRS)

    Morgan, L. Gary

    2007-01-01

    This viewgraph presentation describes the Orbiter Crew Compartment Integration (CCI) stowage. The evolution of orbiter crew compartment stowage volume is also described, along with photographs presented of the on-orbit volume stowage capacity.

  8. Thirteenth satellite of Jupiter. [orbit determination

    NASA Technical Reports Server (NTRS)

    Kowal, C. T.; Aksnes, K.; Marsden, B. G.; Roemer, E.

    1975-01-01

    The discovery, observations, and attempts to determine the orbit of Jupiter XIII are described. It is found that the orbit is very similar to the orbits of Jupiter VI, VII, and X. An ephemeris is provided for the 1975 opposition.

  9. Computed tomography of orbital-facial neurofibromatosis

    SciTech Connect

    Zimmerman, R.A.; Bilaniuk, L.T.; Metzger, R.A.; Grossman, R.I.; Schut, L.; Bruce, D.A.

    1983-01-01

    Twenty-four patients with orbital-facial manifestations of neurofibromations were examined by computed tomography. Delineation of the extent of the disease, and differentiation of the disease processes (orbital tumor, osseous orbital dysplasia, plexiform neurofibromatosis, and buphthalmos) was possible.

  10. Advanced space system for geostationary orbit surveillance

    NASA Astrophysics Data System (ADS)

    Klimenko, N. N.; Nazarov, A. E.

    2016-12-01

    The structure and orbital configuration of the advanced space system for geostationary orbit surveillance, as well as possible approaches to the development of the satellite bus and payload for the geostationary orbit surveillance, are considered.

  11. Ocular complications of orbital venography.

    PubMed

    Safer, J N; Guibor, P

    1975-03-01

    Three ocular complications directly related to orbital venography are described, one resulting in permanent loss of vision,. The patient had lymphangioma of the orbit which evidently had bled secondary to increased venous pressure and injection of contrast bolus. Both of the 2 patients with transient visual disturbances had diabetic retinopathy. The common factor is felt to be an imparied vascular bed which cannot meet the stress of increased venous pressure and contrast medium injection. Conditions which predispose to ocular-orbital stasis and/or hemorrhage are discussed.

  12. Orbital, Rotational, and Climatic Interactions

    NASA Technical Reports Server (NTRS)

    Bills, Bruce G. (Editor)

    1992-01-01

    The report of an international meeting on the topic of Orbital, Rotational, and Climatic Interactions, which was held 9-11 Jul. 1991 at the Johns Hopkins University is presented. The meeting was attended by 22 researchers working on various aspects of orbital and rotational dynamics, paleoclimate data analysis and modeling, solid-Earth deformation studies, and paleomagnetic analyses. The primary objective of the workshop was to arrive at a better understanding of the interactions between the orbital, rotational, and climatic variations of the Earth. This report contains a brief introduction and 14 contributed papers which cover most of the topics discussed at the meeting.

  13. Orbital problems in GPS interferometry

    NASA Astrophysics Data System (ADS)

    Zielinski, Janusz B.

    The GPS orbits and the influence of the orbital errors on the geodetic determination were investigated during the last few years. In the paper, the summary of some analyses is presented concerning the nature of the interferometric observations, the propagation of the orbital errors, and the correlations and covariances in geodetic GPS solutions. One of the results was a proof that, in relative determinations by GPS, the error propagation factor is close to b/10 h, that is almost one order smaller than previously supposed.

  14. Orbit Determination with Very Short Arcs: Preliminary Orbits and Identifications

    NASA Astrophysics Data System (ADS)

    Milani, A.; Gronchi, G. F.; Knezevic, Z.; Sansaturio, M. E.

    2004-05-01

    When the observation of a new asteroid are not enough to compute an orbit we can represent them with an attributable (two angles and their time derivatives). The undetermined range and range rate span an admissible region of solar system orbits, which can be represented by a set of Virtual Asteroids (VAs) selected by an optimal triangulation (see the presentation by G. Gronchi). The four coordinates of the attributable are the result of a fit and have a covariance matrix. Thus the predictions of future observations have a quasi-product structure (admissible region times confidence ellipsoid), approximated by a triangulation with a confidence ellipsoid for each node. If we have >2 observations we can also estimate the geodetic curvature and the acceleration of the observed path on the celestial sphere. If both are significantly measured they constrain the range and the range rate and may allow to reduce the size of the admissible region. To compute a a preliminary orbit starting from two attributables, for each VA (selected in the admissible region of the first arc) we consider the prediction at the time of the second and its covariance matrix, and we compare them with the attributable of the second arc with its covariance. By using the identification penalty (as in the algorithms for orbit identification) we can select as a preliminary orbit the VAs which fits together both arcs in the 8-dimensional space. Two attributables may not be enough to compute an orbit with convergent differential corrections. The preliminary orbit is used in a constrained differential correction, providing solutions along the Line Of Variations, to be used as second generation VAs to predict the observations at the time of a third arc. In general the identification with a third arc ensures a well determined orbit.

  15. JSC Orbital Debris Website Description

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2006-01-01

    Purpose: The website provides information about the NASA Orbital Debris Program Office at JSC, which is the lead NASA center for orbital debris research. It is recognized world-wide for its leadership in addressing orbital debris issues. The NASA Orbital Debris Program Office has taken the international lead in conducting measurements of the environment and in developing the technical consensus for adopting mitigation measures to protect users of the orbital environment. Work at the center continues with developing an improved understanding of the orbital debris environment and measures that can be taken to control its growth. Major Contents: Orbital Debris research is divided into the following five broad efforts. Each area of research contains specific information as follows: 1) Modeling - NASA scientists continue to develop and upgrade orbital debris models to describe and characterize the current and future debris environment. Evolutionary and engineering models are described in detail. Downloadable items include a document in PDF format and executable software. 2) Measurements - Measurements of near-Earth orbital debris are accomplished by conducting ground-based and space-based observations of the orbital debris environment. The data from these sources provide validation of the environment models and identify the presence of new sources. Radar, optical and surface examinations are described. External links to related topics are provided. 3) Protection - Orbital debris protection involves conducting hypervelocity impact measurements to assess the risk presented by orbital debris to operating spacecraft and developing new materials and new designs to provide better protection from the environment with less weight penalty. The data from this work provides the link between the environment defined by the models and the risk presented by that environment to operating spacecraft and provides recommendations on design and operations procedures to reduce the risk as

  16. Independent Orbiter Assessment (IOA): Analysis of the orbital maneuvering system

    NASA Technical Reports Server (NTRS)

    Prust, C. D.; Paul, D. J.; Burkemper, V. J.

    1987-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Orbital Maneuvering System (OMS) hardware are documented. The OMS provides the thrust to perform orbit insertion, orbit circularization, orbit transfer, rendezvous, and deorbit. The OMS is housed in two independent pods located one on each side of the tail and consists of the following subsystems: Helium Pressurization; Propellant Storage and Distribution; Orbital Maneuvering Engine; and Electrical Power Distribution and Control. The IOA analysis process utilized available OMS hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluted and analyzed for possible failure modes and effects. Criticality was asigned based upon the severity of the effect for each failure mode.

  17. Reactionless orbital propulsion using tether deployment

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1990-01-01

    Examples of tether propulsion in orbit without the use of reaction mass are discussed. These include (1) using tether extension to reposition a satellite in orbit without fuel expenditure by extending a mass on the end of the tether; (2) using a tether for eccentricity pumping to add energy to the orbit for boosting and orbital transfer; and (3) length modulation of a spinning tether to transfer angular momentum between the orbit and tether spin, thus allowing changes in orbital angular momentum.

  18. Effects of orbital ellipticity on collisional disruptions of rubble-pile asteroids

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; Baoyin, Hexi; Li, Junfeng; Richardson, Derek C.; Schwartz, Stephen R.

    2015-11-01

    The behavior of debris ejected from asteroids after collisional disruptions has significant implications for asteroid evolution. Analytical approximations of the elliptic restricted three-body system show that the behavior of ejecta varies significantly with the orbital eccentricity and true anomaly of an asteroid. To study these orbital perturbative effects on collision outcomes, we conduct a series of low-speed collision simulations using a combination of an N-body gravity algorithm and the soft-sphere discrete element method. The asteroid is modeled as a gravitational aggregate, which is one of the plausible structures for asteroids whose sizes are larger than several hundreds of meters. To reduce the effect of complicating factors raised by the mutual interaction between post-collision fragments on the outcomes, a low-resolution model and a set of frictionless material parameters are used in the first step of exploration. The results indicate that orbital perturbations on ejecta arising from the eccentricity and true anomaly of the target asteroid at the time of impact cause larger mass loss and lower the catastrophic disruption threshold (the specific energy required to disperse half the total system mass) in collision events. The "universal law" of catastrophic disruption derived by Stewart and Leinhardt (Astrophys. J. Lett. 691:L133-L137, 2009) can be applied to describe the collision outcomes of asteroids on elliptical heliocentric orbits. Through analyses of ejecta velocity distributions, we develop a semi-analytic description of escape speed from the asteroid's surface in an elliptic restricted three-body system and show that resulting perturbations have long-term orbital effects on ejecta and can also have an indirect influence on the velocity field of post-fragments through interparticle collisions. Further exploration with a high-resolution model shows that the long-term perturbative effects systematically increase mass loss, regardless of the target

  19. Aqua satellite orbiting the Earth

    NASA Video Gallery

    This animation shows the Aqua satellite orbiting the Earth on August 27, 2005 by revealing MODIS true-color imagery for that day. This animation is on a cartesian map projection, so the satellite w...

  20. Cost Per Pound From Orbit

    NASA Technical Reports Server (NTRS)

    Merriam, M. L.

    2002-01-01

    Traditional studies of Reusable Launch Vehicle (RLV) designs have focused on designs that are completely reusable except for the fuel. This may not be realistic with current technology . An alternate approach is to look at partially reusable launch vehicles. This raises the question of which parts should be reused and which parts should be expendable. One approach is to consider the cost/pound of returning these parts from orbit. With the shuttle, this cost is about three times the cost/pound of launching payload into orbit. A subtle corollary is that RLVs are much less practical for higher orbits, such as the one on which the International Space Station resides, than they are for low earth orbits.

  1. NASA Orbital Debris Baseline Populations

    NASA Technical Reports Server (NTRS)

    Krisko, Paula H.; Vavrin, A. B.

    2013-01-01

    The NASA Orbital Debris Program Office has created high fidelity populations of the debris environment. The populations include objects of 1 cm and larger in Low Earth Orbit through Geosynchronous Transfer Orbit. They were designed for the purpose of assisting debris researchers and sensor developers in planning and testing. This environment is derived directly from the newest ORDEM model populations which include a background derived from LEGEND, as well as specific events such as the Chinese ASAT test, the Iridium 33/Cosmos 2251 accidental collision, the RORSAT sodium-potassium droplet releases, and other miscellaneous events. It is the most realistic ODPO debris population to date. In this paper we present the populations in chart form. We describe derivations of the background population and the specific populations added on. We validate our 1 cm and larger Low Earth Orbit population against SSN, Haystack, and HAX radar measurements.

  2. The orbit of Pluto's satellite

    NASA Technical Reports Server (NTRS)

    Tholen, D. J.

    1985-01-01

    Nineteen speckle interferometric observations of the Pluto system have been used to improve the determination of the orbital elements for Pluto's satellite. Calibration uncertainties appear to be the dominant source of error, but the observation of a partial occultation of the satellite by Pluto has been used to constrain the orbit solution. The orbital period is found to be in excellent agreement with the rotational period of the planet, reinforcing the belief that the system is completely tidally evolved. The orbital radius and period imply a total mass for the system of 6.8 + or - 0.5 x 10 to the -9th solar masses. Density constraints place an upper limit of 3615 + or - 90 km on the diameter of Pluto, while observations of the first mutual events establish a crude lower limit of about 2800 km.

  3. ARTEMIS Maneuvers into Lunar Orbit

    NASA Video Gallery

    This animation visualizes the maneuvers required to move the ARTEMIS spacecraft from their kidney-shaped paths on each side of the moon to orbiting the moon. It took one and a half years, over 90 o...

  4. Two stage to orbit design

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A preliminary design of a two-stage to orbit vehicle was conducted with the requirements to carry a 10,000 pound payload into a 300 mile low-earth orbit using an airbreathing first stage, and to take off and land unassisted on a 15,000 foot runway. The goal of the design analysis was to produce the most efficient vehicle in size and weight which could accomplish the mission requirements. Initial parametric analysis indicated that the weight of the orbiter and the transonic performance of the system were the two parameters that had the largest impact on the design. The resulting system uses a turbofan ramjet powered first stage to propel a scramjet and rocket powered orbiter to the stage point of Mach 6 to 6.5 at an altitude of 90,000 ft.

  5. Real and Hybrid Atomic Orbitals.

    ERIC Educational Resources Information Center

    Cook, D. B.; Fowler, P. W.

    1981-01-01

    Demonstrates that the Schrodinger equation for the hydrogenlike atom separates in both spheroconal and prolate spheroidal coordinates and that these separations provide a sound theoretical basis for the real and hybrid atomic orbitals. (Author/SK)

  6. A Case of Orbital Histoplasmosis.

    PubMed

    Krakauer, Mark; Prendes, Mark Armando; Wilkes, Byron; Lee, Hui Bae Harold; Fraig, Mostafa; Nunery, William R

    2016-01-01

    Histoplasma capsulatum var capsulatum is a dimorphic fungus endemic to the Ohio and Mississippi River Valleys of the United States. In this case report, a 33-year-old woman who presented with a right orbital mass causing progressive vision loss, diplopia, and facial swelling is described. Lateral orbitotomy with lateral orbital wall bone flap was performed for excisional biopsy of the lesion. The 1.5 × 1.8 × 2.3 cm cicatricial mass demonstrated a granulomatous lesion with necrosis and positive staining consistent with Histoplasma capsulatum var capsulatum infection. To the authors' knowledge, this is the first case of orbital histoplasmosis to be reported in the United States and the first case worldwide of orbital histoplasmosis due to Histoplasma capsulatum var capsulatum.

  7. Visualization of Molecular Orbitals: Formaldehyde

    ERIC Educational Resources Information Center

    Olcott, Richard J.

    1972-01-01

    Describes a computer program that plots a solid" representation of molecular orbital charge density which can be used to analyze wave functions of molecules. Illustrated with diagrams for formaldehyde. (AL)

  8. How to Orbit the Earth.

    ERIC Educational Resources Information Center

    Quimby, Donald J.

    1984-01-01

    Discusses the geometry, algebra, and logic involved in the solution of a "Mindbenders" problem in "Discover" magazine and applies it to calculations of satellite orbital velocity. Extends the solution of this probe to other applications of falling objects. (JM)

  9. Lunar orbital mass spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Lord, W. P.

    1971-01-01

    The design, development, manufacture, test and calibration of five lunar orbital mass spectrometers with the four associated ground support equipment test sets are discussed. A mass spectrometer was installed in the Apollo 15 and one in the Apollo 16 Scientific Instrument Module within the Service Module. The Apollo 15 mass spectrometer was operated with collection of 38 hours of mass spectra data during lunar orbit and 50 hours of data were collected during transearth coast. The Apollo 16 mass spectrometer was operated with collection of 76 hours of mass spectra data during lunar orbit. However, the Apollo 16 mass spectrometer was ejected into lunar orbit upon malfunction of spacecraft boom system just prior to transearth insection and no transearth coast data was possible.

  10. Orbits in a logarithmic potential

    SciTech Connect

    Hooverman, R. H.

    2014-04-15

    The characteristics of charged particle orbits in the logarithmic electrostatic potential field surrounding a straight conducting wire at a fixed potential are investigated. The equations of motion of an electron in a logarithmic potential are derived, the limiting cases are considered, and the results of numerical integration of the equations of motion are presented along with sketches of a few representative orbits. (C.E.S.)

  11. Orbit Prediction Tool for Different Classes of Space Debris Orbits

    NASA Astrophysics Data System (ADS)

    Wnuk, Edwin; Wytrzyszczak, Iwona; Golembiewska, Justyna; Klinkrad, Heiner

    There are two aspects of the orbital evolution of space debris: the long-term evolution and the short-term prediction of individual object orbits. In the case of the long-term evolution (years or tens of years time span) general characteristics (e.g. total number of objects, spa-tial distribution and density) of a future space environment are predicted with the use of a relatively simple theory of motion for statistical analysis of future orbits of a large number of objects -a cloud of particles". In the short-term orbital evolution of space debris objects, as considered in this paper, future positions and velocities of individual objects are calculated for a few days or a few weeks time span. A much more sophisticated theory of satellite motion is applied in this case. The paper presents the orbital prediction tool that uses an analytical and semi-analytical theories of satellite motion. The force model includes all important perturbing factors: geopotential effects with arbitrary degree and order spherical harmonic coefficients taken into account, luni-solar attractions, solar radiation pressure and atmospheric drag. The analytical theory of motion is of the second order and is not sensitive to singularities for small eccentricities and small inclinations. A new algorithm for the transformation between mean and osculating elements for the second order theory is applied. Predicted positions of a satel-lite on a given level of accuracy are calculated only with the use of terms that essentially influence on predicted satellite orbit, all other terms are omitted. The number of terms in for-mulas for perturbations, and thus complexity of the theory, depends on the defined level of accuracy and the type of orbit. In practice, we create a dynamical model for a given class of satellite orbit. Geopotential and luni-solar perturbations are calculated in the two following steps. In the first step, values of secular terms and all amplitudes of periodic terms are calculated

  12. Low Earth orbit communications satellite

    NASA Technical Reports Server (NTRS)

    Moroney, D.; Lashbrook, D.; Mckibben, B.; Gardener, N.; Rivers, T.; Nottingham, G.; Golden, B.; Barfield, B.; Bruening, J.; Wood, D.

    1992-01-01

    A current thrust in satellite communication systems considers a low-Earth orbiting constellations of satellites for continuous global coverage. Conceptual design studies have been done at the time of this design project by LORAL Aerospace Corporation under the program name GLOBALSTAR and by Motorola under their IRIDIUM program. This design project concentrates on the spacecraft design of the GLOBALSTAR low-Earth orbiting communication system. Overview information on the program was gained through the Federal Communications Commission licensing request. The GLOBALSTAR system consists of 48 operational satellites positioned in a Walker Delta pattern providing global coverage and redundancy. The operational orbit is 1389 km (750 nmi) altitude with eight planes of six satellites each. The orbital planes are spaced 45 deg., and the spacecraft are separated by 60 deg. within the plane. A Delta 2 launch vehicle is used to carry six spacecraft for orbit establishment. Once in orbit, the spacecraft will utilize code-division multiple access (spread spectrum modulation) for digital relay, voice, and radio determination satellite services (RDSS) yielding position determination with accuracy up to 200 meters.

  13. Precision Orbit Determination for the Lunar Reconnaissance Orbiter

    NASA Astrophysics Data System (ADS)

    Lemoine, Frank; Rowlands, David; McGarry, Jan; Neumann, Gregory; Chinn, Douglas; Mazarico, Erwan; Torrence, Mark

    The U.S. Lunar Reconnaissance Orbiter (LRO) mission will be launched in October 2008, and will carry out a detailed mapping of the Moon using a science payload of multiple instruments, including the Lunar Orbiter Laser Altimeter (LOLA), and the Lunar Reconnaissance Orbiter Camera (LROC) (Chin, 2007). One of the primary goals of the LRO mission is develop a geodetic grid for the planet. A subsidiary goal is the improvement of the lunar gravity field. The environment for POD on LRO is especially challenging. The spacecraft will orbit the Moon at a mean altitude of 50 km, and the expected error from the Lunar Prospector series of gravity models (to degree 100 or to degree 150) can be expected to be hundreds of meters. LRO will be tracked by S Band Doppler from White Sands, New Mexico, and Dongara, Australia, as well as by one-way laser ranging from Satellite Laser Ranging (SLR) tracking stations on the Earth. However, unlike the Japanese lunar mission SELENE (Kaguya), no direct tracking will be available while the spacecraft is over the lunar farside. We review the status of orbit modelling for LRO, for both the geopotential modelling and the nonconservative force models, as well as anticipated improvements. We discuss the modelling for the one-way laser ranging observable, and how the data from the one-way laser ranging (LR) system will be acquired from selected stations of the global stations of the SLR network. We discuss the orbit determination strategies which we expect to implement on this mission, including the use of altimeter crossovers from the LOLA instrument to supplement the Earth-based tracking and we review the projected orbit determination accuracies that will be attainable.

  14. Structure of the Zodiacal Emission by Spitzer Archive Data

    NASA Astrophysics Data System (ADS)

    Verebélyi, Erika

    2015-08-01

    Dust in the Interplanetary Dust Cloud not just reflects the sunlight (known as zodiacal light) but also has its own thermal emission. At the heliocentric distance of Earth the peak of this emission (with particle size 100 μm) is close to 20 μm. In this study we used the data of four programs completed with the MIPS camera of the Spitzer Space Telescope at 24 μm to probe the large scale brightness distribution as well as the small-scale (subarcmin) structure of the Zodiacal Could. The four programs were:1. The Production of Zodiacal Dust by Asteroids and Comets (ID: 2317)2. High Latitude Dust Bands in the Main Asteroid Belt: Fingerprints of Recent Breakup Events (ID: 20539)3. A New Source of Interplanetary Dust: Type II Dust Trails (ID: 30545)4. First Look Survey - Ecliptic Plane Component (ID: 98)We take into account that while the Spitzer Space Telescope carried out the measurements it was orbiting the Sun at an Earth-trailing orbit and looked at different parts of the Zodiacal Cloud, in many cases looking through the same parts of the cloud from different locations. This gives us the chance to investigate the 3D distribution of zodiacal dust in addition to its large and small scale structure.

  15. Space Tourism: Orbital Debris Considerations

    NASA Astrophysics Data System (ADS)

    Mahmoudian, N.; Shajiee, S.; Moghani, T.; Bahrami, M.

    2002-01-01

    Space activities after a phase of research and development, political competition and national prestige have entered an era of real commercialization. Remote sensing, earth observation, and communication are among the areas in which this growing industry is facing competition and declining government money. A project like International Space Station, which draws from public money, has not only opened a window of real multinational cooperation, but also changed space travel from a mere fantasy into a real world activity. Besides research activities for sending man to moon and Mars and other outer planets, space travel has attracted a considerable attention in recent years in the form of space tourism. Four countries from space fairing nations are actively involved in the development of space tourism. Even, nations which are either in early stages of space technology development or just beginning their space activities, have high ambitions in this area. This is worth noting considering their limited resources. At present, trips to space are available, but limited and expensive. To move beyond this point to generally available trips to orbit and week long stays in LEO, in orbital hotels, some of the required basic transportations, living requirements, and technological developments required for long stay in orbit are already underway. For tourism to develop to a real everyday business, not only the price has to come down to meaningful levels, but also safety considerations should be fully developed to attract travelers' trust. A serious hazard to space activities in general and space tourism in particular is space debris in earth orbit. Orbiting debris are man-made objects left over by space operations, hazardous to space missions. Since the higher density of debris population occurs in low earth orbit, which is also the same orbit of interest to space tourism, a careful attention should be paid to the effect of debris on tourism activities. In this study, after a

  16. Orbital order from the on-site orbital attraction

    NASA Astrophysics Data System (ADS)

    Khodas, M.; Chubukov, A. V.

    2016-09-01

    We study the model of Fe-based superconductors with intraorbital attraction, designed to favor a spontaneous orbital polarization. Previous studies of this model within the two-orbital approximation indicated that the leading instability is toward s -wave superconductivity and the subleading one is toward anti-ferro-orbital order, which breaks the translational symmetry of the crystal. The two-orbital approximation is, however, not consistent with the Fermi surface geometry of Fe superconductors, as it yields the wrong position of one of the hole pockets. Here we analyze the model with the same interaction but with realistic Fermi surface geometry (two hole pockets at the center of the Brillouin zone and two electron pockets at its boundary). We apply the parquet renormalization-group (pRG) technique to detect the leading instability upon the lowering of the temperature. We argue that the pRG analysis strongly favors a q =0 orbital order, which in the band basis is a d -wave Pomeranchuk order.

  17. THE ORBITS OF THE OUTER URANIAN SATELLITES

    SciTech Connect

    Brozovic, M.; Jacobson, R. A.

    2009-04-15

    We report on the numerically integrated orbits for the nine outer Uranian satellites. The orbits are calculated based on fits to the astrometric observations for the period from 1984 to 2006. The results include the state vectors, post-fit residuals, and mean orbital elements. We also assess the accuracy of the orbital fits and discuss the need for future measurements.

  18. An Analytical Satellite Orbit Predictor (ASOP)

    NASA Technical Reports Server (NTRS)

    Starke, S. E.

    1977-01-01

    The documentation and user's guide for the Analytical Satellite Orbit Predictor (ASOP) computer program is presented. The ASOP is based on mathematical methods that represent a new state-of-the-art for rapid orbit computation techniques. It is intended to be used for computation of near-earth orbits including those of the shuttle/orbiter and its payloads.

  19. The 2009 Mars Telecommunications Orbiter

    NASA Technical Reports Server (NTRS)

    Wilson, G. R.; DePaula, R.; Diehl, R. E.; Edwards, C. D.; Fitzgerald, R. J.; Franklin, S. F.; Kerridge, S. A.; Komarek, T. A.; Noreen, G. K.

    2004-01-01

    The first spacecraft with a primary function of providing communication links while orbiting a foreign planet has begun development for a launch in 2009. NASA's Mars Telecommunications Orbiter would use three radio bands to magnify the benefits of other future Mars missions and enable some types of missions otherwise impractical. It would serve as the Mars hub for a growing interplanetary Internet. And it would pioneer the use of planet-to-planet laser communications to demonstrate the possibility for even greater networking capabilities in the future. With Mars Telecommunications Orbiter overhead in the martian sky, the Mars Science Laboratory rover scheduled to follow the orbiter to Mars by about a month could send to Earth more than 100 times as much data per day as it could otherwise send. The orbiter will be designed for the capability of relaying up to 15 gigabits per day from the rover, equivalent to more than three full compact discs each day. The same benefits would accrue to other future major Mars missions from any nation.

  20. Tumor pathology of the orbit.

    PubMed

    Héran, F; Bergès, O; Blustajn, J; Boucenna, M; Charbonneau, F; Koskas, P; Lafitte, F; Nau, E; Roux, P; Sadik, J C; Savatovsky, J; Williams, M

    2014-10-01

    The term orbital tumor covers a wide range of benign and malignant diseases affecting specific component of the orbit or developing in contact with them. They are found incidentally or may be investigated as part of the assessment of a systemic disorder or because of orbital signs (exophthalmos, pain, etc.). Computed tomography, MRI and Color Doppler Ultrasound (CDU), play a varying role depending on the clinical presentation and the disease being investigated. This article reflects long experience in a reference center but does not claim to be exhaustive. We have chosen to consider these tumors from the perspective of their usual presentation, emphasizing the most common causes and suggestive radiological and clinical presentations (progressive or sudden-onset exophthalmos, children or adults, lacrimal gland lesions, periorbital lesions and enophthalmos). We will describe in particular muscle involvement (thyrotoxicosis and tumors), vascular lesions (cavernous sinus hemangioma, orbital varix, cystic lymphangioma), childhood lesions and orbital hematomas. We offer straightforward useful protocols for simple investigation and differential diagnosis. Readers who wish to go further to extend their knowledge in this fascinating area can refer to the references in the bibliography.

  1. Sampling characteristics of satellite orbits

    NASA Technical Reports Server (NTRS)

    Wunsch, Carl

    1989-01-01

    The irregular space-time sampling of any finite region by an orbiting satellite raises difficult questions as to which frequencies and wavenumbers can be determined and which will alias into others. Conventional sampling theorems must be extended to account for both irregular data distributions and observational noise - the sampling irregularity making the system much more susceptible to noise than in regularly sampled cases. The problem is formulated here in terms of least-squares and applied to spacecraft in 10-day and 17-day repeating orbits. The 'diamond-pattern' laid down spatially in such repeating orbits means that either repeat period adequately samples the spatial variables, but the slow overall temporal coverage in the 17-day pattern leads to much greater uncertainty than in the shorter repeat cycle. The result is not definitive and it is not concluded that a 10-day orbit repeat is the most appropriate one. A major conclusion, however, is that different orbital choices have potentially quite different sampling characteristics which need to be analyzed in terms of the spectral characteristics of the moving sea surface.

  2. Virtual Surgical Planning for Orbital Reconstruction

    PubMed Central

    Susarla, Srinivas M.; Duncan, Katherine; Mahoney, Nicholas R.; Merbs, Shannath L.; Grant, Michael P.

    2015-01-01

    The advent of computer-assisted technology has revolutionized planning for complex craniofacial operations, including orbital reconstruction. Orbital reconstruction is ideally suited for virtual planning, as it allows the surgeon to assess the bony anatomy and critical neurovascular structures within the orbit, and plan osteotomies, fracture reductions, and orbital implant placement with efficiency and predictability. In this article, we review the use of virtual surgical planning for orbital decompression, posttraumatic midface reconstruction, reconstruction of a two-wall orbital defect, and reconstruction of a large orbital floor defect with a custom implant. The surgeon managing orbital pathology and posttraumatic orbital deformities can benefit immensely from utilizing virtual planning for various types of orbital pathology. PMID:26692714

  3. The Eccentric Behavior of Nearly Frozen Orbits

    NASA Technical Reports Server (NTRS)

    Sweetser, Theodore H.; Vincent, Mark A.

    2013-01-01

    Frozen orbits are orbits which have only short-period changes in their mean eccentricity and argument of periapse, so that they basically keep a fixed orientation within their plane of motion. Nearly frozen orbits are those whose eccentricity and argument of periapse have values close to those of a frozen orbit. We call them "nearly" frozen because their eccentricity vector (a vector whose polar coordinates are eccentricity and argument of periapse) will stay within a bounded distance from the frozen orbit eccentricity vector, circulating around it over time. For highly inclined orbits around the Earth, this distance is effectively constant over time. Furthermore, frozen orbit eccentricity values are low enough that these orbits are essentially eccentric (i.e., off center) circles, so that nearly frozen orbits around Earth are bounded above and below by frozen orbits.

  4. A criterion to classify asteroids and comets based on the orbital parameters

    NASA Astrophysics Data System (ADS)

    Tancredi, Gonzalo

    2014-05-01

    The classification criterion between asteroids and comets has evolved in recent decades, but the main distinction remains unchanged. Comets present gas and dust ejection from the surface at some point of their orbits, therefore, these objects are considered to be active. On the other hand, asteroids do not show any kind of large scale gas and dust ejection, they are inert. Nevertheless, this classification scheme is impractical when we have more than 500,000 asteroids already discovered. In addition, comets are not active all along their orbits. In order for a comet to display activity at present or in the recent past in the inner region of the Solar System (heliocentric distance <2 AU), the cometary orbit must be unstable in the time scale on the order of ten thousands of years; otherwise, the object should have completely consumed its volatile component. Close encounters with the most massive planets is the only mechanism that could produce “macroscopic” instabilities on a short time scale. The macroscopic changes in the orbital elements can be detected in a numerical integration of the dynamical evolution of the object over a time scale of several thousand years. This procedure to identify asteroids in cometary-like orbits is also impractical because it would require months of computing time. Therefore, a classification scheme based on the orbital elements to identify the border cases between the asteroid and comet populations is urgently required. We present a criterion to classify asteroids and comets and to find the border case based on the Tisserand’s parameter, the Minimum Orbital Intersection Distance (MOID), and considering some information regarding the aphelion and perihelion distances. Objects in mean-motion are disregarded. After applying a filter to the sample of over half a million asteroids already discovered to select the precise orbits and to the sample of 487 short-period comets, we apply the proposed classification criterion. The

  5. Radio frequency interference at the geostationary orbit

    NASA Technical Reports Server (NTRS)

    Sue, M. K.

    1981-01-01

    Growing demands on the frequency spectrum have increased the possibility of radio frequency interference (RFI). Various approaches to obtain in orbit RFI data are compared; this comparision indicates that the most practical way to obtain RFI data for a desired orbit (such as a geostationary orbit) is through the extrapolation of in orbit RFI measurements by a low orbit satellite. It is concluded that a coherent RFI program that uses both experimental data and analytical predictions provides accurate RFI data at minimal cost.

  6. The evolution of comet orbits

    NASA Technical Reports Server (NTRS)

    Everhart, E.

    1976-01-01

    The origin of comets and the evolution of their orbits are discussed. Factors considered include: the law of survival of comets against ejection on hyperbolic orbits; short-period comets are not created by single close encounters of near-parabolic comets with Jupiter; observable long-period comets do not evolve into observable short-period comets; unobservable long-period comets with perihelia near Jupiter can evolve into observable short-period comets; long-period comets cannot have been formed or created within the planetary region of the solar system (excluding the effects of stellar perturbations); it is possible that some of the short-period comets could have been formed inside the orbit of Neptune; circularly-restricted three-body problem, and its associated Jacobi integral, are not valid approximations to use in studying origin and evolution of comets.

  7. The Challenge of Orbital Debris

    NASA Technical Reports Server (NTRS)

    Matney, Mark

    2012-01-01

    Since the dawn of the Space Age more than 50 years ago, humans have been launching objects into the space environment faster than they have been removed by active means or natural decay. This has led to a proliferation of debris -- derelict satellites, discarded rocket upper stages, and pieces from satellite breakups -- in Earth orbit, especially in well-used orbital regimes. This talk will summarize the current knowledge of the debris environment and describe plans to address the challenges orbital debris raises for the future usability of near-Earth space. The talk will be structured around 4 categories: Measurements, Modeling, Shielding, and Mitigation. This will include discussions of the long-term prognosis of debris growth (i.e., the "Kessler Syndrome") as well as plans for active debris removal.

  8. Management of the orbital environment

    NASA Technical Reports Server (NTRS)

    Loftus, Joseph P., Jr.; Kessler, Donald J.; Anz-Meador, Phillip D.

    1991-01-01

    Data regarding orbital debris are presented to shed light on the requirements of environmental management in space, and strategies are given for active intervention and operational strategies. Debris are generated by inadvertent explosions of upper stages, intentional military explosions, and collisional breakups. Design and operation practices are set forth for minimizing debris generation and removing useless debris from orbit in the low-earth and geosynchronous orbits. Self-disposal options include propulsive maneuvers, drag-augmentation devices, and tether systems, and the drag devices are described as simple and passive. Active retrieval and disposition are considered, and the difficulty is examined of removing small debris. Active intervention techniques are required since pollution prevention is more effective than remediation for the problems of both earth and space.

  9. Oncocytic Adenocarcinoma of the Orbit.

    PubMed

    Harris, Gerald J; Paul, Sean; Hunt, Bryan C

    Oncocytic adenocarcinoma of the orbit is a rare tumor, with 1 case of nonlacrimal sac, nonlacrimal gland origin, and a poor outcome previously reported. An 85-year-old man with a 2-month history of left-sided epiphora, enlarging eyelid nodules, and diplopia in left gaze was found on imaging to have a poorly circumscribed, nodular mass of uniform radiodensity in the inferomedial orbit. Incisional biopsy revealed morphologic and immunohistochemical features of oncocytic adenocarcinoma with origin in the caruncle suspected, and CT of the neck, chest, abdomen, and pelvis showed no metastases or remote primary tumor source. Based on multidisciplinary consensus, orbital exenteration with adjuvant radiation therapy was performed, and there was no evidence of residual or recurrent tumor 2 years after treatment.

  10. Orbit of 1976 AA. [asteroid

    NASA Technical Reports Server (NTRS)

    Marsden, B. G.; Williams, J. G.

    1977-01-01

    The orbit of Asteroid 1976 AA is described, with attention given to calculations of its period and its distance from earth, both of which could be accurately and quickly determined by measuring the minor planet's position over wide ranges of hour angle on one to three nights. The geometry of the asteroid's orbit is compared to that of earth's orbit, and the periodicity of the minor planet's approaches to earth is projected. The motion of 1976 AA over an interval of seven centuries into both past and future is also studied; the possibility of its libration with respect to earth or to Venus is examined. Some data on closest approaches of the asteroid to Mars and Venus, as well as to earth, are given.

  11. Gravity Probe B orbit determination

    NASA Astrophysics Data System (ADS)

    Shestople, P.; Ndili, A.; Hanuschak, G.; Parkinson, B. W.; Small, H.

    2015-11-01

    The Gravity Probe B (GP-B) satellite was equipped with a pair of redundant Global Positioning System (GPS) receivers used to provide navigation solutions for real-time and post-processed orbit determination (OD), as well as to establish the relation between vehicle time and coordinated universal time. The receivers performed better than the real-time position requirement of 100 m rms per axis. Post-processed solutions indicated an rms position error of 2.5 m and an rms velocity error of 2.2 mm s-1. Satellite laser ranging measurements provided independent verification of the GPS-derived GP-B orbit. We discuss the modifications and performance of the Trimble Advance Navigation System Vector III GPS receivers. We describe the GP-B precision orbit and detail the OD methodology, including ephemeris errors and the laser ranging measurements.

  12. Assessing Terra Disposal Orbit Candidates from an Orbital Debris Perspective

    NASA Technical Reports Server (NTRS)

    Abraham, Andrew J.; Thompson, Roger C.; Mantziaras, Dimitrios C.

    2016-01-01

    The NASA Terra satellite is reaching the end of its mission life. Because the satellite resides in the 705 km Earth Science Constellation, disposal strategies need to be considered to remove it from this densely populated operational orbit. Of critical importance was the need to examine the future potential risk to other satellite residents of the 705 km constellation due to an unexpected breakup event of the Terra satellite post-disposal. This study quantifies the comparative risk of debris impacts associated with the two leading candidate disposal orbits (701 km vs. 686 km) and characterizes the suitability of each orbit for the purpose of long-term spacecraft disposal. The increase in collision risk to any member of the 705 km Earth Science Constellation is very modest. The long-term, average, total risk (including the ambient background risk) due to a Terra breakup at a disposal of -19 km (i.e., 686 km) relative to the 705 km constellation is 9.7 × 10(exp -6) impacts/day versus 1.0 × 10(exp -5) impacts/day for a disposal of only -4 km (i.e., 701 km). For perspective, note that the nominal space background risk to the 705 km constellation is 9.2 × 10(exp -6) impacts/day which implies a very modest increase in risk (approximately 3% difference between the two cases) due to a Terra breakup in either disposal orbit.

  13. Precise GPS orbits for geodesy

    NASA Technical Reports Server (NTRS)

    Colombo, Oscar L.

    1994-01-01

    The Global Positioning System (GPS) has become, in recent years, the main space-based system for surveying and navigation in many military, commercial, cadastral, mapping, and scientific applications. Better receivers, interferometric techniques (DGPS), and advances in post-processing methods have made possible to position fixed or moving receivers with sub-decimeter accuracies in a global reference frame. Improved methods for obtaining the orbits of the GPS satellites have played a major role in these achievements; this paper gives a personal view of the main developments in GPS orbit determination.

  14. Orbital resonances around black holes.

    PubMed

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  15. The Stability of Periodic Orbits.

    DTIC Science & Technology

    1981-01-21

    I AOB a7 PRIlNCETON UNIV NJ JOSEPH HENRY LABS OF PHYSICS FD 7/S THE STABILITY OF PERIODIC ORBITS. (U) JAN 81 L SNEDOOM N00014-77-C-0711 UNCLASSIFIE-D...NL I - The Stability of Periodic Orbits Leigh Sneddon* Joseph Henry Laboratories of Physics Princeton University Princeton, New Jersey 08544 ABSTRACT...eigenvalue of the Poincare map passes out through the unit circle at -1 : see Appendix 1) 9,10 are observed and are referred to as subharmonic or period

  16. Energy and the Elliptical Orbit

    NASA Astrophysics Data System (ADS)

    Nettles, Bill

    2009-03-01

    In the January 2007 issue of The Physics Teacher, Prentis, Fulton, Hesse, and Mazzino describe a laboratory exercise in which students use a geometrical analysis inspired by Newton to show that an elliptical orbit and an inverse-square law force go hand in hand. The historical, geometrical, and teamwork aspects of the exercise are useful and important. This paper presents an exercise which uses an energy/angular momentum conservation model for elliptical orbits. This exercise can be done easily by an individual student and on regular notebook-sized paper.

  17. Constraints on Triton's Orbital Evolution

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.; Zhang, K.; Agnor, C.

    2005-05-01

    Three models have been proposed for the capture origin of Triton: Collision with a preexisting satellite (Goldreich 1989), Gas drag (McKinnon 1990), and three-body exchange (Agnor and Hamilton 2004). All three scenarios put Triton onto a highly elongated orbit which is subsequently circularized by satellite tides. Our goal here is to use the current state of the Neptunian system to constrain these capture scenarios. Triton strongly affects inner satellites (or an inner disk) directly via close pericenter passages before its orbit circularizes. Since satellite tides nearly conserve angular momentum, a simple tidal model puts Triton's minimum pericenter distance at aT/2 ˜ 7RN, where aT is its current semimajor axis. Our initial simulations show that some satellites orbiting outside Proteus (the outermost of the inner satellites at a=4.67RN) can survive these Triton passages. So why are there no known moonlets beyond 4.67RN? Seeking answers, we have integrated Triton's orbit backwards in time with a more sophisticated model that includes J2, solar perturbations, and satellite tides. We find that Triton's pericenter smoothly descends toward 7RN, as in the simple tidal model, but with superimposed oscillations at i) 1/2 Neptune's orbital period and ii) the nodal and apsidal precession periods. At a ˜ 94RN Triton encounters a Kozai-like resonance between these precession periods which causes its pericenter to dip to ˜ 4.2RN - well within the current orbit of Proteus. If Triton's orbit were ever this large, then the early inner satellite system must have been much smaller than it is today. Additional apsidal and nodal resonances between an early Triton on a highly elliptical orbit and the small inner satellites (with resonant arguments like 2nT - 2Ω sat) are strong enough to drive moonlet inclinations up to several degrees. We are using the stengths and locations of these resonances to further limit possible capture and evolution scenarios and will report on the

  18. [Primary orbital squamous cell carcinoma].

    PubMed

    Campos Arbulú, Ana L; Sadava, Emmanuel E; Sánchez Ruiz, Alejandro; Fernández Vila, Juan M; Dillon, Horacio S; Mezzadri, Norberto A

    2017-01-01

    Primary orbital squamous cell carcinoma is a rare entity. There is little published literature. We report a case of primary squamous cell carcinoma of the orbital soft tissues. Surgical resection offered the best treatment for the patient. Complete resection of the lesion was achieved. The patient received adjuvant radiotherapy due to the proximity of the lesion to the surgical margins. Surgical treatment is feasible and should be considered as part of the surgeon's arsenal. However, therapeutic decisions must be made on a case-by-case basis.

  19. Bar shapes and orbital stochasticity

    SciTech Connect

    Athanassoula, E. )

    1990-06-01

    Several independent lines of evidence suggest that the isophotes or isodensities of bars in barred galaxies are not really elliptical in shape but more rectangular. The effect this might have on the orbits in two different types of bar potentials is studied, and it is found that in both cases the percentage of stochastic orbits is much larger when the shapes are more rectangularlike or, equivalently, when the m = 4 components are more important. This can be understood with the help of the Chirikov criterion, which can predict the limit for the onset of global stochasticity. 9 refs.

  20. Orbiter electrical equipment utilization baseline

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The baseline for utilization of Orbiter electrical equipment in both electrical and Environmental Control and Life Support System (ECLSS) thermal analyses is established. It is a composite catalog of Space Shuttle equipment, as defined in the Shuttle Operational Data Book. The major functions and expected usage of each component type are described. Functional descriptions are designed to provide a fundamental understanding of the Orbiter electrical equipment, to insure correlation of equipment usage within nominal analyses, and to aid analysts in the formulation of off-nominal, contingency analyses.

  1. Nodular Fasciitis of the Orbit.

    PubMed

    Compton, Christopher J; Clark, Jeremy D; Thompson, Matthew P; Lee, Hui Bae H; Nunery, William R

    A 13-month-old boy was presented with new onset proptosis of the right eye. CT scan and MRI showed an enhancing mass in the right superior orbit with local bone remodeling and erosion. A craniotomy was performed for biopsy and sub-total resection. Histopathology and immunohistochemistry confirmed the lesion to be nodular fasciitis. Nodular fasciitis lesions are classically found in the anterior ocular adnexa, especially in pediatric patients. This is the first reported case of nodular fasciitis arising in the posterior orbit of a child younger than 16.

  2. Orbital Resonances Around Black Holes

    NASA Astrophysics Data System (ADS)

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-01

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  3. Orbital dynamics in galaxy mergers

    NASA Astrophysics Data System (ADS)

    Hoffman, Loren

    In the favored vacuum energy + cold dark matter (ACDM) cosmology, galaxies form through a hierarchical merging process. Mergers between comparable-mass sys tems are qualitatively different from the ongoing accretion of small objects by much larger ones, in that they can radically transform the nature of the merging objects, e.g. through violent relaxation of the stars and dark matter, triggered starbursts, and quasar activity. This thesis covers two phenomena unique to major galaxy mergers: the formation of supermassive black hole (SMBH) binary and triple systems, and the transformation of the stellar orbit structure through violent relaxation, triggered gas inflow, and star formation. In a major merger, the SMBHs can spiral in and form a bound binary in less than a Hubble time. If the binary lifetime exceeds the typical time between mergers, then triple black hole (BH) systems may form. We study the statistics of close triple-SMBH encounters in galactic nuclei by computing a series of three-body orbits with physically-motivated initial conditions appropriate for giant elliptical galaxies. Our simulations include a smooth background potential consisting of a stellar bulge plus a dark matter halo, drag forces due to gravitational radiation and dynamical friction on the stars and dark matter, and a simple model of the time evolution of the inner density profile under heating and mass ejection by the SMBHs. We find that the binary pair coalesces as a result of repeated close encounters in ~85% of our runs. In about 40% of the runs the lightest BH is left wandering through the galactic halo or escapes the galaxy altogether. The triple systems typically scour out cores with mass deficits ~1-2 times their total mass. The high coalescence rate and prevalence of very high-eccentricity orbits could provide interesting signals for the future Laser Interferometer Space Antenna (LISA). Our study of remnant orbit structure involved 42 disk-disk mergers at various gas fractions

  4. Precision Orbit Determination for the Lunar Reconnaissance Orbiter: orbit quality and gravity field estimation

    NASA Astrophysics Data System (ADS)

    Mazarico, E.; Rowlands, D. D.; Neumann, G. A.; Lemoine, F. G.; Torrence, M. H.; Smith, D. E.; Zuber, M. T.; Mao, D.

    2010-12-01

    We present results of the Precision Orbit Determination work undertaken by the Lunar Orbiter Laser Altimeter (LOLA) Science Team for the Lunar Reconnaissance Orbiter (LRO) mission, in order to meet the position knowledge accuracy requirements (50-m total position) and to precisely geolocate the LRO datasets. In addition to the radiometric tracking data, one-way laser ranges (LR) between Earth stations and the spacecraft are made possible by a small telescope mounted on the spacecraft high-gain antenna. The photons received from Earth are transmitted to one LOLA detector by a fiber optics bundle. The LOLA timing system enables 5-s LR normal points with precision better than 10cm. Other types of geodetic constraints are derived from the altimetric data itself. The orbit geometry can be constrained at the times of laser groundtrack intersections (crossovers). Due to the Moon's slow rotation, orbit solutions and normal equations including altimeter crossovers are processed and created in one month batches. Recent high-resolution topographic maps near the lunar poles are used to produce a new kind of geodetic constraints. Purely geometric, those do not necessitate actual groundtrack intersections. We assess the contributions of those data types, and the quality of our orbits. Solutions which use altimetric crossover meet the horizontal 50-m requirement, and perform usually better (10-20m). We also obtain gravity field solutions based on LRO and historical data. The various LRO data are accumulated into normal equations, separately for each one month batch and for each measurement type, which enables the final weights to be adjusted during the least-squares inversion step. Expansion coefficients to degree and order 150 are estimated, and a Kaula rule is still needed to stabilize the farside field. The gravity field solutions are compared to previous solutions (GLGM-3, LP150Q, SGM100h) and the geopotential predicted from the latest LOLA spherical harmonic expansion.

  5. Getting a Crew into Orbit

    ERIC Educational Resources Information Center

    Riddle, Bob

    2011-01-01

    Despite the temporary setback in our country's crewed space exploration program, there will continue to be missions requiring crews to orbit Earth and beyond. Under the NASA Authorization Act of 2010, NASA should have its own heavy launch rocket and crew vehicle developed by 2016. Private companies will continue to explore space, as well. At the…

  6. Launching Social Studies into Orbit.

    ERIC Educational Resources Information Center

    Stone, Kirk

    1986-01-01

    As a social studies educator, Christa McAuliffe was delighted that a "non-science teacher" was chosen to become the first teacher to orbit the earth. Her thoughts concerning the NASA space flight and its meaning for the social studies are discussed. (RM)

  7. Atypical presentations of orbital cysticercosis.

    PubMed

    Pushker, Neelam; Chaturvedi, Amrita; Balasubramanya, Ramamurthy; Bajaj, Mandeep S; Kumar, Neena; Sony, Parul

    2005-01-01

    We describe three patients with orbital cysticercosis who presented with atypical clinical or radiologic features previously unreported. All three patients had a cyst with a scolex on imaging studies. After 6 weeks of treatment, all three had almost complete resolution of their features.

  8. Closed Orbits in Phase Space

    NASA Astrophysics Data System (ADS)

    Murphy, Andrew; Haestad, Jace; Morgan, Thomas

    2015-09-01

    We report characteristics of closed classical orbits in an electric field in phase space produced in photoabsorption. Rydberg states of atomic and molecular hydrogen and helium are considered. The core potential used for the hydrogen molecule is an effective one electron one center core potential evaluated at the internuclear equilibrium distance. Poincare surfaces of section in phase space are generated by integrating the equations of motion in semiparabolic coordinates u = (r + z) 1 / 2 and v = (r - z) 1 / 2, and plotting the location in phase space (pv versus v) whenever u = 0, with the electric field in the z direction. Combination orbits produced by Rydberg electron core scattering are studied and the evolution in phase space of these combination orbits due to scattering from one closed orbit into another is investigated. Connections are made to measured laser photoabsorption experiments that excite Rydberg states (20 < n < 30) and produce accompanying scaled energy recurrence spectra. The phase space structures responsible for the spectra are identified.

  9. Biomaterials for orbital fractures repair

    PubMed Central

    Totir, M; Ciuluvica, R; Dinu, I; Careba, I; Gradinaru, S

    2015-01-01

    The unique and complex anatomy of the orbit requires significant contouring of the implants to restore the proper anatomy. Fractures of the orbital region have an incidence of 10-25% from the total facial fractures and the most common age group was the third decade of life. The majority of cases required reconstruction of the orbital floor to support the globe position and restore the shape of the orbit. The reason for this was that the bony walls were comminuted and/ or bone fragments were missing. Therefore, the reconstruction of the missing bone was important rather than reducing the bone fragments. This could be accomplished by using various materials. There is hardly any anatomic region in the human body that is so controversial in terms of appropriate material used for fracture repair: non resorbable versus resorbable, autogenous/ allogeneic/ xenogenous versus alloplastic material, non-prebent versus preformed (anatomical) plates, standard versus custom-made plates, nonporous versus porous material, non-coated versus coated plates. Thus, the importance of the material used for reconstruction becomes more challenging for the ophthalmologist and the oral and maxillofacial surgeon. PMID:25914737

  10. Augmented orbiter heat rejection study

    NASA Technical Reports Server (NTRS)

    Hixon, C. W.

    1981-01-01

    Spacecraft radiator concepts are presented that relieve attitude restrictions required by the shuttle orbiter space radiator for baseline and extended capability STS missions. Cost effective heat rejection kits are considered which add additional capability in the form of attached spacelab radiators or a deployable radiator module.

  11. Energy and the Elliptical Orbit

    ERIC Educational Resources Information Center

    Nettles, Bill

    2009-01-01

    In the January 2007 issue of "The Physics Teacher," Prentis, Fulton, Hesse, and Mazzino describe a laboratory exercise in which students use a geometrical analysis inspired by Newton to show that an elliptical orbit and an inverse-square law force go hand in hand. The historical, geometrical, and teamwork aspects of the exercise are useful and…

  12. Viking orbiter stereo imaging catalog

    NASA Technical Reports Server (NTRS)

    Blasius, K. R.; Vertrone, A. V.; Lewis, B. H.; Martin, M. D.

    1982-01-01

    The extremely long mission of the two Viking Orbiter spacecraft produced a wealth of photos of surface features. Many of these photos can be used to form stereo images allowing the student of Mars to examine a subject in three dimensional. This catalog is a technical guide to the use of stereo coverage within the complex Viking imaging data set.

  13. [Primary orbital tumors in children].

    PubMed

    Składzień, J; Olszewski, E; Reroń, E; Modrzejewski, M; Tomik, J; Paziewski, E

    1996-01-01

    We present the incidence, diagnosis and clinical picture of the primary orbital tumors in children. They were treated in ENT Clinic CM UJ in Kraków between 1981-1990 years. Discovered was preponderance of primary non malignant tumors. The most frequently encountered tumors were dermatomas, angiomas and among the malignant tumors-rhabdomyosarcoma.

  14. Myeloid Sarcoma in the Orbit.

    PubMed

    Qian, Xiaoxiao; Gigantelli, James W; Abromowitch, Minnie; Morgan, Linda A; Suh, Donny W

    2016-12-08

    The authors describe a case of myeloid sarcoma of the orbit in a pediatric patient. An 8-month-old male infant presented to the ophthalmology clinic with a left orbital mass, which had been increasing in size over the previous 2 months. The mass was initially diagnosed at another clinic as an infantile hemangioma, and had been treated with a topical formulation of timolol. In the ophthalmology clinic, orbital magnetic resonance imaging showed a solid enhancing mass. A biopsy was performed, and histopathology revealed myeloid sarcoma. The disease responded well to a standard chemotherapy regimen. Myeloid sarcoma is a rare, extra-medullary presentation that can occur as an isolated tumor, concurrently with or at relapse of acute myeloid leukemia. Because few cases of myeloid sarcoma in the orbit have been reported, this case report aids in the management of myeloid sarcoma in pediatric patients. The report describes an 8-month-old male infant, the youngest patient to develop myeloid sarcoma without preexisting acute myeloid leukemia. [J Pediatr Ophthalmol Strabismus. 2016;53:e64-e68.].

  15. NASA Facts, Orbits and Revolutions.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    This pamphlet is intended for senior high physics students. It contains information on the sidereal and synodic periods of revolution of an orbiting satellite, including their calculation. This pamphlet is one of the NASA Facts Science Series (each of which consists of four pages) and is designed to fit in the standard size three-ring notebook.…

  16. THREE PLANETS ORBITING WOLF 1061

    SciTech Connect

    Wright, D. J.; Wittenmyer, R. A.; Tinney, C. G.; Bentley, J. S.; Zhao, Jinglin

    2016-02-01

    We use archival HARPS spectra to detect three planets orbiting the M3 dwarf Wolf 1061 (GJ 628). We detect a 1.36 M{sub ⊕} minimum-mass planet with an orbital period P = 4.888 days (Wolf 1061b), a 4.25 M{sub ⊕} minimum-mass planet with orbital period P = 17.867 days (Wolf 1061c), and a likely 5.21 M{sub ⊕} minimum-mass planet with orbital period P = 67.274 days (Wolf 1061d). All of the planets are of sufficiently low mass that they may be rocky in nature. The 17.867 day planet falls within the habitable zone for Wolf 1061 and the 67.274 day planet falls just outside the outer boundary of the habitable zone. There are no signs of activity observed in the bisector spans, cross-correlation FWHMs, calcium H and K indices, NaD indices, or Hα indices near the planetary periods. We use custom methods to generate a cross-correlation template tailored to the star. The resulting velocities do not suffer the strong annual variation observed in the HARPS DRS velocities. This differential technique should deliver better exploitation of the archival HARPS data for the detection of planets at extremely low amplitudes.

  17. Nuclear propulsion for orbital transfer

    SciTech Connect

    Beale, G.A.; Lawrence, T.J. )

    1989-06-01

    The state of the art in nuclear propulsion for orbital transfer is discussed. Cryogenic propulsion, electric propulsion, solar-thermal propulsion and direct nuclear propulsion are examined in this context. New technologies with exceptional promise are addressed, emphasizing the particle test bed nuclear engine.

  18. SMC Orbital/Sub-Orbital Debris Mitigation User’s Handbook, Version 1.0

    DTIC Science & Technology

    2002-07-01

    SUBTITLE SMC Orbital/Sub- Orbital Debris Mitigation User’s Handbook Version 1.0 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6... Orbital Debris ..................................................................... A-6 4.1 Design Considerations...orbital (or space) debris and sub- orbital debris . Space debris is defined as any non-functioning man-made object orbiting the Earth. This definition

  19. Orbital Debris Research at NASA

    NASA Technical Reports Server (NTRS)

    Stansbery, Eugene G.

    2009-01-01

    The United States has one of the most active programs of research of the orbital debris environment in the world. Much of the research is conducted by NASA s Orbital Debris Program Office at the Johnson Space Center. Past work by NASA has led to the development of national space policy which seeks to limit the growth of the debris population and limit the risk to spacecraft and humans in space and on the Earth from debris. NASA has also been instrumental in developing consistent international policies and standards. Much of NASA's efforts have been to measure and characterize the orbital debris population. The U.S. Department of Defense tracks and catalogs spacecraft and large debris with it's Space Surveillance Network while NASA concentrates on research on smaller debris. In low Earth orbit, NASA has utilized short wavelength radars such as Haystack, HAX, and Goldstone to statistically characterize the population in number, size, altitude, and inclination. For higher orbits, optical telescopes have been used. Much effort has gone into the understanding and removal of observational biases from both types of measurements. NASA is also striving to understand the material composition and shape characteristics of debris to assess these effects on the risk to operational spacecraft. All of these measurements along with data from ground tests provide the basis for near- and long-term modeling of the environment. NASA also develops tools used by spacecraft builders and operators to evaluate spacecraft and mission designs to assess compliance with debris standards and policies which limit the growth of the debris environment.

  20. Space Shuttle Orbiter-Illustration

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This illustration is an orbiter cutaway view with callouts. The orbiter is both the brains and heart of the Space Transportation System (STS). About the same size and weight as a DC-9 aircraft, the orbiter contains the pressurized crew compartment (which can normally carry up to seven crew members), the huge cargo bay, and the three main engines mounted on its aft end. There are three levels to the crew cabin. Uppermost is the flight deck where the commander and the pilot control the mission. The middeck is where the gallery, toilet, sleep stations, and storage and experiment lockers are found for the basic needs of weightless daily living. Also located in the middeck is the airlock hatch into the cargo bay and space beyond. It is through this hatch and airlock that astronauts go to don their spacesuits and marned maneuvering units in preparation for extravehicular activities, more popularly known as spacewalks. The Space Shuttle's cargo bay is adaptable to hundreds of tasks. Large enough to accommodate a tour bus (60 x 15 feet or 18.3 x 4.6 meters), the cargo bay carries satellites, spacecraft, and spacelab scientific laboratories to and from Earth orbit. It is also a work station for astronauts to repair satellites, a foundation from which to erect space structures, and a hold for retrieved satellites to be returned to Earth. Thermal tile insulation and blankets (also known as the thermal protection system or TPS) cover the underbelly, bottom of the wings, and other heat-bearing surfaces of the orbiter to protect it during its fiery reentry into the Earth's atmosphere. The Shuttle's 24,000 individual tiles are made primarily of pure-sand silicate fibers, mixed with a ceramic binder. The solid rocket boosters (SRB's) are designed as an in-house Marshall Space Flight Center project, with United Space Boosters as the assembly and refurbishment contractor. The solid rocket motor (SRM) is provided by the Morton Thiokol Corporation.

  1. Orbital abscess from an odontogenic infection.

    PubMed

    Kim, Il-Kyu; Kim, Ju-Rok; Jang, Keum-Soo; Moon, Yeon-Sung; Park, Sun-Won

    2007-01-01

    An orbital abscess is a rare but serious complication of an odontogenic infection, which can lead to loss of vision or worse. This paper presents a case of orbital abscess secondary to an infection from the upper molar teeth, which extended to the retobulbar and posterosuperior region of the orbit, close to the superior orbital fissure. The infection spreaded to the pterygopalatine and infratemporal fossa and then to the orbit via the inferior orbital fissure. This paper reviews the clinical presentation, differential diagnosis, route of spread, value of serial CT scanning, treatment and possible complications.

  2. 'Orbital volume restoration rate after orbital fracture'; a CT-based orbital volume measurement for evaluation of orbital wall reconstructive effect.

    PubMed

    Wi, J M; Sung, K H; Chi, M

    2017-01-13

    PurposeTo evaluate the effect of orbital reconstruction and factors related to the effect of orbital reconstruction by assessing of orbital volume using orbital computed tomography (CT) in cases of orbital wall fracture.MethodsIn this retrospective study, 68 patients with isolated blowout fractures were evaluated. The volumes of orbits and herniated orbital tissues were determined by CT scans using a three-dimensional reconstruction technique (the Eclipse Treatment Planning System). Orbital CT was performed preoperatively, immediately after surgery, and at final follow ups (minimum of 6 months). We evaluated the reconstructive effect of surgery making a new formula, 'orbital volume reconstruction rate' from orbital volume differences between fractured and contralateral orbits before surgery, immediately after surgery, and at final follow up.ResultsMean volume of fractured orbits before surgery was 23.01±2.60 cm(3) and that of contralateral orbits was 21.31±2.50 cm(3) (P=0.005). Mean volume of the fractured orbits immediately after surgery was 21.29±2.42 cm(3), and that of the contralateral orbits was 21.33±2.52 cm(3) (P=0.921). Mean volume of fractured orbits at final follow up was 21.50±2.44 cm(3), and that of contralateral orbits was 21.32±2.50 cm(3) (P=0.668). The mean orbital volume reconstruction rate was 100.47% immediately after surgery and 99.17% at final follow up. No significant difference in orbital volume reconstruction rate was observed with respect to fracture site or orbital implant type. Patients that underwent operation within 14 days of trauma had a better reconstruction rate at final follow up than patients who underwent operation over 14 days after trauma (P=0.039).ConclusionComputer-based measurements of orbital fracture volume can be used to evaluate the reconstructive effect of orbital implants and provide useful quantitative information. Significant reduction of orbital volume is observed immediately after orbital wall

  3. CT & CBCT imaging: assessment of the orbits.

    PubMed

    Hatcher, David C

    2012-11-01

    The orbits can be visualized easily on routine or customized protocols for computed tomography (CT) or cone beam CT (CBCT) scans. Detailed orbital investigations are best performed with 3-dimensional imaging methods. CT scans are preferred for visualizing the osseous orbital anatomy and fissures while magnetic resonance imaging is preferred for evaluating tumors and inflammation. CBCT provides high-resolution anatomic data of the sinonasal spaces, airway, soft tissue surfaces, and bones but does not provide much detail within the soft tissues. This article discusses CBCT imaging of the orbits, osseous anatomy of the orbits, and CBCT investigation of selected orbital pathosis.

  4. Orbiter CIU/IUS communications hardware evaluation

    NASA Technical Reports Server (NTRS)

    Huth, G. K.

    1979-01-01

    The DOD and NASA inertial upper stage communication system design, hardware specifications and interfaces were analyzed to determine their compatibility with the Orbiter payload communications equipment (Payload Interrogator, Payload Signal Processors, Communications Interface Unit, and the Orbiter operational communications equipment (the S-Band and Ku-band systems). Topics covered include (1) IUS/shuttle Orbiter communications interface definition; (2) Orbiter avionics equipment serving the IUS; (3) IUS communication equipment; (4) IUS/shuttle Orbiter RF links; (5) STDN/TDRS S-band related activities; and (6) communication interface unit/Orbiter interface issues. A test requirement plan overview is included.

  5. Conversion of Osculating Orbital Elements to Mean Orbital Elements

    NASA Technical Reports Server (NTRS)

    Der, Gim J.; Danchick, Roy

    1996-01-01

    Orbit determination and ephemeris generation or prediction over relatively long elapsed times can be accomplished with mean elements. The most simple and efficient method for orbit determination, which is also known as epoch point conversion, performs the conversion of osculating elements to mean elements by iterative procedures. Previous epoch point conversion methods are restricted to shorter elapsed times with linear convergence. The new method presented in this paper calculates an analytic initial guess of the unknown mean elements from a first order theory of secular perturbations and computes a transition matrix with accurate numerical partials. It thereby eliminates the problem of an inaccurate initial guess and an identity transition matrix employed by previous methods. With a good initial guess of the unknown mean elements and an accurate transition matrix, converging osculating elements to mean elements can be accomplished over long elapsed times with quadratic convergence.

  6. Frozen Orbits-Near Constant or Beneficially Varying Orbital Parameters.

    DTIC Science & Technology

    1986-05-15

    In this approach , the difference between the primary acceleration and all perturbing accelerations is integrated . A reference (or osculating) orbit is...PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK AREA & WORK UNIT NUMBERS .’ AFIT STUDENT AT: University of Colorado to II...I am thankful for the time and financial support making the degree possible. I thank Dr. Felix R. Hoots, Directorate of Astrodynamics at NORAD, and

  7. The Kepler Mission: A wide-field transit search for terrestrial planets [review article

    NASA Astrophysics Data System (ADS)

    Basri, Gibor; Borucki, William J.; Koch, David

    2005-11-01

    The Kepler Mission is a NASA Discovery mission which will continuously monitor the brightness of at least 100,000 main sequence stars, to detect the transits of terrestrial and larger planets. It is scheduled to be launched in 2007 into an Earth-trailing heliocentric orbit. It is a wide-field photometer with a Schmidt-type telescope and array of 42 CCDs covering the 100 square degree field-of-view. It has a 1-m aperture which enables a differential photometric precision of 2 parts in 100,000 for 12th magnitude solar-like stars over a 6.5-hour transit duration. It will continuously observe dwarf stars from 8th to 15th magnitude in the Cygnus constellation, for a period of four years, with a cadence of 4 measurements per hour. Hundreds of terrestrial planets should be detected if they are common around solar-type stars. Ground-based spectrometry of stars with planetary candidates will help eliminate false-positives, and determine stellar characteristics such as mass and metallicity. A null result would imply that terrestrial planets are rare.

  8. Sino-orbital fistula: two case reports.

    PubMed

    McNab, A A

    2000-08-01

    A fistula between the paranasal sinuses and the orbit as a late complication of orbital fractures is rare and may present with intermittent symptoms due to air passing into the orbit. A case note review of two patients with sino-orbital fistula is presented. Two patients, 23- and 30-year-old males, presented with intermittent symptoms of globe displacement, diplopia or discomfort months after repair of an orbital floor fracture with a synthetic orbital floor implant. The symptoms occurred after nose blowing. They were both cured by removal of the implant and partial removal of the tissue surrounding the implant. A sino-orbital fistula may complicate the otherwise routine repair of an orbital floor fracture, but may be cured by removal of the implant and part of the surrounding pseudocapsule.

  9. Variationally optimized basis orbitals for biological molecules

    NASA Astrophysics Data System (ADS)

    Ozaki, T.; Kino, H.

    2004-12-01

    Numerical atomic basis orbitals are variationally optimized for biological molecules such as proteins, polysaccharides, and deoxyribonucleic acid within a density functional theory. Based on a statistical treatment of results of a fully variational optimization of basis orbitals ( full optimized basis orbitals) for 43 biological model molecules, simple sets of preoptimized basis orbitals classified under the local chemical environment (simple preoptimized basis orbitals) are constructed for hydrogen, carbon, nitrogen, oxygen, phosphorous, and sulfur atoms, each of which contains double valence plus polarization basis function. For a wide variety of molecules we show that the simple preoptimized orbitals provide well convergent energy and physical quantities comparable to those calculated by the full optimized orbitals, which demonstrates that the simple preoptimized orbitals possess substantial transferability for biological molecules.

  10. MOOSE: Manned On-Orbit Servicing Equipment

    NASA Technical Reports Server (NTRS)

    Budinoff, J. (Editor); Leontsinis, N. (Editor); Lane, J. (Editor); Singh, R. (Editor); Angelone, K.; Boswell, C.; Chamberlain, I.; Concha, M.; Corrodo, M.; Custodio, O.

    1993-01-01

    The ability to service satellites has thus far been limited to low earth orbit platforms within reach of the Space Shuttle. Other orbits, such as geosynchronous orbits containing high-value spacecraft have not been attainable by a servicing vehicle. The useful life of a satellite can be extended by replacing spent propellant and damaged orbital replacement units, forestalling the need for eventual replacement. This growing need for satellite on-orbits servicing can be met by the Manned On-Orbit Servicing Equipment (MOOSE). Missions requiring orbit transfer capability, precision manipulation and maneuvering, and man-in-the-loop control can be accomplished using MOOSE. MOOSE is a flexible, reusable, single operator, aerobraking spacecraft designed to refuel, repair, and service orbiting spacecraft. MOOSE will be deployed from Space Station Freedom, (SSF), where it will be stored, resupplied, and refurbished.

  11. #1 Stereo Orbit - Launch to Feb 2011

    NASA Video Gallery

    The STEREO mission consists of two spacecraft orbiting the Sun, one moving a bit faster than Earth and the other a bit slower. In the time since the STEREO spacecraft entered these orbits near the ...

  12. Rational orbits around charged black holes

    SciTech Connect

    Misra, Vedant; Levin, Janna

    2010-10-15

    We show that all eccentric timelike orbits in Reissner-Nordstroem spacetime can be classified using a taxonomy that draws upon an isomorphism between periodic orbits and the set of rational numbers. By virtue of the fact that the rationals are dense, the taxonomy can be used to approximate aperiodic orbits with periodic orbits. This may help reduce computational overhead for calculations in gravitational wave astronomy. Our dynamical systems approach enables us to study orbits for both charged and uncharged particles in spite of the fact that charged particle orbits around a charged black hole do not admit a simple one-dimensional effective potential description. Finally, we show that comparing periodic orbits in the Reissner-Nordstroem and Schwarzschild geometries enables us to distinguish charged and uncharged spacetimes by looking only at the orbital dynamics.

  13. Orbiter CIU/IUS communications hardware evaluation

    NASA Technical Reports Server (NTRS)

    Huth, G. K.

    1979-01-01

    Inertial Upper Stage (IUS) and DoD Communication Interface Unit (CIU) communication system design, hardware specifications, and interfaces were evaluated to determine their compatibility with the Orbiter payload communication and data handling equipment and the Orbiter network communication equipment.

  14. Two designs for an orbital transfer vehicle

    NASA Technical Reports Server (NTRS)

    Davis, Richard; Duquette, Miles; Fredrick, Rebecca; Schumacher, Daniel; Somers, Schaeffer; Stafira, Stanley; Williams, James; Zelinka, Mark

    1988-01-01

    The Orbital Transfer Vehicle (OTV) and systems were researched in the following areas: avionics, crew systems, electrical power systems, environmental control/life support systems, navigation and orbital maneuvers, propulsion systems, reaction control systems (RCS), servicing systems, and structures.

  15. Orbiter Kapton wire operational requirements and experience

    NASA Astrophysics Data System (ADS)

    Peterson, R. V.

    1994-09-01

    The agenda of this presentation includes the Orbiter wire selection requirements, the Orbiter wire usage, fabrication and test requirements, typical wiring installations, Kapton wire experience, NASA Kapton wire testing, summary, and backup data.

  16. NASA Now: Orbital Mechanics: Earth Observing Satellites

    NASA Video Gallery

    This NASA Now program is all about satellites and their orbits. Dr. James Gleason, project scientist for NPP, explains what it takes for a satellite to stay in orbit, why there are different types ...

  17. Orbiter Kapton wire operational requirements and experience

    NASA Technical Reports Server (NTRS)

    Peterson, R. V.

    1994-01-01

    The agenda of this presentation includes the Orbiter wire selection requirements, the Orbiter wire usage, fabrication and test requirements, typical wiring installations, Kapton wire experience, NASA Kapton wire testing, summary, and backup data.

  18. An Analytical Satellite Orbit Predictor (ASOP)

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The documentation and user's guide are presented for the analytical satellite orbit predictor computer program which is intended to be used for computation of near-earth orbits including those of the shuttle orbiter and its payloads. The Poincare-Similar elements used make it possible to compute near-earth orbits to within an accuracy of a few meters. Recursive equations are used instead of complicated formulas. Execution time is on the order of a few milliseconds.

  19. Magnetoelectric Coupling Induced by Interfacial Orbital Reconstruction.

    PubMed

    Cui, Bin; Song, Cheng; Mao, Haijun; Wu, Huaqiang; Li, Fan; Peng, Jingjing; Wang, Guangyue; Zeng, Fei; Pan, Feng

    2015-11-01

    Reversible orbital reconstruction driven by ferroelectric polarization modulates the magnetic performance of model ferroelectric/ferromagnetic heterostructures without onerous limitations. Mn-d(x2-y2) orbital occupancy and related interfacial exotic magnetic states are enhanced and weakened by negative and positive electric fields, respectively, filling the missing member-orbital in the mechanism of magnetoelectric coupling and advancing the application of orbitals to microelectronics.

  20. Pursuit/evasion in orbit

    NASA Technical Reports Server (NTRS)

    Kelley, H. J.; Cliff, E. M.; Lutze, F. H.

    1981-01-01

    Maneuvers available to a spacecraft having sufficient propellant to escape an antisatellite satellite (ASAT) attack are examined. The ASAT and the evading spacecraft are regarded as being in circular orbits, and equations of motion are developed for the ASAT to commence a two-impulse maneuver sequence. The ASAT employs thrust impulses which yield a minimum-time-to-rendezvous, considering available fuel. Optimal evasion is shown to involve only in-plane maneuvers, and begins as soon as the ASAT launch information is gathered and thrust activation can be initiated. A closest approach, along with a maximum evasion by the target spacecraft, is calculated to be 14,400 ft. Further research to account for ASATs in parking orbit and for generalization of a continuous control-modeled differential game is indicated.

  1. Pursuit/evasion in orbit

    NASA Astrophysics Data System (ADS)

    Kelley, H. J.; Cliff, E. M.; Lutze, F. H.

    1981-09-01

    Maneuvers available to a spacecraft having sufficient propellant to escape an antisatellite satellite (ASAT) attack are examined. The ASAT and the evading spacecraft are regarded as being in circular orbits, and equations of motion are developed for the ASAT to commence a two-impulse maneuver sequence. The ASAT employs thrust impulses which yield a minimum-time-to-rendezvous, considering available fuel. Optimal evasion is shown to involve only in-plane maneuvers, and begins as soon as the ASAT launch information is gathered and thrust activation can be initiated. A closest approach, along with a maximum evasion by the target spacecraft, is calculated to be 14,400 ft. Further research to account for ASATs in parking orbit and for generalization of a continuous control-modeled differential game is indicated.

  2. Low thrust orbit determination program

    NASA Technical Reports Server (NTRS)

    Hong, P. E.; Shults, G. L.; Huling, K. R.; Ratliff, C. W.

    1972-01-01

    Logical flow and guidelines are provided for the construction of a low thrust orbit determination computer program. The program, tentatively called FRACAS (filter response analysis for continuously accelerating spacecraft), is capable of generating a reference low thrust trajectory, performing a linear covariance analysis of guidance and navigation processes, and analyzing trajectory nonlinearities in Monte Carlo fashion. The choice of trajectory, guidance and navigation models has been made after extensive literature surveys and investigation of previous software. A key part of program design relied upon experience gained in developing and using Martin Marietta Aerospace programs: TOPSEP (Targeting/Optimization for Solar Electric Propulsion), GODSEP (Guidance and Orbit Determination for SEP) and SIMSEP (Simulation of SEP).

  3. Environmental dynamics at orbital altitudes

    NASA Technical Reports Server (NTRS)

    Karr, G. R.

    1976-01-01

    The influence of real satellite aerodynamics on the determination of upper atmospheric density was investigated. A method of analysis of satellite drag data is presented which includes the effect of satellite lift and the variation in aerodynamic properties around the orbit. The studies indicate that satellite lift may be responsible for the observed orbit precession rather than a super rotation of the upper atmosphere. The influence of simplifying assumptions concerning the aerodynamics of objects in falling sphere analysis were evaluated and an improved method of analysis was developed. Wind tunnel data was used to develop more accurate drag coefficient relationships for studying altitudes between 80 and 120 Km. The improved drag coefficient relationships revealed a considerable error in previous falling sphere drag interpretation. These data were reanalyzed using the more accurate relationships. Theoretical investigations of the drag coefficient in the very low speed ratio region were also conducted.

  4. The Orbiting Primate Experiment (OPE)

    NASA Technical Reports Server (NTRS)

    Bourne, G. H.; Debourne, M. N. G.; Mcclure, H. M.

    1977-01-01

    Instrumentation and life support systems are described for an experiment to determine the physiological effects of long term space flight on unrestrained, minimally instrumented rhesus macaques flown in orbit for periods up to six months or one year. On return from orbit, vestibular, cardiovascular, and skeletal muscle function will be tested. Blood chemistry and hematological studies will be conducted as well as tests of the immunological competence of selected animals. Nasal, rectal, and throat swabs will be used for bacterial and viral studies, and histopathological and histochemical investigations will be be made of all organs using light and electron microscopy. The experiment is being considered as a payload for the biomedical experiment scientific satellite.

  5. Lunar Orbiter: Moon and Earth

    NASA Technical Reports Server (NTRS)

    1966-01-01

    The worlds first view of the Earth taken by a spacecraft from the vicinity of the Moon. The photo was transmitted to Earth by the United States Lunar Orbiter I and recieved at the NASA tracking station at Robledo de Chavela near Madrid, Spain. This crescent of the Earth was photographed August 23 at 16:35 GMT when the spacecraft was on its 16th orbit and just about to pass behind the Moon. This is the view the astronauts will have when they come around the backside of the Moon and face the Earth. The Earth is shown on the left of the photo with the U.S. east coast in the upper left, southern Europe toward the dark or night side of the Earth, and Antartica at the bottom of the Earth crescent. The surface of the Moon is shown on the right side of the photograph.

  6. Elliptical orbit performance computer program

    NASA Technical Reports Server (NTRS)

    Myler, T. R.

    1981-01-01

    A FORTRAN coded computer program which generates and plots elliptical orbit performance capability of space boosters for presentation purposes is described. Orbital performance capability of space boosters is typically presented as payload weight as a function of perigee and apogee altitudes. The parameters are derived from a parametric computer simulation of the booster flight which yields the payload weight as a function of velocity and altitude at insertion. The process of converting from velocity and altitude to apogee and perigee altitude and plotting the results as a function of payload weight is mechanized with the ELOPE program. The program theory, user instruction, input/output definitions, subroutine descriptions and detailed FORTRAN coding information are included.

  7. Analytic theory of orbit contraction

    NASA Technical Reports Server (NTRS)

    Vinh, N. X.; Longuski, J. M.; Busemann, A.; Culp, R. D.

    1977-01-01

    The motion of a satellite in orbit, subject to atmospheric force and the motion of a reentry vehicle are governed by gravitational and aerodynamic forces. This suggests the derivation of a uniform set of equations applicable to both cases. For the case of satellite motion, by a proper transformation and by the method of averaging, a technique appropriate for long duration flight, the classical nonlinear differential equation describing the contraction of the major axis is derived. A rigorous analytic solution is used to integrate this equation with a high degree of accuracy, using Poincare's method of small parameters and Lagrange's expansion to explicitly express the major axis as a function of the eccentricity. The solution is uniformly valid for moderate and small eccentricities. For highly eccentric orbits, the asymptotic equation is derived directly from the general equation. Numerical solutions were generated to display the accuracy of the analytic theory.

  8. Moving the Mars Reconnaissance Orbiter

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In late October 2004, NASA's Mars Reconnaissance Orbiter was moved from the High Bay 100,000-class clean room at Lockheed Martin Space Systems, Denver, to the facility's Reverberant Acoustic Lab, where system environmental testing will continue through March 2005. Shown here are technicians guiding the spacecraft as it is lowered onto its transporter interface ring prior to installation of the shipping-container lid.

  9. Comet Orbits: Prediction, Nongravitational Effects

    NASA Technical Reports Server (NTRS)

    Marsden, B. G.

    1972-01-01

    The problems of calculating cometary orbits are discussed, with particular attention to that of predicting the returns of periodic comets. It is shown that the only inherent difficulty arises from the action of nongravitational forces. Recent progress toward an understanding of these forces is described in detail, both from the point of view of fitting the observations and of interpreting the forces in terms of the Whipple icy-conglomerate model.

  10. Viking orbiter system primary mission

    NASA Technical Reports Server (NTRS)

    Goudy, J. R.

    1977-01-01

    An overview of Viking Orbiter (VO) system and subsystem performances during the primary mission (the time period from VO-1 launch on August 20, 1975, through November 15, 1976) is presented. Brief descriptions, key design requirements, pertinent historical information, unique applications or situations, and predicted versus actual performances are included for all VO-1 and VO-2 subsystems, both individually and as an integrated system.

  11. Exotic Orbital Modes in Nuclei

    NASA Astrophysics Data System (ADS)

    von Neumann-Cosel, P.

    2003-06-01

    Experimental evidence for two types of collective excitations in nuclei generated by orbital motion is discussed, viz. a magnetic quadrupole twist mode observed in 180° electron scattering experiments and a toroidal electric dipole mode. The latter may be a source of low-energy pygmy dipole resonances observed in many nuclei. This is discussed in detail for the example of 208Pb based on the recent finding of a resonance at particle threshold in a high-resolution (γ, γ') experiment.

  12. Vigilance problems in orbiter processing

    NASA Technical Reports Server (NTRS)

    Swart, William W.; Safford, Robert R.; Kennedy, David B.; Yadi, Bert A.; Barth, Timothy S.

    1993-01-01

    A pilot experiment was done to determine what factors influence potential performance errors related to vigilance in Orbiter processing activities. The selected activities include post flight inspection for burned gap filler material and pre-rollout inspection for tile processing shim material. It was determined that the primary factors related to performance decrement were the color of the target and the difficulty of the target presentation.

  13. Orbital assembly and maintenance study

    NASA Technical Reports Server (NTRS)

    Gorman, D.; Grant, C.; Kyrias, G.; Lord, C.; Rombach, J.; Salis, M.; Skidmore, R.; Thomas, R.

    1975-01-01

    The requirements, conceptual design, tradeoffs, procedures, and techniques for orbital assembly of the support structure of the microwave power transmission system and the radio astronomy telescope are described. Thermal and stress analyses, packaging, alignment, and subsystems requirements are included along with manned vs. automated and transportation tradeoffs. Technical and operational concepts for the manned and automated maintenance of satellites were investigated and further developed results are presented.

  14. Commercializing the transfer orbit stage

    NASA Technical Reports Server (NTRS)

    Miller, M. W.

    1984-01-01

    Key milestones necessary to establish the transfer orbit stage are examined. The selection of the project concept and synthesis of the company are described followed by an analysis venture capability support and the selection of a major aerospace company as prime contractor. A landmark agreement with NASA sanctioned the commercial TOS concept and provided the critical support necessary to raise the next round of venture capital. Project management and customer commitments are also discussed.

  15. Introduction to Orbital Sciences Corporation

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A general overview of the Orbital Sciences Corporation (OSC) is presented. The following topics are covered: (1) manpower, facilities, and financial growth; (2) organization and management team; (3) the Space Data Division organization; (4) the Chandler facility; (5) Space Data-Products and Services; (6) space transportation systems; (7) spacecraft and space support systems; (8) turn-key suborbital launch services and support systems; and (9) OSC suborbital booster performance.

  16. Information Measures for Statistical Orbit Determination

    ERIC Educational Resources Information Center

    Mashiku, Alinda K.

    2013-01-01

    The current Situational Space Awareness (SSA) is faced with a huge task of tracking the increasing number of space objects. The tracking of space objects requires frequent and accurate monitoring for orbit maintenance and collision avoidance using methods for statistical orbit determination. Statistical orbit determination enables us to obtain…

  17. Orbital-Transfer Vehicle With Aerodynamic Braking

    NASA Technical Reports Server (NTRS)

    Scott, C. D.; Nagy, K.; Roberts, B. B.; Ried, R. C.; Kroll, K.; Gamble, J.

    1986-01-01

    Vehicle includes airbrake for deceleration into lower orbit. Report describes vehicle for carrying payloads between low and high orbits around Earth. Vehicle uses thin, upper atmosphere for braking when returning to low orbit. Since less propellant needed than required for full retrorocket braking, vehicle carries larger payload and therefore reduces cost of space transportation.

  18. Simulation of Atomic and Molecular Orbitals

    ERIC Educational Resources Information Center

    Massey, A. G.; Massey S.

    1976-01-01

    Describes the use of magnets to simulate s, p, and d atomic orbitals from which a wide variety of molecular orbitals can be derived. The technique gives students an idea of molecular orbitals' shapes and stresses the importance of symmetry labels. (MLH)

  19. The geostationary orbit and developing countries

    NASA Technical Reports Server (NTRS)

    Medina, E. R.

    1982-01-01

    The geostationary orbit is becoming congested due to use by several countries throughout the world, and the request for use of this orbit is increasing. There are 188 geostationary stations in operation. An equitable distribution of stations on this orbit is requested.

  20. Prebifurcation periodic ghost orbits in semiclassical quantization

    SciTech Connect

    Kus, M. ); Haake, F. ); Delande, D. )

    1993-10-04

    Classical periodic orbits are stationary-phase points in path integral representations of quantum propagators. We show that complex solutions of the stationary-phase equation, not corresponding to real classical periodic orbits, give additional contributions to the propagator which can be important, especially near bifurcations. We reveal the existence and relevance of such periodic ghost orbits for a kicked top.

  1. Cassini-Huygens in Orbit Around Saturn

    NASA Technical Reports Server (NTRS)

    Matson, Dennis L.; Lebreton, Jean-Pierre; Spilker, J.

    2005-01-01

    The Cassini-Huygens spacecraft was successfully placed in an orbit about Saturn on June 30, 2004. Starting with our approach to Saturn, the instruments carried by the Orbiter have been very active since early 2004. The Huygens probe mission was also recently completed. As a result, all of the Cassini Orbiter investigations and Huygens Probe investigations have scientific results to report.

  2. Outgassing products from orbiter TPS materials

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.; Lash, Tom J.; Rawls, J. Richard

    1995-01-01

    The Space Transportation System (STS) orbiters are known to be significant sources of outgassing in low earth orbit (LEO). Infrared and mass spectra of residues and outgassing from orbiter thermal protection tile and an external blanket are presented. Several sources of methyl and phenyl methyl silicones are identified. About fifty pounds of silicones are estimated to be outgassed during an STS mission.

  3. Some Observations on Molecular Orbital Theory

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 2005

    2005-01-01

    A few flawed predictions in the context of homonuclear diatomic molecules are presented in order to introduce students to molecular orbital (MO) theory. A common misrepresentation of the relationship between the energy of an atomic orbital and the energy of the MO associated with the atomic orbital is illustrated.

  4. Spin-orbit ferromagnetic resonance

    NASA Astrophysics Data System (ADS)

    Ferguson, Andrew

    2013-03-01

    In conventional magnetic resonance techniques the magnitude and direction of the oscillatory magnetic field are (at least approximately) known. This oscillatory field is used to probe the properties of a spin ensemble. Here, I will describe experiments that do the inverse. I will discuss how we use a magnetic resonance technique to map out the current-induced effective magnetic fields in the ferromagnetic semiconductors (Ga,Mn)As and (Ga,Mn)(As,P). These current-induced fields have their origin in the spin-orbit interaction. Effective magnetic fields are observed with symmetries which resemble the Dresselhaus and Rashba spin-orbit interactions and which depend on the diagonal and off-diagonal strain respectively. Ferromagnetic semiconductor materials of different strains, annealing conditions and concentrations are studied and the results compared with theoretical calculations. Our original study measured the rectification voltage coming from the product of the oscillatory magnetoresistance, during magnetisation precession, and the alternating current. More recently we have developed an impedance matching technique which enables us to extract microwave voltages from these high resistance (10 k Ω) samples. In this way we measure the microwave voltage coming from the product of the oscillating magneto-resistance and a direct current. The direct current is observed to affect the magnetisation precession, indicating that anti-damping as well as field-like torques can originate from the spin-orbit interaction.

  5. Proxima's orbit around α Centauri

    NASA Astrophysics Data System (ADS)

    Kervella, P.; Thévenin, F.; Lovis, C.

    2017-01-01

    Proxima and α Centauri AB have almost identical distances and proper motions with respect to the Sun. Although the probability of such similar parameters is, in principle, very low, the question as to whether they actually form a single gravitationally bound triple system has been open since the discovery of Proxima one century ago. Owing to HARPS high-precision absolute radial velocity measurements and the recent revision of the parameters of the α Cen pair, we show that Proxima and α Cen are gravitationally bound with a high degree of confidence. The orbital period of Proxima is ≈ 550 000 yr. With an eccentricity of , Proxima comes within kau of α Cen at periastron, and is currently close to apastron ( kau). This orbital motion may have influenced the formation or evolution of the recently discovered planet orbiting Proxima, as well as circumbinary planet formation around α Cen. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programs 072.C-0488(E), 082.C-0718(B), 183.C-0437(A), 191.C-0505(A) and 096.C-0082(A).

  6. Density-orbital embedding theory

    SciTech Connect

    Gritsenko, O. V.; Visscher, L.

    2010-09-15

    In the article density-orbital embedding (DOE) theory is proposed. DOE is based on the concept of density orbital (DO), which is a generalization of the square root of the density for real functions and fractional electron numbers. The basic feature of DOE is the representation of the total supermolecular density {rho}{sub s} as the square of the sum of the DO {phi}{sub a}, which represents the active subsystem A and the square root of the frozen density {rho}{sub f} of the environment F. The correct {rho}{sub s} is obtained with {phi}{sub a} being negative in the regions in which {rho}{sub f} might exceed {rho}{sub s}. This makes it possible to obtain the correct {rho}{sub s} with a broad range of the input frozen densities {rho}{sub f} so that DOE resolves the problem of the frozen-density admissibility of the current frozen-density embedding theory. The DOE Euler equation for the DO {phi}{sub a} is derived with the characteristic embedding potential representing the effect of the environment. The DO square {phi}{sub a}{sup 2} is determined from the orbitals of the effective Kohn-Sham (KS) system. Self-consistent solution of the corresponding one-electron KS equations yields not only {phi}{sub a}{sup 2}, but also the DO {phi}{sub a} itself.

  7. Prospective Ukrainian lunar orbiter mission

    NASA Astrophysics Data System (ADS)

    Shkuratov, Y.; Litvinenko, L.; Shulga, V.; Yatskiv, Y.; Kislyuk, V.

    Ukraine has launch vehicles that are able to deliver about 300 kg to the lunar orbit. Future Ukrainian lunar program may propose a polar orbiter. This orbiter should fill principal information gaps in our knowledge about the Moon after Clementine and Lunar Prospector missions and the future missions, like Smart-1, Lunar-A, and Selene. We consider that this can be provided by radar studies of the Moon with supporting optical polarimetric observations from lunar polar orbit. These experiments allow one to better understand global structure of the lunar surface in a wide range of scales, from microns to kilometers. We propose three instruments for the prospective lunar orbiter. They are: a synthetic aperture imaging radar (SAR), ground-penetrating radar (GPR), and imaging polarimeter (IP). The main purpose of SAR is to study with high resolution (50 m) the permanently shadowed sites in the lunar polar regions. These sites are cold traps for volatiles, and have a potential of resource utilization. Possible presence of water ice in the regolith in the sites makes them interesting for permanent manned bases on the Moon. Radar imaging and mapping of other interesting regions could be also planned. Multi-frequencies multi-polarization soun d ing of the lunar surface with GPR can provide information about internal structure of the lunar surface from meters to several hundred meters deep. GPR can be used for measuring the megaregolith layer properties, detection of cryptomaria, and studies of internal structure of the largest craters. IP will be a CCD camera with an additional suite of polarizers. Modest spatial resolution (100 m) should provide a total coverage or a large portion of the lunar surface in oblique viewing basically at large phase angles. Polarization degree at large (>90°) phase angles bears information about characteristic size of the regolith particles. Additional radiophysical experiments are considered with the use of the SAR system, e.g., bistatic radar

  8. The orbital record in stratigraphy

    NASA Technical Reports Server (NTRS)

    Fischer, Alfred G.

    1992-01-01

    Orbital signals are being discovered in pre-Pleistocene sediments. Due to their hierarchical nature these cycle patterns are complex, and the imprecision of geochronology generally makes the assignment of stratigraphic cycles to specific orbital cycles uncertain, but in sequences such as the limnic Newark Group under study by Olsen and pelagic Cretaceous sequence worked on by our Italo-American group the relative frequencies yield a definitive match to the Milankovitch hierarchy. Due to the multiple ways in which climate impinges on depositional systems, the orbital signals are recorded in a multiplicity of parameters, and affect different sedimentary facies in different ways. In platform carbonates, for example, the chief effect is via sea-level variations (possibly tied to fluctuating ice volume), resulting in cycles of emergence and submergence. In limnic systems it finds its most dramatic expression in alternations of lake and playa conditions. Biogenic pelagic oozes such as chalks and the limestones derived from them display variations in the carbonate supplied by planktonic organisms such as coccolithophores and foraminifera, and also record variations in the aeration of bottom waters. Whereas early studies of stratigraphic cyclicity relied mainly on bedding variations visible in the field, present studies are supplementing these with instrumental scans of geochemical, paleontological, and geophysical parameters which yield quantitative curves amenable to time-series analysis; such analysis is, however, limited by problems of distorted time-scales. My own work has been largely concentrated on pelagic systems. In these, the sensitivity of pelagic organisms to climatic-oceanic changes, combined with the sensitivity of botton life to changes in oxygen availability (commonly much more restricted in the Past than now) has left cyclic patterns related to orbital forcing. These systems are further attractive because (1) they tend to offer depositional continuity

  9. Management of preseptal and orbital cellulitis

    PubMed Central

    Lee, Seongmu; Yen, Michael T.

    2010-01-01

    Orbital cellulitis describes an infection involving the soft tissues posterior to the orbital septum, including the fat and muscle within the bony orbit. This condition may be associated with severe sight and life-threatening complications. Despite significant advances in antimicrobial therapies and diagnostic technologies, the management of orbital cellulitis often remains challenging, and rapid diagnosis and prompt initiation of therapy are important in minimizing complications and optimizing outcomes. This review summarizes the distinctive characteristics of preseptal and orbital cellulitis, with a focus on anatomic considerations, predisposing conditions, approaches to evaluation, and management strategies. PMID:23960899

  10. On-orbit flight control algorithm description

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Algorithms are presented for rotational and translational control of the space shuttle orbiter in the orbital mission phases, which are external tank separation, orbit insertion, on-orbit and de-orbit. The program provides a versatile control system structure while maintaining uniform communications with other programs, sensors, and control effectors by using an executive routine/functional subroutine format. Software functional requirements are described using block diagrams where feasible, and input--output tables, and the software implementation of each function is presented in equations and structured flow charts. Included are a glossary of all symbols used to define the requirements, and an appendix of supportive material.

  11. Novel Surgical Approaches to the Orbit.

    PubMed

    Campbell, Ashley A; Grob, Seanna R; Yoon, Michael K

    2015-01-01

    Determining safe surgical access to the orbit can be difficult given the complex anatomy and delicacy of the orbital structures. When considering biopsy or removal of an orbital tumor or repair of orbital fractures, careful planning is required to determine the ideal approach. Traditionally, this has at times necessitated invasive procedures with large incisions and extensive bone removal. The purpose of this review was to present newly techniques and devices in orbital surgery that have been reported over the past decade, with aims to provide better exposure and/or minimally invasive approaches and to improve morbidity and/or mortality.

  12. TSS-1 - Orbiter current and voltage experiments

    NASA Technical Reports Server (NTRS)

    Thompson, D. C.; Raitt, W. J.; Bonifazi, C.; Williams, S. D.; Aguero, V. M.; Gilchrist, B. E.; Banks, P. M.

    1993-01-01

    Although the deployment distance of the TSS-1 tethered satellite was only about 1 percent of nominal, experiments to study the current collection and vehicle charging effects at low voltages were performed. We present measurements of Orbiter charging resulting from electron beam emission from the Orbiter, currents in the TSS system with and without electron beam emissions, and the effects of Orbiter thrusters on charging and currents. Generally, charging induced by beam emission was limited to a few volts, though during times with low ambient plasma density the Orbiter was charged up to 80 V. Thrusters are seen to enhance Orbiter charging during beam emission, and reduce ion current collection at other times.

  13. Novel Surgical Approaches to the Orbit

    PubMed Central

    Campbell, Ashley A.; Grob, Seanna R.; Yoon, Michael K.

    2015-01-01

    Determining safe surgical access to the orbit can be difficult given the complex anatomy and delicacy of the orbital structures. When considering biopsy or removal of an orbital tumor or repair of orbital fractures, careful planning is required to determine the ideal approach. Traditionally, this has at times necessitated invasive procedures with large incisions and extensive bone removal. The purpose of this review was to present newly techniques and devices in orbital surgery that have been reported over the past decade, with aims to provide better exposure and/or minimally invasive approaches and to improve morbidity and/or mortality. PMID:26692713

  14. Orbits and Interiors of Planets

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin

    2012-05-01

    The focus of this thesis is a collection of problems of timely interest in orbital dynamics and interior structure of planetary bodies. The first three chapters are dedicated to understanding the interior structure of close-in, gaseous extrasolar planets (hot Jupiters). In order to resolve a long-standing problem of anomalously large hot Jupiter radii, we proposed a novel magnetohydrodynamic mechanism responsible for inflation. The mechanism relies on the electro-magnetic interactions between fast atmospheric flows and the planetary magnetic field in a thermally ionized atmosphere, to induce electrical currents that flow throughout the planet. The resulting Ohmic dissipation acts to maintain the interior entropies, and by extension the radii of hot Jupiters at an enhanced level. Using self-consistent calculations of thermal evolution of hot Jupiters under Ohmic dissipation, we demonstrated a clear tendency towards inflated radii for effective temperatures that give rise to significant ionization of K and Na in the atmosphere, a trend fully consistent with the observational data. Furthermore, we found that in absence of massive cores, low-mass hot Jupiters can over-flow their Roche-lobes and evaporate on Gyr time-scales, possibly leaving behind small rocky cores. Chapters four through six focus on the improvement and implications of a model for orbital evolution of the solar system, driven by dynamical instability (termed the "Nice" model). Hydrodynamical studies of the orbital evolution of planets embedded in protoplanetary disks suggest that giant planets have a tendency to assemble into multi-resonant configurations. Following this argument, we used analytical methods as well as self-consistent numerical N-body simulations to identify fully-resonant primordial states of the outer solar system, whose dynamical evolutions give rise to orbital architectures that resemble the current solar system. We found a total of only eight such initial conditions, providing

  15. Pioneer probe mission with orbiter option

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A spacecraft is described which is based on Pioneer 10 and 11, and existing propulsion technology; it can transport and release a probe for entry into Jupiter's atmosphere, and subsequently maneuver to place the spacecraft in orbit about Jupiter. Orbital operations last 3 years and include maneuvers to provide multiple close satellite encounters which allow the orbit to be significantly changed to explore different parts of the magnetosphere. A mission summary, a guide to related documents, and background information about Jupiter are presented along with mission analysis over the complete mission profile. Other topics discussed include the launch, interplanetary flight, probe release and orbit deflection, probe entry, orbit selection, orbit insertion, periapsis raising, spacecraft description, and the effects of Jupiter's radiation belt on both orbiter and the probe.

  16. Localized and Spectroscopic Orbitals: Squirrel Ears on Water.

    ERIC Educational Resources Information Center

    Martin, R. Bruce

    1988-01-01

    Reexamines the electronic structure of water considering divergent views. Discusses several aspects of molecular orbital theory using spectroscopic molecular orbitals and localized molecular orbitals. Gives examples for determining lowest energy spectroscopic orbitals. (ML)

  17. Kalman Orbit Optimized Loop Tracking

    NASA Technical Reports Server (NTRS)

    Young, Lawrence E.; Meehan, Thomas K.

    2011-01-01

    Under certain conditions of low signal power and/or high noise, there is insufficient signal to noise ratio (SNR) to close tracking loops with individual signals on orbiting Global Navigation Satellite System (GNSS) receivers. In addition, the processing power available from flight computers is not great enough to implement a conventional ultra-tight coupling tracking loop. This work provides a method to track GNSS signals at very low SNR without the penalty of requiring very high processor throughput to calculate the loop parameters. The Kalman Orbit-Optimized Loop (KOOL) tracking approach constitutes a filter with a dynamic model and using the aggregate of information from all tracked GNSS signals to close the tracking loop for each signal. For applications where there is not a good dynamic model, such as very low orbits where atmospheric drag models may not be adequate to achieve the required accuracy, aiding from an IMU (inertial measurement unit) or other sensor will be added. The KOOL approach is based on research JPL has done to allow signal recovery from weak and scintillating signals observed during the use of GPS signals for limb sounding of the Earth s atmosphere. That approach uses the onboard PVT (position, velocity, time) solution to generate predictions for the range, range rate, and acceleration of the low-SNR signal. The low- SNR signal data are captured by a directed open loop. KOOL builds on the previous open loop tracking by including feedback and observable generation from the weak-signal channels so that the MSR receiver will continue to track and provide PVT, range, and Doppler data, even when all channels have low SNR.

  18. Orbital Space Plane Cost Credibility

    NASA Technical Reports Server (NTRS)

    Creech, Steve

    2003-01-01

    NASA's largest new start development program is the Orbital Space Plane (OSP) Program. The program is currently in the formulation stage. One of the critical issues to be resolved, prior to initiating full-scale development, is establishing cost credibility of NASA s budget estimates for development, production, and operations of the OSP. This paper will discuss the processes, tools, and methodologies that NASA, along with its industry partners, are implementing to assure cost credibility for the OSP program. Results of benchmarking of current tools and the development of new cost estimating capabilities and approaches will be discussed.

  19. Neptune Polar Orbiter with Probes

    NASA Technical Reports Server (NTRS)

    Bienstock, Bernard; Atkinson, David; Baines, Kevin; Mahaffy, Paul; Steffes, Paul; Atreya, Sushil; Stern, Alan; Wright, Michael; Willenberg, Harvey; Smith, David; Frampton, Robert; Sichi, Steve; Peltz, Leora; Masciarelli, James; VanCleve, Jeffey

    2005-01-01

    The giant planets of the outer solar system divide into two distinct classes: the gas giants Jupiter and Saturn, which consist mainly of hydrogen and helium; and the ice giants Uranus and Neptune, which are believed to contain significant amounts of the heavier elements oxygen, nitrogen, and carbon and sulfur. Detailed comparisons of the internal structures and compositions of the gas giants with those of the ice giants will yield valuable insights into the processes that formed the solar system and, perhaps, other planetary systems. By 2012, Galileo, Cassini and possibly a Jupiter Orbiter mission with microwave radiometers, Juno, in the New Frontiers program, will have yielded significant information on the chemical and physical properties of Jupiter and Saturn. A Neptune Orbiter with Probes (NOP) mission would deliver the corresponding key data for an ice giant planet. Such a mission would ideally study the deep Neptune atmosphere to pressures approaching and possibly exceeding 1000 bars, as well as the rings, Triton, Nereid, and Neptune s other icy satellites. A potential source of power would be nuclear electric propulsion (NEP). Such an ambitious mission requires that a number of technical issues be investigated, however, including: (1) atmospheric entry probe thermal protection system (TPS) design, (2) probe structural design including seals, windows, penetrations and pressure vessel, (3) digital, RF subsystem, and overall communication link design for long term operation in the very extreme environment of Neptune's deep atmosphere, (4) trajectory design allowing probe release on a trajectory to impact Neptune while allowing the spacecraft to achieve a polar orbit of Neptune, (5) and finally the suite of science instruments enabled by the probe technology to explore the depths of the Neptune atmosphere. Another driving factor in the design of the Orbiter and Probes is the necessity to maintain a fully operational flight system during the lengthy transit time

  20. Orbiter fuel cell improvement assessment

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.

    1981-01-01

    The history of fuel cells and the theory of fuel cells is given. Expressions for thermodynamic and electrical efficiencies are developed. The voltage losses due to electrode activation, ohmic resistance and ionic diffusion are discussed. Present limitations of the Orbiter Fuel Cell, as well as proposed enhancements, are given. These enhancements are then evaluated and recommendations are given for fuel cell enhancement both for short-range as well as long-range performance improvement. Estimates of reliability and cost savings are given for enhancements where possible.

  1. Orbital search for lunar volcanism.

    NASA Technical Reports Server (NTRS)

    Hodges, R. R., Jr.; Hoffman, J. H.; Yeh, T. T. J.; Chang, G. K.

    1972-01-01

    The total rate of volcanic release of gases into the lunar atmosphere is estimated to be less than 60 g/sec. One of the implications of this degassing is that, if it occurs as sporadic releases of large quantities of gas, these events can be detected by an orbiting mass spectrometer, such as that carried on the flight of Apollo 15 and one that will operate during the Apollo 16 mission. The nature of a volcanic perturbation of the lunar atmosphere is discussed, and a lower bound is derived for the expected time between detected events.

  2. Environmental dynamics at orbital altitudes

    NASA Technical Reports Server (NTRS)

    Karr, G. R.

    1976-01-01

    The work reported involved the improvement of aerodynamic theory for free molecular and transition flow regimes. The improved theory was applied to interpretation of the dynamic response of objects traveling through the atmosphere. Satellite drag analysis includes analysis methods, atmospheric super rotation effects, and satellite lift effects on orbital dynamics. Transition flow regimes were studied with falling sphere data and errors resulting in inferred atmospheric parameters from falling sphere techniques. Improved drag coefficients reveal considerable error in previous falling sphere data. The drag coefficient has been studied for the entire spectrum of Knudsen Number and speed ratio, with particular emphasis on the theory of the very low-speed ratio regime.

  3. A Manned Orbital Space Laboratory

    NASA Technical Reports Server (NTRS)

    Schnitzer, Emanuel

    1960-01-01

    A study is under way of a manned orbital space laboratory, some of the purposes of which would be to determine man's adaptability to space and to study structures and systems in space before committing manned spacecraft to long-range missions. It uses an inflatable torus as laboratory and living quarters and has an erectable solar collector as the source of heat for the power plant. The station rotates six times per minute in order to provide some artificial gravity together with stabilization. An escape taxi, which is not shown, is attached to the bottom of the station.

  4. Pearls of Orbital Trauma Management

    PubMed Central

    Roth, Forrest S.; Koshy, John C.; Goldberg, Jonathan S.; Soparkar, Charles N.S.

    2010-01-01

    Orbital fractures account for a significant portion of traumatic facial injuries. Although plastic surgery literature is helpful, additional pearls and insights are provided in this article from the experience of an oculoplastic surgeon. The fundamentals remain the same, but the perceptions differ and provide a healthy perspective on a long-standing issue. The most important thing to remember is that the optimal management plan is often variable, and the proper choice regarding which plan to choose rests upon the clinical scenario and the surgeon having an honest perception of his or her level of expertise and comfort level. PMID:22550464

  5. Viking orbiter stereo imaging catalog

    NASA Technical Reports Server (NTRS)

    Blasius, K. R.; Vetrone, A. V.; Martin, M. D.

    1980-01-01

    The extremely long missions of the two Viking Orbiter spacecraft produced a wealth of photos of surface features. Many of which can be used to form stereo images allowing the earth-bound student of Mars to examine the subject in 3-D. This catalog is a technical guide to the use of stereo coverage within the complex Viking imaging data set. Since that data set is still growing (January, 1980, about 3 1/2 years after the mission began), a second edition of this catalog is planned with completion expected about November, 1980.

  6. PHOTOMETRIC ORBITS OF EXTRASOLAR PLANETS

    SciTech Connect

    Brown, Robert A.

    2009-09-10

    We define and analyze the photometric orbit (PhO) of an extrasolar planet observed in reflected light. In our definition, the PhO is a Keplerian entity with six parameters: semimajor axis, eccentricity, mean anomaly at some particular time, argument of periastron, inclination angle, and effective radius, which is the square root of the geometric albedo times the planetary radius. Preliminarily, we assume a Lambertian phase function. We study in detail the case of short-period giant planets (SPGPs) and observational parameters relevant to the Kepler mission: 20 ppm photometry with normal errors, 6.5 hr cadence, and three-year duration. We define a relevant 'planetary population of interest' in terms of probability distributions of the PhO parameters. We perform Monte Carlo experiments to estimate the ability to detect planets and to recover PhO parameters from light curves. We calibrate the completeness of a periodogram search technique, and find structure caused by degeneracy. We recover full orbital solutions from synthetic Kepler data sets and estimate the median errors in recovered PhO parameters. We treat in depth a case of a Jupiter body-double. For the stated assumptions, we find that Kepler should obtain orbital solutions for many of the 100-760 SPGP that Jenkins and Doyle estimate Kepler will discover. Because most or all of these discoveries will be followed up by ground-based radial velocity observations, the estimates of inclination angle from the PhO may enable the calculation of true companion masses: Kepler photometry may break the 'msin i' degeneracy. PhO observations may be difficult. There is uncertainty about how low the albedos of SPGPs actually are, about their phase functions, and about a possible noise floor due to systematic errors from instrumental and stellar sources. Nevertheless, simple detection of SPGPs in reflected light should be robust in the regime of Kepler photometry, and estimates of all six orbital parameters may be feasible in

  7. Orbiter wheel and tire certification

    NASA Technical Reports Server (NTRS)

    Campbell, C. C., Jr.

    1985-01-01

    The orbiter wheel and tire development has required a unique series of certification tests to demonstrate the ability of the hardware to meet severe performance requirements. Early tests of the main landing gear wheel using conventional slow roll testing resulted in hardware failures. This resulted in a need to conduct high velocity tests with crosswind effects for assurance that the hardware was safe for a limited number of flights. Currently, this approach and the conventional slow roll and static tests are used to certify the wheel/tire assembly for operational use.

  8. On-Orbit Software Analysis

    NASA Technical Reports Server (NTRS)

    Moran, Susanne I.

    2004-01-01

    The On-Orbit Software Analysis Research Infusion Project was done by Intrinsyx Technologies Corporation (Intrinsyx) at the National Aeronautics and Space Administration (NASA) Ames Research Center (ARC). The Project was a joint collaborative effort between NASA Codes IC and SL, Kestrel Technology (Kestrel), and Intrinsyx. The primary objectives of the Project were: Discovery and verification of software program properties and dependencies, Detection and isolation of software defects across different versions of software, and Compilation of historical data and technical expertise for future applications

  9. Orbital debris: A technical assessment

    NASA Technical Reports Server (NTRS)

    Gleghorn, George; Asay, James; Atkinson, Dale; Flury, Walter; Johnson, Nicholas; Kessler, Donald; Knowles, Stephen; Rex, Dietrich; Toda, Susumu; Veniaminov, Stanislav

    1995-01-01

    To acquire an unbiased technical assessment of (1) the research needed to better understand the debris environment, (2) the necessity and means of protecting spacecraft against the debris environment, and (3) potential methods of reducing the future debris hazard, NASA asked the National Research Council to form an international committee to examine the orbital debris issue. The committee was asked to draw upon available data and analyses to: characterize the current debris environment, project how this environment might change in the absence of new measures to alleviate debris proliferation, examine ongoing alleviation activities, explore measures to address the problem, and develop recommendations on technical methods to address the problems of debris proliferation.

  10. The Orbiting Carbon Observatory (OCO)

    NASA Technical Reports Server (NTRS)

    Miller, Charles E.

    2005-01-01

    CO2 is the principal human generated driver of climate change. Accurate forecasting of future climate requires an improved understanding of the global carbon cycle and its interaction with the climate system. The Orbiting Carbon Observatory (OCO) will make global, space-based observations of atmospheric CO2 with the precision, resolution, and coverage needed to understand sources and sinks. OCO data will provide critical information for decision makers including the scientific basis for policy formulation, guide for carbon management strategies and treaty monitoring.

  11. Space Shuttle orbiter separation bolts

    NASA Technical Reports Server (NTRS)

    Ritchie, R. S.

    1979-01-01

    Evolution of the space shuttle from previous spacecraft systems dictated growth and innovative design of previously standard ordnance devices. Initially, one bolt design was programmed for both 747 and external tank application. However, during development and subsequent analyses, two distinct designs evolved. The unique requirements of both bolts include: high combined loading, redundant initiation, flush separation plane, self-righting and shank attenuation. Of particular interest are the test methods, problem areas, and use of subscale models which demonstrated feasibility at an early phase in the program. The techniques incorporated in the shuttle orbiter bolts are applicable to other mechanisms.

  12. Mission Design for the Lunar Reconnaissance Orbiter

    NASA Technical Reports Server (NTRS)

    Beckman, Mark

    2007-01-01

    The Lunar Reconnaissance Orbiter (LRO) will be the first mission under NASA's Vision for Space Exploration. LRO will fly in a low 50 km mean altitude lunar polar orbit. LRO will utilize a direct minimum energy lunar transfer and have a launch window of three days every two weeks. The launch window is defined by lunar orbit beta angle at times of extreme lighting conditions. This paper will define the LRO launch window and the science and engineering constraints that drive it. After lunar orbit insertion, LRO will be placed into a commissioning orbit for up to 60 days. This commissioning orbit will be a low altitude quasi-frozen orbit that minimizes stationkeeping costs during commissioning phase. LRO will use a repeating stationkeeping cycle with a pair of maneuvers every lunar sidereal period. The stationkeeping algorithm will bound LRO altitude, maintain ground station contact during maneuvers, and equally distribute periselene between northern and southern hemispheres. Orbit determination for LRO will be at the 50 m level with updated lunar gravity models. This paper will address the quasi-frozen orbit design, stationkeeping algorithms and low lunar orbit determination.

  13. LLOFX earth orbit to lunar orbit delta V estimation program user and technical documentation

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The LLOFX computer program calculates in-plane trajectories from an Earth-orbiting space station to Lunar orbit in such a way that the journey requires only two delta V burns (one to leave Earth circular orbit and one to circularize into Lunar orbit). The program requires the user to supply the Space Station altitude and Lunar orbit altitude (in km above the surface), and the desired time of flight for the transfer (in hours). It then determines and displays the trans-Lunar injection (TLI) delta V required to achieve the transfer, the Lunar orbit insertion (LOI) delta V required to circularize the orbit around the Moon, the actual time of flight, and whether the transfer orbit is elliptical or hyperbolic. Return information is also displayed. Finally, a plot of the transfer orbit is displayed.

  14. Shadowing Lemma and chaotic orbit determination

    NASA Astrophysics Data System (ADS)

    Spoto, Federica; Milani, Andrea

    2016-03-01

    Orbit determination is possible for a chaotic orbit of a dynamical system, given a finite set of observations, provided the initial conditions are at the central time. The Shadowing Lemma (Anosov 1967; Bowen in J Differ Equ 18:333-356, 1975) can be seen as a way to connect the orbit obtained using the observations with a real trajectory. An orbit is a shadowing of the trajectory if it stays close to the real trajectory for some amount of time. In a simple discrete model, the standard map, we tackle the problem of chaotic orbit determination when observations extend beyond the predictability horizon. If the orbit is hyperbolic, a shadowing orbit is computed by the least squares orbit determination. We test both the convergence of the orbit determination iterative procedure and the behaviour of the uncertainties as a function of the maximum number of map iterations observed. When the initial conditions belong to a chaotic orbit, the orbit determination is made impossible by numerical instability beyond a computability horizon, which can be approximately predicted by a simple formula. Moreover, the uncertainty of the results is sharply increased if a dynamical parameter is added to the initial conditions as parameter to be estimated. The Shadowing Lemma does not dictate what the asymptotic behaviour of the uncertainties should be. These phenomena have significant implications, which remain to be studied, in practical problems of orbit determination involving chaos, such as the chaotic rotation state of a celestial body and a chaotic orbit of a planet-crossing asteroid undergoing many close approaches.

  15. Analytical representations of precise orbit predictions for Earth orbiting space objects

    NASA Astrophysics Data System (ADS)

    Sang, Jizhang; Li, Bin; Chen, Junyu; Zhang, Pin; Ning, Jinsheng

    2017-01-01

    Accurate orbits of Earth orbiting space objects are usually generated from an orbit determination/prediction process using numerical integrators, and presented to users in a tabulated form or a state vector including force model parameters. When dealing with hundreds of thousands of space objects such as in the space conjunction assessment, the memory required for the tabulated orbits or the computing time for propagating orbits using the state vector are both confronting to users. This paper presents two methods of analytically representing numerical orbits considering the accuracy, computing efficiency and memory. The first one is a two-step TLE-based method in which the numerical orbits are first fitted into a TLE set and then correction functions are applied to improve the position accuracy. In the second method, the orbit states are represented in equinoctial elements first, and then again correction functions are applied to reduce the position errors. Experiments using six satellite laser ranging (SLR) satellites and 12 debris objects with accurate orbits show that both methods can represent the accurate orbits over 5 days in an accuracy of a few dozens of meters for the circular orbits and several hundred meters for the eccentric orbits. The computing time is similar to that using the NORAD TLE/SGP4 algorithm, and storage for the orbit elements and function coefficients is about 3-5 KB. These features could make the two methods beneficial for the maintenance of orbit catalog of large numbers of space objects.

  16. Dexterous Orbital Servicing System (DOSS)

    NASA Technical Reports Server (NTRS)

    Price, Charles R.; Berka, Reginald B.; Chladek, John T.

    1994-01-01

    The Dexterous Orbiter Servicing System (DOSS) is a dexterous robotic spaceflight system that is based on the manipulator designed as part of the Flight Telerobotics Servicer program for the Space Station Freedom and built during a 'technology capture' effort that was commissioned when the FTS was cancelled from the Space Station Freedom program. The FTS technology capture effort yielded one flight manipulator and the 1 g hydraulic simulator that had been designed as an integrated test tool and crew trainer. The DOSS concept was developed to satisfy needs of the telerobotics research community, the space shuttle, and the space station. As a flight testbed, DOSS would serve as a baseline reference for testing the performance of advanced telerobotics and intelligent robotics components. For shuttle, the DOSS, configured as a movable dexterous tool, would be used to provide operational flexibility for payload operations and contingency operations. As a risk mitigation flight demonstration, the DOSS would serve the International Space Station to characterize the end to end system performance of the Special Purpose Dexterous Manipulator performing assembly and maintenance tasks with actual ISSA orbital replacement units. Currently, the most likely entrance of the DOSS into spaceflight is a risk mitigation flight experiment for the International Space Station.

  17. Fungal infections of the orbit

    PubMed Central

    Mukherjee, Bipasha; Raichura, Nirav Dilip; Alam, Md. Shahid

    2016-01-01

    Fungal infections of the orbit can lead to grave complications. Although the primary site of inoculation of the infective organism is frequently the sinuses, the patients can initially present to the ophthalmologist with ocular signs and symptoms. Due to its varied and nonspecific clinical features, especially in the early stages, patients are frequently misdiagnosed and even treated with steroids which worsen the situation leading to dire consequences. Ophthalmologists should be familiar with the clinical spectrum of disease and the variable presentation of this infection, as early diagnosis and rapid institution of appropriate therapy are crucial elements in the management of this invasive sino-orbital infection. In this review, relevant clinical, microbiological, and imaging findings are discussed along with the current consensus on local and systemic management. We review the recent literature and provide a comprehensive analysis. In the immunocompromised, as well as in healthy patients, a high index of suspicion must be maintained as delay in diagnosis of fungal pathology may lead to disfiguring morbidity or even mortality. Obtaining adequate diagnostic material for pathological and microbiological examination is critical. Newer methods of therapy, particularly oral voriconazole and topical amphotericin B, may be beneficial in selected patients. PMID:27380972

  18. Introducing the Moon's Orbital Eccentricity

    NASA Astrophysics Data System (ADS)

    Oostra, Benjamin

    2014-11-01

    I present a novel way to introduce the lunar orbital eccentricity in introductory astronomy courses. The Moon is perhaps the clearest illustration of the general orbital elements such as inclination, ascending node, eccentricity, perigee, and so on. Furthermore, I like the students to discover astronomical phenomena for themselves, by means of a guided exercise, rather than just telling them the facts.1 The inclination and nodes may be found by direct observation, monitoring carefully the position of the Moon among the stars. Even the regression of the nodes may be discovered in this way2 To find the eccentricity from students' observations is also possible,3 but that requires considerable time and effort. if a whole class should discover it in a short time, here is a method more suitable for a one-day class or home assignment. The level I aim at is, more or less, advanced high school or first-year college students. I assume them to be acquainted with celestial coordinates and the lunar phases, and to be able to use algebra and trigonometry.

  19. On-orbit Passive Thermography

    NASA Technical Reports Server (NTRS)

    Howell, Patricia A.; Winfree, William P.; Cramer, K. Elliott

    2008-01-01

    On July 12, 2006, British-born astronaut Piers Sellers became the first person to conduct thermal nondestructive evaluation experiments in space, demonstrating the feasibility of a new tool for detecting damage to the reinforced carbon-carbon (RCC) structures of the Shuttle. This new tool was an EVA (Extravehicular Activity, or spacewalk) compatible infrared camera developed by NASA engineers. Data was collected both on the wing leading edge of the Orbiter and on pre-damaged samples mounted in the Shuttle s cargo bay. A total of 10 infrared movies were collected during the EVA totaling over 250 megabytes of data. Images were downloaded from the orbiting Shuttle to Johnson Space Center for analysis and processing. Results are shown to be comparable to ground-based thermal inspections performed in the laboratory with the same type of camera and simulated solar heating. The EVA camera system detected flat-bottom holes as small as 2.54cm in diameter with 50% material loss from the back (hidden) surface in RCC during this first test of the EVA IR Camera. Data for the time history of the specimen temperature and the capability of the inspection system for imaging impact damage are presented.

  20. Investigations of SPS Orbit Drifts

    SciTech Connect

    Drøsdal, Lene; Bracco, Chiara; Cornelis, Karel; Goddard, Brennan; Kain, Verena; Meddahi, Malika; Wenninger, Jorg; Gianfelice-Wendt, Eliana

    2014-07-01

    The LHC is filled from the last pre-injector, the Super Proton Synchrotron (SPS), via two 3 km long transfer lines, TI 2 and TI 8. Over the LHC injection processes, a drift of the beam trajectories has been observed in TI 2 and TI 8, requiring regular correction of the trajectories, in order to ensure clean injection into the LHC. Investigations of the trajectory variations in the transfer lines showed that the main source of short term trajectory drifts are current variations of the SPS extraction septa (MSE). The stability of the power converters has been improved, but the variations are still present and further improvements are being investigated. The stability over a longer period of time cannot be explained by this source alone. The analysis of trajectory variations shows that there are also slow variations in the SPS closed orbit at extraction. A set of SPS orbit measurements has been saved and analysed. These observations will be used together with simulations and observed field errors to locate the second source of variations.

  1. Achromatic orbital angular momentum generator

    NASA Astrophysics Data System (ADS)

    Bouchard, Frédéric; Mand, Harjaspreet; Mirhosseini, Mohammad; Karimi, Ebrahim; Boyd, Robert W.

    2014-12-01

    We describe a novel approach for generating light beams that carry orbital angular momentum (OAM) by means of total internal reflection in an isotropic medium. A continuous space-varying cylindrically symmetric reflector, in the form of two glued hollow axicons, is used to introduce a nonuniform rotation of polarization into a linearly polarized input beam. This device acts as a full spin-to-orbital angular momentum convertor. It functions by switching the helicity of the incoming beam's polarization, and by conservation of total angular momentum thereby generates a well-defined value of OAM. Our device is broadband, since the phase shift due to total internal reflection is nearly independent of wavelength. We verify the broad-band behaviour by measuring the conversion efficiency of the device for three different wavelengths corresponding to the RGB colours, red, green and blue. An average conversion efficiency of 95% for these three different wavelengths is observed. This device may find applications in imaging from micro- to astronomical systems where a white vortex beam is needed.

  2. Mercury orbiter - an interdisciplinary mission

    NASA Astrophysics Data System (ADS)

    Grard, R.; Scoon, G.; Coradini, M.

    Mercury is the innermost and a less known terrestrial planet of the Solar System. It possesses a very high density (5.3 g/cu cm at 10 kbar), a small but unexpected magnetic moment (6 x 10-3 that of Earth), and a tenuous exosphere; ground-based radar observations indicate that water ice may exist at the poles. There are still fundamental questions about its accretion and catering history, and its thermal and chemical evolution. The size of Mercury's magnetosphere is just 5% of that of Earth; substorms last 5 min, on average, and their generation process is influenced by the absence of an ionosphere. The model payload of Mercury Orbiter includes a multi-spectral imager, a gamma-and X -ray detector, a magnetometer, charged-particle analysers, a wave receiver and an ion emitter for spacecraft potential control. The spacecraft, the design of which is inherited from ESA's Cluster spacecraft, has a dry mass of 626 kg and is stabilized at 10 rmp, but the telemetry antenna is despun. The bit rate varies between 1.4 and 9 kb/s over the range 1.6-0.64 AU. The spacecraft, launched from Kourou with an Ariane-5, reaches its destination after two gravity assists at Venus and two at Mercury. Its orbit is polar with periherm and apherm altitudes of 400 and 16 800 km, respectively. The spacecraft's operating lifetime around Mercury is 3 Hermean years.

  3. Orbital Debris Observations with WFCAM

    NASA Astrophysics Data System (ADS)

    Kendrick, R.; Mann, B.; Read, M.; Kerr, T.; Irwin, M.; Cross, N.; Bold, M.,; Varricatt, W.; Madsen, G.

    2014-09-01

    The United Kingdom Infrared Telescope has been operating for 35 years on the summit of Mauna Kea as a premier Infrared astronomical facility. In its 35th year the telescope has been turned over to a new operating group consisting of University of Arizona, University of Hawaii and the LM Advanced Technology Center. UKIRT will continue its astronomical mission with a portion of observing time dedicated to orbital debris and Near Earth Object detection and characterization. During the past 10 years the UKIRT Wide Field CAMera (WFCAM) has been performing large area astronomical surveys in the J, H and K bands. The data for these surveys have been reduced by the Cambridge Astronomical Survey Unit in Cambridge, England and archived by the Wide Field Astronomy Unit in Edinburgh, Scotland. During January and February of 2014 the Wide Field CAMera (WFCAM) was used to scan through the geostationary satellite belt detecting operational satellites as well as nearby debris. Accurate photometric and astrometric parameters have been developed by CASU for each of the detections and all data has been archived by WFAU. This paper will present the January and February results of the orbital debris surveys with WFCAM.

  4. Six Planets Orbiting HD 219134

    NASA Astrophysics Data System (ADS)

    Vogt, Steven S.; Burt, Jennifer; Meschiari, Stefano; Butler, R. Paul; Henry, Gregory W.; Wang, Songhu; Holden, Brad; Gapp, Cyril; Hanson, Russell; Arriagada, Pamela; Keiser, Sandy; Teske, Johanna; Laughlin, Gregory

    2015-11-01

    We present new, high-precision Doppler radial velocity (RV) data sets for the nearby K3V star HD 219134. The data include 175 velocities obtained with the HIRES Spectrograph at the Keck I Telescope and 101 velocities obtained with the Levy Spectrograph at the Automated Planet Finder Telescope at Lick Observatory. Our observations reveal six new planetary candidates, with orbital periods of P = 3.1, 6.8, 22.8, 46.7, 94.2, and 2247 days, spanning masses of {M}{sin}i=3.8, 3.5, 8.9, 21.3, 10.8, and 108 {{M}}\\oplus , respectively. Our analysis indicates that the outermost signal is unlikely to be an artifact induced by stellar activity. In addition, several years of precision photometry with the T10 0.8 m automatic photometric telescope at Fairborn Observatory demonstrated a lack of brightness variability to a limit of ∼0.0002 mag, providing strong support for planetary-reflex motion as the source of the RV variations. The HD 219134 system with its bright (V = 5.6) primary provides an excellent opportunity to obtain detailed orbital characterization (and potentially follow-up observations) of a planetary system that resembles many of the multiple-planet systems detected by Kepler, which are expected to be detected by NASA’s forthcoming TESS Mission and by ESA’s forthcoming PLATO Mission.

  5. LROC - Lunar Reconnaissance Orbiter Camera

    NASA Astrophysics Data System (ADS)

    Robinson, M. S.; Eliason, E.; Hiesinger, H.; Jolliff, B. L.; McEwen, A.; Malin, M. C.; Ravine, M. A.; Thomas, P. C.; Turtle, E. P.

    2009-12-01

    The Lunar Reconnaissance Orbiter (LRO) went into lunar orbit on 23 June 2009. The LRO Camera (LROC) acquired its first lunar images on June 30 and commenced full scale testing and commissioning on July 10. The LROC consists of two narrow-angle cameras (NACs) that provide 0.5 m scale panchromatic images over a combined 5 km swath, and a wide-angle camera (WAC) to provide images at a scale of 100 m per pixel in five visible wavelength bands (415, 566, 604, 643, and 689 nm) and 400 m per pixel in two ultraviolet bands (321 nm and 360 nm) from the nominal 50 km orbit. Early operations were designed to test the performance of the cameras under all nominal operating conditions and provided a baseline for future calibrations. Test sequences included off-nadir slews to image stars and the Earth, 90° yaw sequences to collect flat field calibration data, night imaging for background characterization, and systematic mapping to test performance. LRO initially was placed into a terminator orbit resulting in images acquired under low signal conditions. Over the next three months the incidence angle at the spacecraft’s equator crossing gradually decreased towards high noon, providing a range of illumination conditions. Several hundred south polar images were collected in support of impact site selection for the LCROSS mission; details can be seen in many of the shadows. Commissioning phase images not only proved the instruments’ overall performance was nominal, but also that many geologic features of the lunar surface are well preserved at the meter-scale. Of particular note is the variety of impact-induced morphologies preserved in a near pristine state in and around kilometer-scale and larger young Copernican age impact craters that include: abundant evidence of impact melt of a variety of rheological properties, including coherent flows with surface textures and planimetric properties reflecting supersolidus (e.g., liquid melt) emplacement, blocks delicately perched on

  6. Safety in earth orbit study. Volume 4: Space shuttle orbiter: Safety requirements and guidelines on-orbit phase

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Safety requirements and guidelines are listed for the space shuttle orbiter and for its interface with other vehicles. The requirements and guidelines are specific to the hazards and emergencies in earth orbit. The requirements and guidelines for the orbiter are those with respect to vehicle design, safety devices, warning devices, operational procedures, and residual hazards. The requirements and guidelines for interface with the space station, upper stage vehicles, and sortie payloads are imposed on these vehicles to ensure the safety of the shuttle orbiter. The rationale for the safety requirements and guidelines is also discussed.

  7. Low Earth orbit constellations: Orbit control or not

    NASA Astrophysics Data System (ADS)

    Radzik, Jose; Maral, Gerard

    1993-01-01

    The aim of the study is to list the arguments for and against the adoption of orbit control. The first section is a semi-analytical calculation of the probability of visibility with minimum elevation angle of a single satellite, to be used for altitudes less than 2000 km. Section two evaluates the number of noncontrolled satellites needed to guarantee a given probability of visibility for the whole constellation. Section three gives a comparison between noncontrolled and controlled constellations in the case of very low altitudes (less than 800 km). The main problem is the effect of atmospheric drag which reduces significantly the coverage performance of the satellite at its end of life. Evaluating the semi-major-axis contraction and eccentricity evolution with time allows us to define the noncontrolled satellite constellations.

  8. On the effect of eccentricity of a planetary orbit on the stability of satellite orbits

    NASA Astrophysics Data System (ADS)

    Ichtiaroglou, S.; Voyatzis, G.

    1990-03-01

    The effect of the eccentricity of a planet's orbit on the stability of the orbits of its satellites is studied. The model used is the elliptic Hill case of the planar restricted three-body problem. The linear stability of all the known families of periodic orbits is computed. No stable orbits are found, the majority of them possessing one or two pairs of real eigenvalues of the monodromy matrix, while some with complex instability are found. Two families of periodic orbits, bifurcating from the Lagrangian points of the corresponding circular case are found analytically. These orbits are very unstable and the determination of their stability coefficients is not accurate.

  9. Electric Propulsion for Low Earth Orbit Constellations

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; Sankovic, John M.

    1998-01-01

    Hall effect electric propulsion was evaluated for orbit insertion, satellite repositioning, orbit maintenance and de-orbit applications for a sample low earth orbit satellite constellation. Since the low masses of these satellites enable multiple spacecraft per launch, the ability to add spacecraft to a given launch was used as a figure of merit. When compared to chemical propulsion, the Hall thruster system can add additional spacecraft per launch using planned payload power levels. One satellite can be added to the assumed four satellite baseline chemical launch without additional mission times. Two or three satellites may be added by providing part of the orbit insertion with the Hall system. In these cases orbit insertion times were found to be 35 and 62 days. Depending, on the electric propulsion scenario, the resulting launch vehicle savings is nearly two, three or four Delta 7920 launch vehicles out of the chemical baseline scenario's eight Delta 7920 launch vehicles.

  10. Electric Propulsion for Low Earth Orbit Constellations

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; Sankovic, John M.

    1998-01-01

    Hall Effect electric propulsion was evaluated for orbit insertion, satellite repositioning, orbit maintenance and de-orbit applications for a sample low earth orbit satellite constellation. Since the low masses of these satellites enable multiple spacecraft per launch, the ability to add spacecraft to a given launch was used as a figure of merit. When compared to chemical propulsion, the Hall thruster system can add additional spacecraft per launch using planned payload power levels. One satellite can be added to the assumed four satellite baseline chemical launch without additional mission times. Two or three satellites may be added by providing part of the orbit insertion with the Hall system. In these cases orbit insertion times were found to be 35 and 62 days. Depending on the electric propulsion scenario, the resulting launch vehicle savings is nearly two, three or four Delta 7920 launch vehicles out of the chemical baseline scenarios eight Delta 7920 launch vehicles.

  11. Orbital behavior around a nonuniform celestial body

    NASA Astrophysics Data System (ADS)

    Rosson, Z.; Hall, F.; Vogel, T.

    2016-09-01

    To effectively model the orbit around a nonuniform celestial body, detailed information needs to be determined of the perturbations. This research looked at one of the most crucial perturbations: the nonuniform gravitational field of a celestial body. Given an orbiting particle (a satellite), we utilized numerical methods to calculate its orbit in two dimensions around a discretized center mass structure. The gravitational acceleration imposed on the particle due to each mass point sums vectorally as the particle completes each infinitesimal time step of one orbit. There are noticeable effects on the orbit as the conditions of the center mass change. The development of a simulation code allows for the modelling of the orbit about an irregular body with satisfactory accuracy.

  12. The 1981 Jupiter Orbiter Probe mission

    NASA Technical Reports Server (NTRS)

    Moore, J. W.; Hyde, J. R.; Van Allen, J. A.; Nunamaker, R. S.

    1976-01-01

    Plans for the 1981 Jupiter Orbiter Probe (JOP) mission are presented in some detail. The need for a Jupiter entry probe, remote sensing of the planet, and an orbiter, in addition to flybys, is made clear. Launch hardware, using the Space Shuttle flight system and Interim Upper Stage, is described, along with scientific tasks laid out for the entry probe and the orbiter. Combined analysis of the Jovian magnetosphere and other orbiter missions calls for a two-part orbiter with one part spun and the other de-spun. Related design problems and solutions are described and diagrammed. Jovian moon flybys and orbiter path adjustments by subsequent earth-launched flybys are discussed. The importance of Jupiter data for solar system evolution and possible analysis of early stages of stellar evolution or of a binary system are also treated.

  13. Orbital debris characterization with impact flash signatures

    SciTech Connect

    Ang, J.A.

    1991-12-31

    Orbital debris is recognized as a serious and growing threat to man`s utilization and exploration of space. While some information is available on the material composition of orbital debris, most measurements of orbital debris size and velocity distributions do not distinguish material type. The analysis and understanding of impact flash signatures can lead to an in-situ detector system with the ability to determine size and impact velocity distribution for orbital debris segregated by material type. This detector concept is based on an understanding of how material shock properties govern the flash signature arising from the impact of a piece of orbital debris (impactor) against a witness plate (target). Analytical results are presented that identify the most promising witness plate materials with respect to producing impact flash signatures that characterize the orbital debris material. 7 refs.

  14. Orbital debris characterization with impact flash signatures

    SciTech Connect

    Ang, J.A.

    1991-01-01

    Orbital debris is recognized as a serious and growing threat to man's utilization and exploration of space. While some information is available on the material composition of orbital debris, most measurements of orbital debris size and velocity distributions do not distinguish material type. The analysis and understanding of impact flash signatures can lead to an in-situ detector system with the ability to determine size and impact velocity distribution for orbital debris segregated by material type. This detector concept is based on an understanding of how material shock properties govern the flash signature arising from the impact of a piece of orbital debris (impactor) against a witness plate (target). Analytical results are presented that identify the most promising witness plate materials with respect to producing impact flash signatures that characterize the orbital debris material. 7 refs.

  15. Electronic structure interpolation via atomic orbitals.

    PubMed

    Chen, Mohan; Guo, G-C; He, Lixin

    2011-08-17

    We present an efficient scheme for accurate electronic structure interpolation based on systematically improvable optimized atomic orbitals. The atomic orbitals are generated by minimizing the spillage value between the atomic basis calculations and the converged plane wave basis calculations on some coarse k-point grid. They are then used to calculate the band structure of the full Brillouin zone using the linear combination of atomic orbitals algorithms. We find that usually 16-25 orbitals per atom can give an accuracy of about 10 meV compared to the full ab initio calculations, and the accuracy can be systematically improved by using more atomic orbitals. The scheme is easy to implement and robust, and works equally well for metallic systems and systems with complicated band structures. Furthermore, the atomic orbitals have much better transferability than Shirley's basis and Wannier functions, which is very useful for perturbation calculations.

  16. Novel Detection of Optical Orbital Angular Momentum

    DTIC Science & Technology

    2014-11-16

    AFRL-RD-PS- AFRL-RD-PS TR-2014-0045 TR-2014-0045 Novel Detection of Optical Orbital Angular Momentum David Voelz Klipsch...Orbital Angular Momentum FA9451-13-1-0261 GR0004113 David Voelz Klipsch School of ECE New Mexico State University MSC 3-O, PO Box 30001 Las Cruces, NM...1026 . Government Purpose Rights. A light beam carry Orbital Angular Momentum (OAM) has typical wave front and singularity at the optical axis. The

  17. Large capacity cryopropellant orbital storage facility

    NASA Technical Reports Server (NTRS)

    Schuster, J. R.

    1987-01-01

    A comprehensive study was performed to develop the major features of a large capacity orbital propellant storage facility for the space-based cryogenic orbital transfer vehicle. Projected propellant usage and delivery schedules can be accommodated by two orbital tank sets of 100,000 lb storage capacity, with advanced missions expected to require increased capacity. Information is given on tank pressurization schemes, propellant transfer configurations, pump specifications, the refrigeration system, and flight tests.

  18. Simulator Study of Lunar Orbit Establishment

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Simulator Study of Lunar Orbit Establishment. The film was made using the Lunar Orbit and Landing Approach Simulator (LOLA). It represents the view an astronaut would see if he were looking toward the lunar horizon just prior to and during retrofire for orbit establishment. During this period the astronaut is essentially flying backward, therefore the lunar surface features appear to be moving away during the flight. [Entire movie available on DVD from CASI as Doc ID 20070030976. Contact help@sti.nasa.gov

  19. Numerical Study of Orbital Trajectories about Phobos

    DTIC Science & Technology

    1988-12-01

    COF NUMERICAL STUDY OF ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Robert B. Teets Captain, USAF AFIT/GS0/AA/8 8D- 16 ..................D TIC SELECTEh...ful em t%... . 𔄂 9 ... 3 ...29 ...058_... AFIT/GSO/AA/88D-16 0 NUMERICAL STUDY OF ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Robert B. Teets Captain...ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Presented to the Faculty of the School of Engineering of the Air Force Institute of Technology Air University In

  20. Computed tomography of the eye and orbit

    SciTech Connect

    Hammerschlag, S.B.; Hesselink, J.R.; Weber, A.L.

    1982-01-01

    This book is the product of the evolution of computed tomography (CT) into subspecialization and the need for one source of information for the busy radiologist. The authors have succeeded in providing a readable overview of orbital CT as well as a reference book. The book is divided into seven major catagories of pathology (Neurofibromatosis, Primary Orbital Neoplasms, Secondary and Metastic Tumors of the Orbit, Vascular Disorders, Inflammatory Disease, Occular Lesions, and Trauma) after separate discussions of anatomy and technique.

  1. Perturbed Radius of Geosynchronous-Satellite Orbit

    NASA Astrophysics Data System (ADS)

    Kawase, Sei-Ichiro

    We analyze theoretically how the radius of geosynchronous orbits would vary owing to the perturbations due to the sun/moon gravity, solar radiation pressure, and the oblate earth. The analysis is simple, as it uses a diagrammatic method to solve near-circular orbital motions. Results are obtained in seven terms of corrections to the radius of non-perturbed ideal orbits. Each correction term is derived, with clear physical meaning, from each component of the perturbing forces.

  2. Orbital Debris and NASA's Measurement Program

    NASA Astrophysics Data System (ADS)

    Africano, J. L.; Stansbery, E. G.

    2002-05-01

    Since the launch of Sputnik in 1957, the number of manmade objects in orbit around the Earth has dramatically increased. The United States Space Surveillance Network (SSN) tracks and maintains orbits on over nine thousand objects down to a limiting diameter of about ten centimeters. Unfortunately, active spacecraft are only a small percentage ( ~ 7%) of this population. The rest of the population is orbital debris or ``space junk" consisting of expended rocket bodies, dead payloads, bits and pieces from satellite launches, and fragments from satellite breakups. The number of these smaller orbital debris objects increases rapidly with decreasing size. It is estimated that there are at least 130,000 orbital debris objects between one and ten centimeters in diameter. Most objects smaller than 10 centimeters go untracked! As the orbital debris population grows, the risk to other orbiting objects, most importantly manned space vehicles, of a collision with a piece of debris also grows. The kinetic energy of a solid 1 cm aluminum sphere traveling at an orbital velocity of 10 km/sec is equivalent to a 400 lb. safe traveling at 60 mph. Fortunately, the volume of space in which the orbiting population resides is large, collisions are infrequent, but they do occur. The Space Shuttle often returns to earth with its windshield pocked with small pits or craters caused by collisions with very small, sub-millimeter-size pieces of debris (paint flakes, particles from solid rocket exhaust, etc.), and micrometeoroids. To get a more complete picture of the orbital-debris environment, NASA has been using both radar and optical techniques to monitor the orbital debris environment. This paper gives an overview of the orbital debris environment and NASA's measurement program.

  3. Spontaneous orbital subcutaneous emphysema after sneezing.

    PubMed

    Chiu, Wei-Chieh; Lih, Ma; Huang, Tien-Yi; Ku, Wan-Chen; Wang, Warren

    2008-03-01

    Orbital subcutaneous emphysema develops when air enters the surrounding soft tissue. This occurs as a result facial bone trauma, iatrogenic dental and otolaryngeal procedures, and gas-producing infectious microorganisms. Case reports regarding this phenomenon after sneezing are very uncommon. Although orbital subcutaneous emphysema is not a true emergency, it can be distressful to patients. This case serves to bring awareness to emergency department physicians regarding the possibility of a nontraumatic orbital subcutaneous emphysema and its related complications.

  4. The Orbital Maneuvering Vehicle - A new capability

    NASA Technical Reports Server (NTRS)

    Arcilesi, Charles J.; Holliman, Charles T.

    1988-01-01

    NASA's Orbital Maneuvering Vehicle (OMV) is a reusable remotely-controlled spacecraft for support of orbiting platforms through such functions as satellite delivery, satellite retrieval, satellite reboost, controlled satellite deorbit, satellite inspection, and subsatellite missions. The OMV will be a critical component of the Space Station program's operational scenario; it will be able to operate either from the Space Shuttle Orbiter or the Space Station, and can also be space-based. The maiden flight of the first OMV is projected for 1993.

  5. Orbital Debris: Cost Impact on Setting Policy.

    DTIC Science & Technology

    1996-06-01

    As the exploration of space increases, the problems associated with orbital debris also increase. 0rbital debris continues to grow at a linear rate...and at worst, unusable. When mitigating orbital debris , cost and policy issues must be addressed. Currently no policy exists that makes the mitigation...of orbital debris mandatory but it only strongly recommends mitigation as long as it is cost effective. This thesis addresses the cost impact of

  6. Optimizing Orbital Debris Monitoring with Optical Telescopes

    DTIC Science & Technology

    2010-09-01

    Continued growth in the orbital debris population has renewed concerns over the long-term use of space. Debris poses an increasing risk to manned...in a catalog. Passive optical systems hold great promise to provide a cost-effective means to monitor orbital debris . Recent advances in optical...non-tracking mode for uncued debris detection. The governing radiometric equations for sensing orbital debris are developed, illustrating the

  7. Growth and development of the orbit.

    PubMed

    Berger, Aaron J; Kahn, David

    2012-11-01

    Every surgeon operating on the face, and particularly around the eye, should possess a working knowledge of the critical details related to development of the human orbit and recognized changes that occur during the course of aging. The anatomy of the orbit and periorbital region is complex, and the diagnosis and treatment of patients with orbital/periorbital disease requires expertise in congenital differences and awareness of the changes that occur as individuals age.

  8. ORBE: Orbital integrator for educational purposes

    NASA Astrophysics Data System (ADS)

    Gallardo, Tabare

    2017-02-01

    ORBE performs numerical integration of an arbitrary planetary system composed by a central star and up to 100 planets and minor bodies. ORBE calculates the orbital evolution of a system of bodies by means of the computation of the time evolution of their orbital elements. It is easy to use and is suitable for educational use by undergraduate students in the classroom as a first approach to orbital integrators.

  9. Preliminary constraints on the location of the recently hypothesized new planet of the Solar System from planetary orbital dynamics

    NASA Astrophysics Data System (ADS)

    Iorio, Lorenzo

    2017-01-01

    It has been recently proposed that the observed grouping of either the perihelia and the orbital planes of some observed distant Kuiper Belt Objects (KBOs) can be explained by the shepherding influence of a remote (150 au≲ qX≲350 au), still unseen massive object PX having planetary size (5 m_{oplus} ≲ mX≲20 m_{oplus}) and moving along an ecliptically inclined (22 deg≲ IX≲ 40 deg), eccentric (380 au≲ aX ≲980 au) Heliocentric bound orbit located in space at 80 deg≲ΩX≲120 deg and which is anti-aligned (120 deg≲ω_{ X}≲160 deg) with those of the considered KBOs. The trajectory of Saturn is nowadays known at essentially the same accuracy level of the inner planets due to the telemetry of the Cassini spacecraft. Thus, the expected perturbations dot{π}, dot{Ω} due to PX on the Kronian apsidal and draconitic orbital motions are theoretically investigated to tentatively constrain the configuration space of PX itself. To this aim, we compare our predictions dot{π}_{theo}, dot{Ω}_{theo} to the currently available experimental intervals of values Δdot{Ω}_{obs}, Δdot{π}_{ obs} determined by astronomers in the recent past without explicitly modeling and solving for PX itself. As such, our results, despite being plausible and in agreement to a large extent with other constraints released in the literature, should be regarded as proof-of-principle investigations aimed to encourage more accurate analyses in future. It turns out that the admissible region in its configuration space is moderately narrow as far as its position along its orbit, reckoned by the true anomaly fX, is concerned, being concentrated around approximately 130 deg≲ f X≲240 deg. PX is certainly far from its perihelion (fX=0 deg), in agreement with other recent studies. The future analysis of the data from the ongoing New Horizons mission might be helpful in further constraining the scenario considered here for PX. Its impact on the spacecraft's range over a multi-year span is

  10. COMET C/2011 W3 (LOVEJOY): ORBIT DETERMINATION, OUTBURSTS, DISINTEGRATION OF NUCLEUS, DUST-TAIL MORPHOLOGY, AND RELATIONSHIP TO NEW CLUSTER OF BRIGHT SUNGRAZERS

    SciTech Connect

    Sekanina, Zdenek; Chodas, Paul W. E-mail: Paul.W.Chodas@jpl.nasa.gov

    2012-10-01

    We describe the physical and orbital properties of C/2011 W3. After surviving perihelion passage, the comet was observed to undergo major physical changes. The permanent loss of the nuclear condensation and the formation of a narrow spine tail were observed first at Malargue, Argentina, on December 20 and then systematically at Siding Spring, Australia. The process of disintegration culminated with a terminal fragmentation event on December 17.6 UT. The postperihelion dust tail, observed for {approx}3 months, was the product of activity over <2 days. The nucleus' breakup and crumbling were probably caused by thermal stress due to the penetration of the intense heat pulse deep into the nucleus' interior after perihelion. The same mechanism may be responsible for cascading fragmentation of sungrazers at large heliocentric distances. The delayed response to the hostile environment in the solar corona is at odds with the rubble-pile model, since the residual mass of the nucleus, estimated at {approx}10{sup 12} g (equivalent to a sphere 150-200 m across) just before the terminal event, still possessed nontrivial cohesive strength. The high production rates of atomic oxygen, observed shortly after perihelion, are compatible with a subkilometer-sized nucleus. The spine tail-the product of the terminal fragmentation-was a synchronic feature, whose brightest part contained submillimeter-sized dust grains, released at velocities of up to 30 m s{sup -1}. The loss of the nuclear condensation prevented an accurate orbital-period determination by traditional techniques. Since the missing nucleus must have been located on the synchrone, whose orientation and sunward tip have been measured, we compute the astrometric positions of this missing nucleus as the coordinates of the points of intersection of the spine tail's axis with the lines of forced orbital-period variation, derived from the orbital solutions based on high-quality preperihelion astrometry from the ground. The

  11. Comet C/2011 W3 (Lovejoy): Orbit Determination, Outbursts, Disintegration of Nucleus, Dust-tail Morphology, and Relationship to New Cluster of Bright Sungrazers

    NASA Astrophysics Data System (ADS)

    Sekanina, Zdenek; Chodas, Paul W.

    2012-10-01

    We describe the physical and orbital properties of C/2011 W3. After surviving perihelion passage, the comet was observed to undergo major physical changes. The permanent loss of the nuclear condensation and the formation of a narrow spine tail were observed first at Malargue, Argentina, on December 20 and then systematically at Siding Spring, Australia. The process of disintegration culminated with a terminal fragmentation event on December 17.6 UT. The postperihelion dust tail, observed for ~3 months, was the product of activity over <2 days. The nucleus' breakup and crumbling were probably caused by thermal stress due to the penetration of the intense heat pulse deep into the nucleus' interior after perihelion. The same mechanism may be responsible for cascading fragmentation of sungrazers at large heliocentric distances. The delayed response to the hostile environment in the solar corona is at odds with the rubble-pile model, since the residual mass of the nucleus, estimated at ~1012 g (equivalent to a sphere 150-200 m across) just before the terminal event, still possessed nontrivial cohesive strength. The high production rates of atomic oxygen, observed shortly after perihelion, are compatible with a subkilometer-sized nucleus. The spine tail—the product of the terminal fragmentation—was a synchronic feature, whose brightest part contained submillimeter-sized dust grains, released at velocities of up to 30 m s-1. The loss of the nuclear condensation prevented an accurate orbital-period determination by traditional techniques. Since the missing nucleus must have been located on the synchrone, whose orientation and sunward tip have been measured, we compute the astrometric positions of this missing nucleus as the coordinates of the points of intersection of the spine tail's axis with the lines of forced orbital-period variation, derived from the orbital solutions based on high-quality preperihelion astrometry from the ground. The resulting orbit gives 698

  12. NASA Orbiter Extended Nose Landing Gear

    NASA Technical Reports Server (NTRS)

    King, Steven R.; Jensen, Scott A.; Hansen, Christopher P.

    1999-01-01

    This paper discusses the design, development, test, and evaluation of a prototype Extended Nose Landing Gear (ENLG) for NASA's Space Shuttle orbiters. The ENLG is a proposed orbiter modification developed in-house at NASA's Johnson Space Center (JSC) by a joint government/industry team. It increases the orbiter's nose landing gear (NLG) length, thereby changing the vehicle's angle of attack during rollout, which lowers the aerodynamic forces on the vehicle. This, in combination with a dynamic elevon change, will lower the loads on the orbiter's main landing gear (MLG). The extension is accomplished by adding a telescoping section to the current NLG strut that will be pneumatically extended during NLG deployment.

  13. Payload/orbiter contamination control assessment support

    NASA Technical Reports Server (NTRS)

    Rantanen, R. O.; Ress, E. B.

    1975-01-01

    The development and use is described of a basic contamination mathematical model of the shuttle orbiter which incorporates specific shuttle orbiter configurations and contamination sources. These configurations and sources were evaluated with respect to known shuttle orbiter operational surface characteristics and specific lines-of-sight which encompass the majority of viewing requirements for shuttle payloads. The results of these evaluations are presented as summary tables for each major source. In addition, contamination minimization studies were conducted and recommendations are made, where applicable, to support the shuttle orbiter design and operational planning for those sources which were identified to present a significant contamination threat.

  14. New concepts for Mercury orbiter missions

    NASA Technical Reports Server (NTRS)

    French, J. R.; Stuart, J. R.; Zeldin, B.

    1978-01-01

    The next logical step in the exploration of Mercury is an orbiter mission. A conflict exists between those in the field of planetary sciences who desire a mission with a low circular orbit, and scientists in the fields and particles disciplines, who generally prefer a highly elliptical spacecraft orbit. The thermal environment imposed by the sun and planet render the low orbit intolerable for spacecraft using previous thermal control methods. A thermal control concept and a spacecraft mission concept have been developed which resolve these problems and promise a scientifically significant mission for the mid-1980s.

  15. The accuracy of Halley's cometary orbits

    NASA Astrophysics Data System (ADS)

    Hughes, D. W.

    The accuracy of a scientific computation depends in the main on the data fed in and the analysis method used. This statement is certainly true of Edmond Halley's cometary orbit work. Considering the 420 comets that had been seen before Halley's era of orbital calculation (1695 - 1702) only 24, according to him, had been observed well enough for their orbits to be calculated. Two questions are considered in this paper. Do all the orbits listed by Halley have the same accuracy? and, secondly, how accurate was Halley's method of calculation?

  16. Improved orbiter waste collection system study

    NASA Technical Reports Server (NTRS)

    Bastin, P. H.

    1984-01-01

    Design concepts for improved fecal waste collection both on the space shuttle orbiter and as a precursor for the space station are discussed. Inflight usage problems associated with the existing orbiter waste collection subsystem are considered. A basis was sought for the selection of an optimum waste collection system concept which may ultimately result in the development of an orbiter flight test article for concept verification and subsequent production of new flight hardware. Two concepts were selected for orbiter and are shown in detail. Additionally, one concept selected for application to the space station is presented.

  17. Sun-synchronous satellite orbit determination

    NASA Astrophysics Data System (ADS)

    Ma, Der-Ming; Zhai, Shen-You

    2004-02-01

    The linearized dynamic equations used for on-board orbit determination of Sun-synchronous satellite are derived. Sun-synchronous orbits are orbits with the secular rate of the right ascension of the ascending node equal to the right ascension rate of the mean sun. Therefore the orbit is no more a closed circle but a tight helix about the Earth. In the paper, instead of treating the orbit as a closed circle, the actual helix orbit is taken as nominal trajectory. The details of the linearized equations of motion for the satellite in the Sun-synchronous orbit are derived. The linearized equations are obtained by perturbing the Keplerian motion with the J2 correction and the effect of sun's attraction being neglected. Combined with the GPS navigation equations, the Kalman filter formulation is given. The particular application considered is the circular Sun-synchronous orbit with the altitude of 800 km and inclination of 98.6°. The numerical example simulated by MATLAB® shows that only the pseudo-range data used in the algorithm still gives acceptable results. Based on the simulation results, we can use the on-board GPS receivers' signal only as an alternative to determine the orbit of Sun-Synchronous satellite and therefore circumvents the need for extensive ground support.

  18. GPS as an orbit determination subsystems

    NASA Technical Reports Server (NTRS)

    Fennessey, Richard; Roberts, Pat; Knight, Robin; Vanvolkinburg, Bart

    1995-01-01

    This paper evaluates the use of Global Positioning System (GPS) receivers as a primary source of tracking data for low-Earth orbit satellites. GPS data is an alternative to using range, azimuth, elevation, and range-rate (RAER) data from the Air Force Satellite Control Network antennas, the Space Ground Link System (SGLS). This evaluation is applicable to missions such as Skipper, a joint U.S. and Russian atmosphere research mission, that will rely on a GPS receiver as a primary tracking data source. The Detachment 2, Space and Missile Systems Center's Test Support Complex (TSC) conducted the evaluation based on receiver data from the Space Test Experiment Platform Mission O (STEP-O) and Advanced Photovoltaic and Electronics Experiments (APEX) satellites. The TSC performed orbit reconstruction and prediction on the STEP-0 and APEX vehicles using GPS receiver navigation solution data, SGLS RAER data, and SGLS anglesonly (azimuth and elevation) data. For the STEP-O case, the navigation solution based orbits proved to be more accurate than SGLS RAER based orbits. For the APEX case, navigation solution based orbits proved to be less accurate than SGLS RAER based orbits for orbit prediction, and results for orbit reconstruction were inconclusive due to the lack of a precise truth orbit. After evaluating several different GPS data processing methods, the TSC concluded that using GPS navigation solution data is a viable alternative to using SGLS RAER data.

  19. On-Orbit Compressor Technology Program

    NASA Technical Reports Server (NTRS)

    Deffenbaugh, Danny M.; Svedeman, Steven J.; Schroeder, Edgar C.; Gerlach, C. Richard

    1990-01-01

    A synopsis of the On-Orbit Compressor Technology Program is presented. The objective is the exploration of compressor technology applicable for use by the Space Station Fluid Management System, Space Station Propulsion System, and related on-orbit fluid transfer systems. The approach is to extend the current state-of-the-art in natural gas compressor technology to the unique requirements of high-pressure, low-flow, small, light, and low-power devices for on-orbit applications. This technology is adapted to seven on-orbit conceptual designs and one prototype is developed and tested.

  20. Simple Theory of Geosynchronous-Orbit Perturbations

    NASA Astrophysics Data System (ADS)

    Kawase, Sei-Ichiro

    A simple perturbation theory is introduced for modeling geosynchronous orbits. The theory uses diagrammatic representations of orbits, and derives the perturbations in a direct manner without using differential equations. Perturbations of major importance are derived, including satellite-longitude changes due to the earth’s asymmetric shape, orbital eccentricity increase due to the sun-radiation pressure, and orbital plane inclination due to the sun/moon attraction. The theory clarifies the physical/geometrical meaning of the perturbations while using minimal mathematical analysis.

  1. Space Shuttle Orbiter Approach and Landing Test

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The Approach and Landing Test Program consisted of a series of steps leading to the demonstration of the capability of the Space Shuttle orbiter to safely approach and land under conditions similar to those planned for the final phases of an orbital flight. The tests were conducted with the orbiter mounted on top of a specially modified carrier aircraft. The first step provided airworthiness and performance verification of the carrier aircraft after modification. The second step consisted of three taxi tests and five flight tests with an inert unmanned orbiter. The third step consisted of three mated tests with an active manned orbiter. The fourth step consisted of five flights in which the orbiter was separated from the carrier aircraft. For the final two flights, the orbiter tail cone was replaced by dummy engines to simulate the actual orbital configuration. Landing gear braking and steering tests were accomplished during rollouts following the free flight landings. Ferry testing was integrated into the Approach and Landing Test Program to the extent possible. In addition, four ferry test flights were conducted with the orbiter mated to the carrier aircraft in the ferry configuration after the free-flight tests were completed.

  2. Analysis of initial orbit determination accuracy

    NASA Astrophysics Data System (ADS)

    Vananti, Alessandro; Schildknecht, Thomas

    The Astronomical Institute of the University of Bern (AIUB) is conducting several search campaigns for orbital debris. The debris objects are discovered during systematic survey observations. In general only a short observation arc, or tracklet, is available for most of these objects. From this discovery tracklet a first orbit determination is computed in order to be able to find the object again in subsequent follow-up observations. The additional observations are used in the orbit improvement process to obtain accurate orbits to be included in a catalogue. In this paper, the accuracy of the initial orbit determination is analyzed. This depends on a number of factors: tracklet length, number of observations, type of orbit, astrometric error, and observation geometry. The latter is characterized by both the position of the object along its orbit and the location of the observing station. Different positions involve different distances from the target object and a different observing angle with respect to its orbital plane and trajectory. The present analysis aims at optimizing the geometry of the discovery observations depending on the considered orbit.

  3. A periodic table for black hole orbits

    SciTech Connect

    Levin, Janna; Perez-Giz, Gabe

    2008-05-15

    Understanding the dynamics around rotating black holes is imperative to the success of future gravitational wave observatories. Although integrable in principle, test-particle orbits in the Kerr spacetime can also be elaborate, and while they have been studied extensively, classifying their general properties has been a challenge. This is the first in a series of papers that adopts a dynamical systems approach to the study of Kerr orbits, beginning with equatorial orbits. We define a taxonomy of orbits that hinges on a correspondence between periodic orbits and rational numbers. The taxonomy defines the entire dynamics, including aperiodic motion, since every orbit is in or near the periodic set. A remarkable implication of this periodic orbit taxonomy is that the simple precessing ellipse familiar from planetary orbits is not allowed in the strong-field regime. Instead, eccentric orbits trace out precessions of multileaf clovers in the final stages of inspiral. Furthermore, for any black hole, there is some point in the strong-field regime past which zoom-whirl behavior becomes unavoidable. Finally, we sketch the potential application of the taxonomy to problems of astrophysical interest, in particular its utility for computationally intensive gravitational wave calculations.

  4. On-orbit coldwelding: Fact or friction?

    NASA Technical Reports Server (NTRS)

    Dursch, Harry; Spear, Steve

    1992-01-01

    A study into the potential of on-orbit coldwelding occurring was completed. No instances of cold welding were found during deintegration and subsequent testing and analysis of LDEF hardware. This finding generated wide interest and indicated the need to review previous on-orbit coldwelding experiments and on-orbit spacecraft anomalies to determine whether the absence of coldwelding on LDEF was to be expected. Results show that even though there have been no documented cases of significant on-orbit coldwelding events occurring, precautions should be taken to ensure that neither coldwelding nor galling occurs in the space or prelaunch environment.

  5. Orbital motion of the solar power satellite

    NASA Technical Reports Server (NTRS)

    Graf, O. F., Jr.

    1977-01-01

    A study on the effects of solar radiation pressure on the SPS orbit is documented. It was shown that the eccentricity of the orbit can increase from initially being zero. The SPS configuration is primarily considered but the results are applicable to any geosynchronous satellite that resembles a flat surface continually facing the sun. The orbital evolution of the SPS was investigated over its expected 30 year lifetime and the satellite was assumed to be in free flight. The satellite's motion was described with analytical formulae which could be used to develop an orbit control theory in order to minimize station keeping costs.

  6. Aerodynamic lift effect on satellite orbits

    NASA Technical Reports Server (NTRS)

    Karr, G. R.; Cleland, J. G.; Devries, L. L.

    1975-01-01

    Numerical quadrature is employed to obtain orbit perturbation results from the general perturbation equations. Both aerodynamic lift and drag forces are included in the analysis of the satellite orbit. An exponential atmosphere with and without atmospheric rotation is used. A comparison is made of the perturbations which are caused by atmospheric rotation with those caused by satellite aerodynamic effects. Results indicate that aerodynamic lift effects on the semi-major axis and orbit inclination can be of the same order as the effects of atmosphere rotation depending upon the orientation of the lift vector. The results reveal the importance of including aerodynamic lift effects in orbit perturbation analysis.

  7. SCIAMACHY In-orbit Operations until 2013

    NASA Astrophysics Data System (ADS)

    Gottwald, Manfred; Krieg, Eckhart; Lichtenberg, Günter; Noël, Stefan; Bramstedt, Klaus; Bovensmann, Heinrich

    In 2010 ENVISAT enters its next mission extension phase when a manoeuvre transfers the plat-form from its nominal into a modified orbit. This modified orbit is not only characterized by the lower altitude but also by slightly drifting parameters such as e.g. the inclination or the Mean Local Solar Time at ascending node crossing. Thus all SCIAMACHY measurements requiring an accurate pointing knowledge are affected. How the line-of-sight evolves along the orbit de-pends on orbit altitude and orbital period. Therefore adjustments to SCIAMACHY's on-board instrument configuration are necessary reflecting this orbit chance. Based on a detailed analysis simulating SCIAMACHY operations in the modified orbit until the end of 2013, the impacts on nadir, limb and solar and lunar occultation measurements when orbiting the Earth at a reduced altitude was studied. By modifying SCIAMACHY's configuration these impacts can be compensated for. Thus the current performance of instrument operations, including the pointing knowledge, can be maintained. It ensures acquisition of high quality measurement data for the entire duration of the mission. This presentation describes how the instrument will be configured for achieving successful operations until the end of 2013. In addition a brief outlook is given how the drifting modified orbit may impact an operations phase even beyond 2013 and potential corrective countermeasures.

  8. Orbital Operations for Phobos and Deimos Exploration

    NASA Technical Reports Server (NTRS)

    Wallace, Mark S.; Parker, Jeffrey S.; Strange, Nathan J.; Grebow, Daniel

    2012-01-01

    One of the deep-space human exploration activities proposed for the post-Shuttle era is a mission to one of the moons of Mars, Phobos or Deimos. There are several options available to the mission architect for operations around these bodies. These options include distant retrograde orbits (DROs), Lagrange-point orbits such as halos and Lyapunov orbits, and fixed-point stationkeeping or "hovering." These three orbit options are discussed in the context of the idealized circular restricted three body problem, full-dynamics propagations, and a concept of operations. The discussion is focused on Phobos, but all results hold for Deimos

  9. Determination of GPS orbits to submeter accuracy

    NASA Technical Reports Server (NTRS)

    Bertiger, W. I.; Lichten, S. M.; Katsigris, E. C.

    1988-01-01

    Orbits for satellites of the Global Positioning System (GPS) were determined with submeter accuracy. Tests used to assess orbital accuracy include orbit comparisons from independent data sets, orbit prediction, ground baseline determination, and formal errors. One satellite tracked 8 hours each day shows rms error below 1 m even when predicted more than 3 days outside of a 1-week data arc. Differential tracking of the GPS satellites in high Earth orbit provides a powerful relative positioning capability, even when a relatively small continental U.S. fiducial tracking network is used with less than one-third of the full GPS constellation. To demonstrate this capability, baselines of up to 2000 km in North America were also determined with the GPS orbits. The 2000 km baselines show rms daily repeatability of 0.3 to 2 parts in 10 to the 8th power and agree with very long base interferometry (VLBI) solutions at the level of 1.5 parts in 10 to the 8th power. This GPS demonstration provides an opportunity to test different techniques for high-accuracy orbit determination for high Earth orbiters. The best GPS orbit strategies included data arcs of at least 1 week, process noise models for tropospheric fluctuations, estimation of GPS solar pressure coefficients, and combine processing of GPS carrier phase and pseudorange data. For data arc of 2 weeks, constrained process noise models for GPS dynamic parameters significantly improved the situation.

  10. Mars Science Laboratory Orbit Determination

    NASA Technical Reports Server (NTRS)

    Kruizinga, Gerhard; Gustafson, Eric; Jefferson, David; Martin-Mur, Tomas; Mottinger, Neil; Pelletier, Fred; Ryne, Mark; Thompson, Paul

    2012-01-01

    Mars Science Laboratory (MSL) Orbit Determination (OD) met all requirements with considerable margin, MSL OD team developed spin signature removal tool and successfully used the tool during cruise, A novel approach was used for the MSL solar radiation pressure model and resulted in a very accurate model during the approach phase, The change in velocity for Attitude Control System (ACS) turns was successfully calibrated and with appropriate scale factor resulted in improved change in velocity prediction for future turns, All Trajectory Correction Maneuvers were successfully reconstructed and execution errors were well below the assumed pre-fight execution errors, The official OD solutions were statistically consistent throughout cruise and for OD solutions with different arc lengths as well, Only EPU-1 was sent to MSL. All other Entry Parameter Updates were waived, EPU-1 solution was only 200 m separated from final trajectory reconstruction in the B-plane

  11. Orbit IMU alignment: Error analysis

    NASA Technical Reports Server (NTRS)

    Corson, R. W.

    1980-01-01

    A comprehensive accuracy analysis of orbit inertial measurement unit (IMU) alignments using the shuttle star trackers was completed and the results are presented. Monte Carlo techniques were used in a computer simulation of the IMU alignment hardware and software systems to: (1) determine the expected Space Transportation System 1 Flight (STS-1) manual mode IMU alignment accuracy; (2) investigate the accuracy of alignments in later shuttle flights when the automatic mode of star acquisition may be used; and (3) verify that an analytical model previously used for estimating the alignment error is a valid model. The analysis results do not differ significantly from expectations. The standard deviation in the IMU alignment error for STS-1 alignments was determined to the 68 arc seconds per axis. This corresponds to a 99.7% probability that the magnitude of the total alignment error is less than 258 arc seconds.

  12. The orbital TUS detector simulation

    NASA Astrophysics Data System (ADS)

    Grinyuk, A.; Grebenyuk, V.; Khrenov, B.; Klimov, P.; Lavrova, M.; Panasyuk, M.; Sharakin, S.; Shirokov, A.; Tkachenko, A.; Tkachev, L.; Yashin, I.

    2017-04-01

    The TUS space experiment is aimed at studying energy and arrival distribution of UHECR at E > 7 × 1019 eV by using the data of EAS fluorescent radiation in atmosphere. The TUS mission was launched at the end of April 2016 on board the dedicated ;Lomonosov; satellite. The TUSSIM software package has been developed to simulate performance of the TUS detector for the Fresnel mirror optical parameters, the light concentrator of the photo detector, the front end and trigger electronics. Trigger efficiency crucially depends on the background level which varies in a wide range: from 0.2 × 106 to 15 × 106 ph/(m2 μ s sr) at moonless and full moon nights respectively. The TUSSIM algorithms are described and the expected TUS statistics is presented for 5 years of data collection from the 500 km solar-synchronized orbit with allowance for the variability of the background light intensity during the space flight.

  13. Airbreathing Acceleration Toward Earth Orbit

    SciTech Connect

    Whitehead, J C

    2007-05-09

    As flight speed increases, aerodynamic drag rises more sharply than the availability of atmospheric oxygen. The ratio of oxygen mass flux to dynamic pressure cannot be improved by changing altitude. The maximum possible speed for airbreathing propulsion is limited by the ratio of air capture area to vehicle drag area, approximately Mach 6 at equal areas. Simulation of vehicle acceleration shows that the use of atmospheric oxygen offers a significant potential for minimizing onboard consumables at low speeds. These fundamental calculations indicate that a practical airbreathing launch vehicle would accelerate to near steady-state speed while consuming only onboard fuel, then transition to rocket propulsion. It is suggested that an aircraft carrying a rocket-propelled vehicle to approximately Mach 5 could be a realistic technical goal toward improving access to orbit.

  14. International Space Station in Orbit

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of the International Space Station (ISS) was photographed by one of the crewmembers of the STS-105 mission from the Shuttle Orbiter Discovery after deparating from the ISS. The STS-105 mission was the 11th ISS assembly flight and its goals were the rotation of the ISS Expedition Two crew with the Expedition Three crew, and the delivery of supplies utilizing the Italian-built Multipurpose Logistics Module (MPLM) Leonardo. Aboard Leonardo were six resupply stowage racks, four resupply stowage supply platforms, and two new scientific experiment racks, EXPRESS (Expedite the Processing of Experiments to the Space Station) Racks 4 and 5, which added science capabilities to the ISS. Another payload was the Materials International Space Station Experiment (MISSE), which included materials and other types of space exposure experiments mounted on the exterior of the ISS.

  15. International Space Station in Orbit

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of the International Space Station (ISS) was photographed by one of the crewmembers of the STS-105 mission from the Shuttle Orbiter Discovery after separating from the ISS. The STS-105 mission was the 11th ISS assembly flight and its goals were the rotation of the ISS Expedition Two crew with Expedition Three crew, and the delivery of supplies utilizing the Italian-built Multipurpose Logistic Module (MPLM) Leonardo. Aboard Leonardo were six resupply stowage racks, four resupply stowage supply platforms, and two new scientific experiment racks, EXPRESS (Expedite the Processing of Experiments to the Space Station) Racks 4 and 5, which added science capabilities to the ISS. Another payload was the Materials International Space Station Experiment (MISSE), which included materials and other types of space exposure experiments mounted on the exterior of the ISS.

  16. Mars Observer Orbit Insertion Briefing

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Steve Wall is the host of this video entitled, "Return to the Red Planet". Live animation of the Mars Observer orbiting Mars is presented. Steve Wall explains the spacecraft insertion maneuver and also explains the purpose for the Mars Observer launch. Live coverage of the Cape Canaveral launch of the Mars Observer is also presented. Suzanne Dodd, Chief of the Mission Planning team describes the burn start and how the spacecraft will be captured by Mars' gravity. Glenn Cunningham, Mars Observer Project Manager, gives background information on the Mars Observer and describes the organizations behind the Mars Observer Spacecraft, such as the Deep Space Network, the Mission Operation Support Office, Science Investigators, the Flight Engineering Office, Operations Office, and the Ground Data System Office. Dr. William Piotrowski, Acting Director, Solar System Exploration Division, NASA, talks about the purpose of the Mars Pathfinder which is to develop the technology and systems for landing small science packages on Mars. Mr. Roger Gibbs, Former Mars Observer Spacecraft Systems Engineer, tells us how the Mars Observer was built and describes the structural elements on the Mars Observer. The 11-month cruise period for the spacecraft is given by Joseph Beerer, Manager of the Engineering office. The thrust for the Mars Orbit Insertion is described by Ronald Klemetson, Technical Manager, Propulsion Subsystem Jet Propulsion Laboratory (JPL). George Chen, Lead Engineer Attitude and Articulation Subsystem Spacecraft Team, explains the importance of the attitude control engines on the Spacecraft. Marvin Traxler, Manager of Tracking and Data Acquisition, describes how searching for a signal from the Mars Observer works. See NONP-NASA-VT-2000081555 for a continuation of this discussion with Marvin Traxler.

  17. Orbit determination singularities in the Doppler tracking of a planetary orbiter

    NASA Technical Reports Server (NTRS)

    Wood, L. J.

    1985-01-01

    On a number of occasions, spacecraft launched by the U.S. have been placed into orbit about the moon, Venus, or Mars. It is pointed out that, in particular, in planetary orbiter missions two-way coherent Doppler data have provided the principal data type for orbit determination applications. The present investigation is concerned with the problem of orbit determination on the basis of Doppler tracking data in the case of a spacecraft in orbit about a natural body other than the earth or the sun. Attention is given to Doppler shift associated with a planetary orbiter, orbit determination using a zeroth-order model for the Doppler shift, and orbit determination using a first-order model for the Doppler shift.

  18. Measurements of the STS orbiter's angular stability during in-orbit operations

    NASA Technical Reports Server (NTRS)

    Neupert, Werner M.; Epstein, Gabriel L.; Houston, James; Zarechnak, Andrew

    1995-01-01

    We report on measurements of the angular stability, commonly called 'jitter', of the STS Orbiter during normal operations in space. Measurements were carried out by measuring optically the Orbiter's roll and pitch orientation relative to the solar vector as the orbiter was held in a -Z(sub 0) solar inertial orientation (orbiter bay oriented toward the Sun). We also report observations of an interesting perturbation to the orbiter's orientation noted by the crew during the STS-60 mission. These data may be useful in analyzing the in-orbit response of the Orbiter to thruster firings and other applied torques, and may aid in the planning of future experiments that require fine-pointed operations by the orbiter.

  19. Orbits Close to Asteroid 4769 Castalia

    NASA Technical Reports Server (NTRS)

    Scheeres, D. J.; Ostro, S. J.; Hudson, R. S.; Werner, R. A.

    1996-01-01

    We use a radar-derived physical model of 4769 Castalia (1989 PB) to investigate close orbit dynamics around that kilometer- sized, uniformly rotating asteroid. Our methods of analysis provide a basis for systematic studies of particle dynamics close to any uniformly rotating asteroid. We establish that a Jacobi integral exists for particles orbiting this asteroid, examine the attendant zero-velocity surfaces, find families of periodic orbits, and determine their stability. All synchronous orbits and direct orbits within approx. 3 mean radii of Castalia are unstable and are subject to impact or escape from Castalia. Retrograde orbits are mostly stable and allow particles to orbit close to the asteroid surface. We derive a model which allows us to predict the escape conditions of a particle in orbit about Castalia and the (temporary) capture conditions for a hyperbolic interloper. Orbits within 1.5 km of Castalia are subject to immediate ejection from the system. Hyperbolic orbits with a V(sub infinity) less than 0.4 m/sec can potentially be captured by Castalia if their periapsis radius Is within approx. 2 km. For Castalia this capture region is small, but the results also apply to larger asteroids whose capture regions would also be larger. We determine bounds on ejecta speeds which either ensure ejecta escape or re-impact as functions of location on Castalia's surface. The speeds that ensure escape range from 0.28 to 0.84 m/sec and the speeds that ensure re-impact range from 0 to 0.18 m/sec. Speeds between these two bounds lead either to escape, re-impact, or potentially finite-time stable orbits. We develop a simple criterion which can establish whether a particle could have been ejected from the asteroid in the past and if it will impact the surface in the future.

  20. Small Orbital Stereo Tracking Camera Technology Development

    NASA Technical Reports Server (NTRS)

    Bryan, Tom; MacLeod, Todd; Gagliano, Larry

    2016-01-01

    On-Orbit Small Debris Tracking and Characterization is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crew. This poses a major risk of MOD damage to ISS and Exploration vehicles. In 2015 this technology was added to NASA's Office of Chief Technologist roadmap. For missions flying in or assembled in or staging from LEO, the physical threat to vehicle and crew is needed in order to properly design the proper level of MOD impact shielding and proper mission design restrictions. Need to verify debris flux and size population versus ground RADAR tracking. Use of ISS for In-Situ Orbital Debris Tracking development provides attitude, power, data and orbital access without a dedicated spacecraft or restricted operations on-board a host vehicle as a secondary payload. Sensor Applicable to in-situ measuring orbital debris in flux and population in other orbits or on other vehicles. Could enhance safety on and around ISS. Some technologies extensible to monitoring of extraterrestrial debris as well To help accomplish this, new technologies must be developed quickly. The Small Orbital Stereo Tracking Camera is one such up and coming technology. It consists of flying a pair of intensified megapixel telephoto cameras to evaluate Orbital Debris (OD) monitoring in proximity of International Space Station. It will demonstrate on-orbit optical tracking (in situ) of various sized objects versus ground RADAR tracking and small OD models. The cameras are based on Flight Proven Advanced Video Guidance Sensor pixel to spot algorithms (Orbital Express) and military targeting cameras. And by using twin cameras we can provide Stereo images for ranging & mission redundancy. When pointed into the orbital velocity vector (RAM), objects approaching or near the stereo camera set can be differentiated from the stars moving upward in background.

  1. Small Orbital Stereo Tracking Camera Technology Development

    NASA Technical Reports Server (NTRS)

    Bryan, Tom; Macleod, Todd; Gagliano, Larry

    2015-01-01

    On-Orbit Small Debris Tracking and Characterization is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crew. This poses a major risk of MOD damage to ISS and Exploration vehicles. In 2015 this technology was added to NASA's Office of Chief Technologist roadmap. For missions flying in or assembled in or staging from LEO, the physical threat to vehicle and crew is needed in order to properly design the proper level of MOD impact shielding and proper mission design restrictions. Need to verify debris flux and size population versus ground RADAR tracking. Use of ISS for In-Situ Orbital Debris Tracking development provides attitude, power, data and orbital access without a dedicated spacecraft or restricted operations on-board a host vehicle as a secondary payload. Sensor Applicable to in-situ measuring orbital debris in flux and population in other orbits or on other vehicles. Could enhance safety on and around ISS. Some technologies extensible to monitoring of extraterrestrial debris as well to help accomplish this, new technologies must be developed quickly. The Small Orbital Stereo Tracking Camera is one such up and coming technology. It consists of flying a pair of intensified megapixel telephoto cameras to evaluate Orbital Debris (OD) monitoring in proximity of International Space Station. It will demonstrate on-orbit optical tracking (in situ) of various sized objects versus ground RADAR tracking and small OD models. The cameras are based on Flight Proven Advanced Video Guidance Sensor pixel to spot algorithms (Orbital Express) and military targeting cameras. And by using twin cameras we can provide Stereo images for ranging & mission redundancy. When pointed into the orbital velocity vector (RAM), objects approaching or near the stereo camera set can be differentiated from the stars moving upward in background.

  2. Small Orbital Stereo Tracking Camera Technology Development

    NASA Astrophysics Data System (ADS)

    Gagliano, L.; Bryan, T.; MacLeod, T.

    On-Orbit Small Debris Tracking and Characterization is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crew. This poses a major risk of MOD damage to ISS and Exploration vehicles. In 2015 this technology was added to NASAs Office of Chief Technologist roadmap. For missions flying in or assembled in or staging from LEO, the physical threat to vehicle and crew is needed in order to properly design the proper level of MOD impact shielding and proper mission design restrictions. Need to verify debris flux and size population versus ground RADAR tracking. Use of ISS for In-Situ Orbital Debris Tracking development provides attitude, power, data and orbital access without a dedicated spacecraft or restricted operations on-board a host vehicle as a secondary payload. Sensor Applicable to in-situ measuring orbital debris in flux and population in other orbits or on other vehicles. Could enhance safety on and around ISS. Some technologies extensible to monitoring of extraterrestrial debris as well To help accomplish this, new technologies must be developed quickly. The Small Orbital Stereo Tracking Camera is one such up and coming technology. It consists of flying a pair of intensified megapixel telephoto cameras to evaluate Orbital Debris (OD) monitoring in proximity of International Space Station. It will demonstrate on-orbit optical tracking (in situ) of various sized objects versus ground RADAR tracking and small OD models. The cameras are based on Flight Proven Advanced Video Guidance Sensor pixel to spot algorithms (Orbital Express) and military targeting cameras. And by using twin cameras we can provide Stereo images for ranging & mission redundancy. When pointed into the orbital velocity vector (RAM), objects approaching or near the stereo camera set can be differentiated from the stars moving upward in background.

  3. Orbital hematoma caused by bleeding from orbital branch of the infraorbital artery after reconstruction of an orbital fracture.

    PubMed

    Hwang, Kun; Kim, Joo Ho; Kang, Young Hye

    2014-03-01

    We experienced and report on a case of retrobulbar hematoma caused by bleeding from the orbital branch of the infraorbital artery after a medial orbital wall reconstruction.A healthy 28-year-old man struck his left eye while playing baseball before admission. A computed tomographic scan revealed an approximately 13 × 12-mm-sized fracture of the left orbit medial wall. The medial orbit wall was reconstructed through a subciliary approach on the 18th day after the injury. Approximately 15 hours after the orbit wall reconstruction, the patient complained of pain in the left orbital area, headache, and vomiting. Upon an examination, swelling and ecchymosis were observed on the left eye. His visual acuity was 0.8 (oculus dexter [OD])/0.4 (oculus sinister [OS]) and the intraocular pressure was 18 (OD)/24 (OS) mm Hg by a Goldmann applanation tonometry. A computed tomographic scan showed an intraorbital hematoma and proptosis on the left side. In an emergency operation, a hematoma with a volume of approximately 2 to 3 mL was evacuated and an active bleeding point was noted on the orbital floor, which was thought to be the orbital branch of the infraorbital nerve. The bleeding point was cauterized. After the operation, his visual acuity was 1.0 (OD)/0.8 (OS) and the ocular pressure normalized to 16 (OD)/16 (OS) mm Hg by a Goldmann applanation tonometry.Close observation and meticulous hemostasis along the infraorbital groove may be needed in an orbital floor exploration to prevent postoperative orbital hematoma.

  4. Predictability in orbital reconstruction: A human cadaver study. Part II: Navigation-assisted orbital reconstruction.

    PubMed

    Dubois, Leander; Schreurs, Ruud; Jansen, Jesper; Maal, Thomas J J; Essig, Harald; Gooris, Peter J J; Becking, Alfred G

    2015-12-01

    Preformed orbital reconstruction plates are useful for treating orbital defects. However, intraoperative errors can lead to misplaced implants and poor outcomes. Navigation-assisted surgery may help optimize orbital reconstruction. We aimed to explore whether navigation-assisted surgery is more predictable than traditional orbital reconstruction for optimal implant placement. Pre-injury computed tomography scans were obtained for 10 cadaver heads (20 orbits). Complex orbital fractures (Class III-IV) were created in all orbits, which were reconstructed using a transconjunctival approach with and without navigation. The best possible fit of the stereolithographic file of a preformed orbital mesh plate was used as the optimal position for reconstruction. The accuracy of the implant positions was evaluated using iPlan software. The consistency of orbital reconstruction was lower in the traditional reconstructions than in the navigation group in the parameters of translation and rotation. Implant position also differed significantly in the parameters of translation (p = 0.002) and rotation (pitch: p = 0.77; yaw: p < 0.001; roll: p = 0.001). Compared with traditional orbital reconstruction, navigation-assisted reconstruction provides more predictable anatomical reconstruction of complex orbital defects and significantly improves orbital implant position.

  5. Atomic Orbitals, Molecular Orbitals and Related Concepts: Conceptual Difficulties among Chemistry Students.

    ERIC Educational Resources Information Center

    Tsaparlis, Georgios

    1997-01-01

    Investigates the impact an undergraduate quantum chemistry course has on students' knowledge and understanding of atomic orbitals, molecular orbitals, and related concepts. Analysis reveals that students do not have a clear understanding of these concepts and confuse the various atomic orbital representations. Includes some suggestions and…

  6. Orbital angular momentum: a personal memoir.

    PubMed

    Allen, L

    2017-02-28

    A definitive statement of the model used to describe orbital angular momentum is essentially now available. Its early history, and the interaction of those who played key roles in its development over 20 years ago in its development, is outlined in this Memoir.This article is part of the themed issue 'Optical orbital angular momentum'.

  7. Orbital dissection defatting technique for Graves disease.

    PubMed

    Hecht, S D; Guibor, P; Wolfley, D; Wiggs, E O

    1984-04-01

    Five patients with Graves disease and bilateral proptosis were treated with different incisional approaches. They all underwent orbital decompression by removal of the anterior medial orbital walls, the anterior ethmoidal sinuses, the orbital floors, and multiple incisions of the orbital periosteums . The defatting technique, which consists of applying manual anterior orbital pressure with alternate removing of small lobules of fat, was added when it was intraoperatively decided by Hertel exophthalmometer measurement that more decompression was needed. It is estimated that one-third more reduction in proptosis resulted. An average total decrease in proptosis of 9 mm per orbit occurred. Both visual accuities and visual fields returned to normal. The only important complication was the development of hypertropia in down gaze in one patient. A potential value of this technique is its use with orbital floor decompression alone. It may be possible to avoid removing the medial and lateral walls of the orbit, thereby decreasing complications. Defatting may also be a valuable addition in those rare cases where all decompression techniques available are needed to affect an adequate decompression.

  8. Guidance for an aeroassisted orbital transfer vehicle

    NASA Technical Reports Server (NTRS)

    Hall, Kenneth R.

    1988-01-01

    The use of atmospheric drag for slowing satellite in high energy, high apogee orbits to a lower energy, lower apogee orbit about the Earth is investigated. The high energy orbit is assumed to intercept the Earth's atmosphere. Guidance for the atmospheric phase of the trajectory may be done using the aerodynamic forces generated by the passage through the atmosphere. This research was concerned with the investigation of several methods of guidance during the atmospheric phase to cause a significant reduction in the final velocity as the vehicle leaves the atmosphere. In addition, the velocity direction was controlled to exit to a desired target orbit. Lastly excess aerodynamic lift was used to effect a plane change between the entry orbit plane and the exit orbit plane to achieve a desired orbit plane. The guidance methods were applied to a 3 degree-of-freedom simulation which included an oblate Earth gravity model and a rotating atmosphere. Simulation results were compared on the basis of speed of computation of the guidance parameters and amount of added velocity necessary to achieve the desired orbit.

  9. Space missions orbits around small worlds

    NASA Astrophysics Data System (ADS)

    Cardoso dos Santos, Josué; dos Santos Carvalho, Jean Paulo; Vilhena de Moraes, Rodolpho; Bertachini de Almeida Prado, Antônio Fernando

    2015-08-01

    Space missions under study to visit icy moons and small worlds in our solar system will requires orbits with low-altitude and high inclinations. These orbits provides a better coverage to map the surface and to analyse the gravitational and magnetic fields. In this context, obtain these orbits has become important in planning of these missions. Celestial bodies like Haumea, Europa, Ganymede, Callisto, Enceladus, Titan and Triton are among the objects under study study to receive missions in a near future. In order to obtain low-altitude and high inclined orbits for future exploration of these bodies, this work aims to present an analytical study to describe and evaluate gravitational disturbances over a spacecraft's orbit around a minor body. An analytical model for the third-body perturbation is presented. Perturbations due to the non-sphericity of the minor body are considered. The effects on spacecraft's orbital elements are analyzed to provide the the more useful and desired orbits. The dynamic of these orbits is explored by numerical simulations. The results present good accordance with the literature.

  10. Space shuttle orbiter test flight series

    NASA Technical Reports Server (NTRS)

    Garrett, D.; Gordon, R.; Jackson, R. B.

    1977-01-01

    The proposed studies on the space shuttle orbiter test taxi runs and captive flight tests were set forth. The orbiter test flights, the approach and landing tests (ALT), and the ground vibration tests were cited. Free flight plans, the space shuttle ALT crews, and 747 carrier aircraft crew were considered.

  11. Orbitals: Some Fiction and Some Facts

    ERIC Educational Resources Information Center

    Autschbach, Jochen

    2012-01-01

    The use of electron orbitals in quantum theory and chemistry is discussed. Common misconceptions are highlighted. Suggestions are made how chemistry educators may describe orbitals in the first and second year college curriculum more accurately without introducing unwanted technicalities. A comparison is made of different ways of graphically…

  12. On-Orbit Propulsion OMS/RCS

    NASA Technical Reports Server (NTRS)

    Hurlbert, Eric A.

    2001-01-01

    This slide presentation reviews the Space Shuttle's On-Orbit Propulsion systems: the Orbital Maneuvering System (OMS) and the Reaction Control System (RCS). The functions of each of the systems is described, and the diagrams of the systems are presented. The OMS/RCS thruster is detailed and a trade study comparison of non-toxic propellants is presented.

  13. SMM parallel battery operation in orbit

    NASA Technical Reports Server (NTRS)

    Broderick, R.

    1982-01-01

    A parallel battery system for the SMM spacecraft is described. The battery system performance as a function of lifetime over orbit was evaluated. The following equipment performance specifications were examined during a typical orbit: battery current and discharges, voltage limitations, battery temperature variations, and current sensor performance. Tabulated battery performance data is also included.

  14. A Catalog of Selected Viking Orbiter Images

    NASA Technical Reports Server (NTRS)

    Turner, R. L.; Carroll, R. D.

    1983-01-01

    This collection of Viking Orbiter photomosaics is designed to facilitate identification and location of the various pictures with respect to the surface of Mars. Only a representative set of the nearly 50,000 images taken by the two Viking Orbiters, and computer-processed prior to December 1978, are contained in the mosaics and in the picture listings.

  15. Giant Solitary Fibrous Tumor of Orbit.

    PubMed

    Tenekeci, Goktekin; Sari, Alper; Vayisoglu, Yusuf; Serin, Onur

    2015-07-01

    Solitary fibrous tumors (SFTs) have been reported in various locations in the body. Solitary fibrous tumors are extremely rare tumors, especially when located in the orbit. Diagnosis of SFT cannot be made based on histopathology only because it exhibits a variable microscopic appearance, and necessitates immunohistochemistry to confirm the diagnosis. A 51-year-old man was admitted to our clinic for the evaluation of a mass bulging in his left eye. Clinical examination revealed a painless mass extruding out of the orbital cavity with dimensions of 8 × 7  cm. Exenteration of the left eye including the upper and lower eyelid and reconstruction of the orbital cavity using a temporoparietal fascia flap and a temporal muscle flap was performed. SFT of orbital region is known as a slow growing and painless tumor. Based on previous studies, increased mitotic rate of the tumor gives the impression that the tumor has a malignant nature. Until now a small number or orbital SFTs were reported and none of them presented with a giant mass protruding out of the orbital cavity. We present a unique case of orbital SFT filling the whole orbital cavity and protruding outward as a giant mass. This case has been reported to expand our knowledge in this debated entity.

  16. Orbital angular momentum: a personal memoir

    NASA Astrophysics Data System (ADS)

    Allen, L.

    2017-02-01

    A definitive statement of the model used to describe orbital angular momentum is essentially now available. Its early history, and the interaction of those who played key roles in its development over 20 years ago in its development, is outlined in this Memoir. This article is part of the themed issue 'Optical orbital angular momentum'.

  17. Inverse-Square Orbits: A Geometric Approach.

    ERIC Educational Resources Information Center

    Rainwater, James C.; Weinstock, Robert

    1979-01-01

    Presents a derivation of Kepler's first law of planetary motion from Newtonian principles. Analogus derivations of the hyperbolic and parabolic orbits of nonreturning comets and the hyperbolic orbit for a particle in a repulsive inverse-square field are also presented. (HM)

  18. Interagency Report on Orbital Debris, 1995

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This 1995 report updates the findings and recommendations of the 1989 report and reflects the authors' progress in understanding and managing the orbital debris environment. It provides an up-to-date portrait of their measurement, modeling, and mitigation efforts; and a set of recommendations outlining specific steps they should pursue, both domestically and internationally, to minimize the potential hazard posed by orbital debris.

  19. Closed orbit correction in the SSC

    SciTech Connect

    Bourianoff, G.; Cole, B.; Ferede, H.; Pilat, F.

    1991-05-01

    A global correction scheme proposed for use in the SSC is described. Various features of the SSC lattice that impact the ability to correct the orbit are discussed. Typical results for the residual RMS closed orbit in the arc is calculated to be 0.65mm with peak values of 3mm. 3 refs., 1 fig., 2 tabs.

  20. Maneuver Estimation Model for Geostationary Orbit Determination

    DTIC Science & Technology

    2006-06-01

    MODEL FOR GEOSTATIONARY ORBIT DETERMINATION THESIS Presented to the Faculty Department of Aeronautics and Astronautics Graduate...FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT/GA/ENY/06-J01 MANEUVER ESTIMATION MODEL FOR GEOSTATIONARY ORBIT DETERMINATION...used to model the relative motion of a geostationary satellite about its intended location and a nonlinear least squares algorithm was developed to