Science.gov

Sample records for handling collision debris

  1. Modeling collisions in circumstellar debris disks

    NASA Astrophysics Data System (ADS)

    Nesvold, Erika

    2015-10-01

    Observations of resolved debris disks show a spectacular variety of features and asymmetries, including inner cavities and gaps, inclined secondary disks or warps, and eccentric, sharp-edged rings. Embedded exoplanets could create many of these features via gravitational perturbations, which sculpt the disk directly and by generating planetesimal collisions. In this thesis, I present the Superparticle Model/Algorithm for Collisions in Kuiper belts and debris disks (SMACK), a new method for simultaneously modeling, in 3-D, the collisional and dynamical evolution of planetesimals in a debris disk with planets. SMACK can simulate azimuthal asymmetries and how these asymmetries evolve over time. I show that SMACK is stable to numerical viscosity and numerical heating over 107 yr, and that it can reproduce analytic models of disk evolution. As an example of the algorithm's capabilities, I use SMACK to model the evolution of a debris ring containing a planet on an eccentric orbit and demonstrate that differential precession creates a spiral structure as the ring evolves, but collisions subsequently break up the spiral, leaving a narrower eccentric ring. To demonstrate SMACK's utility in studying debris disk physics, I apply SMACK to simulate a planet on a circular orbit near a ring of planetesimals that are experiencing destructive collisions. Previous simulations of a planet opening a gap in a collisionless debris disk have found that the width of the gap scales as the planet mass to the 2/7th power (alpha = 2/7). I find that gap sizes in a collisional disk still obey a power law scaling with planet mass, but that the index alpha of the power law depends on the age of the system t relative to the collisional timescale t coll of the disk by alpha = 0.32(t/ tcoll)-0.04, with inferred planet masses up to five times smaller than those predicted by the classical gap law. The increased gap sizes likely stem from the interaction between collisions and the mean motion

  2. Contribution of explosion and future collision fragments to the orbital debris environment

    NASA Technical Reports Server (NTRS)

    Su, S.-Y.; Kessler, D. J.

    1985-01-01

    The time evolution of the near-earth man-made orbital debris environment modeled by numerical simulation is presented in this paper. The model starts with a data base of orbital debris objects which are tracked by the NORAD ground radar system. The current untrackable small objects are assumed to result from explosions and are predicted from data collected from a ground explosion experiment. Future collisions between earth orbiting objects are handled by the Monte Carlo method to simulate the range of collision possibilities that may occur in the real world. The collision fragmentation process between debris objects is calculated using an empirical formula derived from a laboratory spacecraft impact experiment to obtain the number versus size distribution of the newly generated debris population. The evolution of the future space debris environment is compared with the natural meteoroid background for the relative spacecraft penetration hazard.

  3. Contribution of explosion and future collision fragments to the orbital debris environment

    NASA Technical Reports Server (NTRS)

    Su, S.-Y.; Kessler, D. J.

    1985-01-01

    The time evolution of the near-earth man-made orbital debris environment modeled by numerical simulation is presented in this paper. The model starts with a data base of orbital debris objects which are tracked by the NORAD ground radar system. The current untrackable small objects are assumed to result from explosions and are predicted from data collected from a ground explosion experiment. Future collisions between earth orbiting objects are handled by the Monte Carlo method to simulate the range of collision possibilities that may occur in the real world. The collision fragmentation process between debris objects is calculated using an empirical formula derived from a laboratory spacecraft impact experiment to obtain the number versus size distribution of the newly generated debris population. The evolution of the future space debris environment is compared with the natural meteoroid background for the relative spacecraft penetration hazard.

  4. Modeling Collisions in Circumstellar Debris Disks with SMACK

    NASA Astrophysics Data System (ADS)

    Nesvold, Erika; Kuchner, Marc J.

    2015-01-01

    Observations of resolved debris disks show a spectacular variety of features and asymmetries, including inner cavities and gaps, inclined secondary disks or warps, and eccentric, sharp-edged rings. Embedded exoplanets could create many of these features via gravitational perturbations, which sculpt the disk directly and by generating planetesimal collisions.The Superparticle-Method Algorithm for Collisions in Kuiper belts and debris disks (SMACK) is the first code to simultaneously model the dynamical and collisional evolution of planetesimals in three dimensions. We use SMACK to investigate the effects of collisions on the morphology of a disk of planetesimals perturbed by a planet and apply our model to a number of resolved debris disks including Fomalhaut, beta Pictoris, and HR 4796. We find that collisions can significantly alter the morphology of disks. Including collisions can yield estimates for planet masses 5x smaller than collisionless models, and collisions can expand the pericenter glow model of eccentric rings to explain observed apocentric excesses at long wavelengths.

  5. Probability of collision during the early evolution of debris clouds

    NASA Astrophysics Data System (ADS)

    Jenkin, Alan B.

    1996-02-01

    It has been a common practice in the literature to use the kinetic theory of gases, in order to obtain an estimate of the probability of collision posed to an orbital asset by the background debris population. This has been advantageous, because it features the use of the Poisson distribution to model encounters between an asset and background objects. This model yields a very simple method for computing probability of collision. It is fairly accurate in earth orbital studies over periods of several years in certain orbital regimes. It also has been the practice to use the Poisson model for debris clouds while they still are in their early evolutionary phase. However, newly formed debris clouds resulting from orbital fragmentations are characterized by fragments with relative motion that is highly correlated by the central gravitational field, thereby eliminating any resemblance to a gas. While the use of the Poisson model in this context has been criticized, it generally has been used anyway due to the lack of a well-known and accepted alternative model. A precise probabilistic assessment generally involves Monte Carlo analysis. This method is effective but often is computationally burdensome. By making some simple assumptions that hold in the vast majority of scenarios, it is shown that collision hazard for short-term debris cloud evolution can in fact be described by a Poisson model. These assumptions concern the way in which a fragmentation process is modeled and the orbital geometry between assets and a debris cloud. The derivation of this result is quite different from that used in kinetic gas theory but is nonetheless a direct application of standard probability theory. The ramification for short term debris cloud modeling is a theoretical substantiation of formulations in software like program DEBRIS. The purpose of this paper is to present the derivation and substantiation of this result.

  6. New insights on the orbital debris collision hazard at GEO

    NASA Astrophysics Data System (ADS)

    McKnight, Darren S.; Di Pentino, Frank R.

    2013-04-01

    An analysis is performed of the orbital debris collision hazard to operational spacecraft at geosynchronous orbit (GEO). As part of the examination, the contribution of individual components of the population are considered and presented to provide a clearer linkage between object characteristic and resulting risk. Our examination of GEO collision risk reveals several critical new insights: (1) the current probability of collision in GEO is relatively low, yet the future is difficult to predict due to our limited ability to observe objects in GEO and the uncertainty in past and future debris-generating events in GEO; (2) the probability of collision in GEO is not uniform by longitude — it is seven times greater in regions centered about the geopotential wells; (3) the probability of a mission-terminating collision is greatly dependent upon the approximately 2200 objects in the 10 cm-1 m range observed in GEO but not yet cataloged; (4) hardware relocated to GEO "graveyard" disposal orbits pose a potential additional, but not fully understood, collision hazard to operational GEO satellites; and (5) the collision hazard throughout the course of a day or year is highly episodic (i.e. non-uniform).

  7. Harnessing Adaptive Optics for Space Debris Collision Mitigation

    NASA Astrophysics Data System (ADS)

    Zovaro, A.; Bennet, F.; Copeland, M.; Rigaut, F.; d'Orgeville, C.; Grosse, D.

    2016-09-01

    Human kind's continued use of space depends upon minimising the build-up of debris in low Earth-orbit (LEO). Preventing collisions between satellites and debris is essential given that a single collision can generate thousands of new debris objects. However, in-orbit manoeuvring of satellites is extremely expensive and shortens their operational life. Adjusting the orbits of debris objects instead of satellites would shift the responsibility of collision avoidance away from satellite operators altogether, thereby offering a superior solution. The Research School of Astronomy and Astrophysics at the Australian National University, partnered with Electro Optic Systems (EOS) Space Systems, Lockheed Martin Corporation and the Space Environment Research Centre (SERC) Limited, are developing the Adaptive Optics Tracking and Pushing (AOTP) system. AOTP will be used to perturb the orbits of debris objects using photon pressure from a 10 kW IR laser beam launched from the 1.8 m telescope at Mount. Stromlo Observatory, Australia. Initial simulations predict that AOTP will be able to displace debris objects 10 cm in size by up to 100 m with several overhead passes. An operational demonstrator is planned for 2019. Turbulence will distort the laser beam as it propagates through the atmosphere, resulting in a lower photon flux on the target and reduced pointing accuracy. To mitigate these effects, adaptive optics (AO) will be used to apply wavefront correction to the beam prior to launch. A unique challenge in designing the AO system arises from the high slew rate needed to track objects in LEO, which in turn requires laser guide star AO for satisfactory wavefront correction. The optical design and results from simulations of estimated performance of AOTP will be presented. In particular, design considerations associated with the high-power laser will be detailed.

  8. Considering the collision probability of Active Debris Removal missions

    NASA Astrophysics Data System (ADS)

    Lidtke, Aleksander A.; Lewis, Hugh G.; Armellin, Roberto; Urrutxua, Hodei

    2017-02-01

    Active Debris Removal (ADR) methods are being developed due to a growing concern about the congestion on-orbit and sustainability of spaceflight. This study examined the probability of an on-orbit collision between an ADR target, whilst being de-orbited, and all the objects in the public catalogue published by the US Strategic Command. Such a collision could have significant effects because the target is likely to be located in a densely populated orbital regime and thus follow-on collisions could take place. Six impulsive and three low-thrust example ADR mission trajectories were screened for conjunctions. Extremely close conjunctions were found to result in as much as 99% of the total accumulated collision probability. The need to avoid those conjunctions is highlighted, which raises concerns about ADR methods that do not support collision avoidance. Shortening the removal missions, at an expense of more ΔV and so cost, will also lower their collision probability by reducing the number of conjunctions that they will experience.

  9. Debris-cloud collisions: Accretion studies in the space station

    NASA Technical Reports Server (NTRS)

    Schultz, P. H.; Gault, D. E.

    1986-01-01

    The growth of planetesimals in the Solar system reflects the success of collisional aggregation over disruption. Recent experiments performed at the NASA-Ames Vertical Gun Range are discussed using the production of debris cloud impaction to model protoplanetary accretion. The impact experiment assessed the differences between clustered and single body impacts on particulate surfaces. The preliminary results would indicate that collisions between two debris clouds might produce aggregates, thereby increasing particle sizes, whereas a single particle impacting a particle results in disruption and comminution. Such an experiment could provide new insight for early planetary growth processes and for interpreting the record of this stage. The use of the microgravity environment of the Space Station to further the research is discussed.

  10. Operational Impact of Improved Space Tracking on Collision Avoidance in the Future LEO Space Debris Environment

    DTIC Science & Technology

    2010-09-01

    curtails on orbit explosions and ASAT demonstrations, studies indicate that the number of debris objects in Low Earth Orbit (LEO) will continue to grow...Defense (DoD) and Intelligence Community (IC) in Low Earth Orbit (LEO). The following debris field and space tracking performance parameters were...objects at the time of closest approach. Keywords: Orbital Debris, Conjunction, Collision Avoidance, Future Debris Field Report Documentation Page

  11. Process Knowledge Summary Report for Materials and Fuels Complex Contact-Handled Transuranic Debris Waste

    SciTech Connect

    R. P. Grant; P. J. Crane; S. Butler; M. A. Henry

    2010-02-01

    This Process Knowledge Summary Report summarizes the information collected to satisfy the transportation and waste acceptance requirements for the transfer of transuranic (TRU) waste between the Materials and Fuels Complex (MFC) and the Advanced Mixed Waste Treatment Project (AMWTP). The information collected includes documentation that addresses the requirements for AMWTP and the applicable portion of their Resource Conservation and Recovery Act permits for receipt and treatment of TRU debris waste in AMWTP. This report has been prepared for contact-handled TRU debris waste generated by the Idaho National Laboratory at MFC. The TRU debris waste will be shipped to AMWTP for purposes of supercompaction. This Process Knowledge Summary Report includes information regarding, but not limited to, the generation process, the physical form, radiological characteristics, and chemical contaminants of the TRU debris waste, prohibited items, and packaging configuration. This report, along with the referenced supporting documents, will create a defensible and auditable record for waste originating from MFC.

  12. Debris-cloud collisions: Accretion studies in the Space Station

    NASA Technical Reports Server (NTRS)

    Schultz, Peter H.; Gault, D. E.

    1987-01-01

    The growth of planetesimals in the Solar System reflects the success of collisional aggregation over disruption. It is widely assumed that aggregation must represent relatively low encounter velocities between two particles in order to avoid both disruption and high-ejecta velocities. Such an assumption is supported by impact experiments and theory. Experiments involving particle-particle impacts, however, may be pertinent to only one type of collisional process in the early Solar System. Most models envision a complex protoplanetary nebular setting involving gas and dust. Consequently, collisions between clouds of dust or solids and dust may be a more relistic picture of protoplanetary accretion. Recent experiments performed at the NASA-Ames Vertical Gun Range have produced debris clouds impacting particulate targets with velocities ranging from 100 m/s to 6 km/s. The experiments produced several intriguing results that not only warrant further study but also may encourage experiments with the impact conditions permitted in a microgravity environment. Possible Space Station experiments are briefly discussed.

  13. Fraction of space debris collisions that are catastrophic

    SciTech Connect

    Canavan, G.H.

    1996-08-01

    Analytic calculations estimate the fraction of catalog collisions that are catastrophic by a modification of collision rates. Most catalog collisions are catastrophic. Impactors of 60 kg or larger participate in about half of the catastrophic collisions. Analytic estimates give accurate values for catastrophic collisions, which are complicated numerically.

  14. Operational support to collision avoidance activities by ESA's space debris office

    NASA Astrophysics Data System (ADS)

    Braun, V.; Flohrer, T.; Krag, H.; Merz, K.; Lemmens, S.; Bastida Virgili, B.; Funke, Q.

    2016-09-01

    The European Space Agency's (ESA) Space Debris Office provides a service to support operational collision avoidance activities. This support currently covers ESA's missions Cryosat-2, Sentinel-1A and -2A, the constellation of Swarm-A/B/C in low-Earth orbit (LEO), as well as missions of third-party customers. In this work, we describe the current collision avoidance process for ESA and third-party missions in LEO. We give an overview on the upgrades developed and implemented since the advent of conjunction summary messages (CSM)/conjunction data messages (CDM), addressing conjunction event detection, collision risk assessment, orbit determination, orbit and covariance propagation, process control, and data handling. We pay special attention to the effect of warning thresholds on the risk reduction and manoeuvre rates, as they are established through risk mitigation and analysis tools, such as ESA's Debris Risk Assessment and Mitigation Analysis (DRAMA) software suite. To handle the large number of CDMs and the associated risk analyses, a database-centric approach has been developed. All CDMs and risk analysis results are stored in a database. In this way, a temporary local "mini-catalogue" of objects close to our target spacecraft is obtained, which can be used, e.g., for manoeuvre screening and to update the risk analysis whenever a new ephemeris becomes available from the flight dynamics team. The database is also used as the backbone for a Web-based tool, which consists of the visualization component and a collaboration tool that facilitates the status monitoring and task allocation within the support team as well as communication with the control team. The visualization component further supports the information sharing by displaying target and chaser motion over time along with the involved uncertainties. The Web-based solution optimally meets the needs for a concise and easy-to-use way to obtain a situation picture in a very short time, and the support for

  15. The Kuiper Belt, Exozodiacal Dust, Debris Disks: It's All About Collisions

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2010-01-01

    Debris disks around other stars, like the disks around Fomalhaut, Vega, and Epsilon Eridani, are often described as more massive versions of the Kuiper Belt. But for a long time, it's been hard to test this notion, because grain-grain collisions dominate the grain lifetimes and we lacked the tools to model the effect of collisions on the appearance of the disks. I'll describe a new breakthrough that has allowed us to make 3-D models of collisions in debris disks and exozodiacal clouds for the first time, and I'll show the latest supercomputer simulations of these systems, illustrating the effects of planets and collisions in sculpting these disks. These models will be the key to interpreting debris disk images from HST, Herschel, SOFIA, JWST, and ALMA, as well as understanding the exozodiacal dust backgrounds for direct imaging of exo-Earths.

  16. The Kuiper Belt, Exozodiacal Dust, Debris Disks: It's All About Collisions

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2010-01-01

    Debris disks around other stars, like the disks around Fomalhaut, Vega, and Epsilon Eridani, are often described as more massive versions of the Kuiper Belt. But for a long time, it's been hard to test this notion, because grain-grain collisions dominate the grain lifetimes and we lacked the tools to model the effect of collisions on the appearance of the disks. I'll describe a new breakthrough that has allowed us to make 3-D models of collisions in debris disks and exozodiacal clouds for the first time, and I'll show the latest supercomputer simulations of these systems, illustrating the effects of planets and collisions in sculpting these disks. These models will be the key to interpreting debris disk images from HST, Herschel, SOFIA, JWST, and ALMA, as well as understanding the exozodiacal dust backgrounds for direct imaging of exo-Earths.

  17. Collisions and drag in debris discs with eccentric parent belts

    NASA Astrophysics Data System (ADS)

    Löhne, T.; Krivov, A. V.; Kirchschlager, F.; Sende, J. A.; Wolf, S.

    2017-08-01

    Context. High-resolution images of circumstellar debris discs reveal off-centred rings that indicate past or ongoing perturbation, possibly caused by secular gravitational interaction with unseen stellar or substellar companions. The purely dynamical aspects of this departure from radial symmetry are well understood. However, the observed dust is subject to additional forces and effects, most notably collisions and drag. Aims: To complement the studies of dynamics, we therefore aim to understand how the addition of collisional evolution and drag forces creates new asymmetries and strengthens or overrides existing ones. Methods: We augmented our existing numerical code Analysis of Collisional Evolution (ACE) by an azimuthal dimension, the longitude of periapse. A set of fiducial discs with global eccentricities ranging from 0 to 0.4 was evolved over gigayear timescales. Size distribution and spatial variation of dust were analysed and interpreted. We discuss the basic impact of belt eccentricity on spectral energy distributions and images. Results: We find features imposed on characteristic timescales. First, radiation pressure defines size cut-offs that differ between periapse and apoapse, resulting in an asymmetric halo. The differences in size distribution make the observable asymmetry of the halo depend on wavelength. Second, collisional equilibrium prefers smaller grains on the apastron side of the parent belt, reducing the effect of pericentre glow and the overall asymmetry. Third, Poynting-Robertson drag fills the region interior to an eccentric belt such that the apastron side is more tenuous. Interpretation and prediction of the appearance in scattered light is problematic when spatial and size distribution are coupled.

  18. Signatures of massive collisions in debris discs. A self-consistent numerical model

    NASA Astrophysics Data System (ADS)

    Kral, Q.; Thébault, P.; Augereau, J.-C.; Boccaletti, A.; Charnoz, S.

    2015-01-01

    Context. Violent stochastic collisional events have been invoked as a possible explanation for some debris discs displaying pronounced azimuthal asymmetries or having a luminosity excess exceeding that expected for systems at collisional steady-state. So far, no thorough modelling of the consequences of such stochastic events has been carried out, mainly because of the extreme numerical challenge of coupling the dynamical and collisional evolution of the released dust. Aims: We perform the first fully self-consistent modelling of the aftermath of massive breakups in debris discs. We follow the collisional and dynamical evolution of dust released after the breakup of a Ceres-sized body at 6 AU from its central star. We investigate the duration, magnitude, and spatial structure of the signature left by such a violent event, as well as its observational detectability. Methods: We use the recently developed LIDT-DD code, which handles the coupled collisional and dynamical evolution of debris discs. The main focus is placed on the complex interplay between destructive collisions, Keplerian dynamics, and radiation pressure forces. We use the GRaTer package to estimate the system's luminosity at different wavelengths. Results: The breakup of a Ceres-sized body at 6 AU creates an asymmetric dust disc that is homogenized by the coupled action of collisions and dynamics on a timescale of a few 105 years. After a transient period where it is very steep, the particle size distribution in the system relaxes to a collisional steady-state law after ~104 years. The luminosity excess in the breakup's aftermath should be detectable by mid-IR photometry, from a 30 pc distance, over a period of ~106 years that exceeds the duration of the asymmetric phase of the disc (a few 105 years). As for the asymmetric structures, we derive synthetic images for the VLT/SPHERE and JWST/MIRI instruments, showing that they should be clearly visible and resolved from a 10 pc distance. Images at 1.6

  19. Collision risk investigation for an operational spacecraft caused by space debris

    NASA Astrophysics Data System (ADS)

    Zhang, Binbin; Wang, Zhaokui; Zhang, Yulin

    2017-04-01

    The collision probability between an operational spacecraft and a population of space debris is investigated. By dividing the 3-dimensional operational space of the spacecraft into several space volume cells (SVC) and proposing a boundary selection method to calculate the collision probability in each SVC, the distribution of the collision risk, as functions of the time, the orbital height, the declination, the impact elevation, the collision velocity, etc., can be obtained. Thus, the collision risk could be carefully evaluated over a time span for the general orbital configurations of the spacecraft and the space debris. As an application, the collision risk for the Tiangong-2 space laboratory caused by the cataloged space debris is discussed and evaluated. Results show that most of the collision threat comes from the front left and front right in Tiangong-2's local, quasi-horizontal plane. And the collision probability will also accumulate when Tiangong-2 moves to the largest declinations (about {±} 42°). As a result, the manned space activities should be avoided at those declinations.

  20. Collision-less Coupling between Explosive Debris Plasma and Magnetized Ambient Plasma

    NASA Astrophysics Data System (ADS)

    Bondarenko, Anton Sergeivich

    The explosive expansion of a dense debris plasma cloud into relatively tenuous, magnetized, ambient plasma characterizes a wide variety of astrophysical and space environments, including supernova remnants, interplanetary coronal mass ejections, and ionospheric explosions. In these and other related phenomena, collision-less electro-magnetic processes rather than Coulomb collisions typically mediate the transfer of momentum and energy from the debris plasma to the ambient plasma. In an effort to better understand the detailed physics of collision-less coupling mechanisms, compliment in situ measurements, and provide validation of previous computational and theoretical work, the present research utilizes a unique experimental platform at the University of California, Los Angeles (UCLA) to study the interaction of explosive debris plasma with magnetized ambient plasma in a reproducible laboratory setting. Specifically, by jointly employing the Large Plasma Device (LAPD) and the Phoenix laser facility, the super-Alfvenic, quasi-perpendicular expansion of laser-produced carbon (C) and hydrogen (H) debris plasma through preformed, magnetized helium (He) ambient plasma is investigated via a variety of sophisticated diagnostics, including emission spectroscopy, wavelength-filtered imaging, a magnetic flux probe, and a Langmuir probe. The key result is the direct observation of collision-less coupling via large Doppler shifts in a He II ion spectral line, which indicate that the ambient ions accelerate in response to the explosive debris plasma. Specifically, the He II ions accelerate along a trajectory that qualitatively corresponds to the large-scale laminar electric field generated by the debris expansion. A custom computational approach is utilized to simulate the initial He II ion response to the explosive debris plasma, and a synthetic Doppler-shifted wavelength spectrum constructed from the simulated ion velocities excellently reproduces the experimental

  1. Collision frequency of artificial satellites - The creation of a debris belt

    NASA Technical Reports Server (NTRS)

    Kessler, D. J.; Cour-Palais, B. G.

    1978-01-01

    The probability of satellite collisions increases with the number of satellites. In the present paper, possible time scales for the growth of a debris belt from collision fragments are determined, and possible consequences of continued unrestrained launch activities are examined. Use is made of techniques formerly developed for studying the evolution (growth) of the asteroid belt. A model describing the flux from the known earth-orbiting satellites is developed, and the results from this model are extrapolated in time to predict the collision frequency between satellites. Hypervelocity impact phenomena are then examined to predict the debris flux resulting from collisions. The results are applied to design requirements for three types of future space missions.

  2. CURRENT APPLICATIONS OF THREE MILE ISLAND-2 CORE AND DEBRIS HANDLING AT THE IDAHO NATIONAL LABORATORY

    SciTech Connect

    Carmack, William Jonathan; Braase, Lori Ann

    2015-09-01

    Fuel recovery from severe accidents requires careful planning and execution. The Idaho National Laboratory played a key role in the Three Mile Island (TMI) fuel and core recovery. This involved technology development to locate and handle the damaged fuel; characterization of fuel and debris; analysis of fuel interaction with structural components and materials; development of fuel drying technology for long-term storage. However, one of the critical activities from the TMI project was the extensive effort document all the activities and archive the reports and photos. A historical review of the TMI project at the INL leads to the identification of current applications and considerations for facility designs, fuel handling, robotic applications, material characterization, etc.

  3. Collision-less Coupling between Explosive Debris Plasmas and Magnetized Background Plasmas

    NASA Astrophysics Data System (ADS)

    Bondarenko, Anton; Schaeffer, Derek; Clark, S. Eric; Everson, Erik; Lee, Bo Ram; Constantin, Carmen; Niemann, Christoph

    2015-11-01

    The explosive expansion of debris plasma into magnetized background plasma characterizes a variety of astrophysical and space environments, including supernova remnants, interplanetary coronal mass ejections, and ionospheric explosions. In these and other related phenomena, collision-less electro-magnetic processes rather than Coulomb collisions typically mediate the transfer of momentum and energy from the debris to the background. A unique experiment that jointly utilizes the Large Plasma Device (LAPD) and the Phoenix laser facility at UCLA has investigated the super-Alfvénic, quasi-perpendicular expansion of a laser-produced carbon (C) debris plasma through a preformed, magnetized helium (He) background plasma via a variety of diagnostics, including emission spectroscopy, wavelength-filtered imaging, and magnetic field probes. Collision-less coupling is directly observed via Doppler shifts in the He II 468.6 nm spectral line, which indicate that the He II ions are accelerated by the laminar electric field that develops due to the expanding C debris. By utilizing an early-time model of the C debris density and velocity, the laminar electric field is calculated and used in combination with the measured magnetic field to simulate He II ion trajectories and velocities. A synthetic Doppler-shifted wavelength spectrum of the He II 468.6 nm spectral line is generated from the simulated He II ion velocities and found to agree well with the measurements.

  4. SMACK: A NEW ALGORITHM FOR MODELING COLLISIONS AND DYNAMICS OF PLANETESIMALS IN DEBRIS DISKS

    SciTech Connect

    Nesvold, Erika R.; Kuchner, Marc J.; Pan, Margaret; Rein, Hanno E-mail: Marc.Kuchner@nasa.gov E-mail: rein@ias.edu

    2013-11-10

    We present the Superparticle-Method/Algorithm for Collisions in Kuiper belts and debris disks (SMACK), a new method for simultaneously modeling, in three dimensions, the collisional and dynamical evolution of planetesimals in a debris disk with planets. SMACK can simulate azimuthal asymmetries and how these asymmetries evolve over time. We show that SMACK is stable to numerical viscosity and numerical heating over 10{sup 7} yr and that it can reproduce analytic models of disk evolution. We use SMACK to model the evolution of a debris ring containing a planet on an eccentric orbit. Differential precession creates a spiral structure as the ring evolves, but collisions subsequently break up the spiral, leaving a narrower eccentric ring.

  5. SMACK: A New Algorithm for Modeling Collisions and Dynamics of Planetesimals in Debris Disks

    NASA Technical Reports Server (NTRS)

    Nesvold, Erika Rose; Kuchner, Marc J.; Rein, Hanno; Pan, Margaret

    2013-01-01

    We present the Superparticle Model/Algorithm for Collisions in Kuiper belts and debris disks (SMACK), a new method for simultaneously modeling, in 3-D, the collisional and dynamical evolution of planetesimals in a debris disk with planets. SMACK can simulate azimuthal asymmetries and how these asymmetries evolve over time. We show that SMACK is stable to numerical viscosity and numerical heating over 10(exp 7) yr, and that it can reproduce analytic models of disk evolution. We use SMACK to model the evolution of a debris ring containing a planet on an eccentric orbit. Differential precession creates a spiral structure as the ring evolves, but collisions subsequently break up the spiral, leaving a narrower eccentric ring.

  6. NASA's Orbital Debris Conjuction Assessment and Collision Avoidance Strategy

    NASA Technical Reports Server (NTRS)

    Gavin, Richard T.

    2010-01-01

    NASA has successfully used debris avoidance maneuvers to protect our spacecraft for more than 20 . years. This process which started out using parametric data and maneuver boxes has seen considerable evolution and now allows us to continue nominal operations for all but the most threatening objects. This has greatly reduced the interruptions to the critical mission objectives being pursued by NASA s Space Station, Space Shuttle, and robotic satellites.

  7. Analysis of Damage Probability for Collision Between Space Debris and a Satellite in Low-Earth Orbit

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Eun; Park, Sang-Young; Kim, Young-Rok; Choi, Kyu-Hong; Kim, Eung-Hyun; Kim, Gyu-Sun

    2007-06-01

    Space environment becomes more hazardous for satellite because of increasing number of space debris. This research is to analyze collision hazards between KOMPSAT 3 in low-earth orbit and space debris generated by the explosion of FengYun satellite on the January 11, 2007. Based on the observed data of the space debris from FengYun satellite, the mass and number distribution of the debris are estimated including undetectable debris from the explosion of FengYun satellite. The spatial density and flux for the space debris can be calculated according to size. This study also brings out the analysis for the assessment of collision probability and damage probability. The algorithm developed in the current paper can be used to estimate the level of risk due to space debris for the satellites that will be launched in the future.

  8. Operational Impact of Improved Space Tracking on Collision Avoidance in the Future LEO Space Debris Environment

    NASA Astrophysics Data System (ADS)

    Sibert, D.; Borgeson, D.; Peterson, G.; Jenkin, A.; Sorge, M.

    2010-09-01

    Even if global space policy successfully curtails on orbit explosions and ASAT demonstrations, studies indicate that the number of debris objects in Low Earth Orbit (LEO) will continue to grow solely from debris on debris collisions and debris generated from new launches. This study examines the threat posed by this growing space debris population over the next 30 years and how improvements in our space tracking capabilities can reduce the number of Collision Avoidance (COLA) maneuvers required keep the risk of operational satellite loss within tolerable limits. Particular focus is given to satellites operated by the Department of Defense (DoD) and Intelligence Community (IC) in Low Earth Orbit (LEO). The following debris field and space tracking performance parameters were varied parametrically in the experiment to study the impact on the number of collision avoidance maneuvers required: - Debris Field Density (by year 2009, 2019, 2029, and 2039) - Quality of Track Update (starting 1 sigma error ellipsoid) - Future Propagator Accuracy (error ellipsoid growth rates - Special Perturbations in 3 axes) - Track Update Rate for Debris (stochastic) - Track Update Rate for Payloads (stochastic) Baseline values matching present day tracking performance for quality of track update, propagator accuracy, and track update rate were derived by analyzing updates to the unclassified Satellite Catalog (SatCat). Track update rates varied significantly for active payloads and debris and as such we used different models for the track update rates for military payloads and debris. The analysis was conducted using the System Effectiveness Analysis Simulation (SEAS) an agent based model developed by the United States Air Force Space Command’s Space and Missile Systems Center to evaluate the military utility of space systems. The future debris field was modeled by The Aerospace Corporation using a tool chain which models the growth of the 10cm+ debris field using high fidelity

  9. Constraints on Planetesimal Collision Models in Debris Disks

    NASA Astrophysics Data System (ADS)

    MacGregor, Meredith A.; Wilner, David J.; Chandler, Claire; Ricci, Luca; Maddison, Sarah T.; Cranmer, Steven R.; Andrews, Sean M.; Hughes, A. Meredith; Steele, Amy

    2016-06-01

    Observations of debris disks offer a window into the physical and dynamical properties of planetesimals in extrasolar systems through the size distribution of dust grains. In particular, the millimeter spectral index of thermal dust emission encodes information on the grain size distribution. We have made new VLA observations of a sample of seven nearby debris disks at 9 mm, with 3\\prime\\prime resolution and ˜5 μJy beam-1rms. We combine these with archival ATCA observations of eight additional debris disks observed at 7 mm, together with up-to-date observations of all disks at (sub)millimeter wavelengths from the literature, to place tight constraints on the millimeter spectral indices and thus grain size distributions. The analysis gives a weighted mean for the slope of the power-law grain size distribution, n(a)\\propto {a}-q, of < q> =3.36+/- 0.02, with a possible trend of decreasing q for later spectral type stars. We compare our results to a range of theoretical models of collisional cascades, from the standard self-similar, steady-state size distribution (q = 3.5) to solutions that incorporate more realistic physics such as alternative velocity distributions and material strengths, the possibility of a cutoff at small dust sizes from radiation pressure, and results from detailed dynamical calculations of specific disks. Such effects can lead to size distributions consistent with the data, and plausibly the observed scatter in spectral indices. For the AU Mic system, the VLA observations show clear evidence of a highly variable stellar emission component; this stellar activity obviates the need to invoke the presence of an asteroid belt to explain the previously reported compact millimeter source in this system.

  10. LightForce Photon-Pressure Collision Avoidance: Efficiency Assessment on an Entire Catalogue of Space Debris

    NASA Technical Reports Server (NTRS)

    Stupl, Jan Michael; Faber, Nicolas; Foster, Cyrus; Yang Yang, Fan; Levit, Creon

    2013-01-01

    The potential to perturb debris orbits using photon pressure from ground-based lasers has been confirmed by independent research teams. Two useful applications of this scheme are protecting space assets from impacts with debris and stabilizing the orbital debris environment, both relying on collision avoidance rather than de-orbiting debris. This paper presents the results of a new assessment method to analyze the efficiency of the concept for collision avoidance. Earlier research concluded that one ground based system consisting of a 10 kW class laser, directed by a 1.5 m telescope with adaptive optics, can prevent a significant fraction of debris-debris collisions in low Earth orbit. That research used in-track displacement to measure efficiency and restricted itself to an analysis of a limited number of objects. As orbit prediction error is dependent on debris object properties, a static displacement threshold should be complemented with another measure to assess the efficiency of the scheme. In this paper we present the results of an approach using probability of collision. Using a least-squares fitting method, we improve the quality of the original TLE catalogue in terms of state and co-state accuracy. We then calculate collision probabilities for all the objects in the catalogue. The conjunctions with the highest risk of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the collision probability in a 20 minute window around the original conjunction. We then use different criteria to evaluate the utility of the laser-based collision avoidance scheme and assess the number of base-line ground stations needed to mitigate a significant number of high probability conjunctions. Finally, we also give an account how a laser ground station can be used for both orbit deflection and debris tracking.

  11. Probing Terrestrial Planet Formation by Witnessing Large Collisions in Extreme Debris Disks

    NASA Astrophysics Data System (ADS)

    Su, Kate

    2015-12-01

    The Kepler results indicate that many young planetary systems build terrestrial planets. The most dramatic phases of this process are thought to be oligarchic and chaotic growth, roughly up to ages of 200 million years, when violent collisions occur between bodies of sizes up to proto-planets. Such events should be marked by the production of huge amounts of debris, including clouds of dust, as has been observed in some of the extreme debris disks (young stars with high fractional dust luminosity and prominent solid-state features in the mid-infrared). The newly discovered variable emission from extreme debris disks provides a unique opportunity to learn about asteroid-sized bodies in young exoplanetary systems and to explore planetesimal collisions and their aftermaths during the era of terrestrial- planet-building.We have a on-going Spitzer program to monitor a dozen of young, dusty debris systems to investigate the incidence, nature, and evolution of these impacts through time-domain observations. I will highlight recent results from time-series monitoring of a 35 Myr-old disk around ID8 in NGC 2547, and discuss future directions for the study of the detailed process of large impacts in the era of terrestrial planet formation using space facilities.

  12. Satellite Collision Modeling with Physics-Based Hydrocodes: Debris Generation Predictions of the Iridium-Cosmos Collision Event and Other Impact Events

    SciTech Connect

    Springer, H K; Miller, W O; Levatin, J L; Pertica, A J; Olivier, S S

    2010-09-06

    Satellite collision debris poses risks to existing space assets and future space missions. Predictive models of debris generated from these hypervelocity collisions are critical for developing accurate space situational awareness tools and effective mitigation strategies. Hypervelocity collisions involve complex phenomenon that spans several time- and length-scales. We have developed a satellite collision debris modeling approach consisting of a Lagrangian hydrocode enriched with smooth particle hydrodynamics (SPH), advanced material failure models, detailed satellite mesh models, and massively parallel computers. These computational studies enable us to investigate the influence of satellite center-of-mass (CM) overlap and orientation, relative velocity, and material composition on the size, velocity, and material type distributions of collision debris. We have applied our debris modeling capability to the recent Iridium 33-Cosmos 2251 collision event. While the relative velocity was well understood in this event, the degree of satellite CM overlap and orientation was ill-defined. In our simulations, we varied the collision CM overlap and orientation of the satellites from nearly maximum overlap to partial overlap on the outermost extents of the satellites (i.e, solar panels and gravity boom). As expected, we found that with increased satellite overlap, the overall debris cloud mass and momentum (transfer) increases, the average debris size decreases, and the debris velocity increases. The largest predicted debris can also provide insight into which satellite components were further removed from the impact location. A significant fraction of the momentum transfer is imparted to the smallest debris (< 1-5mm, dependent on mesh resolution), especially in large CM overlap simulations. While the inclusion of the smallest debris is critical to enforcing mass and momentum conservation in hydrocode simulations, there seems to be relatively little interest in their

  13. Dynamical study of low Earth orbit debris collision avoidance using ground based laser

    NASA Astrophysics Data System (ADS)

    Khalifa, N. S.

    2015-06-01

    The objective of this paper was to investigate the orbital velocity changes due to the effect of ground based laser force. The resulting perturbations of semi-major axis, miss distance and collision probability of two approaching objects are studied. The analytical model is applied for low Earth orbit debris of different eccentricities and area to mass ratio and the numerical test shows that laser of medium power ∼5 kW can perform a small change Δ V ‾ of an average magnitude of 0.2 cm/s which can be accumulated over time to be about 3 cm/day. Moreover, it is confirmed that applying laser Δ V ‾ results in decreasing collision probability and increasing miss distance in order to avoid collision.

  14. Spectroscopic Measurements of Collision-less Coupling Between Explosive Debris Plasmas and Ambient, Magnetized Background Plasmas

    NASA Astrophysics Data System (ADS)

    Bondarenko, Anton; Schaeffer, Derek; Everson, Erik; Vincena, Stephen; van Compernolle, Bart; Constantin, Carmen; Clark, Eric; Niemann, Christoph

    2013-10-01

    Emission spectroscopy is currently being utilized in order to assess collision-less momentum and energy coupling between explosive debris plasmas and ambient, magnetized background plasmas of astrophysical relevance. In recent campaigns on the Large Plasma Device (LAPD) (nelec =1012 -1013 cm-3, Telec ~ 5 eV, B0 = 200 - 400 G) utilizing the new Raptor laser facility (1053 nm, 100 J per pulse, 25 ns FWHM), laser-ablated carbon debris plasmas were generated within ambient, magnetized helium background plasmas and prominent spectral lines of carbon and helium ions were studied in high spectral (0 . 01 nm) and temporal (50 ns) resolution. Time-resolved velocity components extracted from Doppler shift measurements of the C+4 227 . 1 nm spectral line along two perpendicular axes reveal significant deceleration as the ions stream and gyrate within the helium background plasma, indicating collision-less momentum coupling. The He+1 320 . 3 nm and 468 . 6 nm spectral lines of the helium background plasma are observed to broaden and intensify in response to the carbon debris plasma, indicative of strong electric fields (Stark broadening) and energetic electrons. The experimental results are compared to 2D hybrid code simulations.

  15. Planetary Collisions Outside the Solar System: Time Domain Characterization of Extreme Debris Disks

    NASA Astrophysics Data System (ADS)

    Meng, Huan Y. A.; Su, Kate Y. L.; Rieke, George H.; Rujopakarn, Wiphu; Myers, Gordon; Cook, Michael; Erdelyi, Emery; Maloney, Chris; McMath, James; Persha, Gerald; Poshyachinda, Saran; Reichart, Daniel E.

    2015-05-01

    Luminous debris disks of warm dust in the terrestrial planet zones around solar-like stars were recently found to vary, which is indicative of ongoing large-scale collisions of rocky objects. We use Spitzer 3.6 and 4.5 μm time-series observations in 2012 and 2013 (extended to 2014 in one case) to monitor five more debris disks with unusually high fractional luminosities (“extreme debris disk”), including P1121 in the open cluster M47 (80 Myr), HD 15407A in the AB Dor moving group (80 Myr), HD 23514 in the Pleiades (120 Myr), HD 145263 in the Upper Sco Association (10 Myr), and the field star BD+20 307 (≳1 Gyr). Together with the published results for ID8 in NGC 2547 (35 Myr), this makes the first systematic time-domain investigation of planetary impacts outside the solar system. Significant variations with timescales shorter than a year are detected in five out of the six extreme debris disks we monitored. However, different systems show diverse sets of characteristics in the time domain, including long-term decay or growth, disk temperature variations, and possible periodicity.

  16. Remote Maneuver of Space Debris Using Photon Pressure for Active Collision Avoidance

    NASA Astrophysics Data System (ADS)

    Smith, C.

    2014-09-01

    The Space Environment Research Corporation (SERC) is a consortium of companies and research institutions that have joined together to pursue research and development of technologies and capabilities that will help to preserve the orbital space environment. The consortium includes, Electro Optics Systems (Australia), Lockheed Martin Australia, Optus Satellite Systems (Australia), The Australian national University, RMIT University, National Institute of Information and Communications Technology (NICT, Japan) as well as affiliates from NASA Ames and ESA. SERC is also the recipient of and Australian Government Cooperative Research Centre grant. SERC will pursue a wide ranging research program including technologies to improve tracking capability and capacity, orbit determination and propagation algorithms, conjunction analysis and collision avoidance. All of these technologies will contribute to the flagship program to demonstrate active collision avoidance using photon pressure to provide remote maneuver of space debris. This project joins of the proposed NASA Lightforce concept with infrastructure and capabilities provided by SERC. This paper will describe the proposed research and development program to provide an on-orbit demonstration within the next five years for remote maneuver of space debris.

  17. Planetary Collisions outside the Solar System: Time Domain Characterization of Extreme Debris Disks

    NASA Astrophysics Data System (ADS)

    Meng, Huan; Su, Kate Y. L.; Rieke, George

    2015-01-01

    Luminous debris disks of warm dust in the terrestrial planet zones around solar-like stars are recently found to vary, indicative of ongoing collisions of rocky objects. We use Spitzer 3.6 and 4.5 micron time-series observations in 2012 and 2013 to monitor 5 more extreme debris disks, including P1121 in the open cluster M47 (80 Myr), HD 15407A in the AB Dor moving group (80 Myr), HD 23514 in the Pleiades (120 Myr), HD 145263 in the Upper Sco Association (10 Myr), and the field star BD+20 207 (>1 Gyr). Together with the published results for ID8 in NGC 2547 (35 Myr), this makes the first systematic time-domain investigation of planetary impacts outside the solar system. Significant variations with timescales shorter than a year are detected in five out of the six extreme debris disks we have monitored. However, different systems show diverse sets of characteristics in the time domain, including long-term trends, disk temperature variations, and possible periodicity.

  18. Limiting Future Collision Risk to Spacecraft: An Assessment of NASA's Meteoroid and Orbital Debris Programs

    NASA Technical Reports Server (NTRS)

    2011-01-01

    Over the past 50 years, various NASA communities have contributed significantly to maturing NASA s meteoroid and orbital debris (MMOD)1 programs to their current state. As a result of these community efforts, and to NASA s credit, NASA s MMOD programs and models are now widely used and respected by the providers and users of both government and commercial satellites, nationally as well as internationally. Satellites have been redesigned to protect critical components from MMOD damage by moving critical components from exterior surfaces to deep inside a satellite s structure. Orbits are monitored and altered to minimize the risk of collision with tracked orbital debris. MMOD shielding added to the International Space Station (ISS) protects critical components and astronauts from potentially catastrophic damage that might result from smaller, untracked debris and meteoroid impacts. The space shuttle, as it orbited Earth, and whether docked to the ISS or not, was optimally oriented to protect its fragile thermal protection and thermal radiation systems from MMOD damage. In addition, astronauts inspected its thermal protection system for MMOD damage before the shuttle reentered Earth s atmosphere; Orion, NASA s capsule to carry astronauts to low Earth orbit, includes designs to mitigate the threat of MMOD damage and provide increased safety to the crew. When a handful of reasonable assumptions are used in NASA s MMOD models, scenarios are uncovered that conclude that the current orbital debris environment has already reached a "tipping point." That is, the amount of debris - in terms of the population of large debris objects, as well as overall mass of debris in orbit - currently in orbit has reached a threshold where it will continually collide with itself, further increasing the population of orbital debris. This increase will lead to corresponding increases in spacecraft failures, which will only create more feedback into the system, increasing the debris population

  19. Limiting Future Collision Risk to Spacecraft: An Assessment of NASA's Meteoroid and Orbital Debris Programs

    NASA Technical Reports Server (NTRS)

    2011-01-01

    Over the past 50 years, various NASA communities have contributed significantly to maturing NASA s meteoroid and orbital debris (MMOD)1 programs to their current state. As a result of these community efforts, and to NASA s credit, NASA s MMOD programs and models are now widely used and respected by the providers and users of both government and commercial satellites, nationally as well as internationally. Satellites have been redesigned to protect critical components from MMOD damage by moving critical components from exterior surfaces to deep inside a satellite s structure. Orbits are monitored and altered to minimize the risk of collision with tracked orbital debris. MMOD shielding added to the International Space Station (ISS) protects critical components and astronauts from potentially catastrophic damage that might result from smaller, untracked debris and meteoroid impacts. The space shuttle, as it orbited Earth, and whether docked to the ISS or not, was optimally oriented to protect its fragile thermal protection and thermal radiation systems from MMOD damage. In addition, astronauts inspected its thermal protection system for MMOD damage before the shuttle reentered Earth s atmosphere; Orion, NASA s capsule to carry astronauts to low Earth orbit, includes designs to mitigate the threat of MMOD damage and provide increased safety to the crew. When a handful of reasonable assumptions are used in NASA s MMOD models, scenarios are uncovered that conclude that the current orbital debris environment has already reached a "tipping point." That is, the amount of debris - in terms of the population of large debris objects, as well as overall mass of debris in orbit - currently in orbit has reached a threshold where it will continually collide with itself, further increasing the population of orbital debris. This increase will lead to corresponding increases in spacecraft failures, which will only create more feedback into the system, increasing the debris population

  20. Azimuthal asymmetries in the debris disk around HD 61005. A massive collision of planetesimals?

    NASA Astrophysics Data System (ADS)

    Olofsson, J.; Samland, M.; Avenhaus, H.; Caceres, C.; Henning, Th.; Moór, A.; Milli, J.; Canovas, H.; Quanz, S. P.; Schreiber, M. R.; Augereau, J.-C.; Bayo, A.; Bazzon, A.; Beuzit, J.-L.; Boccaletti, A.; Buenzli, E.; Casassus, S.; Chauvin, G.; Dominik, C.; Desidera, S.; Feldt, M.; Gratton, R.; Janson, M.; Lagrange, A.-M.; Langlois, M.; Lannier, J.; Maire, A.-L.; Mesa, D.; Pinte, C.; Rouan, D.; Salter, G.; Thalmann, C.; Vigan, A.

    2016-06-01

    Context. Debris disks offer valuable insights into the latest stages of circumstellar disk evolution, and can possibly help us to trace the outcomes of planetary formation processes. In the age range 10 to 100 Myr, most of the gas is expected to have been removed from the system, giant planets (if any) must have already been formed, and the formation of terrestrial planets may be on-going. Pluto-sized planetesimals, and their debris released in a collisional cascade, are under their mutual gravitational influence, which may result into non-axisymmetric structures in the debris disk. Aims: High angular resolution observations are required to investigate these effects and constrain the dynamical evolution of debris disks. Furthermore, multi-wavelength observations can provide information about the dust dynamics by probing different grain sizes. Methods: Here we present new VLT/SPHERE and ALMA observations of the debris disk around the 40 Myr-old solar-type star HD 61005. We resolve the disk at unprecedented resolution both in the near-infrared (in scattered and polarized light) and at millimeter wavelengths. We perform a detailed modeling of these observations, including the spectral energy distribution. Results: Thanks to the new observations, we propose a solution for both the radial and azimuthal distribution of the dust grains in the debris disk. We find that the disk has a moderate eccentricity (e ~ 0.1) and that the dust density is two times larger at the pericenter compared to the apocenter. Conclusions: With no giant planets detected in our observations, we investigate alternative explanations besides planet-disk interactions to interpret the inferred disk morphology. We postulate that the morphology of the disk could be the consequence of a massive collision between ~1000 km-sized bodies at ~61 au. If this interpretation holds, it would put stringent constraints on the formation of massive planetesimals at large distances from the star. Based on observations

  1. SILICATE DUST SIZE DISTRIBUTION FROM HYPERVELOCITY COLLISIONS: IMPLICATIONS FOR DUST PRODUCTION IN DEBRIS DISKS

    SciTech Connect

    Takasawa, S.; Nakamura, A. M.; Arakawa, M.; Seto, Y.; Sangen, K.; Setoh, M.; Machii, N.; Kadono, T.; Shigemori, K.; Hironaka, Y.; Fujioka, S.; Sano, T.; Watari, T.; Dohi, K.; Ohno, S.; Maeda, M.; Sakaiya, T.; Otani, K.; Takeuchi, T.

    2011-06-01

    Fragments generated by high-velocity collisions between solid planetary bodies are one of the main sources of new interplanetary dust particles. However, only limited ranges of collision velocity, ejecta size, and target materials have been studied in previous laboratory experiments, and the collision condition that enables the production of dust-sized particles remains unclear. We conducted hypervelocity impact experiments on silicate rocks at relative velocities of 9 to 61 km s{sup -1}, which is beyond the upper limit of previous laboratory studies. Sub-millimeter-diameter aluminum and gold spheres were accelerated by laser ablation and were shot into dunite and basalt targets. We analyzed the surfaces of aerogel blocks deployed near the targets using an electron probe micro analyzer and counted the number of particles that contained the target material. The size distributions of ejecta ranged from five to tens of microns in diameter. The total cross-sectional area of dust-sized ejecta monotonically increased with the projectile kinetic energy, independent of impact velocity, projectile diameter, and projectile and target material compositions. The slopes of the cumulative ejecta-size distributions ranged from -2 to -5. Most of the slopes were steeper than the -2.5 or -2.7 that is expected for a collisional equilibrium distribution in a collision cascade with mass-independent or mass-dependent catastrophic disruption thresholds, respectively. This suggests that the steep dust size-distribution proposed for the debris disk around HD172555 (an A5V star) could be due to a hypervelocity collision.

  2. Energy deposited in the high luminosity inner triplets of the LHC by collision debris

    SciTech Connect

    Wildner, E.; Broggi, F.; Cerutti, F.; Ferrari, A.; Hoa, C.; Koutchouk, J.-P.; Mokhov, N.V.; /Fermilab

    2008-06-01

    The 14 TeV center of mass proton-proton collisions in the LHC produce not only debris interesting for physics but also showers of particles ending up in the accelerator equipment, in particular in the superconducting magnet coils. Evaluations of this contribution to the heat, that has to be transported by the cryogenic system, have been made to guarantee that the energy deposition in the superconducting magnets does not exceed limits for magnet quenching and the capacity of the cryogenic system. The models of the LHC base-line are detailed and include description of, for energy deposition, essential elements like beam-pipes and corrector magnets. The evaluations made using the Monte-Carlo code FLUKA are compared to previous studies using MARS. For the consolidation of the calculations, a dedicated comparative study of these two codes was performed for a reduced setup.

  3. An Upper Bound on Orbital Debris Collision Probability When Only One Object has Position Uncertainty Information

    NASA Technical Reports Server (NTRS)

    Frisbee, Joseph H., Jr.

    2015-01-01

    no good because the analyst defaults to no knowledge of the combined, relative position error covariance matrix. It is reasonable to think, given an assumption of no covariance information, an analyst might still attempt to determine the error covariance matrix that results in an upper bound on the P (sub c). Without some guidance on limits to the shape, size and orientation of the unknown covariance matrix, the limiting case is a degenerate ellipse lying along the relative miss vector in the collision plane. Unless the miss position is exceptionally large or the at-risk object is exceptionally small, this method results in a maximum P (sub c) too large to be of practical use. For example, assuming that the miss distance is equal to the current ISS alert volume along-track (+ or -) distance of 25 kilometers and that the at-risk area has a 70 meter radius. The maximum (degenerate ellipse) P (sub c) is about 0.00136. At 40 kilometers, the maximum P (sub c) would be 0.00085 which is still almost an order of magnitude larger than the ISS maneuver threshold of 0.0001. In fact, a miss distance of almost 340 kilometers is necessary to reduce the maximum P (sub c) associated with this degenerate ellipse to the ISS maneuver threshold value. Such a result is frequently of no practical value to the analyst. Some improvement may be made with respect to this problem by realizing that while the position error covariance matrix of one of the objects (usually the debris object) may not be known the position error covariance matrix of the other object (usually the asset) is almost always available. Making use of the position error covariance information for the one object provides an improvement in finding a maximum P (sub c) which, in some cases, may offer real utility. The equations to be used are presented and their use discussed.

  4. Monitoring hazardous near-Earth-object debris at 1 au using interplanetary magnetic signatures resulting from meteoroid-asteroid collisions

    NASA Astrophysics Data System (ADS)

    Lai, H.; Russell, C.; Wei, H.; Connors, M.; Delzanno, G.

    2014-07-01

    While telescopic observations can determine accurately the orbits of potentially hazardous NEOs, they do not resolve the debris trail that accompanies these objects. The density of impactors increases with decreasing size, and these smaller objects upon impact can release material from the parent object and at times may completely disrupt it. This material leaves the region in which the collision occurred with momentum gained or lost in the collision and may move out of the original safe orbit into one that is hazardous to Earth. Thus we are at greater risk of a hazardous collision than our telescopic observations lead us to believe. Because material in these debris trails suffers disruptive collisions with the numerous but much smaller solar system meteoroid populations, and because this material becomes ionized and interacts with the solar wind, we can use magnetometers in space to monitor the amount and size distribution of potentially hazardous objects near 1 au. We have applied this to materials accompanying asteroid 138175 in its orbit around the Sun. Statistical results reveal that those materials are of tens of meters in diameter and have significant dispersion about the asteroid's orbit. A temporal study from 1970s to present shows that the lifetime of those co-orbiting materials are decades, which can be explained by their orbital resonance with Earth and Venus.

  5. A 3-D collision handling algorithm for surgery simulation based on feedback fuzzy logic.

    PubMed

    García-Pérez, Verónica; Muñoz-Moreno, Emma; Aja-Fernández, Santiago; Alberola-López, Carlos

    2009-07-01

    In this paper, we propose a new method for collision handling between 3-D deformable (organs) and rigid (surgical tools) objects valid for nonstructured interaction scenes and, specifically, for laparoscopic surgery simulators. During the simulation step, vertices of the organ detected as collided must be accurately shifted out of the tool to elude a visual interpenetration. The proposed approach obtains the new position of each collided vertex of the organ taking into account both kinematic information of the surgical tool and geometric information of the organ surface that surrounds the vertex under analysis. Three parameters inferred from a fuzzy feedback system weigh the nature of the tool motion with respect to the organ. Experimental results show that the solution proposed in this paper is able to avoid the interpenetration among the multiple colliding points efficiently with physically and spatially coherent results.

  6. Handling collision debris in quad- and dipole-first LHC IR options

    SciTech Connect

    Mokhov, N.V.; Rakhno, I.L.; /Fermilab

    2006-12-01

    Detailed MARS15 Monte Carlo energy deposition calculations are performed for two main designs of the LHC interaction regions (IR) capable to achieve a luminosity of 10{sup 35} cm{sup -2} s{sup -1}: a traditional quadrupole-first scheme and the one with a dual-bore inner triplet with separation dipoles placed in front of the quadrupoles. It is shown that with the appropriate design of the Nb3Sn magnets, IR layout and a number of protective measures implemented, both schemes are feasible for the LHC luminosity upgrade up to 10{sup 35} cm{sup -2} s{sup -1}.

  7. LIDT-DD: A new hybrid model to understand debris discs observations - The case of massive collisions.

    NASA Astrophysics Data System (ADS)

    Kral, Q.; Thébault, P.; Augereau, J.-C.; Boccaletti, A.; Charnoz, S.

    2014-12-01

    LIDT-DD is a new hybrid model coupling the collisional and dynamical evolution in debris discs in a self-consistent way. It has been developed in a way that allows to treat a large number of different astrophysical cases where collisions and dynamics have an important role. This interplay was often totally neglected in previous studies whereas, even for the simplest configurations, the real physics of debris discs imposes strong constraints and interactions between dynamics and collisions. After presenting the LIDT-DD model, we will describe the evolution of violent stochastic collisional events with this model. These massive impacts have been invoked as a possible explanation for some debris discs displaying pronounced azimuthal asymmetries or having a luminosity excess exceeding that expected for systems at collisional steady-state. So far, no thorough modelling of the consequences of such stochastic events has been carried out, mainly because of the extreme numerical challenge of coupling the dynamical and collisional evolution of the released dust. We follow the collisional and dynamical evolution of dust released after the breakup of a Ceres-sized body at 6 AU from its central star. We investigate the duration, magnitude and spatial structure of the signature left by such a violent event, as well as its observational detectability. We use the GRaTer package to estimate the system's luminosity at different wavelengths and derive synthetic images for the SPHERE/VLT and MIRI/JWST instruments.

  8. Star Formation in Collision Debris: Insights from the Modeling of Their Spectral Energy Distribution

    NASA Astrophysics Data System (ADS)

    Boquien, M.; Duc, P.-A.; Galliano, F.; Braine, J.; Lisenfeld, U.; Charmandaris, V.; Appleton, P. N.

    2010-12-01

    During galaxy-galaxy interactions, massive gas clouds can be injected into the intergalactic medium which in turn become gravitationally bound, collapse, and form stars, star clusters, or even dwarf galaxies. The objects resulting from this process are both "pristine," as they are forming their first generation of stars, and chemically evolved because the metallicity inherited from their parent galaxies is high. Such characteristics make them particularly interesting laboratories in which to study star formation. After having investigated their star-forming properties, we use photospheric, nebular, and dust modeling to analyze their spectral energy distribution (SED) from the far-ultraviolet to the mid-infrared regime for a sample of seven star-forming regions. Our analysis confirms that the intergalactic star-forming regions in Stephan's Quintet, around Arp 105 and NGC 5291, appear devoid of stellar populations older than 109 years. We also find an excess of light in the near-infrared regime (from 2 μm to 4.5 μm) which cannot be attributed to stellar photospheric or nebular contributions. This excess is correlated with the star formation rate intensity suggesting that it is probably due to emission by very small grains fluctuating in temperature as well as the polycyclic aromatic hydrocarbons line at 3.3 μm. Comparing the attenuation via the Balmer decrement to the mid-infrared emission allows us to check the reliability of the attenuation estimate. It suggests the presence of embedded star-forming regions in NGC 5291 and NGC 7252. Overall the SED of star-forming regions in collision debris (and Tidal Dwarf Galaxies) resemble more that of dusty star-forming regions in galactic disks than to that of typical star-forming dwarf galaxies.

  9. STAR FORMATION IN COLLISION DEBRIS: INSIGHTS FROM THE MODELING OF THEIR SPECTRAL ENERGY DISTRIBUTION

    SciTech Connect

    Boquien, M.; Duc, P.-A.; Galliano, F.; Charmandaris, V.; Appleton, P. N.

    2010-12-15

    During galaxy-galaxy interactions, massive gas clouds can be injected into the intergalactic medium which in turn become gravitationally bound, collapse, and form stars, star clusters, or even dwarf galaxies. The objects resulting from this process are both 'pristine', as they are forming their first generation of stars, and chemically evolved because the metallicity inherited from their parent galaxies is high. Such characteristics make them particularly interesting laboratories in which to study star formation. After having investigated their star-forming properties, we use photospheric, nebular, and dust modeling to analyze their spectral energy distribution (SED) from the far-ultraviolet to the mid-infrared regime for a sample of seven star-forming regions. Our analysis confirms that the intergalactic star-forming regions in Stephan's Quintet, around Arp 105 and NGC 5291, appear devoid of stellar populations older than 10{sup 9} years. We also find an excess of light in the near-infrared regime (from 2 {mu}m to 4.5 {mu}m) which cannot be attributed to stellar photospheric or nebular contributions. This excess is correlated with the star formation rate intensity suggesting that it is probably due to emission by very small grains fluctuating in temperature as well as the polycyclic aromatic hydrocarbons line at 3.3 {mu}m. Comparing the attenuation via the Balmer decrement to the mid-infrared emission allows us to check the reliability of the attenuation estimate. It suggests the presence of embedded star-forming regions in NGC 5291 and NGC 7252. Overall the SED of star-forming regions in collision debris (and Tidal Dwarf Galaxies) resemble more that of dusty star-forming regions in galactic disks than to that of typical star-forming dwarf galaxies.

  10. Growth in the quantity of debris in Space as AN effect of mutual mechanical collisions of various types

    NASA Astrophysics Data System (ADS)

    Sotskiy, M. Yu.; Veldanov, V. A.; Selivanov, V. V.

    2017-06-01

    Estimates are determined of the potential consequences of mutual collisions of dangerous space objects both among themselves and with operating space systems. Research extrapolating the existing objective estimates and supervision of pollution in low Earth orbits shows the probability of catastrophic growth in the number of objects and orbital debris in low orbits leading to the practical impossibility of further peaceful scientific exploration of space. The development of methodologies and technologies regarding the comprehensive investigation of shock impacts on space objects and systems becomes the actual task for the creation of conditions for the safe development of peaceful space explorations. Research involving the collision processes, including the dynamics and associated consequences, developing means and pathways of protection for spaceships, protection of structures and systems from the influence of high-speed objects, means and methods to remove debris from space, and the use of dangerous objects. The technology of measurements with applications in tensometry provides data acquisition concerning the shock impulse in a wide range of collision conditions, and ensuring a physical and constructive variety of the impacting objects is considered.

  11. Algorithms for the Computation of Debris Risks

    NASA Technical Reports Server (NTRS)

    Matney, Mark

    2017-01-01

    Determining the risks from space debris involve a number of statistical calculations. These calculations inevitably involve assumptions about geometry - including the physical geometry of orbits and the geometry of non-spherical satellites. A number of tools have been developed in NASA's Orbital Debris Program Office to handle these calculations; many of which have never been published before. These include algorithms that are used in NASA's Orbital Debris Engineering Model ORDEM 3.0, as well as other tools useful for computing orbital collision rates and ground casualty risks. This paper will present an introduction to these algorithms and the assumptions upon which they are based.

  12. Algorithms for the Computation of Debris Risk

    NASA Technical Reports Server (NTRS)

    Matney, Mark J.

    2017-01-01

    Determining the risks from space debris involve a number of statistical calculations. These calculations inevitably involve assumptions about geometry - including the physical geometry of orbits and the geometry of satellites. A number of tools have been developed in NASA’s Orbital Debris Program Office to handle these calculations; many of which have never been published before. These include algorithms that are used in NASA’s Orbital Debris Engineering Model ORDEM 3.0, as well as other tools useful for computing orbital collision rates and ground casualty risks. This paper presents an introduction to these algorithms and the assumptions upon which they are based.

  13. LightForce photon-pressure collision avoidance: Efficiency analysis in the current debris environment and long-term simulation perspective

    NASA Astrophysics Data System (ADS)

    Yang Yang, Fan; Nelson, Bron; Aziz, Jonathan; Carlino, Roberto; Dono Perez, Andres; Faber, Nicolas; Foster, Cyrus; Frost, Chad; Henze, Chris; Karacalıoğlu, Arif Göktuğ; Levit, Creon; Marshall, William; Mason, James; O'Toole, Conor; Swenson, Jason; Worden, Simon P.; Stupl, Jan

    2016-09-01

    This work provides an efficiency analysis of the LightForce space debris collision avoidance scheme in the current debris environment and describes a simulation approach to assess its impact on the long-term evolution of the space debris environment. LightForce aims to provide just-in-time collision avoidance by utilizing photon pressure from ground-based industrial lasers. These ground stations impart minimal accelerations to increase the miss distance for a predicted conjunction between two objects. In the first part of this paper we will present research that investigates the short-term effect of a few systems consisting of 20 kW class lasers directed by 1.5 m diameter telescopes using adaptive optics. The results found such a network of ground stations to mitigate more than 85 percent of conjunctions and could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. While these are impressive numbers that indicate LightForce's utility in the short-term, the remaining 15 % of possible collisions contain (among others) conjunctions between two massive objects that would add large amount of debris if they collide. Still, conjunctions between massive objects and smaller objects can be mitigated. Hence, we choose to expand the capabilities of the simulation software to investigate the overall effect of a network of LightForce stations on the long-term debris evolution. In the second part of this paper, we will present the planned simulation approach for that effort. For the efficiency analysis of collision avoidance in the current debris environment, we utilize a simulation approach that uses the entire Two Line Element (TLE) catalog in LEO for a given day as initial input. These objects are propagated for one year and an all-on-all conjunction analysis is performed. For conjunctions that fall below a range threshold, we calculate the probability of collision and record those values. To assess efficiency, we compare a baseline

  14. Revealing Asymmetries in the HD181327 Debris Disk: A Recent Massive Collision or Interstellar Medium Warping

    NASA Technical Reports Server (NTRS)

    Stark, Christopher C.; Schneider, Glenn; Weinberger, Alycia J.; Debes, John H.; Grady, Carol A.; Jang-Condell, Hannah; Kuchner, Marc J.

    2014-01-01

    New multi-roll coronagraphic images of the HD181327 debris disk obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope reveal the debris ring in its entirety at high signal-to-noise ratio and unprecedented spatial resolution. We present and apply a new multi-roll image processing routine to identify and further remove quasi-static point-spread function-subtraction residuals and quantify systematic uncertainties. We also use a new iterative image deprojection technique to constrain the true disk geometry and aggressively remove any surface brightness asymmetries that can be explained without invoking dust density enhancements/ deficits. The measured empirical scattering phase function for the disk is more forward scattering than previously thought and is not well-fit by a Henyey-Greenstein function. The empirical scattering phase function varies with stellocentric distance, consistent with the expected radiation pressured-induced size segregation exterior to the belt. Within the belt, the empirical scattering phase function contradicts unperturbed debris ring models, suggesting the presence of an unseen planet. The radial profile of the flux density is degenerate with a radially varying scattering phase function; therefore estimates of the ring's true width and edge slope may be highly uncertain.We detect large scale asymmetries in the disk, consistent with either the recent catastrophic disruption of a body with mass greater than 1% the mass of Pluto, or disk warping due to strong interactions with the interstellar medium.

  15. Revealing Asymmetries in the HD 181327 Debris Disk: A Recent Massive Collision or Interstellar Medium Warping

    NASA Astrophysics Data System (ADS)

    Stark, Christopher C.; Schneider, Glenn; Weinberger, Alycia J.; Debes, John H.; Grady, Carol A.; Jang-Condell, Hannah; Kuchner, Marc J.

    2014-07-01

    New multi-roll coronagraphic images of the HD 181327 debris disk obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope reveal the debris ring in its entirety at high signal-to-noise ratio and unprecedented spatial resolution. We present and apply a new multi-roll image processing routine to identify and further remove quasi-static point-spread function-subtraction residuals and quantify systematic uncertainties. We also use a new iterative image deprojection technique to constrain the true disk geometry and aggressively remove any surface brightness asymmetries that can be explained without invoking dust density enhancements/deficits. The measured empirical scattering phase function for the disk is more forward scattering than previously thought and is not well-fit by a Henyey-Greenstein function. The empirical scattering phase function varies with stellocentric distance, consistent with the expected radiation pressured-induced size segregation exterior to the belt. Within the belt, the empirical scattering phase function contradicts unperturbed debris ring models, suggesting the presence of an unseen planet. The radial profile of the flux density is degenerate with a radially varying scattering phase function; therefore estimates of the ring's true width and edge slope may be highly uncertain. We detect large scale asymmetries in the disk, consistent with either the recent catastrophic disruption of a body with mass >1% the mass of Pluto, or disk warping due to strong interactions with the interstellar medium.

  16. Revealing asymmetries in the HD 181327 debris disk: A recent massive collision or interstellar medium warping

    SciTech Connect

    Stark, Christopher C.; Kuchner, Marc J.; Schneider, Glenn; Weinberger, Alycia J.; Debes, John H.; Grady, Carol A.; Jang-Condell, Hannah

    2014-07-01

    New multi-roll coronagraphic images of the HD 181327 debris disk obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope reveal the debris ring in its entirety at high signal-to-noise ratio and unprecedented spatial resolution. We present and apply a new multi-roll image processing routine to identify and further remove quasi-static point-spread function-subtraction residuals and quantify systematic uncertainties. We also use a new iterative image deprojection technique to constrain the true disk geometry and aggressively remove any surface brightness asymmetries that can be explained without invoking dust density enhancements/deficits. The measured empirical scattering phase function for the disk is more forward scattering than previously thought and is not well-fit by a Henyey-Greenstein function. The empirical scattering phase function varies with stellocentric distance, consistent with the expected radiation pressured-induced size segregation exterior to the belt. Within the belt, the empirical scattering phase function contradicts unperturbed debris ring models, suggesting the presence of an unseen planet. The radial profile of the flux density is degenerate with a radially varying scattering phase function; therefore estimates of the ring's true width and edge slope may be highly uncertain. We detect large scale asymmetries in the disk, consistent with either the recent catastrophic disruption of a body with mass >1% the mass of Pluto, or disk warping due to strong interactions with the interstellar medium.

  17. Detection of Orbital Debris Collision Risks for the Automated Transfer Vehicle

    NASA Technical Reports Server (NTRS)

    Peret, L.; Legendre, P.; Delavault, S.; Martin, T.

    2007-01-01

    In this paper, we present a general collision risk assessment method, which has been applied through numerical simulations to the Automated Transfer Vehicle (ATV) case. During ATV ascent towards the International Space Station, close approaches between the ATV and objects of the USSTRACOM catalog will be monitored through collision rosk assessment. Usually, collision risk assessment relies on an exclusion volume or a probability threshold method. Probability methods are more effective than exclusion volumes but require accurate covariance data. In this work, we propose to use a criterion defined by an adaptive exclusion area. This criterion does not require any probability calculation but is more effective than exclusion volume methods as demonstrated by our numerical experiments. The results of these studies, when confirmed and finalized, will be used for the ATV operations.

  18. LightForce Photon-pressure Collision Avoidance: Efficiency Analysis in the Current Debris Environment and Long-Term Simulation Perspective

    NASA Technical Reports Server (NTRS)

    Yang, Fan Y.; Nelson, Bron; Carlino, Roberto; Perez, Andres D.; Faber, Nicolas; Henze, Chris; Karacahoglu, Arif G.; O'Toole, Conor; Swenson, Jason; Stupl, Jan

    2015-01-01

    This work provides an efficiency analysis of the LightForce space debris collision avoidance scheme in the current debris environment and describes a simulation approach to assess its impact on the long-term evolution of the space debris environment. LightForce aims to provide just-in-time collision avoidance by utilizing photon pressure from ground-based industrial lasers. These ground stations impart minimal accelerations to increase the miss distance for a predicted conjunction between two objects. In the first part of this paper we will present research that investigates the short-term effect of a few systems consisting of 10kW class lasers directed by 1.5 m diameter telescopes using adaptive optics. The results found such a network of ground stations to mitigate more than 85 percent of conjunctions and could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. While these are impressive numbers that indicate LightForce's utility in the short-term, the remaining 15 percent of possible collisions contain (among others) conjunctions between two massive objects that would add large amount of debris if they collide. Still, conjunctions between massive objects and smaller objects can be mitigated. Hence we choose to expand the capabilities of the simulation software to investigate the overall effect of a network of LightForce stations on the long-term debris evolution. In the second part of this paper, we will present the planed simulation approach for that effort.

  19. Debris Disk Variability - Exploring the Diverse Outcomes of Large Collisions during the Eras of Oligarchic and Chaotic Growth

    NASA Astrophysics Data System (ADS)

    Su, Kate

    The potential to study Earth-like planets in habitable zones has electrified the astronomical community as well as the general public. Nearly all our efforts toward this goal address mature planets, detected through radial velocity or transit techniques. However, none of these efforts will reveal the steps by which these planets grow from embryos to their current sizes through collisions of objects ranging in size from asteroids to protoplanets, a process that lasts for the first 200 Myr of their existence. The critical stages of terrestrial planet formation (and in some cases destruction) have only been in the realm of computer simulations. Observational inputs to these simulations have, until now, been limited, largely based on indirect detection of planets and statistical distributions of debris disk incidence. However, the newly discovered variable emission by extreme debris disks (young 10-200 Myr systems with fractional dust luminosity on the order of 1%) provides a unique opportunity to learn about asteroid-sized bodies in young exoplanetary systems and to explore planetesimal collisions and their aftermaths during the era of terrestrial planet building. The first such system identified, NGC 2547-ID8 (a 35 Myr solar-type star), is the most thoroughly studied. Data taken by Spitzer between 2012 and 2013 showed a significant brightening followed by monthly quasi-periodic variations on top of a year-long flux decline. The disk variability is best explained by a large impact involving asteroids a few hundred km in size. This dramatic event produced an optically thick cloud of mm-size droplets condensed from the impact produced vapor. The subsequent collisional cascades inside the cloud and the large optical depth of the resulting dust, combined with its orbital motion, produced complex variability in the disk output. Further monitoring with Spitzer shows that additional collisional events are occurring in ID8. ID8 is one of a dozen extreme disks observed to vary

  20. Spectroscopic Measurements of Collision-less Coupling Between Laser-Produced, Super-Alfvénic Debris Plasmas and Magnetized, Ambient Plasmas

    NASA Astrophysics Data System (ADS)

    Bondarenko, Anton; Everson, E.; Schaeffer, D.; Constantin, C.; Vincena, S.; Van Compernolle, B.; Clark, S.; Niemann, C.

    2013-06-01

    Emission spectroscopy is currently being utilized in order to assess collision-less momentum and energy coupling between super-Alfvénic debris plasmas and magnetized, ambient plasmas of astrophysical relevance. In a recent campaign on the Large Plasma Device (LAPD) utilizing the Phoenix laboratory Raptor laser (130 J, 25 ns FWHM), laser-ablated carbon debris plasmas were generated within magnetized, ambient helium plasmas (nelec ≈ 3×1012 cm-3, Telec ≈ 5.5 eV, B0 = 200 G), and prominent spectral lines of carbon and helium ions were studied in high resolution (˜ 0.01 nm). Time-resolved Doppler shift and width measurements of a C V ion spectral line reveal significant deceleration as the ions stream through the background plasma, which may indirectly indicate momentum coupling. Spectral lines of He II ions are observed to intensify by orders of magnitude and broaden, indicating energy transfer from the debris plasma to the background plasma.

  1. A Summary of the NASA ISS Space Debris Collision Avoidance Program

    NASA Technical Reports Server (NTRS)

    Frisbee, Joseph

    2002-01-01

    Creating and implementing a process for the mitigation of the impact hazards due to cornets and asteroids will prove to be a complex and involved process. The closest similar program is the collision avoidance process currently used for protection of the International Space Station (ISS). This process, in operation for over three years, has many similarities to the NEG risk problem. By reviewing the ISS program, a broader perspective on the complications of and requirements for a NEO risk mitigation program might be obtained. Specifically, any lessons learned and continuing issues of concern might prove useful in the development of a NEO risk assessment and mitigation program.

  2. A collision in 2009 as the origin of the debris trail of asteroid P/2010 A2.

    PubMed

    Snodgrass, Colin; Tubiana, Cecilia; Vincent, Jean-Baptiste; Sierks, Holger; Hviid, Stubbe; Moissl, Richard; Boehnhardt, Hermann; Barbieri, Cesare; Koschny, Detlef; Lamy, Philippe; Rickman, Hans; Rodrigo, Rafael; Carry, Benoît; Lowry, Stephen C; Laird, Ryan J M; Weissman, Paul R; Fitzsimmons, Alan; Marchi, Simone

    2010-10-14

    The peculiar object P/2010 A2 was discovered in January 2010 and given a cometary designation because of the presence of a trail of material, although there was no central condensation or coma. The appearance of this object, in an asteroidal orbit (small eccentricity and inclination) in the inner main asteroid belt attracted attention as a potential new member of the recently recognized class of main-belt comets. If confirmed, this new object would expand the range in heliocentric distance over which main-belt comets are found. Here we report observations of P/2010 A2 by the Rosetta spacecraft. We conclude that the trail arose from a single event, rather than a period of cometary activity, in agreement with independent results. The trail is made up of relatively large particles of millimetre to centimetre size that remain close to the parent asteroid. The shape of the trail can be explained by an initial impact ejecting large clumps of debris that disintegrated and dispersed almost immediately. We determine that this was an asteroid collision that occurred around 10 February 2009.

  3. Benefits of Active Debris Removal on the LEO Debris Population

    NASA Astrophysics Data System (ADS)

    Maniwa, Kazuaki; Hanada, Toshiya; Kawamoto, Satomi

    Since the launch of Sputnik, orbital debris population continues to increase due to ongoing space activities, on-orbit explosions, and accidental collisions. In the future, a great deal of fragments can be expected to be created by explosions and collisions. In spite of prevention of satellite and rocket upper stage explosions and other mitigation measures, debris population in low Earth orbit may not be stabilized. To better limit the growth of the future debris population, it is necessary to remove the existing debris actively. This paper studies about the effectiveness of active debris removal in low Earth orbit where the collision rate with and between space debris is high. This study does not consider economic problems, but investigates removing debris which may stabilize well the current debris population based on the concept of Japan Aerospace Exploration Agency.

  4. 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)

  5. 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

  6. Active Debris Removal

    NASA Technical Reports Server (NTRS)

    Burns, Susan H.

    2012-01-01

    Orbital debris in Low Earth Orbit (LEO) is an international problem that threatens the success of future space ventures. An analysis of a wide variety of alternative solutions for active debris removal (ADR) has been performed. The solution selected is an efficient, effective, and executable solution to remove large debris in LEO, primarily spent rocket bodies. Removing large debris objects is a critical step in reducing the hazard from orbital debris, because of the large amount of medium and small debris created through large body collisions. Based on the analysis of alternatives, the concept and design for a vehicle which could efficiently address the debris hazard by disposing of several large objects per mission has been developed. This concept establishes a comprehensive, detailed technical approach for an actual end-to-end, on-orbit ADR solution to remove large debris. This robust solution enables the start of solving the problem of debris removal before it reaches a critical and potentially irreversible state by "getting there as soon as possible, as economically as possible, with the most capability".

  7. Orbital debris issues

    NASA Technical Reports Server (NTRS)

    Kessler, D. J.

    1985-01-01

    Man-made orbital debris, identified as a potential hazard to future space activities, is grouped into size categories. At least 79 satellites have broken up in orbit to date and, in combination with exploded rocket casings and antisatellite debris, threaten 10 km/sec collisions with other orbiting platforms. Only 5 percent of the debris is connected to payloads. The total population of orbiting objects over 4 cm in diameter could number as high as 15,000, and at 1 cm in diameter could be 32,000, based on NASA and NORAD studies. NASA has initiated the 10 yr Space Debris Assessment Program to characterize the hazards of orbiting debris, the potential damage to typical spacecraft components, and to identify means of controlling the damage.

  8. A contribution to the definition of a new method to predict the catastrophic disintegration of spacecraft after collision with large orbital debris

    NASA Astrophysics Data System (ADS)

    Zaccariotto, M.; Francesconi, A.; Galvanetto, U.

    2016-10-01

    The main limitation of the currently adopted method for predicting spacecraft catastrophic fragmentation due to a collision with large debris is the total independence of the critical value of the energy-to-target mass ratio from both the satellite configuration and the impact point; in fact these two issues are not accounted for by the classical 40 J/g rule. To go beyond this limitation, the method proposed in this paper evaluates the distribution of impact energy into the system using the mechanical properties of the structural parts and the knowledge of the impact location. In this way, it becomes possible to predict how impact energy is partitioned among some selected macroscopic structural parts, each of them is finally evaluated versus its own minimum value of impact energy for which the part is fragmented (shattering threshold). Energy partition is performed by solving a system of equations written according to Statistical Energy Analysis (SEA). The paper describes in detail the proposed energy-partition method and presents its application to a geometrical representative model of a spacecraft subject to impact at different points. Results are finally compared to those obtained by the application of the classical 40 J/g rule. It is shown that the evaluation of spacecraft disintegration is highly influenced by the impact point and the structural properties of the components.

  9. Adaptive optics for laser space debris removal

    NASA Astrophysics Data System (ADS)

    Bennet, Francis; Conan, Rodolphe; D'Orgeville, Celine; Dawson, Murray; Paulin, Nicolas; Price, Ian; Rigaut, Francois; Ritchie, Ian; Smith, Craig; Uhlendorf, Kristina

    2012-07-01

    Space debris in low Earth orbit below 1500km is becoming an increasing threat to satellites and spacecrafts. Radar and laser tracking are currently used to monitor the orbits of thousands of space debris and active satellites are able to use this information to manoeuvre out of the way of a predicted collision. However, many satellites are not able to manoeuvre and debris-on debris collisions are becoming a signicant contributor to the growing space debris population. The removal of the space debris from orbit is the preferred and more denitive solution. Space debris removal may be achieved through laser ablation, whereby a high power laser corrected with an adaptive optics system could, in theory, allow ablation of the debris surface and so impart a remote thrust on the targeted object. The goal of this is to avoid collisions between space debris to prevent an exponential increase in the number of space debris objects. We are developing an experiment to demonstrate the feasibility of laser ablation for space debris removal. This laser ablation demonstrator utilises a pulsed sodium laser to probe the atmosphere ahead of the space debris and the sun re ection of the space debris is used to provide atmospheric tip{tilt information. A deformable mirror is then shaped to correct an infrared laser beam on the uplink path to the debris. We present here the design and the expected performance of the system.

  10. Debris impact on Earth-orbiting spacecraft

    NASA Technical Reports Server (NTRS)

    Smith, D. G.

    1985-01-01

    The accumulation of Earth-orbiting space debris leads to important new design considerations. Some 5,000 orbiting objects, many of them explosion fragments, are currently being tracked and future collision of these objects with each other is predicted. These collisions will occur at high velocities. Each collision will be explosive, ejecting thousands, of new orbiting objects, in turn increasing the frequency of future collisions. The debris population may thus become self-regenerative, and the future flux of orbiting debris will exceed that of meteoroids. As a result, a large space structure in Earth-orbit for several years has a significant probability of impact by debris objects. As a design problem, debris impact is significantly different from meteoroid impact. Protection against such large objects may require structural measures. The consideration of debris impact in the design of large, Earth-orbiting spacecraft is recommended.

  11. Orbiting Space Debris: Dangers, Measurement and Mitigation

    DTIC Science & Technology

    1992-01-01

    B.5 Raw Video Signal of Debris Streak - Single Frame 281 Figure B.6 50 Shifted and Added Video Frames After 282 Background Subtraction Figure B.7...caused collisions. The leading candidate for a hyper-velocity collision with debris is the Cosmos 1275 fragmentation in 1981 which created 281 ...sensitivity. 280 SA ~ .0 . n I I4 MOM- Figure B.5 Raw Video Signal of Debris Streak - Single Frame 281 Figure B.6 50 Shifted and Added Video Frames After

  12. Threats to U.S. National Security Interests in Space: Orbital Debris Mitigation and Removal

    DTIC Science & Technology

    2014-01-08

    platforms in space from collisions with orbital debris . Some experts maintain the population growth of debris in space will be primarily driven by catastrophic collisions that are likely to occur every five to nine years.

  13. Rates inferred from the space debris catalog

    SciTech Connect

    Canavan, G.H.

    1996-08-01

    Collision and fragmentation rates are inferred from the AFSPC space debris catalog and compare with estimates from other treatments. The collision rate is evaluated without approximation. The fragmentation rate requires additional empirical assessments. The number of fragments per collision is low compared to analytic and numerical treatments, is peaked low, and falls rapidly with altitude.

  14. Shielding against debris

    NASA Technical Reports Server (NTRS)

    Cour-Palais, Burton G.; Avans, Sherman L.

    1988-01-01

    The damage to spacecraft caused by debris and design of the Space Station to minimize damage from debris are discussed. Although current estimates of the debris environment show that fragments bigger than 2 cm are not likely to hit the Space Station, orbital debris from about 0.5 mm to 2 cm will pose a hazard, especially on brittle surfaces, such as glass. Spacesuits are being designed to reduce debris caused dangers to astronauts during EVA. About 5 cm of high-strength aluminum are needed to prevent penetration by a 1 cm piece of aluminum with a mass near 1.5 g colliding at 10 km/sec. Because aluminum bumpers have the drawback of metallic debris ejected outward after a hypervelocity collision, the use of nonmetallic materials for bumpers is being studied. Methods of reducing the weight and volume of the shield for the Space Station are also being researched. A space station habitation module using bumpers has a 99.6 percent chance of avoiding penetration during its lifetime.

  15. 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

  16. An Assessment of the Current LEO Debris Environment and the Need for Active Debris Removal

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi

    2010-01-01

    The anti-satellite test on the Fengun-1 C weather satellite in early 2007 and the collision between Iridium 33 and Cosmos 2251 in 2009 dramatically altered the landscape of the human-made orbital debris environment in the low Earth orbit (LEO). The two events generated approximately 5500 fragments large enough to be tracked by the U.S. Space Surveillance Network. Those fragments account for more than 60% increase to the debris population in LEO. However, even before the ASAT test, model analyses already indicated that the debris population (for those larger than 10 cm) in LEO had reached a point where the population would continue to increase, due to collisions among existing objects, even without any future launches. The conclusion implies that as satellites continue to be launched and unexpected breakup events continue to occur, commonly-adopted mitigation measures will not be able to stop the collision-driven population growth. To remediate the debris environment in LEO, active debris removal must be considered. This presentation will provide an updated assessment of the debris environment after the Iridium 33/Cosmos 2251 collision, an analysis of several future environment projections based on different scenarios, and a projection of collision activities in LEO in the near future. The need to use active debris removal to stabilize future debris environment will be demonstrated and the effectiveness of various active debris removal strategies will be quantified.

  17. Debris disks: a theorist's view

    NASA Astrophysics Data System (ADS)

    Krivov, A. V.

    2007-08-01

    Debris disks are roughly solar system-sized, optically thin, gas-poor dust disks that encircle a notable fraction of main-sequence stars at ages ranging from about 10 Myr to several Gyr. They are thought to be continuously replenished by collisions between "exoasteroids" and activity of "exocomets", small bodies left over from the planet formation process. I will first outline main physical mechanisms operating in debris disks and compare them with other dusty systems: protoplanetary disks, dusty planetary rings, and classical Saturn's rings. I will then review basic methods and essential results of debris disks modeling, covering both steady-state and stochastic models of axisymmetric and structured disks.

  18. An Introduction to Space Debris

    NASA Astrophysics Data System (ADS)

    Wright, David

    2008-04-01

    Space debris is any human-made object in orbit that no longer serves a useful purpose, including defunct satellites, discarded equipment and rocket stages, and fragments from the breakup of satellites and rocket stages. It is a concern because--due to its very high speed in orbit--even relatively small pieces can damage or destroy satellites in a collision. Since debris at high altitudes can stay in orbit for decades or longer, it accumulates as more is produced and the risk of collisions with satellites grows. Since there is currently no effective way to remove large amounts of debris from orbit, controlling the production of debris is essential for preserving the long-term use of space. Today there are 860 active satellites in orbit, supporting a wide range of civil and military uses. The 50 years of space activity since the launch of Sputnik 1 has also resulted in well over half a million pieces of orbiting debris larger than 1 cm in size. There are two main sources of space debris: (1) routine space activity and the accidental breakup of satellites and stages placed in orbit by such activity, and (2) the testing or use of destructive anti-satellite (ASAT) weapons that physically collide with satellites at high speed. The international community is attempting to reduce the first category by developing strict guidelines to limit the debris created as a result of routine space activities. However, the destruction of a single large spy satellite by an ASAT weapon could double the total amount of large debris in low earth orbit, and there are currently no international restrictions on these systems. This talk will give an introduction to what's in space, the origins of space debris, efforts to stem its growth, the threat it poses to satellites in orbit, and the long-term evolution of the debris population.

  19. Orbiting space debris: Dangers, measurement and mitigation

    NASA Astrophysics Data System (ADS)

    McNutt, Ross T.

    1992-06-01

    Space debris is a growing environmental problem. Accumulation of objects in earth orbit threatens space systems through the possibility of collisions and runaway debris multiplication. The amount of debris in orbit is uncertain due to the lack of information on the population of debris between 1 and 10 centimeters diameter. Collisions with debris even smaller than 1 cm can be catastrophic due to the high orbital velocities involved. Research efforts are under way at NASA, United States Space Command and the Air Force Phillips Laboratory to detect and catalog the debris population in near-earth space. Current international and national laws are inadequate to control the proliferation of space debris. Space debris is a serious problem with large economic, military, technical and diplomatic components. Actions need to be taken now to: determine the full extent of the orbital debris problem; accurately predict the future evolution of the debris population; decide the extent of the debris mitigation procedures required; implement these policies on a global basis via an international treaty. Action must be initiated now, before the loss of critical space systems such as the space shuttle or the space station.

  20. Orbiting space debris: Dangers, measurement, and mitigation

    NASA Astrophysics Data System (ADS)

    McNutt, Ross T.

    1992-01-01

    Space debris is a growing environmental problem. Accumulation of objects in Earth orbit threatens space systems through the possibility of collisions and runaway debris multiplication. The amount of debris in orbit is uncertain due to the lack of information on the population of debris between 1 and 10 centimeters diameter. Collisions with debris even smaller than 1 cm can be catastrophic due to the high orbital velocities involved. Research efforts are under way at NASA, Unites States Space Command and the Air Force Phillips Laboratory to detect and catalog the debris population in near-Earth space. Current international and national laws are inadequate to control the proliferation of space debris. Space debris is a serious problem with large economic, military, technical, and diplomatic components. Actions need to be taken now for the following reasons: determine the full extent of the orbital debris problem; accurately predict the future evolution of the debris population; decide the extent of the debris mitigation procedures required; implement these policies on a global basis via an international treaty. Action must be initiated now, before the the loss of critical space systems such as the Space Shuttle or the Space Station.

  1. A high severity space hazard - Orbital debris

    NASA Technical Reports Server (NTRS)

    Bahr, G. K.; Disimile, P. J.

    1990-01-01

    This paper examines the orbital debris-meteoroid hazard that will be encountered by the Space Station Freedom. Recent reports on the orbital debris studies are discussed with special attention given to the procedures and techniques that can be used to minimize the impact damage, to avoid the collision, and to design shielding distribution so as to reduce the penetration damage.

  2. Woody debris

    Treesearch

    Donna B. Scheungrab; Carl C. Trettin; Russ Lea; Martin F. Jurgensen

    2000-01-01

    Woody debris can be defined as any dead, woody plant material, including logs, branches, standing dead trees, and root wads. Woody debris is an important part of forest and stream ecosystems because it has a role in carbon budgets and nutrient cycling, is a source of energy for aquatic ecosystems, provides habitat for terrestrial and aquatic organisms, and contributes...

  3. Reading the Signatures of Extrasolar Planets in Debris Disks

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc J.

    2009-01-01

    An extrasolar planet sculpts the famous debris dish around Fomalhaut; probably ma ny other debris disks contain planets that we could locate if only we could better recognize their signatures in the dust that surrounds them. But the interaction between planets and debris disks involves both orbital resonances and collisions among grains and rocks in the disks --- difficult processes to model simultanemus]y. I will describe new 3-D models of debris disk dynamics that incorporate both collisions and resonant trapping of dust for the first time, allowing us to decode debris disk images and read the signatures of the planets they contain.

  4. Space Debris & its Mitigation

    NASA Astrophysics Data System (ADS)

    Kaushal, Sourabh; Arora, Nishant

    2012-07-01

    Space debris has become a growing concern in recent years, since collisions at orbital velocities can be highly damaging to functioning satellites and can also produce even more space debris in the process. Some spacecraft, like the International Space Station, are now armored to deal with this hazard but armor and mitigation measures can be prohibitively costly when trying to protect satellites or human spaceflight vehicles like the shuttle. This paper describes the current orbital debris environment, outline its main sources, and identify mitigation measures to reduce orbital debris growth by controlling these sources. We studied the literature on the topic Space Debris. We have proposed some methods to solve this problem of space debris. We have also highlighted the shortcomings of already proposed methods by space experts and we have proposed some modification in those methods. Some of them can be very effective in the process of mitigation of space debris, but some of them need some modification. Recently proposed methods by space experts are maneuver, shielding of space elevator with the foil, vaporizing or redirecting of space debris back to earth with the help of laser, use of aerogel as a protective layer, construction of large junkyards around international space station, use of electrodynamics tether & the latest method proposed is the use of nano satellites in the clearing of the space debris. Limitations of the already proposed methods are as follows: - Maneuvering can't be the final solution to our problem as it is the act of self-defence. - Shielding can't be done on the parts like solar panels and optical devices. - Vaporizing or redirecting of space debris can affect the human life on earth if it is not done in proper manner. - Aerogel has a threshold limit up to which it can bear (resist) the impact of collision. - Large junkyards can be effective only for large sized debris. In this paper we propose: A. The Use of Nano Tubes by creating a mesh

  5. Reduction of CO2 and orbital debris: can CO2 emission trading principles be applied to debris reduction?

    NASA Astrophysics Data System (ADS)

    Orlando, Giovanni; Kinnersley, Mark; Starke, Juergen; Hugel, Sebastian; Hartner, Gloria; Singh, Sanjay; Loubiere, Vincent; Staebler, Dominik-Markus; O'Brien-Organ, Christopher; Schwindt, Stefan; Serreau, Francois; Sharma, Mohit

    In the past years global pollution and the specific situation of global warming changes have been strongly influencing public opinion and thus obliged politicians to initiate/ negotiate in-ternational agreements to control, avoid or at least reduce the impact of CO2 emissions e.g. The Kyoto Protocol (1997) and the International Copenhagen conference on Climate Change (2009). In the orbital debris area the collision between the Iridium33 and Cosmos 2251 satel-lites in 2009 has again pushed to the forefront the discussion of the space pollution by space debris and the increasing risk of critical and catastrophic events during the nominal life time of space objects. It is shown by simulations that for Low Earth Orbits the critical debris situation is already achieved and the existing space objects will probably produce sufficient space debris elements -big enough -to support the cascade effect (Kessler Syndrome). In anal-ogy with CO2 emissions, potential recommendations / regulations to reduce the production of Space Debris or its permanence in orbit, are likely to open new markets involving Miti-gation and Removal of Space Debris. The principle approach for the CO2 emission trading model will be investigated and the applicability for the global space debris handling will be analysed. The major differences of the two markets will be derived and the consequences in-dicated. Potential alternative solutions will be proposed and discussed. For the example of the CO2 emission trading principles within EU and worldwide legal conditions for space debris (national / international laws and recommendations) will be considered as well as the commer-cial approach from the controlled situation of dedicated orders to a free / competitive market in steps. It is of interest to consider forms of potential industrial organisations and interna-tional co-operations to react on a similar architecture for the debris removal trading including incentives and penalties for the different

  6. Behavior of tethered debris with flexible appendages

    NASA Astrophysics Data System (ADS)

    Aslanov, Vladimir S.; Yudintsev, Vadim V.

    2014-11-01

    Active exploration of the space leads to growth of a near-Earth space pollution. The frequency of the registered collisions of space debris with functional satellites highly increased during last 10 years. As a rule a large space debris can be observed from the Earth and catalogued, then it is possible to avoid collision with the active spacecraft. However every large debris is a potential source of a numerous small debris particles. To reduce debris population in the near Earth space the large debris should be removed from working orbits. The active debris removal technique is considered that intend to use a tethered orbital transfer vehicle, or a space tug attached by a tether to the space debris. This paper focuses on the dynamics of the space debris with flexible appendages. Mathematical model of the system is derived using the Lagrange formalism. Several numerical examples are presented to illustrate the mutual influence of the oscillations of flexible appendages and the oscillations of a tether. It is shown that flexible appendages can have a significant influence on the attitude motion of the space debris and the safety of the transportation process.

  7. Space Debris Environment Remediation Concepts

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.; Klinkrad, Heiner

    2009-01-01

    Long-term projections of the space debris environment indicate that even drastic measures, such as an immediate, complete halt of launch and release activities, will not result in a stable environment of man-made space objects. Collision events between already existing space hardware will within a few decades start to dominate the debris population, and result in a net increase of the space debris population, also in size regimes which may cause further catastrophic collisions. Such a collisional cascading will ultimately lead to a run-away situation ("Kessler syndrome"), with no further possibility of human intervention. The International Academy of Astronautics (IAA) has been investigating the status and the stability of the space debris environment in several studies by first looking into space traffic management possibilities and then investigating means of mitigating the creation of space debris. In an ongoing activity, an IAA study group looks at ways of active space debris environment remediation. In contrast to the former mitigation study, the current activity concentrates on the active removal of small and large objects, such as defunct spacecraft, orbital stages, and mission-related objects, which serve as a latent mass reservoir that fuels initial catastrophic collisions and later collisional cascading. The paper will outline different mass removal concepts, e.g. based on directed energy, tethers (momentum exchange or electrodynamic), aerodynamic drag augmentation, solar sails, auxiliary propulsion units, retarding surfaces, or on-orbit capture. Apart from physical principles of the proposed concepts, their applicability to different orbital regimes, and their effectiveness concerning mass removal efficiency will be analyzed. The IAA activity on space debris environment remediation is a truly international project which involves more than 23 contributing authors from 9 different nations.

  8. Nuclear-powered space debris sweeper

    NASA Technical Reports Server (NTRS)

    Metzger, John D.; Leclaire, Rene J., Jr.; Howe, Steven D.; Burgin, Karen C.

    1989-01-01

    Future spacecraft design will be affected by collisions with man-made debris orbiting the earth. Most of this orbital space debris comes from spent rocket stages. It is projected that the source of future debris will be the result of fragmentation of large objects through hypervelocity collisions. Orbiting spacecraft will have to be protected from hypervelocity debris in orbit. The options are to armor the spacecraft, resulting in increased mass, or actively removing the debris from orbit. An active space debris sweeper is described which will utilize momentum transfer to the debris through laser-induced ablation to alter its orbital parameters to reduce orbital lifetime with eventual entry into the earth's atmosphere where it will burn. The paper describes the concept, estimates the amount of velocity change (Delta V) that can be imparted to an object through laser-induced ablation, and investigates the use of a neutral particle beam for the momentum transfer. The space sweeper concept could also be extended to provide a collision avoidance system for the space station and satellites, or could be used for collision protection during interplanetary travel.

  9. 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.

  10. 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.

  11. Space debris: modeling and detectability

    NASA Astrophysics Data System (ADS)

    Wiedemann, C.; Lorenz, J.; Radtke, J.; Kebschull, C.; Horstmann, A.; Stoll, E.

    2017-01-01

    High precision orbit determination is required for the detection and removal of space debris. Knowledge of the distribution of debris objects in orbit is necessary for orbit determination by active or passive sensors. The results can be used to investigate the orbits on which objects of a certain size at a certain frequency can be found. The knowledge of the orbital distribution of the objects as well as their properties in accordance with sensor performance models provide the basis for estimating the expected detection rates. Comprehensive modeling of the space debris environment is required for this. This paper provides an overview of the current state of knowledge about the space debris environment. In particular non-cataloged small objects are evaluated. Furthermore, improvements concerning the update of the current space debris model are addressed. The model of the space debris environment is based on the simulation of historical events, such as fragmentations due to explosions and collisions that actually occurred in Earth orbits. The orbital distribution of debris is simulated by propagating the orbits considering all perturbing forces up to a reference epoch. The modeled object population is compared with measured data and validated. The model provides a statistical distribution of space objects, according to their size and number. This distribution is based on the correct consideration of orbital mechanics. This allows for a realistic description of the space debris environment. Subsequently, a realistic prediction can be provided concerning the question, how many pieces of debris can be expected on certain orbits. To validate the model, a software tool has been developed which allows the simulation of the observation behavior of ground-based or space-based sensors. Thus, it is possible to compare the results of published measurement data with simulated detections. This tool can also be used for the simulation of sensor measurement campaigns. It is

  12. Orbiting Debris: a Space Environmental Problem. Background Paper

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Artificial debris, deposited in a multitude of orbits about the Earth as the result of the exploration and use of the space environment, poses a growing hazard to future space operations. Unless nations sharply reduce the amount of orbital debris they produce, future space activites could suffer loss of capability, loss of income, and even loss of life as a result of collisions between spacecraft and debris. This background paper discusses the sources of debris and how they can be greatly reduced.

  13. The Orbital Debris Problem and the Challenges for Environment Remediation

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.

    2013-01-01

    Orbital debris scientists from major international space agencies, including JAXA and NASA, have worked together to predict the trend of the future environment. A summary presentation was given to the United Nations in February 2013. The orbital debris population in LEO will continue to increase. Catastrophic collisions will continue to occur every 5 to 9 years center dot To limit the growth of the future debris population and to better protect future spacecraft, active debris removal, should be considered.

  14. Orbiting Debris: a Space Environmental Problem. Background Paper

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Artificial debris, deposited in a multitude of orbits about the Earth as the result of the exploration and use of the space environment, poses a growing hazard to future space operations. Unless nations sharply reduce the amount of orbital debris they produce, future space activites could suffer loss of capability, loss of income, and even loss of life as a result of collisions between spacecraft and debris. This background paper discusses the sources of debris and how they can be greatly reduced.

  15. Debris Flow

    NASA Image and Video Library

    2015-04-14

    This image captured by NASA 2001 Mars Odyssey spacecraft shows downslope movement of material from the hill at the top of the image. Linear ridges and channels are visible on the surface to the debris flow deposit.

  16. Debris Production in Hypervelocity Impact ASAT Engagements

    DTIC Science & Technology

    1990-12-01

    collisions and asteroid collisions and asserts, "When normalized by the total ejected mass, as in Equa- tion 6, the distribution of fragments from...in asteroids ), Kessler derives an equation for the number of fragments re- sulting from a collision between earth-orbiting objects (15:2640). The...34 into space). Another possible method to negate satellites without creating orbiting debris is to develop a co-orbital hunter- killer which could

  17. Space Debris Environent Remediation Concepts

    NASA Astrophysics Data System (ADS)

    Klinkrad, H.; Johnson, N. L.

    2009-03-01

    Long-term projections of the space debris environment indicate that even drastic measures, such as an immediate, complete halt of launch and release activities, will not result in a stable environment of man-made space objects. Collision events between already existing space hardware will within a few decades start to dominate the debris population, and result in a net increase of the space debris population, also at sizes which may cause further catastrophic collisions. A collisional cascading may ultimately lead to a run-away situation ("Kessler syndrome"), with no further possibility of human intervention.The International Academy of Astronautics (IAA) has been investigating the status and the stability of the space debris environment in several studies by first looking into space traffic management possibilities, and then investigating means of mitigating the creation of space debris. In an on-going activity, an IAA study group looks into methods of active space debris environment remediation. In contrast to the former mitigation study, the current activity concentrates on the active removal of large objects, such as defunct spacecraft, orbital stages, and mission-related objects, which serve as a latent mass reservoir that fuels initial castastrophic collisions and later collisional cascading. The paper will outline different mass removal concepts, e.g. based on directed energy, tethers (momentum exchange or electro-dynamic), aerodynamic drag augmentation, solar sails, auxiliary propulsion units, retarding surfaces, or on-orbit capture. Apart from physical principles of the proposed concepts, their applicability to different orbital regimes, and their effectiveness concerning mass removal efficiency will be discussed.

  18. Orbital debris: Technical issues and future directions

    NASA Technical Reports Server (NTRS)

    Potter, Andrew (Editor)

    1992-01-01

    An international conference on orbital debris sponsored jointly by the American Institute of Aeronautics and Astronautics, NASA, and the Department of Defense, was held in Baltimore, Maryland, 16-19 Apr. 1990. Thirty-three papers were presented. The papers were grouped into the areas of measurements, modeling, and implications of orbital debris for space flight. New radar and optical measurements of orbital debris were presented that showed the existence of a large population of small debris. Modeling of potential future environments showed that runaway growth of the debris population from random collisions was a real possibility. New techniques for shielding against orbital debris and methods for removal of satellites from orbit were discussed.

  19. Space debris executive summary

    SciTech Connect

    Canavan, G.H.; Judd, O.; Naka, R.F.

    1996-09-01

    Spacecraft, boosters, and fragments are potential hazards to space vehicles, and it is argued that collisions between them could produce a cascade that could preclude activity in LEO in 25 to 50 years. That has generated pressure for constraints on military space operations, so the AF SAB performed a study of technical aspects of the debris problem. The Study was independent of the efforts of the Air Force Space Command (AFSPC) as well as those of and NASA Johnson Space Center (JSC), which is the principal advocate for cascades and constraints. Most work on space debris has been performed by AFSPC and JSC, so the Study was in part an assessment of their efforts, in which both have been cooperative. The Study identified the main disagreements and quantified their impacts. It resolved some issues and provided bounds for the rest. It treated radar and optical observations; launch, explosion, and decay rates; and the number and distribution of fragments from explosions and collisions. That made it possible to address hazard to manned spacecraft at low altitudes and the possibility of cascading at higher altitudes, both of which now appear less likely.

  20. 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.

  1. Space traffic hazards from orbital debris mitigation strategies

    NASA Astrophysics Data System (ADS)

    Smirnov, N. N.; Kiselev, A. B.; Smirnova, M. N.; Nikitin, V. F.

    2015-04-01

    The paper gives coverage of recent advances in mathematical modeling of long term orbital debris evolution within the frames of continua approach. Under the approach the evolution equations contain a number of source terms responsible for the variations of quantities of different fractions of orbital debris population due to fragmentations and collisions. Mechanisms of hypervelocity collisions of debris fragments with pressurized vessels are investigated. The spacecraft shield honeycomb concept is suggested based on principles of impact energy conversion and redistribution and consumption by destroyable structures. The paper is devoted to the 100th anniversary of the founder of space debris research in Moscow State University Prof. G.A. Tyulin.

  2. Active Debris Removal Using Modified Launch Vehicle Upper Stages

    NASA Astrophysics Data System (ADS)

    Nasseri, S. Ali; Emanuelli, Matteo; Raval, Siddharth; Turconi, Andrea

    2013-09-01

    During the past few years, several research programs have assessed the current state and future evolution of space debris in the Low Earth Orbit region. These studies indicate that space debris density could reach a critical level such that there will be a continuous increase in the number of debris objects, primarily driven by debris-debris collision activity known as the Kessler effect. These studies also highlight the urgency for active debris removal.An Active Debris Removal System (ADRS) is capable of approaching the debris object through a close-range rendezvous, stabilizing its attitude, establishing physical contact, and finally de-orbiting the debris object. The de-orbiting phase could be powered by propulsion systems such as chemical rockets or electrodynamic tether (EDT) systems.The aim of this project is to model and evaluate a debris removal mission in which an adapted rocket upper stage, equipped with an electrodynamic tether (EDT) system, is employed for de-orbiting a debris object. This ADRS package is installed initially as part of a launch vehicle on a normal satellite deployment mission, and a far-approach manoeuvre will be required to align the ADRS' orbit with that of the target debris. We begin by selecting a suitable target debris and launch vehicle, and then proceed with modelling the entire debris removal mission from launch to de-orbiting of the target debris object using Analytical Graphic Inc.'s Systems Tool Kit (STK).

  3. NASA's Long-term Debris Environment and Active Debris Removal Modeling Activities

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.

    2009-01-01

    This slide presentation reviews the modeling activities for modeling of the long-term debris environment, the updated assessments of the environment, and the necessity to model the effectiveness of the technologies aimed at the removal of orbital debris. The model being used is named a LEO to GEO environment debris (LEGEND). It is a high fidelity three dimensional numerical simulation model with the capability to treat objects individually. It uses a Monte Carlo approach and a collision probability evaluation algorithm to simulate future satellite breakups and the growth of the debris populations.

  4. The physics of debris flows

    USGS Publications Warehouse

    Iverson, R.M.

    1997-01-01

    Recent advances in theory and experimentation motivate a thorough reassessment of the physics of debris flows. Analyses of flows of dry, granular solids and solid-fluid mixtures provide a foundation for a comprehensive debris flow theory, and experiments provide data that reveal the strengths and limitations of theoretical models. Both debris flow materials and dry granular materials can sustain shear stresses while remaining static; both can deform in a slow, tranquil mode characterized by enduring, frictional grain contacts; and both can flow in a more rapid, agitated mode characterized by brief, inelastic grain collisions. In debris flows, however, pore fluid that is highly viscous and nearly incompressible, composed of water with suspended silt and clay, can strongly mediate intergranular friction and collisions. Grain friction, grain collisions, and viscous fluid flow may transfer significant momentum simultaneously. Both the vibrational kinetic energy of solid grains (measured by a quantity termed the granular temperature) and the pressure of the intervening pore fluid facilitate motion of grains past one another, thereby enhancing debris flow mobility. Granular temperature arises from conversion of flow translational energy to grain vibrational energy, a process that depends on shear rates, grain properties, boundary conditions, and the ambient fluid viscosity and pressure. Pore fluid pressures that exceed static equilibrium pressures result from local or global debris contraction. Like larger, natural debris flows, experimental debris flows of ???10 m3 of poorly sorted, water-saturated sediment invariably move as an unsteady surge or series of surges. Measurements at the base of experimental flows show that coarse-grained surge fronts have little or no pore fluid pressure. In contrast, finer-grained, thoroughly saturated debris behind surge fronts is nearly liquefied by high pore pressure, which persists owing to the great compressibility and moderate

  5. Comparison of space debris estimates

    SciTech Connect

    Canavan, G.H.; Judd, O.P.; Naka, R.F.

    1996-10-01

    Debris is thought to be a hazard to space systems through impact and cascading. The current environment is assessed as not threatening to defense systems. Projected reductions in launch rates to LEO should delay concerns for centuries. There is agreement between AFSPC and NASA analyses on catalogs and collision rates, but not on fragmentation rates. Experiments in the laboratory, field, and space are consistent with AFSPC estimates of the number of fragments per collision. A more careful treatment of growth rates greatly reduces long-term stability issues. Space debris has not been shown to be an issue in coming centuries; thus, it does not appear necessary for the Air Force to take additional steps to mitigate it.

  6. JSC Orbital Debris Website Description

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2006-01-01

    required. These data also help in the analysis and interpretation of impact features on returned spacecraft surfaces. 4) Mitigation - Controlling the growth of the orbital debris population is a high priority for NASA, the United States, and the major space-faring nations of the world to preserve near-Earth space for future generations. Mitigation measures can take the form of curtailing or preventing the creation of new debris, designing satellites to withstand impacts by small debris, and implementing operational procedures ranging from utilizing orbital regimes with less debris, adopting specific spacecraft attitudes, and even maneuvering to avoid collisions with debris. Downloadable items include several documents in PDF format and executable software.and 5) Reentry - Because of the increasing number of objects in space, NASA has adopted guidelines and assessment procedures to reduce the number of non-operational spacecraft and spent rocket upper stages orbiting the Earth. One method of postmission disposal is to allow reentry of these spacecraft, either from orbital decay (uncontrolled entry) or with a controlled entry. Orbital decay may be achieved by firing engines to lower the perigee altitude so that atmospheric drag will eventually cause the spacecraft to enter. However, the surviving debris impact footprint cannot be guaranteed to avoid inhabited landmasses. Controlled entry normally occurs by using a larger amount of propellant with a larger propulsion system to drive the spacecraft to enter the atmosphere at a steeper flight path angle. It will then enter at a more precise latitude, longitude, and footprint in a nearly uninhabited impact region, generally located in the ocean.

  7. JSC Orbital Debris Website Description

    NASA Astrophysics Data System (ADS)

    Johnson, Nicholas L.

    2006-01-01

    required. These data also help in the analysis and interpretation of impact features on returned spacecraft surfaces. 4) Mitigation - Controlling the growth of the orbital debris population is a high priority for NASA, the United States, and the major space-faring nations of the world to preserve near-Earth space for future generations. Mitigation measures can take the form of curtailing or preventing the creation of new debris, designing satellites to withstand impacts by small debris, and implementing operational procedures ranging from utilizing orbital regimes with less debris, adopting specific spacecraft attitudes, and even maneuvering to avoid collisions with debris. Downloadable items include several documents in PDF format and executable software.and 5) Reentry - Because of the increasing number of objects in space, NASA has adopted guidelines and assessment procedures to reduce the number of non-operational spacecraft and spent rocket upper stages orbiting the Earth. One method of postmission disposal is to allow reentry of these spacecraft, either from orbital decay (uncontrolled entry) or with a controlled entry. Orbital decay may be achieved by firing engines to lower the perigee altitude so that atmospheric drag will eventually cause the spacecraft to enter. However, the surviving debris impact footprint cannot be guaranteed to avoid inhabited landmasses. Controlled entry normally occurs by using a larger amount of propellant with a larger propulsion system to drive the spacecraft to enter the atmosphere at a steeper flight path angle. It will then enter at a more precise latitude, longitude, and footprint in a nearly uninhabited impact region, generally located in the ocean.

  8. 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.

  9. Orbital Debris: Quarterly News, Volume 14, Issue 2

    NASA Technical Reports Server (NTRS)

    Liou, J. C. (Editor); Shoots, Debi (Editor)

    2010-01-01

    This bulletin contains articles from the Orbital Debris Program office. This issue's articles are: "Orbital Debris Success Story --A Decade in the Making", "Old and New Satellite Breakups Identified," "Update on Three Major Debris Clouds," and "MMOD Inspection of the HST Bay 5 Multi-Layer Insulation Panel" about micrometeoroid and orbital debris (MMOD) inspection of the Hubble Space Telescope (HST) insulation panel. A project review is also included (i.e., "Small Debris Observations from the Iridium 33/Cosmos 2251 Collision.") There are also abstra cts of conference papers from the staff of the program office.

  10. Orbital Debris Quarterly News, Vol. 13, No. 2

    NASA Technical Reports Server (NTRS)

    Liou, J.-C. (Editor); Shoots, Debi (Editor)

    2009-01-01

    Topics include: debris clouds left by satellite collision; debris flyby near the International Space Station; and break-up of an ullage motor from a Russian Proton launch vehicle. Findings from the analysis of the STS-126 Shuttle Endeavour window impact damage are provided. Abstracts from the NASA Orbital Debris program office are presented and address a variety of topics including: Reflectance Spectra Comparison of Orbital Debris, Intact Spacecraft, and Intact Rocket Bodies in the GEO Regime; Shape Distribution of Fragments From Microsatellite Impact Tests; Micrometeoroid and Orbital Debris Threat Mitigation Techniques for the Space Shuttle Orbiter; Space Debris Environment Remediation Concepts; and, In Situ Measurement Activities at the NASA Orbital Debris Program Office. Additionally, a Meeting Report is provided for the 12 meeting of the NASA/DoD Orbital Debris Working Group.

  11. Development of the Space Debris Sensor (SDS)

    NASA Technical Reports Server (NTRS)

    Hamilton, Joe; Liou, J. -C.; Anz-Meador, P.; Matney, M.; Christiansen, E.

    2017-01-01

    Debris Resistive/Acoustic Grid Orbital Navy-NASA Sensor (DRAGONS) is an impact sensor designed to detect and characterize collisions with small orbital debris: from 50 microns to greater than 1millimeter debris size detection; Characterizes debris size, speed, direction, and density. The Space Debris Sensor (SDS) is a flight demonstration of DRAGONS on the International Space Station: Approximately 1 square meter of detection area facing the ISS velocity vector; Minimum two year mission on Columbus External Payloads Facility (EPF); Minimal obstruction from ISS hardware; Development is nearing final checkout and integration with the ISS; Current launch schedule is SpaceX13, about September 2017, or SpaceX14, about Jan 2018.

  12. Spatial Density Evolution of Space Debris Environment

    NASA Astrophysics Data System (ADS)

    Li, Canan; Pang, Baojun; Ding, Li

    2009-03-01

    It is known that the space debris provide great risks to the safety of on-orbit space vehicles, which makes it necessary to establish a model to evaluate their impact risks. In order to provide the scenario of the future space debris environment for space vehicle designers, this paper addresses a simplified mathematical model for the future evolution of space debris environment. While the spatial density is of more concern to engineers, this paper is devoted to study the evolution of the distribution of spatial density of space debris. Given the initial spatial density, this paper develops the algorithm to obtained the spatial density of space debris at any moment of future, by considering the orbital propagation and collisions.

  13. Orbital debris removal and meteoroid deflection

    NASA Astrophysics Data System (ADS)

    Campbell, Jonathan W.; Taylor, Charles R.; Smalley, Larry L.; Dickerson, Thomas

    1998-11-01

    Orbital debris in low-Earth orbit in the size range from 1 to 10 cm in diameter can be detected but not tracked reliably enough to be avoided by spacecraft. It can cause catastrophic damage even to a shielded spacecraft. With adaptive optics, a ground-based pulsed laser ablating the debris surface can produce enough propulsion in several hundred pulses to cause such debris to reenter the atmosphere. A single laser station could remove all of the 1 - 10 cm debris in three years or less. A technology demonstration of laser space propulsion is proposed which would pave the way for the implementation of such a debris removal system. The cost of the proposed demonstration is comparable with the estimated annual cost of spacecraft operations in the present orbital debris environment. Orbital debris is not the only space junk that is deleterious to the Earth's environment. Collisions with asteroids have caused major havoc to the Earth's biosphere many times in the ancient past. Since the possibility still exists for major impacts of asteroids with the Earth, it shown that it is possible to scale up the systems to prevent these catastrophic collisions providing sufficient early warning is available from new generation space telescopes plus deep space radar tracking.

  14. The ESA Space Debris Mitigation Handbook 2002

    NASA Astrophysics Data System (ADS)

    Klinkrad, H.; Beltrami, P.; Hauptmann, S.; Martin, C.; Sdunnus, H.; Stokes, H.; Walker, R.; Wilkinson, J.

    2004-01-01

    The ESA Space Debris Mitigation Handbook 2002 was jointly produced by an industrial consortium and ESA, under an ESA contract. The Handbook is a non-regulatory, self-standing document, providing technical information in support of European debris mitigation standards. The necessity of debris mitigation is illustrated in the context of historic launch activities and operational practices, which led to the current debris environment, with corresponding collision flux levels. Based on detailed population evolution models, this initial population is analyzed with respect to its growth and stability under different traffic assumptions. The implementation of debris mitigation measures, in particular the de-orbiting of spacecraft and upper stages, is shown to reduce the debris growth to an acceptable level within a few decades. The risk on ground due to re-entering space objects, its assessment, and its control is also analyzed. For on-orbit systems, collision risk reduction by avoidance manoeuvres, and passive protection by shielding is outlined. ESA's Handbook also compares recommended debris mitigation and risk reduction practices proposed by several other space agencies. The Handbook will be available at the begin of 2003.

  15. The ESA Space Debris Mitigation Handbook 2002

    NASA Astrophysics Data System (ADS)

    Klinkrad, H.; Beltrami, P.; Hauptmann, S.; Martin, C.; Sdunnus, H.; Stokes, H.; Walker, R.; Wilkinson, J.

    The ESA Space Debris Mitigation Handbook 2002 was jointly produced by an industrial consortium and ESA, under an ESA contract. The Handbook is a non-regulatory, self-standing document, providing technical information in support of European debris mitigation standards. The necessity of debris mitigation is illustrated in the context of historic launch activities and operational practices, which led to the current debris environment, with corresponding collision flux levels. Based on detailed population evolution models, this initial population is analysed with respect to its growth and stability under different traffic assumptions. The implementation of debris mitigation measures, in particular the de-orbiting of spacecraft and upper stages, is shown to reduce the debris growth to an acceptable level within a few decades. The risk on ground due to re-entering space objects, its assessment, and its control is also analysed. For on-orbit systems, collision risk reduction by avoidance manoeuvres, and passive protection by shielding is outlined. ESA's Handbook also compares recommended debris mitigation and risk reduction practices proposed by several other space agencies. The Handbook will be available by the end of 2002.

  16. Orbital Debris: the Growing Threat to Space Operations

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2010-01-01

    For nearly 50 years the amount of man-made debris in Earth orbit steadily grew, accounting for about 95% of all cataloged space objects over the past few decades. The Chinese anti-satellite test in January 2007 and the accidental collision of two spacecraft in February 2009 created more than 4000 new cataloged debris, representing an increase of 40% of the official U.S. Satellite Catalog. The frequency of collision avoidance maneuvers for both human space flight and robotic operations is increasing along with the orbital debris population. However, the principal threat to space operations is driven by the smaller and much more numerous uncataloged debris. Although the U.S. and the international aerospace communities have made significant progress in recognizing the hazards of orbital debris and in reducing or eliminating the potential for the creation of new debris, the future environment is expected to worsen without additional corrective measures.

  17. Orbital Debris Quarterly News, Volume 13, Issue 4

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi (Editor); Shoots, Debi (Editor)

    2009-01-01

    Although NASA has conducted research on orbital debris since the 1960s, the NASA Orbital Debris Program Office is now considered to have been established in October 1979, following the recognition by senior NASA officials of orbital debris as a space environmental issue and the allocation by NASA Headquarters Advanced Programs Office to the Lyndon B. Johnson Space Center (JSC) of funds specifically dedicated for orbital debris investigations. In the 30 years since, the NASA Orbital Debris Program Office has pioneered the characterization of the orbital debris environment and its potential effects on current and future space systems, has developed comprehensive orbital debris mitigation measures, and has led efforts by the international aerospace community in addressing the challenges posed by orbital debris. In 1967 the Flight Analysis Branch at the Manned Spacecraft Center (renamed the Lyndon B. Johnson Space Center in 1973) evaluated the risks of collisions between an Apollo spacecraft and orbital debris. Three years later the same group calculated collision risks for the forthcoming Skylab space station, which was launched in 1973. By 1976, the nucleus of NASA s yet-to-be-formed orbital debris research efforts, including Andrew Potter, Burton Cour-Palais, and Donald Kessler, was found in JSC s Environmental Effects Office, examining the potential threat of orbital debris to large space platforms, in particular the proposed Solar Power Satellites (SPS).

  18. Orbital evolution of space debris due to aerodynamic forces

    NASA Astrophysics Data System (ADS)

    Crowther, R.

    1993-08-01

    The concepts used in the AUDIT (Assessment Using Debris Impact Theory) debris modelling suite are introduced. A sensitivity analysis is carried out to determine the dominant parameters in the modelling process. A test case simulating the explosion of a satellite suggest that at the parent altitude there is a greater probability of collision with more massive fragments.

  19. Collector/Compactor for Waste or Debris

    NASA Technical Reports Server (NTRS)

    Mangialiardi, John K.

    1987-01-01

    Device collects and compacts debris by sweeping through volume with net. Consists of movable vane, fixed vane, and elastic net connected to both vanes. Movable vane is metal strip curved to follow general contour of container with clearance to prevent interference with other parts on inside wall of container. One end of movable vane mounted in bearing and other end connected to driveshaft equipped with handle. User rotates movable vane, net stretched and swept through container. Captures most of debris coarser than mesh as it moves, compressing debris as it arrives at fixed vane. Applications include cleaning swimming pools and tanks.

  20. Collector/Compactor for Waste or Debris

    NASA Technical Reports Server (NTRS)

    Mangialiardi, John K.

    1987-01-01

    Device collects and compacts debris by sweeping through volume with net. Consists of movable vane, fixed vane, and elastic net connected to both vanes. Movable vane is metal strip curved to follow general contour of container with clearance to prevent interference with other parts on inside wall of container. One end of movable vane mounted in bearing and other end connected to driveshaft equipped with handle. User rotates movable vane, net stretched and swept through container. Captures most of debris coarser than mesh as it moves, compressing debris as it arrives at fixed vane. Applications include cleaning swimming pools and tanks.

  1. Collision avoidance in space

    NASA Technical Reports Server (NTRS)

    Kessler, D. J.; Cour-Palais, B. G.; Taylor, R. E.; Landry, P. M.

    1980-01-01

    Collisions in earth orbital space between operational payloads and various forms of space debris (nonoperational payloads, nonfunctional mission-related objects and fragments resulting from collisions and explosions) are discussed and possible means of avoiding them are considered. From 10,000 to 15,000 objects are estimated to be in earth orbital space, most of which represent spacecraft fragments and debris too small to be detected and tracked by earth-based sensors, and it is considered likely that some of them will be or have already been involved in direct collisions with the ever increasing number of operational satellites and space stations. Means of protecting proposed large space structures and smaller spacecraft from significant damage by larger space objects, particularly in the 400-4000 km altitude range where most debris occurs, include structural redundancy and the double shielding of sensitive components. Other means of collision avoidance are the collection or relocation of satellites, rocket bodies and other objects by the Space Shuttle, the prevention of explosions and the disposal of spent rocket parts by reentry. Finally, a management structure would be required to administer guidelines for the prevention and elimination of space debris.

  2. Handling Difficult Towers in the Calibration of the PHENIX Muon Piston Calorimeter (MPC) for Analysis of RHIC Au+Au Collisions

    NASA Astrophysics Data System (ADS)

    Lallow, Emran; Phenix Collaboration

    2015-10-01

    The PHENIX Muon Piston Calorimeter (MPC) is an electromagnetic detector with a kinematic coverage of (3 . 1 < | η | < 3 . 9). This allows for measurements at high forward and backward pseudorapidity and will be used to measure transverse energy in √{SNN} = 200, 62.4, 39, and 7.7 GeV RHIC Au+Au collisions in this kinematic region. The towers will be calibrated by using an iterative procedure in which neutral pions are reconstructed from their decay photons. To augment the iterative process, rough calibrations of individual towers can be obtained by direct examination of ADC distributions. These rough calibrations serve as input to the more rigorous neutral pion reconstruction method and will be described in this poster. This material is based upon work supported by the National Science Foundation under Grant No. 1507841.

  3. Columbia Debris

    NASA Image and Video Library

    2003-05-06

    George D'Heilly and John Cassanto, scientists with Instrumentation Technology Associates, Inc., display for the media part of the apparatus recovered during the search for Columbia debris. It was part of the Commercial ITA Biomedical Experiments payload on mission STS-107 that included the Growth of Bacterial Biofilm on Surfaces during Spaceflight (GOBBSS) experiment and crystals grown for cancer research. The GOBBSS experiment was sponsored by the Planetary Society, with joint participation of an Israeli and a Palestinian student, and developed by the Israeli Aerospace Medical Institute and JSC Astrobiology Center.

  4. The fast debris evolution model

    NASA Astrophysics Data System (ADS)

    Lewis, H. G.; Swinerd, G. G.; Newland, R. J.; Saunders, A.

    2009-09-01

    The 'particles-in-a-box' (PIB) model introduced by Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] removed the need for computer-intensive Monte Carlo simulation to predict the gross characteristics of an evolving debris environment. The PIB model was described using a differential equation that allows the stability of the low Earth orbit (LEO) environment to be tested by a straightforward analysis of the equation's coefficients. As part of an ongoing research effort to investigate more efficient approaches to evolutionary modelling and to develop a suite of educational tools, a new PIB model has been developed. The model, entitled Fast Debris Evolution (FADE), employs a first-order differential equation to describe the rate at which new objects ⩾10 cm are added and removed from the environment. Whilst Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] based the collision theory for the PIB approach on collisions between gas particles and adopted specific values for the parameters of the model from a number of references, the form and coefficients of the FADE model equations can be inferred from the outputs of future projections produced by high-fidelity models, such as the DAMAGE model. The FADE model has been implemented as a client-side, web-based service using JavaScript embedded within a HTML document. Due to the simple nature of the algorithm, FADE can deliver the results of future projections immediately in a graphical format, with complete user-control over key simulation parameters. Historical and future projections for the ⩾10 cm LEO debris environment under a variety of different scenarios are possible, including business as usual, no future launches, post-mission disposal and remediation. A selection of results is presented with comparisons with predictions made using the DAMAGE environment model

  5. Instability of the Current Space Debris Population in Low Earth Orbit

    NASA Astrophysics Data System (ADS)

    Maniwa, Kazuaki; Hanada, Toshiya; Kawamoto, Satomi

    Since the launch of Sputnik, orbital debris population continues to increase due to ongoing space activities, on-orbit explosions, and accidental collisions. In the future, it is expected that a great deal of fragments will be created by explosions and collisions. Thus, the number of space debris may increase exponentially (Kessler Syndrome). This paper analyzes the Kessler Syndrome using the Low Earth Orbital Debris Environmental Evolutionary Model (LEODEEM) developed at Kyushu University with collaboration from JAXA. The purpose of the study aims at understanding the issues related to space environment conservation. The results provide effective conditions of Active Debris Removal which is one of the space debris mitigation procedures.

  6. Space Debris and Space Safety - Looking Forward

    NASA Astrophysics Data System (ADS)

    Ailor, W.; Krag, H.

    Man's activities in space are creating a shell of space debris around planet Earth which provides a growing risk of collision with operating satellites and manned systems. Including both the larger tracked objects and the small, untracked debris, more than 98% of the estimated 600,000 objects larger than 1 cm currently in orbit are “space junk”--dead satellites, expended rocket stages, debris from normal operations, fragments from explosions and collisions, and other material. Recognizing the problem, space faring nations have joined together to develop three basic principles for minimizing the growth of the debris population: prevent on-orbit breakups, remove spacecraft and orbital stages that have reached the end of their mission operations from the useful densely populated orbit regions, and limit the objects released during normal operations. This paper provides an overview of what is being done to support these three principles and describes proposals that an active space traffic control service to warn satellite operators of pending collisions with large objects combined with a program to actively remove large objects may reduce the rate of future collisions. The paper notes that cost and cost effectiveness are important considerations that will affect the evolution of such systems.

  7. Engineering Challenges for Active Debris Removal

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi

    2011-01-01

    Recent modeling studies on the instability of the debris population in the low Earth orbit (LEO) region and the collision between Iridium 33 and Cosmos 2251 have underlined the need for active debris removal. A 2009 analysis by the NASA Orbital Debris Program Office shows that, in order to maintain the LEO debris population at a constant level for the next 200 years, an active debris removal of about five objects per year is needed. The targets identified for removal are those with the highest mass and collision probability products in the environment. Many of these objects are spent upper stages with masses ranging from 1 to more than 8 metric tons, residing in several altitude regions and concentrated in about 10 inclination bands. To remove five of those objects on a yearly basis, in a cost-effective manner, represents many challenges in engineering, technology development, and operations. This paper outlines a conceptual end-to-end debris removal operation, including launch, precision tracking, rendezvous, stabilization (of the tumbling targets), capture, and deorbit of the targets; and highlights major challenges associated with the operations. Pros and cons of several proposed removal techniques are also evaluated.

  8. Small Orbital Debris Mitigation Mission Architecture

    NASA Technical Reports Server (NTRS)

    Wiegmann, Bruce M.

    2011-01-01

    Small orbital debris in LEO (1-10 cm in size) presents a clear and present danger to operational LEO spacecraft. This debris field has dramatically increased (nearly doubled) in recent years following the Chinese ASAT Test in 2007 and the Iridium/Cosmos collision in 2009. Estimates of the number of small debris have grown to 500,000 objects after these two events; previously the population was 300,000 objects. These small, untracked debris objects (appproximately 500,000) outnumber the larger and tracked objects (appproximately 20,000) by a factor 25 to 1. Therefore, the risk of the small untracked debris objects to operational spacecraft is much greater than the risk posed by the larger and tracked LEO debris objects. A recent study by The Aerospace Corporation found that the debris environment will increase the costs of maintaining a constellation of government satellites by 5%, a constellation of large commercial satellites by 11%, and a constellation of factory built satellites by 26% from $7.6 billion to $9.57 billion. Based upon these facts, the NASA Marshall Space Flight Center (MSFC) Advanced Concepts Office (ACO) performed an architecture study on Small Orbital Debris Active Removal (SODAR) using a space-based nonweapons- class laser satellite for LEO debris removal. The goal of the SODAR study was to determine the ability of a space-based laser system to remove the most pieces of debris (1 cm to 10 cm, locations unknown), in the shortest amount of time, with the fewest number of spacecraft. The ESA developed MASTER2005 orbital debris model was used to probabilistically classify the future debris environment including impact velocity, magnitude, and directionality. The study ground rules and assumptions placed the spacecraft into a high inclination Low Earth Orbit at 800 km as an initial reference point. The architecture study results found that a spacecraft with an integrated forward-firing laser is capable of reducing the small orbital debris flux within

  9. Prize of the best thesis 2015: Study of debris discs through state-of-the-art numerical modelling

    NASA Astrophysics Data System (ADS)

    Kral, Q.; Thébault, P.

    2015-12-01

    This proceeding summarises the thesis entitled ``Study of debris discs with a new generation numerical model'' by Quentin Kral, for which he obtained the prize of the best thesis in 2015. The thesis brought major contributions to the field of debris disc modelling. The main achievement is to have created, almost ex-nihilo, the first truly self-consistent numerical model able to simultaneously follow the coupled collisional and dynamical evolutions of debris discs. Such a code has been thought as being the ``Holy Grail'' of disc modellers for the past decade, and while several codes with partial dynamics/collisions coupling have been presented, the code developed in this thesis, called ``LIDT-DD'' is the first to achieve a full coupling. The LIDT-DD model, which is the first of a new-generation of fully self-consistent debris disc models is able to handle both planetesimals and dust and create new fragments after each collision. The main idea of LIDT-DD development was to merge into one code two approaches that were so far used separately in disc modelling, that is, an N-body algorithm to investigate the dynamics, and a statistical scheme to explore the collisional evolution. This complex scheme is not straightforward to develop as there are major difficulties to overcome: 1) collisions in debris discs are highly destructive and produce clouds of small fragments after each single impact, 2) the smallest (and most numerous) of these fragments have a strongly size-dependent dynamics because of the radiation pressure, and 3) the dust usually observed in discs is precisely these smallest grains. These extreme constraints had so far prevented all previous attempts at developing self-consistent disc models to succeed. The thesis contains many examples of the use of LIDT-DD that are not yet published but the case of the collision between two asteroid-like bodies is studied in detail. In particular, LIDT-DD is able to predict the different stages that should be observed

  10. Orbital Debris Quarterly News, Volume 13, No. 3

    NASA Technical Reports Server (NTRS)

    Liou, J.-C. (Editor); Shoots, Debi (Editor)

    2009-01-01

    This issue of the Orbital Debris Quarterly contains articles on the congressional hearing that was held on orbital debris and space traffic; the update received by the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) on the collision of the Iridium 33 and Cosmos 2251 satellites; the micrometeoroid and orbital debris (MMOD) inspection of the Hubble Space Telescope Wide Field Planetary Camera; an analysis of the reentry survivability of the Global Precipitation Measurement (GPM) spacecraft; an update on recent major breakup fragments; and a graph showing the current debris environment in low Earth orbit.

  11. Space Shuttle Debris Transport

    NASA Technical Reports Server (NTRS)

    Gomez, Reynaldo J., III

    2010-01-01

    This slide presentation reviews the assessment of debris damage to the Space Shuttle, and the use of computation to assist in the space shuttle applications. The presentation reviews the sources of debris, a mechanism for determining the probability of damaging debris impacting the shuttle, tools used, eliminating potential damaging debris sources, the use of computation to assess while inflight damage, and a chart showing the applications that have been used on increasingly powerful computers simulate the shuttle and the debris transport.

  12. Droplet Handling

    NASA Astrophysics Data System (ADS)

    Torii, Toru

    When quantitative analysis or quantitative chemical synthesis is performed using a micrototal analysis system (microTAS), the technologies for precise metering, transporting, and mixing of droplets are required. In this chapter, several technologies for the handling of droplets are described. For metering, dispensing and transporting of droplets, pneumatic and electrokinetic forces are used. Separation of cells and particles is also performed by electrical operation. Other handling technique, such as ultrasonic or centrifugal force applications, are also reviewed. Robotic synthesis devices or high throughput screening devices are promising applications for these technologies.

  13. Droplet handling.

    PubMed

    Torii, Toru

    2010-01-01

    When quantitative analysis or quantitative chemical synthesis is performed using a micrototal analysis system (microTAS), the technologies for precise metering, transporting, and mixing of droplets are required. In this chapter, several technologies for the handling of droplets are described. For metering, dispensing and transporting of droplets, pneumatic and electrokinetic forces are used. Separation of cells and particles is also performed by electrical operation. Other handling technique, such as ultrasonic or centrifugal force applications, are also reviewed. Robotic synthesis devices or high throughput screening devices are promising applications for these technologies.

  14. Segregation dynamics in debris flows

    NASA Astrophysics Data System (ADS)

    Hill, K. M.; Fei, M.

    2014-12-01

    Debris flows are massive flows consisting of mixtures of particles of different sizes and interstitial fluids such as water and mud. In sheared mixtures of different-sized (same density) particles, it is well known that larger particles tend to go up (toward the free surface), and the smaller particles, down, commonly referred to as the "Brazil-nut problem" or "kinetic sieving". When kinetic sieving fluxes are combined with advection in flows, they can give rise to a spectacular range of segregation patterns. These segregation / advection dynamics are recognized as playing a role in the coarsening of a debris flow front (its "snout") and the coarsening of the self-formed channel sides or levees. Since particle size distribution influences the flow dynamics including entrainment of bed materials, modeling segregation dynamics in debris flows is important for modeling the debris flows themselves. In sparser systems, the Brazil-nut segregation is well-modeled using kinetic theory applied to dissipative systems, where an underlying assumption involves random, uncorrelated collisions. In denser systems, where kinetic theory breaks down we have recently developed a new mixture model that demonstrates the segregation fluxes are driven by two effects associated with the kinetic stress or granular temperature (the kinetic energy associated with velocity fluctuations): (1) the difference between the partitioning of kinetic and contact stresses among the species in the mixture and (2) a kinetic stress gradient. Both model frameworks involve the temperature gradient as a driving force for segregation, but kinetic theory sends larger particles toward lower temperatures, and our mixture model sends larger particles away from lower temperatures. Which framework works under what conditions appears to depend on correlations in the flow such as those manifested in clusters and force chains. We discuss the application of each theoretical framework to representing segregation dynamics

  15. Orbital debris minimization and mitigation techniques

    NASA Technical Reports Server (NTRS)

    Loftus, Joseph P., Jr.; Anz-Meador, Phillip D.; Reynolds, Robert

    1992-01-01

    Man's activity in space has generated significant amounts of debris that remain in orbit for periods of sufficient duration to become a hazard to future space activities. Upper stages and spacecraft that have ended their functional life are the largest objects. In the past, additional debris has been generated by inadvertent explosions of upper stages and spacecraft, by intentional explosions for military reasons, and possibly by a few breakups resulting from collisions. In the future, debris can be generated by collisions among spacecraft as the number of orbital objects continues to grow at rates greater than natural forces remove them from orbit. There are design and operations practices that can minimize the inadvertent generation of debris. There are other design and operations options for removing objects from space at the end of their useful service so they are not available as a source for the generation of future debris. Those studies are the primary concern of this paper. The most economic removal of objects is achieved when those objects have the capability to execute the necessary maneuvers with their own systems and resources. The most costly option is to have some other system remove the spacecraft after it has become a derelict. Numerous options are being studied to develop systems and techniques that can remove spacecraft from useful orbits at the end of their useful life and do so for the least mass penalty and economic cost.

  16. Orbital debris minimization and mitigation techniques

    NASA Technical Reports Server (NTRS)

    Loftus, Joseph P., Jr.; Anz-Meador, Phillip D.; Reynolds, Robert

    1992-01-01

    Man's activity in space has generated significant amounts of debris that remain in orbit for periods of sufficient duration to become a hazard to future space activities. Upper stages and spacecraft that have ended their functional life are the largest objects. In the past, additional debris has been generated by inadvertent explosions of upper stages and spacecraft, by intentional explosions for military reasons, and possibly by a few breakups resulting from collisions. In the future, debris can be generated by collisions among spacecraft as the number of orbital objects continues to grow at rates greater than natural forces remove them from orbit. There are design and operations practices that can minimize the inadvertent generation of debris. There are other design and operations options for removing objects from space at the end of their useful service so they are not available as a source for the generation of future debris. Those studies are the primary concern of this paper. The most economic removal of objects is achieved when those objects have the capability to execute the necessary maneuvers with their own systems and resources. The most costly option is to have some other system remove the spacecraft after it has become a derelict. Numerous options are being studied to develop systems and techniques that can remove spacecraft from useful orbits at the end of their useful life and do so for the least mass penalty and economic cost.

  17. DIAGNOSING CIRCUMSTELLAR DEBRIS DISKS

    SciTech Connect

    Hahn, Joseph M.

    2010-08-20

    A numerical model of a circumstellar debris disk is developed and applied to observations of the circumstellar dust orbiting {beta} Pictoris. The model accounts for the rates at which dust is produced by collisions among unseen planetesimals, and the rate at which dust grains are destroyed due to collisions. The model also accounts for the effects of radiation pressure, which is the dominant perturbation on the disk's smaller but abundant dust grains. Solving the resulting system of rate equations then provides the dust abundances versus grain size and dust abundances over time. Those solutions also provide the dust grains' collisional lifetime versus grain size, and the debris disk's optical depth and surface brightness versus distance from the star. Comparison to observations then yields estimates of the unseen planetesimal disk's radius, and the rate at which the disk sheds mass due to planetesimal grinding. The model can also be used to measure or else constrain the dust grain's physical and optical properties, such as the dust grains' strength, their light-scattering asymmetry parameter, and the grains' efficiency of light scattering Q{sub s}. The model is then applied to optical observations of the edge-on dust disk orbiting {beta} Pictoris, and good agreement is achieved when the unseen planetesimal disk is broad, with 75 {approx}< r {approx}< 150 AU. If it is assumed that the dust grains are bright like Saturn's icy rings (Q{sub s} = 0.7), then the cross section of dust in the disk is A{sub d} {approx_equal} 2 x 10{sup 20} km{sup 2} and its mass is M{sub d} {approx_equal} 11 lunar masses. In this case, the planetesimal disk's dust-production rate is quite heavy, M-dot {sub d{approx}}9 M {sub +} Myr{sup -1}, implying that there is or was a substantial amount of planetesimal mass there, at least 110 Earth masses. If the dust grains are darker than assumed, then the planetesimal disk's mass-loss rate and its total mass are heavier. In fact, the apparent dearth

  18. LEGEND, a LEO-to-GEO Environment Debris Model

    NASA Technical Reports Server (NTRS)

    Liou, Jer Chyi; Hall, Doyle T.

    2013-01-01

    LEGEND (LEO-to-GEO Environment Debris model) is a three-dimensional orbital debris evolutionary model that is capable of simulating the historical and future debris populations in the near-Earth environment. The historical component in LEGEND adopts a deterministic approach to mimic the known historical populations. Launched rocket bodies, spacecraft, and mission-related debris (rings, bolts, etc.) are added to the simulated environment. Known historical breakup events are reproduced, and fragments down to 1 mm in size are created. The LEGEND future projection component adopts a Monte Carlo approach and uses an innovative pair-wise collision probability evaluation algorithm to simulate the future breakups and the growth of the debris populations. This algorithm is based on a new "random sampling in time" approach that preserves characteristics of the traditional approach and captures the rapidly changing nature of the orbital debris environment. LEGEND is a Fortran 90-based numerical simulation program. It operates in a UNIX/Linux environment.

  19. Evaluation of a satellite constellation for active debris removal

    NASA Astrophysics Data System (ADS)

    Sahara, Hironori

    2014-12-01

    This paper analyzes an example of a three-dimensional constellation of debris removal satellites and proposes an effective constellation using a delta-V analysis that discusses the advisability of rendezvousing satellites with space debris. Lambert's Equation was used to establish a means of analysis to construct a constellation of debris removal satellites, which has a limit of delta-V injection by evaluating the amount of space debris that can be rendezvoused by a certain number of removal satellite. Consequently, we determine a constellation of up to 38 removal satellites for debris removal, where the number of space debris rendezvoused by a single removal satellite is not more than 25, removing up to 584 pieces of debris total. Even if we prepare 38 removal satellites in their respective orbits, it is impossible to remove all of the space debris. Although many removal satellites, over 100 for example, can remove most of the space debris, this method is economically disproportionate. However, we can also see the removal satellites are distributed nearly evenly. Accordingly, we propose a practical two-stage strategy. The first stage is to implement emergent debris removal with the 38 removal satellites. When we find a very high probability of collision between a working satellite and space debris, one of the removal satellites in the constellation previously constructed in orbit initiates a maneuver of emergent debris removal. The second stage is a long-term space debris removal strategy to suppress the increase of space debris derived from collisions among the pieces of space debris. The constellation analyzed in this paper, which consists of the first 38 removal satellites, can remove half of the over 1000 dangerous space debris among others, and then the constellation increases the number of the following removal satellites in steps. At any rate, an adequate orbital configuration and constellation form is very important for both space debris removal and

  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. Roll Call Debris - Race

    EPA Pesticide Factsheets

    Marine debris degrades ocean habitats, endangers marine and coastal wildlife, causes navigation hazards, results in economic losses to industry and governments, and threatens human health and safety. EPA Pacific Southwest (Region 9) is tapping existing programs and resources to advance the prevention, reduction and clean-up of marine debris in the North Pacific Ocean. EPA Pacific Southwest activities build upon specific recommendations of the Interagency Marine Debris Coordinating Committee by targeting threats and sources of debris and responding to debris impacts. EPA is initiating a three-pronged effort to reduce sources of marine debris, prevent trash from entering the oceans, and assess the human and ecosystem impacts and potential for cleanup.

  2. Fleet Debris Levels

    EPA Pesticide Factsheets

    Marine debris degrades ocean habitats, endangers marine and coastal wildlife, causes navigation hazards, results in economic losses to industry and governments, and threatens human health and safety. EPA Pacific Southwest (Region 9) is tapping existing programs and resources to advance the prevention, reduction and clean-up of marine debris in the North Pacific Ocean. EPA Pacific Southwest activities build upon specific recommendations of the Interagency Marine Debris Coordinating Committee by targeting threats and sources of debris and responding to debris impacts. EPA is initiating a three-pronged effort to reduce sources of marine debris, prevent trash from entering the oceans, and assess the human and ecosystem impacts and potential for cleanup.

  3. Special Report Debris - Race

    EPA Pesticide Factsheets

    Marine debris degrades ocean habitats, endangers marine and coastal wildlife, causes navigation hazards, results in economic losses to industry and governments, and threatens human health and safety. EPA Pacific Southwest (Region 9) is tapping existing programs and resources to advance the prevention, reduction and clean-up of marine debris in the North Pacific Ocean. EPA Pacific Southwest activities build upon specific recommendations of the Interagency Marine Debris Coordinating Committee by targeting threats and sources of debris and responding to debris impacts. EPA is initiating a three-pronged effort to reduce sources of marine debris, prevent trash from entering the oceans, and assess the human and ecosystem impacts and potential for cleanup.

  4. Measurement of Satellite Impact Test Fragments for Modeling Orbital Debris

    NASA Technical Reports Server (NTRS)

    Hill, Nicole M.

    2009-01-01

    There are over 13,000 pieces of catalogued objects 10cm and larger in orbit around Earth [ODQN, January 2009, p12]. More than 6000 of these objects are fragments from explosions and collisions. As the earth-orbiting object count increases, debris-generating collisions in the future become a statistical inevitability. To aid in understanding this collision risk, the NASA Orbital Debris Program Office has developed computer models that calculate quantity and orbits of debris both currently in orbit and in future epochs. In order to create a reasonable computer model of the orbital debris environment, it is important to understand the mechanics of creation of debris as a result of a collision. The measurement of the physical characteristics of debris resulting from ground-based, hypervelocity impact testing aids in understanding the sizes and shapes of debris produced from potential impacts in orbit. To advance the accuracy of fragment shape/size determination, the NASA Orbital Debris Program Office recently implemented a computerized measurement system. The goal of this system is to improve knowledge and understanding of the relation between commonly used dimensions and overall shape. The technique developed involves scanning a single fragment with a hand-held laser device, measuring its size properties using a sophisticated software tool, and creating a three-dimensional computer model to demonstrate how the object might appear in orbit. This information is used to aid optical techniques in shape determination. This more automated and repeatable method provides higher accuracy in the size and shape determination of debris.

  5. Active removal of orbital debris by induced hypervelocity impact of injected dust grains

    NASA Astrophysics Data System (ADS)

    Ganguli, G.; Crabtree, C.; Velikovich, A.; Rudakov, L.; Chappie, S.

    2014-02-01

    Collisions of an active satellite with a small (1mm - cm) untrackable orbital debris can be mission ending. It has been recently established that we are at the tipping point for collisional cascade of larger objects to exponential growth of small orbital debris. This will make access to near-Earth space hazardous without first clearing the existing debris from this region. We present a concept for elimination of small debris by deploying micron scale dust to artificially enhance the drag on the debris. The key physics that makes this technique viable is the possibility of large momentum boost realized through hypervelocity dust/debris collision. By deploying high mass density micron scale dust in a narrow altitude band temporarily it is possible to artificially enhance drag on debris spread over a very large volume and force rapid reentry. The injected dust will also reenter the atmosphere leaving no permanent residue in space.

  6. POST Earthquake Debris Management - AN Overview

    NASA Astrophysics Data System (ADS)

    Sarkar, Raju

    Every year natural disasters, such as fires, floods, earthquakes, hurricanes, landslides, tsunami, and tornadoes, challenge various communities of the world. Earthquakes strike with varying degrees of severity and pose both short- and long-term challenges to public service providers. Earthquakes generate shock waves and displace the ground along fault lines. These seismic forces can bring down buildings and bridges in a localized area and damage buildings and other structures in a far wider area. Secondary damage from fires, explosions, and localized flooding from broken water pipes can increase the amount of debris. Earthquake debris includes building materials, personal property, and sediment from landslides. The management of this debris, as well as the waste generated during the reconstruction works, can place significant challenges on the national and local capacities. Debris removal is a major component of every post earthquake recovery operation. Much of the debris generated from earthquake is not hazardous. Soil, building material, and green waste, such as trees and shrubs, make up most of the volume of earthquake debris. These wastes not only create significant health problems and a very unpleasant living environment if not disposed of safely and appropriately, but also can subsequently impose economical burdens on the reconstruction phase. In practice, most of the debris may be either disposed of at landfill sites, reused as materials for construction or recycled into useful commodities Therefore, the debris clearance operation should focus on the geotechnical engineering approach as an important post earthquake issue to control the quality of the incoming flow of potential soil materials. In this paper, the importance of an emergency management perspective in this geotechnical approach that takes into account the different criteria related to the operation execution is proposed by highlighting the key issues concerning the handling of the construction

  7. POST Earthquake Debris Management — AN Overview

    NASA Astrophysics Data System (ADS)

    Sarkar, Raju

    Every year natural disasters, such as fires, floods, earthquakes, hurricanes, landslides, tsunami, and tornadoes, challenge various communities of the world. Earthquakes strike with varying degrees of severity and pose both short- and long-term challenges to public service providers. Earthquakes generate shock waves and displace the ground along fault lines. These seismic forces can bring down buildings and bridges in a localized area and damage buildings and other structures in a far wider area. Secondary damage from fires, explosions, and localized flooding from broken water pipes can increase the amount of debris. Earthquake debris includes building materials, personal property, and sediment from landslides. The management of this debris, as well as the waste generated during the reconstruction works, can place significant challenges on the national and local capacities. Debris removal is a major component of every post earthquake recovery operation. Much of the debris generated from earthquake is not hazardous. Soil, building material, and green waste, such as trees and shrubs, make up most of the volume of earthquake debris. These wastes not only create significant health problems and a very unpleasant living environment if not disposed of safely and appropriately, but also can subsequently impose economical burdens on the reconstruction phase. In practice, most of the debris may be either disposed of at landfill sites, reused as materials for construction or recycled into useful commodities Therefore, the debris clearance operation should focus on the geotechnical engineering approach as an important post earthquake issue to control the quality of the incoming flow of potential soil materials. In this paper, the importance of an emergency management perspective in this geotechnical approach that takes into account the different criteria related to the operation execution is proposed by highlighting the key issues concerning the handling of the construction

  8. The Fast Debris Evolution Model

    NASA Astrophysics Data System (ADS)

    Lewis, Hugh G.; Swinerd, Graham; Newland, Rebecca; Saunders, Arrun

    The ‘Particles-in-a-box' (PIB) model introduced by Talent (1992) removed the need for computerintensive Monte Carlo simulation to predict the gross characteristics of an evolving debris environment. The PIB model was described using a differential equation that allows the stability of the low Earth orbit (LEO) environment to be tested by a straightforward analysis of the equation's coefficients. As part of an ongoing research effort to investigate more efficient approaches to evolutionary modelling and to develop a suite of educational tools, a new PIB model has been developed. The model, entitled Fast Debris Evolution (FaDE), employs a first-order differential equation to describe the rate at which new objects (˜ 10 cm) are added and removed from the environment. Whilst Talent (1992) based the collision theory for the PIB approach on collisions between gas particles and adopted specific values for the parameters of the model from a number of references, the form and coefficients of the FaDE model equations can be inferred from the outputs of future projections produced by high-fidelity models, such as the DAMAGE model. The FaDE model has been implemented as a client-side, web-based service using Javascript embedded within a HTML document. Due to the simple nature of the algorithm, FaDE can deliver the results of future projections immediately in a graphical format, with complete user-control over key simulation parameters. Historical and future projections for the ˜ 10 cm low Earth orbit (LEO) debris environment under a variety of different scenarios are possible, including business as usual, no future launches, post-mission disposal and remediation. A selection of results is presented with comparisons with predictions made using the DAMAGE environment model. The results demonstrate that the FaDE model is able to capture comparable time-series of collisions and number of objects as predicted by DAMAGE in several scenarios. Further, and perhaps more importantly

  9. Lightcurves of Extreme Debris Disks

    NASA Astrophysics Data System (ADS)

    Rieke, George; Meng, Huan; Su, Kate

    2012-12-01

    We have recently discovered that some planetary debris disks with extreme fractional luminosities are variable on the timescale of a few years. This behavior opens a new possibility to understand planet building. Two of the known variable disks are around solar-like stars in the age range of 30 to 100+ Myr, which is the expected era of the final stages of terrestrial planet building. Such variability can be attributed to violent collisions (up to ones on the scale of the Moon-forming event between the proto-Earth and another proto-planet). The collisional cascades that are the aftermaths of these events can produce large clouds of tiny dust grains, possibly even condensed from silica vapor. A Spitzer pilot program has obtained the lightcurve of such a debris disk and caught two minor outbursts. Here we propose to continue the lightcurve monitoring with higher sampling rates and to expand it to more disks. The proposed time domain observations are a new dimension of debris disk studies that can bring unique insight to their evolution, providing important constraints on the collisional and dynamical models of terrestrial planet formation.

  10. HOT DEBRIS DUST AROUND HD 106797

    SciTech Connect

    Fujiwara, Hideaki; Onaka, Takashi; Yamashita, Takuya; Ishihara, Daisuke; Kataza, Hirokazu; Ootsubo, Takafumi; Murakami, Hiroshi; Nakagawa, Takao; Hirao, Takanori; Enya, Keigo; Fukagawa, Misato; Marshall, Jonathan P.; White, Glenn J.

    2009-04-10

    Photometry of the A0 V main-sequence star HD 106797 with AKARI and Gemini/T-ReCS is used to detect excess emission over the expected stellar photospheric emission between 10 and 20 {mu}m, which is best attributed to hot circumstellar debris dust surrounding the star. The temperature of the debris dust is derived as T {sub d} {approx} 190 K by assuming that the excess emission is approximated by a single temperature blackbody. The derived temperature suggests that the inner radius of the debris disk is {approx}14 AU. The fractional luminosity of the debris disk is 1000 times brighter than that of our own zodiacal cloud. The existence of such a large amount of hot dust around HD 106797 cannot be accounted for by a simple model of the steady state evolution of a debris disk due to collisions, and it is likely that transient events play a significant role. Our data also show a narrow spectral feature between 11 and 12 {mu}m attributable to crystalline silicates, suggesting that dust heating has occurred during the formation and evolution of the debris disk of HD 106797.

  11. Conceptual design of an orbital debris collector

    NASA Technical Reports Server (NTRS)

    Odonoghue, Peter (Editor); Brenton, Brian; Chambers, Ernest; Schwind, Thomas; Swanhart, Christopher; Williams, Thomas

    1991-01-01

    The current Lower Earth Orbit (LEO) environment has become overly crowded with space debris. An evaluation of types of debris is presented in order to determine which debris poses the greatest threat to operation in space, and would therefore provide a feasible target for removal. A target meeting these functional requirements was found in the Cosmos C-1B Rocket Body. These launchers are spent space transporters which constitute a very grave risk of collision and fragmentation in LEO. The motion and physical characteristics of these rocket bodies have determined the most feasible method of removal. The proposed Orbital Debris Collector (ODC) device is designed to attach to the Orbital Maneuvering Vehicle (OMV), which provides all propulsion, tracking, and power systems. The OMV/ODC combination, the Rocket Body Retrieval Vehicle (RBRV), will match orbits with the rocket body, use a spin table to match the rotational motion of the debris, capture it, despin it, and remove it from orbit by allowing it to fall into the Earth's atmosphere. A disposal analysis is presented to show how the debris will be deorbited into the Earth's atmosphere. The conceptual means of operation of a sample mission is described.

  12. Geosynchronous satellite collision avoidance

    NASA Technical Reports Server (NTRS)

    Fraser, W.

    1985-01-01

    The increases in the number of satellite systems, the growing dependency on these systems, and the potentially hazardous conjunctions in space, dictates careful management of satellite positions. The potential for satellite collision increases as more objects are placed in orbit. At geosynchronous altitudes active satellites maintain fixed longitudinal station-keeping control while inactive satellites and debris generally drift around the globe or oscillate about two geopotential stable points. Portions of the total objects in geosynchronous orbit are tracked by ground stations while a significant number of additional pieces of space debris regularly pass through geosynchronous orbit altitudes. The probability of an operational satellite colliding with another satellite or a piece of space debris will increase in the number of space objects, their sizes, and on-orbit lifetimes.

  13. Drag-o-llision Models of Extrasolar Planets in Debris Disks

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2009-01-01

    An extrasolar planet sculpts the famous debris disk around Fomalhaut; probably many other debris disks contain planets that we could locate if only we could better recognize their signatures in the dust that surrounds them. But the interaction between planets and debris disks involves both orbital resonances and collisions among grains and rocks in the disks---difficult processes to model simultaneously. The author describes new 3-D models of debris disk dynamics, Drag-o-llision models, that incorporate both collisions and resonant trapping of dust for the first time. The author also discusses the implications of these models for coronagraphic imaging with Gemini and other telescopes.

  14. 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.

  15. Turbomachinery debris remover

    DOEpatents

    Krawiec, Donald F.; Kraf, Robert J.; Houser, Robert J.

    1988-01-01

    An apparatus for removing debris from a turbomachine. The apparatus includes housing and remotely operable viewing and grappling mechanisms for the purpose of locating and removing debris lodged between adjacent blades in a turbomachine.

  16. Active Debris Removal and the Challenges for Environment Remediation

    NASA Technical Reports Server (NTRS)

    Liou, J. C.

    2012-01-01

    Recent modeling studies on the instability of the debris population in the low Earth orbit (LEO) region and the collision between Iridium 33 and Cosmos 2251 have underlined the need for active debris removal. A 2009 analysis by the NASA Orbital Debris Program Office shows that, in order to maintain the LEO debris population at a constant level for the next 200 years, an active debris removal of about five objects per year is needed. The targets identified for removal are those with the highest mass and collision probability products in the environment. Many of these objects are spent upper stages with masses ranging from 1 to more than 8 metric tons, residing in several altitude regions and concentrated in about 7 inclination bands. To remove five of those objects on a yearly basis, in a cost-effective manner, represents many challenges in technology development, engineering, and operations. This paper outlines the fundamental rationale for considering active debris removal and addresses the two possible objectives of the operations -- removing large debris to stabilize the environment and removing small debris to reduce the threat to operational spacecraft. Technological and engineering challenges associated with the two different objectives are also discussed.

  17. Operational Collision Avoidance

    NASA Technical Reports Server (NTRS)

    Guit, Bill

    2015-01-01

    This presentation will describe the early days of the EOS Aqua and Aura operational collision avoidance process. It will highlight EOS debris avoidance maneuvers, EOS high interest event statistic and A-Train systematic conjunctions and conclude with future challenges. This is related to earlier e-DAA (tracking number 21692) that an abstract was submitted to a different conference. Eric Moyer, ESMO Deputy Project Manager has reviewed and approved this presentation on May 6, 2015

  18. Debris exhaust system

    DOEpatents

    McBride, Donald D.; Bua, Dominic; Domankevitz, Yacov; Nishioka, Norman

    1998-01-01

    A debris removal system removes debris from a work site by flowing fluid away from the work site toward the periphery of a structure. The fluid flow can be kept constant around the periphery so that debris is removed evenly. The structure can have a reduced cross section between the fluid inlet and the work site so that the resulting increased fluid velocity works to prevent debris from escaping.

  19. Debris exhaust system

    DOEpatents

    McBride, D.D.; Bua, D.; Domankevitz, Y.; Nishioka, N.

    1998-06-23

    A debris removal system removes debris from a work site by flowing fluid away from the work site toward the periphery of a structure. The fluid flow can be kept constant around the periphery so that debris is removed evenly. The structure can have a reduced cross section between the fluid inlet and the work site so that the resulting increased fluid velocity works to prevent debris from escaping. 9 figs.

  20. Engineering and Technology Challenges for Active Debris Removal

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi

    2011-01-01

    After more than fifty years of space activities, the near-Earth environment is polluted with man-made orbital debris. The collision between Cosmos 2251 and the operational Iridium 33 in 2009 signaled a potential collision cascade effect, also known as the "Kessler Syndrome", in the environment. Various modelling studies have suggested that the commonly-adopted mitigation measures will not be sufficient to stabilize the future debris population. Active debris removal must be considered to remediate the environment. This paper summarizes the key issues associated with debris removal and describes the technology and engineering challenges to move forward. Fifty-four years after the launch of Sputnik 1, satellites have become an integral part of human society. Unfortunately, the ongoing space activities have left behind an undesirable byproduct orbital debris. This environment problem is threatening the current and future space activities. On average, two Shuttle window panels are replaced after every mission due to damage by micrometeoroid or orbital debris impacts. More than 100 collision avoidance maneuvers were conducted by satellite operators in 2010 to reduce the impact risks of their satellites with respect to objects in the U.S. Space Surveillance Network (SSN) catalog. Of the four known accident collisions between objects in the SSN catalog, the last one, collision between Cosmos 2251 and the operational Iridium 33 in 2009, was the most significant. It was the first ever accidental catastrophic destruction of an operational satellite by another satellite. It also signaled the potential collision cascade effect in the environment, commonly known as the "Kessler Syndrome," predicted by Kessler and Cour-Palais in 1978 [1]. Figure 1 shows the historical increase of objects in the SSN catalog. The majority of the catalog objects are 10 cm and larger. As of April 2011, the total objects tracked by the SSN sensors were more than 22,000. However, approximately 6000 of

  1. Dimensional analysis of natural debris flows

    NASA Astrophysics Data System (ADS)

    Zhou, Gordon; Ouyang, Chaojun

    2015-04-01

    Debris flows occur when masses of poorly sorted sediment, agitated and saturated with water, surge down slopes in response to gravitational attraction. They are of great concern because they often cause catastrophic disasters due to the long run-out distance and large impact forc-es. Different from rock avalanches and sediment-laden water floods, both solid and fluid phases affected by multiple parameters can influence the motion of debris flows and govern their rheological properties. A dimensional analysis for a systematic study of the governing parameters is presented in this manuscript. Multiple dimensionless numbers with clear physical meanings are critically reviewed. Field data on natural debris flows are available here based on the fifty years' observation and measurement in the Jiangjia Gully, which is located in the Dongchuan City, Yunnan Province of China. The applications of field data with the dimensional analysis for studying natural debris flows are demonstrated. Specific values of dimensionless numbers (e.g., modified Savage Number, Reynolds number, Friction number) for classifying flowing regimes of natural debris flows on the large scales are obtained. Compared to previous physical model tests conducted mostly on small scales, this study shows that the contact friction between particles dominates in natural debris flows. In addition, the solid inertial stress due to particle collisions and the pore fluid viscous shear stress play key roles in governing the dynamic properties of debris flows and the total normal stress acting on the slope surfaces. The channel width as a confinement to the flows can affect the solids discharge per unit width significantly. Furthermore, a dimensionless number related to pore fluid pressure dissipation is found for distinguishing surge flows and continuous flows in field satisfactorily. It indicates that for surge debris flows, the high pore fluid pressures generated in granular body dissipate quite slowly and may

  2. Relative motion in a debris cloud

    NASA Astrophysics Data System (ADS)

    Kebe, Fatoumata

    2016-07-01

    After an explosion or collision in space, a hundred or thousands of debris are generated. To be able to study a debris cloud it's necessary to develop new analysis tools. In that sense, we have studied several representations of the relative motion with the parent body's orbit as the reference. Thus, in the case of an explosion the original spacecraft has a circular orbit which will be the reference one in the relative motion's equations while, in the case of a collision, we will take one of the spacecraft's orbit as the reference. We mainly focus on the relative motion method that used the differential elements instead of the Cartesian coordinates as it allows to take into account the main perturbation.

  3. The Space Debris Crisis: Time for an International Treaty

    DTIC Science & Technology

    2011-03-23

    Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The growth of man-made debris in Earth’s orbits has accelerated in the past decade to the...point that uncontrolled cascading collisions between debris and active spacecraft is now occurring in low Earth orbit (LEO). A Chinese anti-satellite...space environment around Earth. The main objective of this treaty would be to ensure Earth’s orbits do not become so congested that their use would

  4. Application of femtosecond laser range finder in space debris monitoring

    NASA Astrophysics Data System (ADS)

    Yuan, Jiang; Ji, Rongyi; Zhou, Weihu

    2016-11-01

    The space-based long-distance ranging of space debris will help to avoid collision. Compared with radar and telescope, the infrared binocular monitoring system can track and range space debris quickly. Because the measurement range is related to the baseline length, two cameras are placed on different satellites. Due to the lack of rigid connection between satellites, femtosecond laser ranging is used to measure the attitude of the camera.

  5. Innovative and Cost Effective Remediation of Orbital Debris

    DTIC Science & Technology

    2014-04-25

    NASA) Orbital Debris Program Office prioritized the hazard posed by thousands of large objects in orbit as a function of object mass and collision...Earth orbit (LEO) and this value is expected to increase significantly in the next decades. 1 The resulting hazard to operational spacecraft could... debris population growth that would render certain altitudes too hazardous for satellite operations. NASA researchers also determined that the

  6. NASA Safety Standard: Guidelines and Assessment Procedures for Limiting Orbital Debris

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Collision with orbital debris is a hazard of growing concern as historically accepted practices and procedures have allowed man-made objects to accumulate in orbit. To limit future debris generation, NASA Management Instruction (NMI) 1700.8, 'Policy to Limit Orbital Debris Generation,' was issued in April of 1993. The NMI requires each program to conduct a formal assessment of the potential to generate orbital debris. This document serves as a companion to NMI 1700.08 and provides each NASA program with specific guidelines and assessment methods to assure compliance with the NMI. Each main debris assessment issue (e.g., Post Mission Disposal) is developed in a separate chapter.

  7. VARIABILITY OF THE INFRARED EXCESS OF EXTREME DEBRIS DISKS

    SciTech Connect

    Meng, Huan Y. A.; Rieke, George H.; Su, Kate Y. L.; Rujopakarn, Wiphu; Ivanov, Valentin D.; Vanzi, Leonardo

    2012-05-20

    Debris disks with extremely large infrared excesses (fractional luminosities >10{sup -2}) are rare. Those with ages between 30 and 130 Myr are of interest because their evolution has progressed well beyond that of protoplanetary disks (which dissipate with a timescale of order 3 Myr), yet they represent a period when dynamical models suggest that terrestrial planet building may still be progressing through large, violent collisions that could yield large amounts of debris and large infrared excesses. For example, our Moon was formed through a violent collision of two large protoplanets during this age range. We report two disks around the solar-like stars ID8 and HD 23514 in this age range where the 24 {mu}m infrared excesses vary on timescales of a few years, even though the stars are not variable in the optical. Variations this rapid are difficult to understand if the debris is produced by collisional cascades, as it is for most debris disks. It is possible that the debris in these two systems arises in part from condensates from silicate-rich vapor produced in a series of violent collisions among relatively large bodies. If their evolution is rapid, the rate of detection of extreme excesses would indicate that major collisions may be relatively common in this age range.

  8. Handling Metalloproteinases.

    PubMed

    Fridrich, Sven; Karmilin, Konstantin; Stöcker, Walter

    2016-02-02

    Substrate cleavage by metalloproteinases involves nucleophilic attack on the scissile peptide bond by a water molecule that is polarized by a catalytic metal, usually a zinc ion, and a general base, usually the carboxyl group of a glutamic acid side chain. The zinc ion is most often complexed by imidazole nitrogens of histidine side chains. This arrangement suggests that the physiological pH optimum of most metalloproteinases is in the neutral range. In addition to their catalytic metal ion, many metalloproteinases contain additional transition metal or alkaline earth ions, which are structurally important or modulate the catalytic activity. As a consequence, these enzymes are generally sensitive to metal chelators. Moreover, the catalytic metal can be displaced by adventitious metal ions from buffers or biological fluids, which may fundamentally alter the catalytic function. Therefore, handling, purification, and assaying of metalloproteinases require specific precautions to warrant their stability. Copyright © 2016 John Wiley & Sons, Inc.

  9. Collisions in the Oort Cloud

    SciTech Connect

    Stern, S.A.

    1988-03-01

    The present assessment of the consequentiality of physical collisions between Oort Cloud objects by a first-generation model indicates that natural power-law population structures produce significant numbers of collisions between each comet and smaller objects over the age of the solar system. These collisions are held to constitute a feedback mechanism for small debris production. The impacts yield extensive comet surface evolution in the cloud, in conditions where the number of small orbiting objects conforms to the standard power-law populations. 16 references.

  10. Debris mapping sensor technology project summary: Technology flight experiments program area of the space platforms technology program

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The topics presented are covered in viewgraph form. Programmatic objectives are: (1) to improve characterization of the orbital debris environment; and (2) to provide a passive sensor test bed for debris collision detection systems. Technical objectives are: (1) to study LEO debris altitude, size and temperature distribution down to 1 mm particles; (2) to quantify ground based radar and optical data ambiguities; and (3) to optimize debris detection strategies.

  11. A space-based concept for a collision warning sensor

    NASA Technical Reports Server (NTRS)

    Talent, David L.; Vilas, Faith

    1990-01-01

    This paper describes a concept for a space-based collision warning sensor experiment, the Debris Collision Warning Sensor (DCWS) experiment, in which the sensor will rely on passive sensing of debris in optical and IR passband. The DCWS experiment will be carried out under various conditions of solar phase angle and pass geometry; debris from 1.5 m to 1 mm diam will be observable. The mission characteristics include inclination in the 55-60 deg range and an altitude of about 500 km. The results of the DCWS experiment will be used to generate collision warning scenarios for the Space Station Freedom.

  12. Observations of Human-Made Debris in Earth Orbit

    NASA Technical Reports Server (NTRS)

    Cowardia, Heather

    2011-01-01

    Orbital debris is defined as any human-made object in orbit about the Earth that no longer serves a useful purpose. Beginning in 1957 with the launch of Sputnik 1, there have been more than 4,700 launches, with each launch increasing the potential for impacts from orbital debris. Almost 55 years later there are over 16,000 catalogued objects in orbit over 10 cm in size. Agencies world-wide have realized this is a growing issue for all users of the space environment. To address the orbital debris issue, the Inter-Agency Space Debris Coordination Committee (IADC) was established to collaborate on monitoring, characterizing, and modeling orbital debris, as well as formulating policies and procedures to help control the risk of collisions and population growth. One area of fundamental interest is measurements of the space debris environment. NASA has been utilizing radar and optical measurements to survey the different orbital regimes of space debris for over 25 years, as well as using returned surfaces to aid in determining the flux and size of debris that are too small to detect with ground-based sensors. This paper will concentrate on the optical techniques used by NASA to observe the space debris environment, specifically in the Geosynchronous earth Orbit (GEO) region where radar capability is severely limited.

  13. Space debris clearing with lasers: Myth and reality

    NASA Astrophysics Data System (ADS)

    Bohn, Willy L.

    2012-07-01

    Since the Chinese anti-missile test in 2007 the problem of space debris and their threat to all space assets has become known to a larger community. Today, advances in laser sources and large mirrors including adaptive optics have matured and are in principle available. The paper first addresses the current situation of accumulated space debris and future predictions of collisions in space. Second, different solutions to mitigate the debris problem will be reviewed with emphasis on the use of high power pulsed lasers as derived from fundamental relations governing the momentum imparted to the debris by the laser pulse and causing their re-entry into the atmosphere with subsequent burn up. Unfortunately the required laser specifications lead to a demand of laser sources which cannot be satisfied with currently available devices. Therefore, two novel laser architectures will be presented. Finally, operational concepts and safety aspects will be addressed in order to evaluate the prospects of laser debris removal.

  14. Space Debris Environmental Evolutionary Model in Low Earth Orbit

    NASA Astrophysics Data System (ADS)

    Narumi, Tomohiro; Hanada, Toshiya; Kawamoto, Satomi

    Study and long-term prediction of orbital debris environment in low Earth orbits are urgent needs for secure human space development and exploration. This paper introduces some results of Low Earth Orbital Debris Environmental Evolutionary Model (LEODEEM) being researched at Kyushu University with collaboration from JAXA for the purpose of discussing problems of space environment conservation. The model calculates LEO debris evolution (less than 2,000 km altitude of perigee) taking into account collisions, and future launch traffic. It becomes possible to predict a long term LEO environment and investigate future mission hazard evaluation by using this model.

  15. Geosynchronous Debris Conjunction Lead-Time Requirements for Autonomous Low-Thrust Disposal Guidance

    NASA Astrophysics Data System (ADS)

    Anderson, Paul V.; Schaub, Hanspeter

    2016-12-01

    Autonomous, low-thrust guidance for active disposal of geosynchronous debris, subject to collision avoidance with the local debris population, is studied. A bisection method is employed to determine trajectory modifications to avoid a conjuncting debris object by a range of distances, assuming a range of collision lead times. A parametric study is performed, in which re-orbit thrust accelerations are varied from 10-6 to 10-3 m/s 2, to demonstrate how the continuous-thrust level impacts the required lead time to achieve a desired debris miss distance. The lowest thrust levels considered show that a 6-12 hour lead time is required to achieve a 1-10 km debris separation at the predicted collision time.

  16. Geosynchronous Debris Conjunction Lead-Time Requirements for Autonomous Low-Thrust Disposal Guidance

    NASA Astrophysics Data System (ADS)

    Anderson, Paul V.; Schaub, Hanspeter

    2017-06-01

    Autonomous, low-thrust guidance for active disposal of geosynchronous debris, subject to collision avoidance with the local debris population, is studied. A bisection method is employed to determine trajectory modifications to avoid a conjuncting debris object by a range of distances, assuming a range of collision lead times. A parametric study is performed, in which re-orbit thrust accelerations are varied from 10-6 to 10-3 m/s 2, to demonstrate how the continuous-thrust level impacts the required lead time to achieve a desired debris miss distance. The lowest thrust levels considered show that a 6-12 hour lead time is required to achieve a 1-10 km debris separation at the predicted collision time.

  17. Orbital debris minimization and mitigation techniques

    NASA Astrophysics Data System (ADS)

    Loftus, Joseph P.; Anz-Meador, Philip D.; Reynolds, Robert

    1993-08-01

    Man's activity in space has generated significant amounts of debris that remain in orbit long enough to become a hazard to future space activities. Upper stages and spacecraft that have ended their functional life are the largest objects. In the past, additional debris has been generated by inadvertent explosions of upper stages and spacecraft, by intentional explosions for military reasons, and possibly by a few breakups resulting from collisions. In the future, debris can be generated by collisions among spacecraft as the number of orbital objects continues to grow at a rate greater than the rate at which natural forces remove them from orbit. Some design and operations practices can minimize the inadvertent generation of debris, and others can remove objects from space at the end of their useful service so they are not a source for the generation of future debris. Those studies are the primary concern of this paper. The issues are different in the low Earth orbits and in the geosynchronous orbits. In low Earth orbit, the hazards generated by potential collisions among spacecraft are severe because the events take place at such high velocities. In geosynchronous orbit, the collision consequence is not so severe because the relative velocities are low-less than 1 km/s. But because of the value of the limited arc and the extremely long lifetime of the satellites, debris generated in the orbit must be removed to a different orbit at the end of life if it is not to be a hazard to future operational spacecraft. The issue at present seems to be how high the reboost maneuver must be and what the system design and maneuver strategy should be to ensure effectiveness. The most economic removal of objects is achieved when those objects have the capability to execute the necessary maneuvers with their own systems and resources. The most costly option is to have some other system remove the object after it has become a derelict. Numerous options are being studied to develop

  18. Modeling the long-term evolution of space debris

    DOEpatents

    Nikolaev, Sergei; De Vries, Willem H.; Henderson, John R.; Horsley, Matthew A.; Jiang, Ming; Levatin, Joanne L.; Olivier, Scot S.; Pertica, Alexander J.; Phillion, Donald W.; Springer, Harry K.

    2017-03-07

    A space object modeling system that models the evolution of space debris is provided. The modeling system simulates interaction of space objects at simulation times throughout a simulation period. The modeling system includes a propagator that calculates the position of each object at each simulation time based on orbital parameters. The modeling system also includes a collision detector that, for each pair of objects at each simulation time, performs a collision analysis. When the distance between objects satisfies a conjunction criterion, the modeling system calculates a local minimum distance between the pair of objects based on a curve fitting to identify a time of closest approach at the simulation times and calculating the position of the objects at the identified time. When the local minimum distance satisfies a collision criterion, the modeling system models the debris created by the collision of the pair of objects.

  19. Orbital Debris Engineering Model (ORDEM) v.3

    NASA Technical Reports Server (NTRS)

    Matney, Mark; Krisko, Paula; Xu, Yu-Lin; Horstman, Matthew

    2013-01-01

    A model of the manmade orbital debris environment is required by spacecraft designers, mission planners, and others in order to understand and mitigate the effects of the environment on their spacecraft or systems. A manmade environment is dynamic, and can be altered significantly by intent (e.g., the Chinese anti-satellite weapon test of January 2007) or accident (e.g., the collision of Iridium 33 and Cosmos 2251 spacecraft in February 2009). Engineering models are used to portray the manmade debris environment in Earth orbit. The availability of new sensor and in situ data, the re-analysis of older data, and the development of new analytical and statistical techniques has enabled the construction of this more comprehensive and sophisticated model. The primary output of this model is the flux [#debris/area/time] as a function of debris size and year. ORDEM may be operated in spacecraft mode or telescope mode. In the former case, an analyst defines an orbit for a spacecraft and "flies" the spacecraft through the orbital debris environment. In the latter case, an analyst defines a ground-based sensor (telescope or radar) in terms of latitude, azimuth, and elevation, and the model provides the number of orbital debris traversing the sensor's field of view. An upgraded graphical user interface (GUI) is integrated with the software. This upgraded GUI uses project-oriented organization and provides the user with graphical representations of numerous output data products. These range from the conventional flux as a function of debris size for chosen analysis orbits (or views), for example, to the more complex color-contoured two-dimensional (2D) directional flux diagrams in local spacecraft elevation and azimuth.

  20. Debris analysis workstation: from concept to reality

    NASA Astrophysics Data System (ADS)

    Spencer, David B.; Maethner, Scott R.; Shubert, Ann J.; Yates, Ken W.

    1995-06-01

    Determining the hazards from debris generating events is a design and safety consideration for a number of space systems, both currently operating and planned. To meet these and other requirements, the US Air Force Phillips Laboratory Space Debris Research Program is developing a simulation platform called the Debris Analysis Workstation (DAW) which provides an analysis capability for assessing a wide variety of debris studies. DAW integrates several component debris analysis models and data visualization tools into a single analysis platform that meets the needs for DoD space debris analysis, and is both user friendly and modular. This allows for studies to be performed expeditiously by analysts that are not debris experts. DAW has gone from concept to reality with the recent deliveries of Versions 0.1 to 0.4 to a number of customers. The current version of DAW incorporates a spacecraft break-up model, drag inclusive propagator, a collision dispersion model, a graphical user interface, and data visualization routines, which together provide capabilities to conduct missile intercept range safety analyses. Work is progressing to add new capabilities with the incorporation of additional models and improved designs. The existing tools are in their initial integrated form, but the 'glue' that will ultimately bring them together into an integrated, user-friendly system, is an object oriented language layer that is scheduled to be added in 1995. Other candidate component models that are under consideration for incorporation include additional orbital propagators, error estimation routines, dispersion models, and other breakup models. At present, DAW resides on a SUN workstation, although future versions could be tailored for other platforms, depending on the need.

  1. Overview of the space debris environment

    NASA Astrophysics Data System (ADS)

    Meshishnek, M. J.

    1995-03-01

    There is a component of the space environment that is man-made pollution, termed 'space debris' it exists at all inclinations and, primarily, at altitudes of roughly 350 km to 2000 km. The size of this debris ranges from several meters to a fraction of a micrometer in diameter, and the particle distribution follows an inverse power law, with the smaller size component far exceeding that of the larger. Debris is composed primarily of alumina from solid rocket motor exhausts, aluminum from spacecraft structures, and zinc and titanium oxides from thermal control coatings. The accepted model of the space debris environment is that of Kessler et al., a complex model that predicts the number of particles that will impact a surface as a function of altitude, inclination, solar cycle, and particle diameter, as well as their collision velocities. Recent data from LDEF has demonstrated both the accuracy and shortcomings of the Kessler model. Measured debris impactor fluxes are in good agreement with the model for ram surfaces. However, predictions of the model for other surfaces of a spacecraft are less accurate, most notably for the wake or trailing side. While the Kessler model is appropriate for long-term, average flux predictions, spatial-temporal impact fluxes measured on LDEF dramatically illustrated the presence of strong debris clouds that do not dissipate quickly in space and will encounter an orbiting spacecraft cyclically and repeatedly over its lifetime. LDEF data has also indicated the presence of debris in elliptical orbits, a fact not predicted by the Kessler model. This fact is responsible for the discrepancy between measured impact fluxes and predictions on trailing edge surfaces.

  2. Observations of space debris

    NASA Technical Reports Server (NTRS)

    Taff, L. G.

    1991-01-01

    Optical observations of near Earth and deep-space debris conducted at M.I.T.'s artificial satellite observatory will be discussed. A brief review of observing technique, regions of high debris density, and amount of debris in orbit will be given. The unique, duplex facilities of the observatory allow the discrimination of debris from meteors, the construction of an orbital element set, and real-time identification of catalogued artificial satellites. Near-Earth debris is present in large numbers in all the popular near-Earth orbits; at least 5-6 times the 5000-6000 objects in the NORAD catalog. In deep-space, the new presence of Ariane-related debris adds significantly to the existing population which is treble that catalogued by NORAD.

  3. 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.

  4. Space debris detection and mitigation

    SciTech Connect

    Allahdadi, F.

    1993-01-01

    Space debris is defined as all useless man-made objects in space. This conference covers the following areas: debris detection, tracking, and surveillance; orbital debris analytical modeling; debris environment and safety issues; and orbital debris mitigation. Separate abstracts were prepared for 26 papers in this conference.

  5. Debris Disks: An Overview

    NASA Astrophysics Data System (ADS)

    Backman, D.

    2004-12-01

    An overview regarding planetary debris disks: First, more history to complement Low and Aumann's summary appearing elsewhere in this volume. Then, commentary on the nature of debris disks and what we've learned from them: properties of the original ``Fabulous Four" archetypes, results from surveys showing that a large fraction of ordinary stars may be hosts for debris disks, and relatively detailed discussion of β Pictoris, the most prominent disk. Finally, discussion of the connection between debris disks, our solar system's Kuiper Belt, and the zodiacal dust cloud. Open questions about these objects will be highlighted which can lead on to the remainder of the proceedings.

  6. Effect of impactor area on collision rate estimates

    SciTech Connect

    Canavan, G.H.

    1996-08-01

    Analytic and numercial estimates provide an assessment of the effect of impactor area on space debris collision rates, which is sufficiently small and insensitive to parameters of inerest that it could be neglected or corrected.

  7. Space Debris Birth to Death Analysis from Concern to Consequences

    NASA Astrophysics Data System (ADS)

    Finkleman, D.; Alfano, S.; Johnson, T.; Kelso, T.; Vallado, D.; Oltrogge, D.

    We present the space debris operational process in the context of real circumstances that would have required early assessment, prompt warning, and responsive mitigations. We have applied several widely used collision and explosion models to the prompt debris environment, short term moderation of the debris cloud through reentry, mid-term assessment of conjunctions with operational satellites, and identification of the long term persistent aftermath. We provide distributions of fragment sizes, masses, and radar cross sections which we use to identify the trackable population and the remaining population which is either imperceptible to space surveillance radars. We examine predicted conjunctions between FY1C Debris (Catalog 31473)/Meteor 2-2, FY1C Debris (31379)/Meteor 2-12, and ISIS-2/Cosmos 2271. These illustrate early assessment of collision probability and consequences, triage among high probability conjunctions to conduct additional analysis judiciously, and the consequences of collisions between objects of disparate masses. We highlight deficiencies in essential analytical tools and databases. We offer guidance for further investigation and seek better capabilities to serve this important need.

  8. Orbital debris mitigation: The iridiumTM way

    NASA Astrophysics Data System (ADS)

    Penny, Robert E.; Swan, Peter A.

    1993-08-01

    ``May our foresight in controlling the growth of artificial space debris provide boundless opportunities for the exploration of the cosmos for generations to come.'' This key space operations vision is given in the forward to Artificial Space Debris by Johnson and McKnight. The Iridium™ Program Office's vision is not quite so altruistic; however, it has been driven to a similar belief by the magnitude of 66 satellites sharing the same orbit. Early in the development of the program, the necessity to address the debris issues surfaced. It was evident that the national policy was geared to minimize debris and common sense mandated that Motorola protect its chosen orbit of polar, circular at 780 km altitude. For the Iridium™ Block I (100 satellites) and Block II (100 satellites) commercial communication constellations to be successful and economical, debris must be actively mitigated. This drove a debris mitigation program with the following major aspects: orbit planning, launch and deployment activities, station keeping and collision avoidance, safe-mode, de-boost activities, and potential shielding requirements. Loss of a satellite from our own debris is not acceptable, while loss from other debris must be minimized. This paper will present the Iridium™ approach to mitigate the dangers of orbital debris. The natural and man-made debris characteristics will be summarized, the system's level approach to protecting ``our orbit'' will be shown and the operational concepts for safe-mode and de-orbit will be explained. This commercial constellation's operational twist will enhance the orbital environment by actively ensuring the mitigation of debris: The Iridium™ way!

  9. A Parametric Study on Using Active Debris Removal to Stabilize the Future LEO Debris Environment

    NASA Technical Reports Server (NTRS)

    Liou, J.C.

    2010-01-01

    Recent analyses of the instability of the orbital debris population in the low Earth orbit (LEO) region and the collision between Iridium 33 and Cosmos 2251 have reignited the interest in using active debris removal (ADR) to remediate the environment. There are; however, monumental technical, resources, operational, legal, and political challenges in making economically viable ADR a reality. Before a consensus on the need for ADR can be reached, a careful analysis of the effectiveness of ADR must be conducted. The goal is to demonstrate the feasibility of using ADR to preserve the future environment and to guide its implementation to maximize the benefit-cost ratio. This paper describes a comprehensive sensitivity study on using ADR to stabilize the future LEO debris environment. The NASA long-term, orbital debris evolutionary model, LEGEND, is used to quantify the effects of many key parameters. These parameters include (1) the starting epoch of ADR implementation, (2) various target selection criteria, (3) the benefits of collision avoidance maneuvers, (4) the consequence of targeting specific inclination or altitude regimes, (5) the consequence of targeting specific classes of vehicles, and (6) the timescale of removal. Additional analyses on the importance of postmission disposal and how future launches might affect the requirements to stabilize the environment are also included.

  10. A Parametric Study on Using Active Debris Removal to Stabilize the Future LEO Debris Environment

    NASA Technical Reports Server (NTRS)

    Liou, J.C.

    2010-01-01

    Recent analyses of the instability of the orbital debris population in the low Earth orbit (LEO) region and the collision between Iridium 33 and Cosmos 2251 have reignited the interest in using active debris removal (ADR) to remediate the environment. There are; however, monumental technical, resources, operational, legal, and political challenges in making economically viable ADR a reality. Before a consensus on the need for ADR can be reached, a careful analysis of the effectiveness of ADR must be conducted. The goal is to demonstrate the feasibility of using ADR to preserve the future environment and to guide its implementation to maximize the benefit-cost ratio. This paper describes a comprehensive sensitivity study on using ADR to stabilize the future LEO debris environment. The NASA long-term, orbital debris evolutionary model, LEGEND, is used to quantify the effects of many key parameters. These parameters include (1) the starting epoch of ADR implementation, (2) various target selection criteria, (3) the benefits of collision avoidance maneuvers, (4) the consequence of targeting specific inclination or altitude regimes, (5) the consequence of targeting specific classes of vehicles, and (6) the timescale of removal. Additional analyses on the importance of postmission disposal and how future launches might affect the requirements to stabilize the environment are also included.

  11. Orbital Debris Mitigation

    NASA Technical Reports Server (NTRS)

    Kelley, R. L.; Jarkey, D. R.; Stansbery, G.

    2014-01-01

    Policies on limiting orbital debris are found throughout the US Government, many foreign space agencies, and as adopted guidelines in the United Nations. The underlying purpose of these policies is to ensure the environment remains safe for the operation of robotic and human spacecraft in near- Earth orbit. For this reason, it is important to consider orbital debris mitigation during the design of all space vehicles. Documenting compliance with the debris mitigation guidelines occurs after the vehicle has already been designed and fabricated for many CubeSats, whereas larger satellites are evaluated throughout the design process. This paper will provide a brief explanation of the US Government Orbital Debris Mitigation Standard Practices, a discussion of international guidelines, as well as NASA's process for compliance evaluation. In addition, it will discuss the educational value of considering orbital debris mitigation requirements as a part of student built satellite design.

  12. Laser Remote Maneuver of Space Debris at the Space Environment Research Center

    NASA Astrophysics Data System (ADS)

    Bold, M.

    2016-09-01

    Active satellites have the ability to maneuver to avoid collision with other space objects. Unfortunately the majority of objects in space are debris objects that do not have the ability to maneuver. In the future the population of debris objects will grow and the probability of collision will increase. This paper will provide details on plans to use a ground based laser with uplink adaptive optics compensation to apply photon pressure to debris objects and maneuver them out of harm's way. This work is ongoing at the Space Environment Research Centre at Mt. Stromlo Australia with collaborative efforts from Lockheed Martin, Electro-Optics Systems Inc. and the Australian National University.

  13. Laser remote maneuver of space debris at the Space Environment Research Centre

    NASA Astrophysics Data System (ADS)

    Bold, Matthew M.

    2016-09-01

    Active satellites have the ability to maneuver to avoid collision with other space objects. Unfortunately the majority of objects in space are debris objects that do not have the ability to maneuver. In the future the population of debris objects will grow and the probability of collision will increase. This paper will provide details on plans to use a ground based laser with uplink adaptive optics compensation to apply photon pressure to debris objects and maneuver them out of harm's way. This work is ongoing at the Space Environment Research Centre at Mt. Stromlo Australia with collaborative efforts from Lockheed Martin, Electro-Optics Systems Inc. and the Australian National University.

  14. Development of high precision laser measurement to Space Debris and Applications in SHAO

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongping; Chen, Juping; Xiong, Yaoheng; Han, Xingwei

    2016-07-01

    Artificial space debris has become the focus during the space exploration because of producing the damage for the future active spacecrafts and high precision measurement for space debris are required for debris surveillance and collision avoidance. Laser ranging technology is inherently high accurate and will play an important role in precise orbit determination, accurate catalog of space debris. Shanghai Astronomical Observatory (SHAO) of CAS, has been developing the technology of laser measurement to space debris for several years. According to characteristics of laser echoes from space debris and the experiences of relevant activities, high repetition rate, high power laser system and low dark noise APD detector with high quantum efficiency and high transmissivity of narrow bandwidth spectral filter are applied to laser measurement to space debris in SHAO. With these configurations, great achievements of laser measurement to space debris are made with hundreds of passes of laser data from space debris in the distance between 500km and 2500km with Radar Cross Section (RCS) of more than 10 m^{2} to less than 0.5m^{2} at the measuring precision of less than 1m (RMS). For better application of laser ranging technology, Chinese Space Debris Observation network, consisting of Shanghai, Changchun and Kunming station, has been preliminary developed and the coordinated observation has been performed to increase the measuring efficiency for space debris. It is referred from data that laser ranging technology can be as the essential high accuracy measurement technology in the study of space debris.

  15. Numerical modeling of the debris flows runout

    NASA Astrophysics Data System (ADS)

    Federico, Francesco; Cesali, Chiara

    2017-06-01

    Rapid debris flows are identified among the most dangerous of all landslides. Due to their destructive potential, the runout length has to be predicted to define the hazardous areas and design safeguarding measures. To this purpose, a continuum model to predict the debris flows mobility is developed. It is based on the well known depth-integrated avalanche model proposed by Savage and Hutter (S&H model) to simulate the dry granular materials flows. Conservation of mass and momentum equations, describing the evolving geometry and the depth averaged velocity distribution, are re-written taking into account the effects of the interstitial pressures and the possible variation of mass along the motion due to erosion/deposition processes. Furthermore, the mechanical behaviour of the debris flow is described by a recently developed rheological law, which allows to take into account the dissipative effects of the grain inelastic collisions and friction, simultaneously acting within a `shear layer', typically at the base of the debris flows. The governing PDEs are solved by applying the finite difference method. The analysis of a documented case is finally carried out.

  16. Modeling debris-covered glaciers: response to steady debris deposition

    NASA Astrophysics Data System (ADS)

    Anderson, Leif S.; Anderson, Robert S.

    2016-05-01

    Debris-covered glaciers are common in rapidly eroding alpine landscapes. When thicker than a few centimeters, surface debris suppresses melt rates. If continuous debris cover is present, ablation rates can be significantly reduced leading to increases in glacier length. In order to quantify feedbacks in the debris-glacier-climate system, we developed a 2-D long-valley numerical glacier model that includes englacial and supraglacial debris advection. We ran 120 simulations on a linear bed profile in which a hypothetical steady state debris-free glacier responds to a step increase of surface debris deposition. Simulated glaciers advance to steady states in which ice accumulation equals ice ablation, and debris input equals debris loss from the glacier terminus. Our model and parameter selections can produce 2-fold increases in glacier length. Debris flux onto the glacier and the relationship between debris thickness and melt rate strongly control glacier length. Debris deposited near the equilibrium-line altitude, where ice discharge is high, results in the greatest glacier extension when other debris-related variables are held constant. Debris deposited near the equilibrium-line altitude re-emerges high in the ablation zone and therefore impacts melt rate over a greater fraction of the glacier surface. Continuous debris cover reduces ice discharge gradients, ice thickness gradients, and velocity gradients relative to initial debris-free glaciers. Debris-forced glacier extension decreases the ratio of accumulation zone to total glacier area (AAR). Our simulations reproduce the "general trends" between debris cover, AARs, and glacier surface velocity patterns from modern debris-covered glaciers. We provide a quantitative, theoretical foundation to interpret the effect of debris cover on the moraine record, and to assess the effects of climate change on debris-covered glaciers.

  17. Controlling the growth of future LEO debris populations with active debris removal

    NASA Astrophysics Data System (ADS)

    Liou, J.-C.; Johnson, N. L.; Hill, N. M.

    2010-03-01

    Active debris removal (ADR) was suggested as a potential means to remediate the low Earth orbit (LEO) debris environment as early as the 1980s. The reasons ADR has not become practical are due to its technical difficulties and the high cost associated with the approach. However, as the LEO debris populations continue to increase, ADR may be the only option to preserve the near-Earth environment for future generations. An initial study was completed in 2007 to demonstrate that a simple ADR target selection criterion could be developed to reduce the future debris population growth. The present paper summarizes a comprehensive study based on more realistic simulation scenarios, including fragments generated from the 2007 Fengyun-1C event, mitigation measures, and other target selection options. The simulations were based on the NASA long-term orbital debris projection model, LEGEND. A scenario where, at the end of mission lifetimes, spacecraft and upper stages were moved to 25-year decay orbits, was adopted as the baseline environment for comparison. Different annual removal rates and different ADR target selection criteria were tested, and the resulting 200-year future environment projections were compared with the baseline scenario. Results of this parametric study indicate that (1) an effective removal strategy can be developed using a selection criterion based on the mass and collision probability of each object, and (2) the LEO environment can be stabilized in the next 200 years with an ADR removal rate of five objects per year.

  18. Controlling the Growth of Future LEO Debris Populations with Active Debris Removal

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.; Johnson, N. L.; Hill, N. M.

    2008-01-01

    Active debris removal (ADR) was suggested as a potential means to remediate the low Earth orbit (LEO) debris environment as early as the 1980s. The reasons ADR has not become practical are due to its technical difficulties and the high cost associated with the approach. However, as the LEO debris populations continue to increase, ADR may be the only option to preserve the near-Earth environment for future generations. An initial study was completed in 2007 to demonstrate that a simple ADR target selection criterion could be developed to reduce the future debris population growth. The present paper summarizes a comprehensive study based on more realistic simulation scenarios, including fragments generated from the 2007 Fengyun-1C event, mitigation measures, and other target selection options. The simulations were based on the NASA long-term orbital debris projection model, LEGEND. A scenario, where at the end of mission lifetimes, spacecraft and upper stages were moved to 25-year decay orbits, was adopted as the baseline environment for comparison. Different annual removal rates and different ADR target selection criteria were tested, and the resulting 200-year future environment projections were compared with the baseline scenario. Results of this parametric study indicate that (1) an effective removal strategy can be developed based on the mass and collision probability of each object as the selection criterion, and (2) the LEO environment can be stabilized in the next 200 years with an ADR removal rate of five objects per year.

  19. Controlling the Growth of Future LEO Debris Populations with Active Debris Removal

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.; Johnson, N. L.; Hill, N. M.

    2008-01-01

    Active debris removal (ADR) was suggested as a potential means to remediate the low Earth orbit (LEO) debris environment as early as the 1980s. The reasons ADR has not become practical are due to its technical difficulties and the high cost associated with the approach. However, as the LEO debris populations continue to increase, ADR may be the only option to preserve the near-Earth environment for future generations. An initial study was completed in 2007 to demonstrate that a simple ADR target selection criterion could be developed to reduce the future debris population growth. The present paper summarizes a comprehensive study based on more realistic simulation scenarios, including fragments generated from the 2007 Fengyun-1C event, mitigation measures, and other target selection options. The simulations were based on the NASA long-term orbital debris projection model, LEGEND. A scenario, where at the end of mission lifetimes, spacecraft and upper stages were moved to 25-year decay orbits, was adopted as the baseline environment for comparison. Different annual removal rates and different ADR target selection criteria were tested, and the resulting 200-year future environment projections were compared with the baseline scenario. Results of this parametric study indicate that (1) an effective removal strategy can be developed based on the mass and collision probability of each object as the selection criterion, and (2) the LEO environment can be stabilized in the next 200 years with an ADR removal rate of five objects per year.

  20. The CDF data handling system

    SciTech Connect

    Dmitry O. Litvintsev

    2003-11-05

    The Collider Detector at Fermilab (CDF) records proton-antiproton collisions at center of mass energy of 2.0 TeV at the Tevatron collider. A new collider run, Run II, of the Tevatron started in April 2001. Increased luminosity will result in about 1 PB of data recorded on tapes in the next two years. Currently the CDF experiment has about 260 TB of data stored on tapes. This amount includes raw and reconstructed data and their derivatives. The data storage and retrieval are managed by the CDF Data Handling (DH) system. This system has been designed to accommodate the increased demands of the Run II environment and has proven robust and reliable in providing reliable flow of data from the detector to the end user. This paper gives an overview of the CDF Run II Data Handling system which has evolved significantly over the course of this year. An outline of the future direction of the system is given.

  1. Space debris characterization in support of a satellite breakup model

    NASA Technical Reports Server (NTRS)

    Fortson, Bryan H.; Winter, James E.; Allahdadi, Firooz A.

    1992-01-01

    The Space Kinetic Impact and Debris Branch began an ambitious program to construct a fully analytical model of the breakup of a satellite under hypervelocity impact. In order to provide empirical data with which to substantiate the model, debris from hypervelocity experiments conducted in a controlled laboratory environment were characterized to provide information of its mass, velocity, and ballistic coefficient distributions. Data on the debris were collected in one master data file, and a simple FORTRAN program allows users to describe the debris from any subset of these experiments that may be of interest to them. A statistical analysis was performed, allowing users to determine the precision of the velocity measurements for the data. Attempts are being made to include and correlate other laboratory data, as well as those data obtained from the explosion or collision of spacecraft in low earth orbit.

  2. ICAN: A novel laser architecture for space debris removal

    NASA Astrophysics Data System (ADS)

    Soulard, Rémi; Quinn, Mark N.; Tajima, Toshiki; Mourou, Gérard

    2014-12-01

    The development of a fiber based laser architecture will enable novel applications in environments which have hitherto been impossible due to size, efficiency and power of traditional systems. Such a new architecture has been developed by the International Coherent Amplification Network (ICAN) project. Here we present an analysis of utilizing an ICAN laser for the purpose of tracking and de-orbiting hyper-velocity space debris. With an increasing number of new debris from collisions of active, derelict and new payloads in orbit, there is a growing danger of runaway debris impacts. Due to its compactness and efficiency, it is shown that space-based operation would be possible. For different design parameters such as fiber array size, it is shown that the kHz repetition rate and kW average power of ICAN would be sufficient to de-orbit small 1-10 cm debris within a single instance via laser ablation.

  3. SILICA-RICH BRIGHT DEBRIS DISK AROUND HD 15407A

    SciTech Connect

    Fujiwara, Hideaki; Onaka, Takashi; Yamashita, Takuya; Takeda, Yoichi; Ishihara, Daisuke; Kataza, Hirokazu; Murakami, Hiroshi; Fukagawa, Misato

    2012-04-20

    We report an intriguing debris disk toward the F3V star HD 15407A in which an extremely large amount of warm fine dust ({approx}10{sup -7} M{sub Circled-Plus }) is detected. The dust temperature is derived as {approx}500-600 K and the location of the debris dust is estimated as 0.6-1.0 AU from the central star, a terrestrial planet region. The fractional luminosity of the debris disk is {approx}0.005, which is much larger than those predicted by steady-state models of the debris disk produced by planetesimal collisions. The mid-infrared spectrum obtained by Spitzer indicates the presence of abundant {mu}m-sized silica dust, suggesting that the dust comes from the surface layer of differentiated large rocky bodies and might be trapped around the star.

  4. RemoveDEBRIS: An in-orbit active debris removal demonstration mission

    NASA Astrophysics Data System (ADS)

    Forshaw, Jason L.; Aglietti, Guglielmo S.; Navarathinam, Nimal; Kadhem, Haval; Salmon, Thierry; Pisseloup, Aurélien; Joffre, Eric; Chabot, Thomas; Retat, Ingo; Axthelm, Robert; Barraclough, Simon; Ratcliffe, Andrew; Bernal, Cesar; Chaumette, François; Pollini, Alexandre; Steyn, Willem H.

    2016-10-01

    Since the beginning of the space era, a significant amount of debris has progressively been generated. Most of the objects launched into space are still orbiting the Earth and today these objects represent a threat as the presence of space debris incurs risk of collision and damage to operational satellites. A credible solution has emerged over the recent years: actively removing debris objects by capturing them and disposing of them. This paper provides an update to the mission baseline and concept of operations of the EC FP7 RemoveDEBRIS mission drawing on the expertise of some of Europe's most prominent space institutions in order to demonstrate key active debris remove (ADR) technologies in a low-cost ambitious manner. The mission will consist of a microsatellite platform (chaser) that ejects 2 CubeSats (targets). These targets will assist with a range of strategically important ADR technology demonstrations including net capture, harpoon capture and vision-based navigation using a standard camera and LiDAR. The chaser will also host a drag sail for orbital lifetime reduction. The mission baseline has been revised to take into account feedback from international and national space policy providers in terms of risk and compliance and a suitable launch option is selected. A launch in 2017 is targeted. The RemoveDEBRIS mission aims to be one of the world's first in-orbit demonstrations of key technologies for active debris removal and is a vital prerequisite to achieving the ultimate goal of a cleaner Earth orbital environment.

  5. Space debris hazard to defense systems

    SciTech Connect

    Canavan, G.H.

    1996-05-01

    Natural and man-made debris are argued to present hazards to space systems, but recent data indicate that at low altitudes, the impact rates from small particles may have been overestimated by an order of magnitude. At high altitudes, small particles only present an impact hazard to large satellites; they would not support a cascade. Large particles would apparently produce a cascade only on time scales of centuries or millennia. Radar and optical data should be capable of resolving these uncertainties, but their observations are, as yet, inconsistent. While independent analytic and numerical estimates of collision and cascade rates agree, given consistent inputs, different groups produced significantly different estimates of debris growth rates. This note examines the basis for these discrepancies.

  6. GENERALIZED VISCOPLASTIC MODELING OF DEBRIS FLOW.

    USGS Publications Warehouse

    Chen, Cheng-lung

    1988-01-01

    The earliest model developed by R. A. Bagnold was based on the concept of the 'dispersive' pressure generated by grain collisions. Some efforts have recently been made by theoreticians in non-Newtonian fluid mechanics to modify or improve Bagnold's concept or model. A viable rheological model should consist both of a rate-independent part and a rate-dependent part. A generalized viscoplastic fluid (GVF) model that has both parts as well as two major rheological properties (i. e. , the normal stress effect and soil yield criterion) is shown to be sufficiently accurate, yet practical for general use in debris-flow modeling. In fact, Bagnold's model is found to be only a particular case of the GVF model. analytical solutions for (steady) uniform debris flows in wide channels are obtained from the GVF model based on Bagnold's simplified assumption of constant grain concentration.

  7. Current orbital debris environment

    NASA Technical Reports Server (NTRS)

    Kessler, Donald J.

    1989-01-01

    NASA has instituted a plan for the definition of activities and resources required over the coming decade for the deepening of current understanding of anthropogenic orbital debris, and its effects on future mission operations. This understanding will be the basis of policy definition and policy implementation efforts. The most immediate requirement is the definition of the debris environment, with emphasis on data for debris sizes smaller than 4 cm. Systems-damage criteria and hypervelocity-impact theory will then be used to define the hazard to specific spacecraft.

  8. Avoiding Collisions in Space: Is It Time for an International Space Integration Center?

    DTIC Science & Technology

    2007-03-30

    fuel consumption, forcing a choice between collision mitigation and mission duration. To that end, the 1995 USG Orbital Debris Mitigation Standards...are in the process of adopting guidelines like the USG Orbital Debris Mitigation Standard Practices. The short fall of these policies is an... Orbital Debris Program Office, “ Orbital Debris Frequently Asked Questions,” available from http://orbitaldebris.jsc.nasa.gov/faqs.html#1; Internet

  9. The Top 10 Questions for Active Debris Removal

    NASA Technical Reports Server (NTRS)

    Liou, J. -C.

    2010-01-01

    This slide presentation reviews the requirement and issues around removal of debris from the earth orbital environment. The 10 questions discussed are: 1. Which region (LEO/MEO/GEO) has the fastest projected growth rate and the highest collision activities? 2. Can the commonly-adopted mitigation measures stabilize the future environment? 3. What are the objectives of active debris removal (ADR)? 4. How can effective ADR target selection criteria to stabilize the future LEO environment be defined? 5. What are the keys to remediate the future LEO environment? 6. What is the timeframe for ADR implementation? 7. What is the effect of practical/operational constraints? 8. What are the collision probabilities and masses of the current objects? 9. What are the benefits of collision avoidance maneuvers? 10. What is the next step?

  10. Statistical analysis of the inherent variability in the results of evolutionary debris models

    NASA Astrophysics Data System (ADS)

    Lidtke, Aleksander A.; Lewis, Hugh G.; Armellin, Roberto

    2017-04-01

    Space debris simulations, e.g. those performed by the Inter-Agency Debris Coordination Committee (Liou et al., 2013), showed that the number of objects in orbit is likely to increase. This study analyses the uncertainty in the results of space debris simulations performed using semi-stochastic models that necessitate the use of Monte Carlo simulations, which are often used by the Inter-Agency Debris Coordination Committee, amongst other studies. Statistics of the possible numbers of objects in orbit and collisions over the next 200 years are generated for the ;mitigation only; scenario using a sample of 25,000 Monte Carlo runs. Bootstraps on the mean, median, variance, skewness and kurtosis of these distributions are performed. It is shown that the distribution of the objects predicted to be on-orbit becomes log-normal as collisions occur, and that Monte Carlo samples larger than traditionally used are needed to capture the debris simulation uncertainty.

  11. Stochastic modeling of hypervelocity impacts in attitude propagation of space debris

    NASA Astrophysics Data System (ADS)

    Sagnières, Luc B. M.; Sharf, Inna

    2017-02-01

    Bombardment of orbital debris and micrometeoroids on active and inoperative satellites is becoming an increasing threat to space operations and has significant consequences on space missions. Concerns with orbital debris have led agencies to start developing debris removal missions and knowing a target's rotational parameters ahead of time is crucial to the eventual success of such a mission. A new method is proposed, enabling the inclusion of hypervelocity impacts into spacecraft attitude propagation models by considering the transfer of angular momentum from collisions as a stochastic jump process. Furthermore, the additional momentum transfer due to ejecta created during these hypervelocity impacts, an effect known as momentum enhancement, is considered. In order to assess the importance of collisions on attitude propagation, the developed model is applied to two pieces of space debris by using impact fluxes from ESA's Meteoroid and Space Debris Terrestrial Environment Reference (MASTER) model.

  12. Orbital Debris: Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    Stansbery, Gene; Johnson, Nicholas

    2013-01-01

    In the early days of spaceflight, the gBig Sky h theory was the near universally accepted paradigm for dealing with collisions of orbiting objects. This theory was also used during the early years of the aviation industry. Just as it did in aviation, the gBig Sky h theory breaks down as more and more objects accumulate in the environment. Fortunately, by the late 1970 fs some visionaries in NASA and the US Department of Defense (DoD) realized that trends in the orbital environment would inevitably lead to increased risks to operational spacecraft from collisions with other orbiting objects. The NASA Orbital Debris Program was established at and has been conducted at Johnson Space Center since 1979. At the start of 1979, fewer than 5000 objects were being tracked by the US Space Surveillance Network and very few attempts had been made to sample the environment for smaller sizes. Today, the number of tracked objects has quadrupled. Ground ]based and in situ measurements have statistically sampled the LEO environment over most sizes and mitigation guidelines and requirements are common among most space faring nations. NASA has been a leader, not only in defining the debris environment, but in promoting awareness of the issues in the US and internationally, and in providing leadership in developing policies to address the issue. This paper will discuss in broad terms the evolution of the NASA debris program from its beginnings to its present broad range of debris related research. The paper will discuss in some detail current research topics and will attempt to predict future research trends.

  13. 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.

  14. New method for estimating low-earth-orbit collision probabilities

    NASA Technical Reports Server (NTRS)

    Vedder, John D.; Tabor, Jill L.

    1991-01-01

    An unconventional but general method is described for estimating the probability of collision between an earth-orbiting spacecraft and orbital debris. This method uses a Monte Caralo simulation of the orbital motion of the target spacecraft and each discrete debris object to generate an empirical set of distances, each distance representing the separation between the spacecraft and the nearest debris object at random times. Using concepts from the asymptotic theory of extreme order statistics, an analytical density function is fitted to this set of minimum distances. From this function, it is possible to generate realistic collision estimates for the spacecraft.

  15. New method for estimating low-earth-orbit collision probabilities

    NASA Technical Reports Server (NTRS)

    Vedder, John D.; Tabor, Jill L.

    1991-01-01

    An unconventional but general method is described for estimating the probability of collision between an earth-orbiting spacecraft and orbital debris. This method uses a Monte Caralo simulation of the orbital motion of the target spacecraft and each discrete debris object to generate an empirical set of distances, each distance representing the separation between the spacecraft and the nearest debris object at random times. Using concepts from the asymptotic theory of extreme order statistics, an analytical density function is fitted to this set of minimum distances. From this function, it is possible to generate realistic collision estimates for the spacecraft.

  16. Disposal of Cleaning Debris

    DTIC Science & Technology

    1976-04-01

    trees. In addition, the debris contains some plastic bottles , balls, rubber items, and glass . The wood debris is in various stages of...the upper portion, which contains vegetation falls into the river. Plastic bottles and various other discarded objects periodically float into the...the reservoir includes tree stumps, tree branches, tree trunks, tires, oil drums, plastic bottles , signs from recreational areas in the White

  17. Albedo estimates for debris

    NASA Technical Reports Server (NTRS)

    Potter, A. E.; Henize, Karl G.; Talent, D. L.

    1989-01-01

    The albedo of upper-stage breakup debris is proposed as an accurate discriminator among the various possible causes of breakup, which encompass residual fuel explosions and hypervelocity particle impacts. The fragments from an impact are covered with a thin layer of soot deposited from the destruction of polymeric circuit boards, while pressure vessel explosion fragments can be expected to remain soot-free. Albedo also facilitates the interpretation of small-debris optical telescope measurements.

  18. Investigation of Orbital Debris: Mitigation, Removal, and Modeling the Debris Population

    NASA Astrophysics Data System (ADS)

    Slotten, Joel

    The population of objects in orbit around Earth has grown since the late 1950s. Today there are over 21,000 objects over 10 cm in length in orbit, and an estimated 500,000 more between 1 and 10 cm. Only a small fraction of these objects are operational satellites. The rest are debris: old derelict spacecraft or rocket bodies, fragments created as the result of explosions or collisions, discarded objects, slag from solid rockets, or even flaked off paint. Traveling at up to 7 km/s, a collision with even a 1 cm piece of debris could severely damage or destroy a satellite. This dissertation examines three aspects of orbital debris. First, the concept of a self-consuming satellite is explored. This nanosatellite would use its own external structure as propellant to execute a deorbit maneuver at the end of its operational life, thus allowing it to meet current debris mitigation standards. Results from lab experiments examining potential materials for this concept have shown favorable results. Second, Particle in Cell techniques are modified and used to model the plasma plume from a micro-cathode arc thruster. This model is then applied to the concept of an ion beam shepherd satellite. This satellite would use its plasma plume to deorbit another derelict satellite. Results from these simulations indicate the micro-cathode arc thruster could potentially deorbit a derelict CubeSat in a matter of a few weeks. Finally, the orbital debris population at geosynchronous orbit is examined, focusing on variations in the density of the population as a function of longitude. New insights are revealed demonstrating that the variation in population density is slightly less than previously reported.

  19. Impact of high-risk conjunctions on Active Debris Removal target selection

    NASA Astrophysics Data System (ADS)

    Lidtke, Aleksander A.; Lewis, Hugh G.; Armellin, Roberto

    2015-10-01

    Space debris simulations show that if current space launches continue unchanged, spacecraft operations might become difficult in the congested space environment. It has been suggested that Active Debris Removal (ADR) might be necessary in order to prevent such a situation. Selection of objects to be targeted by ADR is considered important because removal of non-relevant objects will unnecessarily increase the cost of ADR. One of the factors to be used in this ADR target selection is the collision probability accumulated by every object. This paper shows the impact of high-probability conjunctions on the collision probability accumulated by individual objects as well as the probability of any collision occurring in orbit. Such conjunctions cannot be predicted far in advance and, consequently, not all the objects that will be involved in such dangerous conjunctions can be removed through ADR. Therefore, a debris remediation method that would address such events at short notice, and thus help prevent likely collisions, is suggested.

  20. Practical aspects of analyzing vegetable oils in fire debris.

    PubMed

    Schwenk, Lisa M; Reardon, Michelle R

    2009-07-01

    Vegetable oils undergo burning, self-heating, and spontaneous ignition, resulting in their presence in fire debris. As these processes can affect the fatty acid content of vegetable oils, it is important that debris be properly handled in order to obtain reliable and informative data. This research investigated changes in vegetable oil content as a result of storage conditions and different types of burning. Material spiked with vegetable oils and burned was stored under various long-term conditions, and debris was tested by heating overnight using passive headspace concentration. Results indicated that refrigeration is ideal for fire debris samples suspected of containing vegetable oils and that including passive headspace concentration in the analytical scheme would not affect oils. Spontaneous ignition experiments were conducted to compare the effects of various burning processes on vegetable oil content. Vegetable oils that experienced nonpiloted ignition, self-heating, and spontaneous ignition produced noticeably different chromatograms from those that underwent piloted ignition.

  1. Space Debris Symposium (A6.) Measurements and Space Surveillance (1.): Measurements of the Small Particle Debris Cloud from the 11 January, 2007 Chinese Anti-satellite Test

    NASA Technical Reports Server (NTRS)

    Matney, Mark J.; Stansbery, Eugene; J.-C Liou; Stokely, Christopher; Horstman, Matthew; Whitlock, David

    2008-01-01

    On January 11, 2007, the Chinese military conducted a test of an anti-satellite (ASAT) system, destroying their own Fengyun-1C spacecraft with an interceptor missile. The resulting hypervelocity collision created an unprecedented number of tracked debris - more than 2500 objects. These objects represent only those large enough for the US Space Surveillance Network (SSN) to track - typically objects larger than about 5-10 cm in diameter. There are expected to be even more debris objects at sizes too small to be seen and tracked by the SSN. Because of the altitude of the target satellite (865 x 845 km orbit), many of the debris are expected to have long orbital lifetimes and contribute to the orbital debris environment for decades to come. In the days and weeks following the ASAT test, NASA was able to use Lincoln Laboratory s Haystack radar on several occasions to observe portions of the ASAT debris cloud. Haystack has the capability of detecting objects down to less than one centimeter in diameter, and a large number of centimeter-sized particles corresponding to the ASAT cloud were clearly seen in the data. While Haystack cannot track these objects, the statistical sampling procedures NASA uses can give an accurate statistical picture of the characteristics of the debris from a breakup event. For years computer models based on data from ground hypervelocity collision tests (e.g., the SOCIT test) and orbital collision experiments (e.g., the P-78 and Delta-180 on-orbit collisions) have been used to predict the extent and characteristics of such hypervelocity collision debris clouds, but until now there have not been good ways to verify these models in the centimeter size regime. It is believed that unplanned collisions of objects in space similar to ASAT tests will drive the long-term future evolution of the debris environment in near-Earth space. Therefore, the Chinese ASAT test provides an excellent opportunity to test the models used to predict the future debris

  2. Space Debris Symposium (A6.) Measurements and Space Surveillance (1.): Measurements of the Small Particle Debris Cloud from the 11 January, 2007 Chinese Anti-satellite Test

    NASA Technical Reports Server (NTRS)

    Matney, Mark J.; Stansbery, Eugene; J.-C Liou; Stokely, Christopher; Horstman, Matthew; Whitlock, David

    2008-01-01

    On January 11, 2007, the Chinese military conducted a test of an anti-satellite (ASAT) system, destroying their own Fengyun-1C spacecraft with an interceptor missile. The resulting hypervelocity collision created an unprecedented number of tracked debris - more than 2500 objects. These objects represent only those large enough for the US Space Surveillance Network (SSN) to track - typically objects larger than about 5-10 cm in diameter. There are expected to be even more debris objects at sizes too small to be seen and tracked by the SSN. Because of the altitude of the target satellite (865 x 845 km orbit), many of the debris are expected to have long orbital lifetimes and contribute to the orbital debris environment for decades to come. In the days and weeks following the ASAT test, NASA was able to use Lincoln Laboratory s Haystack radar on several occasions to observe portions of the ASAT debris cloud. Haystack has the capability of detecting objects down to less than one centimeter in diameter, and a large number of centimeter-sized particles corresponding to the ASAT cloud were clearly seen in the data. While Haystack cannot track these objects, the statistical sampling procedures NASA uses can give an accurate statistical picture of the characteristics of the debris from a breakup event. For years computer models based on data from ground hypervelocity collision tests (e.g., the SOCIT test) and orbital collision experiments (e.g., the P-78 and Delta-180 on-orbit collisions) have been used to predict the extent and characteristics of such hypervelocity collision debris clouds, but until now there have not been good ways to verify these models in the centimeter size regime. It is believed that unplanned collisions of objects in space similar to ASAT tests will drive the long-term future evolution of the debris environment in near-Earth space. Therefore, the Chinese ASAT test provides an excellent opportunity to test the models used to predict the future debris

  3. Characterization of Debris from the DebriSat Hypervelocity Test

    NASA Technical Reports Server (NTRS)

    Rivero, M.; Kleespies, J.; Patankar, K.; Fitz-Coy, N.; Liou, J.-C.; Sorge, M.; Huynh, T.; Opiela, J.; Krisko, P.; Cowardin, H.

    2015-01-01

    The DebriSat project is an effort by NASA and the DoD to update the standard break-up model for objects in orbit. The DebriSat object, a 56 kg representative LEO satellite, was subjected to a hypervelocity impact in April 2014. For the hypervelocity test, the representative satellite was suspended within a "soft-catch" arena formed by polyurethane foam panels to minimize the interactions between the debris generated from the hypervelocity impact and the metallic walls of the test chamber. After the impact, the foam panels and debris not caught by the panels were collected and shipped to the University of Florida where the project has now advanced to the debris characterization stage. The characterization effort has been divided into debris collection, measurement, and cataloguing. Debris collection and cataloguing involves the retrieval of debris from the foam panels and cataloguing the debris in a database. Debris collection is a three-step process: removal of loose debris fragments from the surface of the foam panels; X-ray imaging to identify/locate debris fragments embedded within the foam panel; extraction of the embedded debris fragments identified during the X-ray imaging process. As debris fragments are collected, they are catalogued into a database specifically designed for this project. Measurement involves determination of size, mass, shape, material, and other physical properties and well as images of the fragment. Cataloguing involves a assigning a unique identifier for each fragment along with the characterization information.

  4. Characterizing Debris Disks Around Young Suns

    NASA Astrophysics Data System (ADS)

    Rieke, George; Gorlova, Nadya; Muzerolle, James; Rebull, Luisa; Siegler, Nick; Stauffer, John; Su, Kate; Young, Erick

    2006-05-01

    There is geological evidence that in the first few hundred Myr of the birth of the Solar System there was an epoch of strong bombardment caused by the collisions between growing planetesimals. Spitzer has the capability to probe that epoch in other stars by observing dust emission from debris disks around young solar system analogs. The MIPS GTO and FEPS Legacy teams have carried out a 24 micron survey of debris disks in a number of rich open clusters, with ages ranging from a few to 100 Myr. However, only a few of these clusters are close enough to detect fluxes in the MIPS bands to photospheric levels in solar mass stars; even fewer are close enough (<160 pc) to study disk properties by means of IRS spectroscopy. This proposal consists of two parts. 1) We will build on our previous investigation of the Pleiades core where we discovered a few solar analogs with MIPS excesses signaling debris disks. The excess fraction is tentatively bigger than among older field stars. To confirm this conclusion, we propose to observe the remaining F-G stars that are situated in the Pleiades corona and thus less affected by interstellar cirrus. 2) We will obtain IRS spectra for debris candidates in the Pleiades (100 Myr) as well as in two other intermediate-age clusters -- IC 2391 (50 Myr) and M47 (80 Myr). Disk spectra will allow us to constrain the disk geometry and other properties of debris dust, and to search for correlations of theses properties with the spectral type/mass of the host star. The IRS sample includes a range of spectral types from A to G stars. This program will provide the first representative sample of dust emission spectra at the intermediate age of 50-100 Myr, which likely corresponds to the final stages of terrestrial planet formation.

  5. The Orbital Debris Problem and the Challenges for Environment Remediation

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.

    2014-01-01

    LEO debris population will continue to increase even with a good implementation of the commonly-adopted mitigation measures. The root-cause of the increase is catastrophic collisions involving large/massive intact objects (rocket bodies or spacecraft). The major mission-ending risks for most operational spacecraft, however, come from impacts with debris just above the threshold of the protection shields (5-mm to 1-cm). A solution-driven approach is to seek: Concepts for removal of massive intacts with high P(collision); Concepts capable of preventing collisions involving intacts; Concepts for removal of 5-mm to 1-cm debris; Enhanced impact protection shields for valuable space assets. Key questions for remediation consideration of orbital debris: What is the acceptable threat level? What are the mission objectives? What is the appropriate roadmap/timeframe for remediation? Support advanced technology development when an economically viable approach is identified. Address non-technical issues, such as policy, coordination, ownership, legal, and liability at the national and international levels.

  6. LightForce: An Update on Orbital Collision Avoidance Using Photon Pressure

    NASA Technical Reports Server (NTRS)

    Stupl, Jan; Mason, James; De Vries, Willem; Smith, Craig; Levit, Creon; Marshall, William; Salas, Alberto Guillen; Pertica, Alexander; Olivier, Scot; Ting, Wang

    2012-01-01

    We present an update on our research on collision avoidance using photon-pressure induced by ground-based lasers. In the past, we have shown the general feasibility of employing small orbit perturbations, induced by photon pressure from ground-based laser illumination, for collision avoidance in space. Possible applications would be protecting space assets from impacts with debris and stabilizing the orbital debris environment. Focusing on collision avoidance rather than de-orbit, the scheme avoids some of the security and liability implications of active debris removal, and requires less sophisticated hardware than laser ablation. In earlier research we concluded that one ground based system consisting of a 10 kW class laser, directed by a 1.5 m telescope with adaptive optics, could avoid a significant fraction of debris-debris collisions in low Earth orbit. This paper describes our recent efforts, which include refining our original analysis, employing higher fidelity simulations and performing experimental tracking tests. We investigate the efficacy of one or more laser ground stations for debris-debris collision avoidance and satellite protection using simulations to investigate multiple case studies. The approach includes modeling of laser beam propagation through the atmosphere, the debris environment (including actual trajectories and physical parameters), laser facility operations, and simulations of the resulting photon pressure. We also present the results of experimental laser debris tracking tests. These tests track potential targets of a first technical demonstration and quantify the achievable tracking performance.

  7. Debris-flow deposition: Effects of pore-fluid pressure and friction concentrated at flow margins

    USGS Publications Warehouse

    Major, J.J.; Iverson, R.M.

    1999-01-01

    Measurements of pore-fluid pressure and total bed-normal stress at the base of several ???10 m3 experimental debris flows provide new insight into the process of debris-flow deposition. Pore-fluid pressures nearly sufficient to cause liquefaction were developed and maintained during flow mobilization and acceleration, persisted in debris-flow interiors during flow deceleration and deposition, and dissipated significantly only during postdepositional sediment consolidation. In contrast, leading edges of debris flows exhibited little or no positive pore-fluid pressure. Deposition therefore resulted from grain-contact friction and bed friction concentrated at flow margins. This finding contradicts models that invoke widespread decay of excess pore-fluid pressure, uniform viscoplastic yield strength, or pervasive grain-collision stresses to explain debris-flow deposition. Furthermore, the finding demonstrates that deposit thickness cannot be used to infer the strength of flowing debris.

  8. A Review of the Recent NASA Long-Term Orbital Debris Environment Projection and Active Debris Removal Modeling Activities

    NASA Technical Reports Server (NTRS)

    Liou, J.C.

    2009-01-01

    The NASA Orbital Debris Program Office (ODPO) developed a high fidelity debris evolutionary model, LEGEND (a LEO-to-GEO Environment Debris model), in 2004 to enhance its capability to better model the near-Earth environment. LEGEND can mimic the growth of the historical debris population and project it into the future based on user-defined scenarios. The first major LEGEND study concluded that even without any future launches, the LEO population would continue to increase due to mutual collisions among existing objects. In reality, the increase will be worse than this prediction because of ongoing satellite launches and unexpected major breakups. Even with a full implementation of the commonly-adopted mitigation measures, the LEO population growth is inevitable. To preserve the near-Earth environment for future generations, active debris removal (ADR) must be considered. A follow-up LEGEND ADR study was completed recently. The main results indicate that (1) the mass and collision probability of each object can be used to establish an effective removal selection criterion and (2) a removal rate of 5 objects per year is sufficient to stabilize the LEO environment. Due to the limitation of removal techniques, however, different target selection criteria (in size, altitude, inclination, etc.) may be more practical. A careful evaluation of the effectiveness of different proposed techniques must be carried out to maximize the long-term benefit to the environment.

  9. Debris measure subsystem of the nanosatellite IRECIN

    NASA Astrophysics Data System (ADS)

    Ferrante, M.; di Ciolo, L.; Ortenzi, A.; Petrozzi, M.; del Re, V.

    2003-09-01

    The on board resources, needed to perform the mission tasks, are very limited in nano-satellites. This paper proposes an Electronic real-time system that acquires space debris measures. It uses a piezo-electric sensor. The described device is a subsystem on board of the IRECIN nanosatellite composed mainly by a r.i.s.c. microprocessor, an electronic part that interfaces to the debris sensor in order to provide a low noise electrical and suitable range to ADC 12 bit converter, and finally a memory in order to store the data. The microprocessor handles the Debris Measure System measuring the impacts number, their intensity and storing their waves form. This subsystem is able to communicate with the other IRECIN subsystems through I2C Bus and principally with the "Main Microprocessor" subsystem allowing the data download directly to the Ground Station. Moreover this subsystem lets free the "Main Microprocessor Board" from the management and charge of debris data. All electronic components are SMD technology in order to reduce weight and size. The realized Electronic board are completely developed, realized and tested at the Vitrociset S.P.A. under control of Research and Development Group. The proposed system is implemented on the IRECIN, a modular nanosatellite weighting less than 1.5 kg, constituted by sixteen external sides with surface-mounted solar cells and three internal Al plates, kept together by four steel bars. Lithium-ions batteries are added for eclipse operations. Attitude is determined by two three-axis magnetometers and the solar panels data. Control is provided by an active magnetic control system. The spacecraft will be spin-stabilized with the spin-axis normal to the orbit. debris and micrometeoroids mass and velocity.

  10. A methodology for selective removal of orbital debris

    NASA Technical Reports Server (NTRS)

    Ash, R. L.; Odonoghue, P. J.; Chambers, E. J.; Raney, J. P.

    1992-01-01

    Earth-orbiting objects, large enough to be tracked, were surveyed for possible systematic debris removal. Based upon the statistical collision studies of others, it was determined that objects in orbits approximately 1000 km above the Earth's surface are at greatest collisional risk. Russian C-1B boosters were identified as the most important target of opportunity for debris removal. Currently, more than 100 in tact boosters are orbiting the Earth with apogees between 950 km and 1050 km. Using data provided by Energia USA, specific information on the C-1B booster, in terms of rendezvous and capture strategies, was discussed.

  11. Orbital plane constraint applicable for in-situ measurement of sub-millimeter-size debris

    NASA Astrophysics Data System (ADS)

    Furumoto, Masahiro; Fujita, Koki; Hanada, Toshiya; Matsumoto, Haruhisa; Kitazawa, Yukihito

    2017-03-01

    Space debris smaller than 1 mm in size still have enough energy to cause a fatal damage on a spacecraft, but such tiny debris cannot be followed or tracked from the ground. Therefore, IDEA the project for In-situ Debris Environmental Awareness, which aims to detect sub-millimeter-size debris using a group of micro satellites, has been initiated at Kyushu University. First, this paper reviews the previous study on the nature of orbits on which debris may be detected through in-situ measurements proposed in the IDEA project. Second, this paper derives a simple equation that constrains the orbital plane on which debris is detected through in-situ measurements. Third, this paper also investigates the nature and sensitivity of this simple constraint equation to clear how frequently impacts have to be confirmed to reduce the measurement error. Finally, this paper introduces a torus model to describe the collision flux observed from the previous study approximately. This collision flux approximation agrees rather well with the observed collision flux. It is concluded, therefore, that the simple constraint equation and collision flux approximation introduced in this paper can replace the analytical method adopted by the previous study to conduct a further investigation more effectively.

  12. Current and Future Impact Risks from Small Debris to Operational Satellites

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi; Kessler, Don

    2011-01-01

    The collision between Iridium 33 and Cosmos 2251 in 2009 signaled the potential onset of the collision cascade effect, commonly known as the "Kessler Syndrome", in the low Earth orbit (LEO) region. Recent numerical simulations have shown that the 10 cm and larger debris population in LEO will continue to increase even with a good implementation of the commonly-adopted mitigation measures. This increase is driven by collisions involving large and massive intacts, i.e., rocket bodies and spacecraft. Therefore, active debris removal (ADR) of large and massive intacts with high collision probabilities has been argued as a direct and effective means to remediate the environment in LEO. The major risk for operational satellites in the environment, however, comes from impacts with debris just above the threshold of the protection shields. In general, these are debris in the millimeter to centimeter size regime. Although impacts by these objects are insufficient to lead to catastrophic breakup of the entire vehicle, the damage is certainly severe enough to cause critical failure of the key instruments or the entire payload. The focus of this paper is to estimate the impact risks from 5 mm and 1 cm debris to active payloads in LEO (1) in the current environment and (2) in the future environment based on different projection scenarios, including ADR. The goal of the study is to quantify the benefits of ADR in reducing debris impact risks to operational satellites.

  13. Material Density Distribution of Small Debris in Earth Orbit

    NASA Technical Reports Server (NTRS)

    Krisko, P. H.; Xu, Y.-l.; Opiela, J. N.; Hill, N. M.; Matney, M. J.

    2008-01-01

    Over 200 spacecraft and rocket body breakups in Earth orbit have populated that regime with debris fragments in the sub-micron through meter size range. Though the largest debris fragments can cause significant collisional damage to active (operational) spacecraft, these are few and trackable by radar. Fragments on the order of a millimeter to a centimeter in size are as yet untrackable. But this smaller debris can result in damage to critical spacecraft systems and, under the worst conditions, fragmenting collision events. Ongoing research at the NASA Orbital Debris Program Office on the sources of these small fragments has focused on the material components of spacecraft and rocket bodies and on breakup event morphology. This has led to fragment material density estimates, and also the beginnings of shape categorizations. To date the NASA Standard Breakup Model has not considered specific material density distinctions of small debris. The basis of small debris in that model is the fourth hypervelocity impact event of the Satellite Orbital Debris Characterization Impact Test (SOCIT) series. This test targeted a flight-ready, U.S. Transit navigation satellite with a solid aluminum sphere impactor. Results in this event yield characteristic length (size) and area-to-mass distributions of fragments smaller than 10 cm in the NASA model. Recent re-analysis of the SOCIT4 small fragment dataset highlighted the material-specific characteristics of metals and non-metals. Concurrent analysis of Space Shuttle in-situ impact data showed a high percentage of aluminum debris in shuttle orbit regions. Both analyses led to the definition of three main on-orbit debris material density categories -low density (< 2 g/cc), medium density (2 to 6 g/cc), and high density (> 6 g/cc). This report considers the above studies in an explicit extension of the NASA Standard Breakup Model where separate material densities for debris are generated and these debris fragments are propagated in

  14. Orbital debris removal using ground-based lasers

    NASA Technical Reports Server (NTRS)

    Taylor, Charles R.

    1996-01-01

    Orbiting the Earth are spent rocket stages, non-functioning satellites, hardware from satellite deployment and staging, fragments of exploded spacecraft, and other relics of decades of space exploration: orbital debris. The United States Space Command tracks and maintains a catalog of the largest objects. The catalog contains over 7000 objects. Recent studies have assessed the debris environment in an effort to estimate the number of smaller particles and the probability of a collision causing catastrophic damage to a functioning spacecraft. The results of the studies can be used to show, for example, that the likelihood of a collision of a particle larger than about one centimeter in diameter with the International Space Station during a 10-year period is a few percent, roughly in agreement with earlier estimates for Space Station Freedom. Particles greater than about one centimeter in diameter pose the greatest risk to shielded spacecraft. There are on the order of 105 such particles in low Earth orbit. The United States National Space Policy, begun in 1988, is to minimize debris consistent with mission requirements. Measures such as venting unused fuel to prevent explosions, retaining staging and deployment hardware, and shielding against smaller debris have been taken by the U.S. and other space faring nations. There is at present no program to remove debris from orbit. The natural tendency for upper atmospheric drag to remove objects from low Earth orbit is more than balanced by the increase in the number of debris objects from new launches and fragmentation of existing objects. In this paper I describe a concept under study by the Program Development Laboratory of Marshall Space Flight Center and others to remove debris with a ground-based laser. A longer version of this report, including figures, is available from the author.

  15. Transportation and handling loads

    NASA Technical Reports Server (NTRS)

    Ostrem, F. E.

    1971-01-01

    Criteria and recommended practices are presented for the prediction and verification of transportation and handling loads for the space vehicle structure and for monitoring these loads during transportation and handling of the vehicle or major vehicle segments. Elements of the transportation and handling systems, and the forcing functions and associated loads are described. The forcing functions for common carriers and typical handling devices are assessed, and emphasis is given to the assessment of loads at the points where the space vehicle is supported during transportation and handling. Factors which must be considered when predicting the loads include the transportation and handling medium; type of handling fixture; transport vehicle speed; types of terrain; weather (changes in pressure of temperature, wind, etc.); and dynamics of the transportation modes or handling devices (acceleration, deceleration, and rotations of the transporter or handling device).

  16. Insights into Planet Formation from Debris Disks. II. Giant Impacts in Extrasolar Planetary Systems

    NASA Astrophysics Data System (ADS)

    Wyatt, Mark C.; Jackson, Alan P.

    2016-12-01

    Giant impacts refer to collisions between two objects each of which is massive enough to be considered at least a planetary embryo. The putative collision suffered by the proto-Earth that created the Moon is a prime example, though most Solar System bodies bear signatures of such collisions. Current planet formation models predict that an epoch of giant impacts may be inevitable, and observations of debris around other stars are providing mounting evidence that giant impacts feature in the evolution of many planetary systems. This chapter reviews giant impacts, focussing on what we can learn about planet formation by studying debris around other stars. Giant impact debris evolves through mutual collisions and dynamical interactions with planets. General aspects of this evolution are outlined, noting the importance of the collision-point geometry. The detectability of the debris is discussed using the example of the Moon-forming impact. Such debris could be detectable around another star up to 10 Myr post-impact, but model uncertainties could reduce detectability to a few 100 yr window. Nevertheless the 3 % of young stars with debris at levels expected during terrestrial planet formation provide valuable constraints on formation models; implications for super-Earth formation are also discussed. Variability recently observed in some bright disks promises to illuminate the evolution during the earliest phases when vapour condensates may be optically thick and acutely affected by the collision-point geometry. The outer reaches of planetary systems may also exhibit signatures of giant impacts, such as the clumpy debris structures seen around some stars.

  17. The Collision of Iridium 33 and Cosmos 2251: The Shape of Things to Come

    NASA Technical Reports Server (NTRS)

    Nicholas, Johnson

    2009-01-01

    The collision of Iridium 33 and Cosmos 2251 was the most severe accidental fragmentation on record. More than 1800 debris approx. 10 cm and larger were produced. If solar activity returns to normal, half of the tracked debris will reenter within five years. Less than 60 cataloged debris had reentered by 1 October 2009. Some debris from both satellites will remain in orbit through the end of the century. The collision rate of one every five years will increase without future removal of large derelict spacecraft and launch vehicle orbital stages.

  18. Space debris detection

    NASA Astrophysics Data System (ADS)

    Eather, Robert H.

    1992-12-01

    A feasibility study on the possibility of detecting less than or = 10 cm space debris using a large-aperture ground-based telescope (with an intensified CCD detector) was completed, showing that detection should be possible. A detector system was designed and built, and installed on the 2.54 m WRDC telescope at Wright Patterson AFB. Bad seeing conditions in the Dayton area prevented the expected debris detection. Subsequently, a small 40 cm telescope was built and operated from the Haystack Observatory (Groton, MA). Known objects were used to test pointing and acquisition procedures, and the system was then shipped to Rattlesnake Observatory (Richland, WA) for participation in the ODERAC's debris calibration experiment from the Space Shuttle. This experiment failed, and our instrument has been stored at Rattlesnake in anticipation of a new ODERAC's flight in late 1993.

  19. Active Space Debris Charging for Contactless Electrostatic Disposal Maneuvers

    NASA Astrophysics Data System (ADS)

    Schaub, H.; Sternovsky, Z.

    2013-08-01

    We assess the feasibility of removing large space debris from geosynchronous orbit (GEO) by means of a tug spacecraft that uses electrostatic forces to pull the debris without touching. The advantage of this method is that it can operate with a separation distance of multiple craft radii, thus reducing the risk of collision. Further, the debris does not have to be detumbled first to engage the re-orbit maneuver. The charging of the tug-debris system to high potentials is achieved by active charge transfer using a directed electron beam and an auxiliary ion bleeder. Our simple charging model takes into account the primary electron beam current, UV induced photoelectron emission, collection of plasma particles, secondary electron emission and the recapture of emitted particles. The results show that by active charging high potentials can be both achieved and maintained. The resulting mN level electrostatic force is sufficient for the safe re-orbiting of debris objects over an acceptable period of a few months. The capability of debris removal is becoming a pressing need as the increasing population of dysfunctional satellites poses a threat to the future of satellite operations at GEO.

  20. Space debris removal system using a small satellite

    NASA Astrophysics Data System (ADS)

    Nishida, Shin-Ichiro; Kawamoto, Satomi; Okawa, Yasushi; Terui, Fuyuto; Kitamura, Shoji

    2009-07-01

    Since the number of satellites in Earth orbit is steadily increasing, space debris will eventually pose a serious problem to near-Earth space activities if left unchecked, and so effective measures to mitigate it are becoming urgent. Equipping new satellites with an end-of-life de-orbit or orbital lifetime reduction capability could be an effective means of reducing the amount of debris by reducing the probability of the collisions between objects. On the other hand, the active removal of space debris and the retrieval of failed satellites by spacecraft are other possible measures. The Institute of Aerospace Technology, Japan Aerospace Exploration Agency (JAXA), is studying a micro-satellite system for active space debris removal, and is examining the applicability of electro-dynamic tether (EDT) technology as its high efficiency orbital transfer system. A small EDT package provides a possible means for lowering the orbits of objects without the need for propellant. Capture is indispensable for the retrieval of large space debris objects, and we propose a flexible robot arm for this purpose. This paper discusses a space debris removal satellite system and describes the development status of prototypes of the EDT package and a new robot arm for capturing non-cooperative targets.

  1. Meteoroid/Debris Shielding

    NASA Technical Reports Server (NTRS)

    Christiansen, Eric L.

    2003-01-01

    This report provides innovative, low-weight shielding solutions for spacecraft and the ballistic limit equations that define the shield's performance in the meteoroid/debris environment. Analyses and hypervelocity impact testing results are described that have been used in developing the shields and equations. Spacecraft shielding design and operational practices described in this report are used to provide effective spacecraft protection from meteoroid and debris impacts. Specific shield applications for the International Space Station (ISS), Space Shuttle Orbiter and the CONTOUR (Comet Nucleus Tour) space probe are provided. Whipple, Multi-Shock and Stuffed Whipple shield applications are described.

  2. Electrochemical behavior of simulated debris from a severe accident using a molten salt system

    SciTech Connect

    Takahashi, Yuya; Nakamura, Hitoshi; Yamada, Akira; Mizuguchi, Koji; Fujita, Reiko

    2013-07-01

    In a severe nuclear accident, the fuel in the reactor may melt, forming debris, which contains a UO{sub 2}-ZrO{sub 2} stable oxide mixture and parts of the reactor, such as Zircaloy and iron components. Proper handling of the debris is a critically important issue. The debris does not have the same composition as spent fuel, and so it is impossible to apply conventional reprocessing technology directly. In this study, we successfully separated Zr and Fe from simulated debris using NaCl-KCl molten salt electrolysis, and we selectively recovered the Zr and Fe. The simulated debris was made from Zr, Fe, and CeO{sub 2}. The CeO{sub 2} was used for simulating stable UO{sub 2}-ZrO{sub 2}. With this approach, it should be possible to reduce the volume of the debris by recovering metals, which can then be treated as low level radioactive wastes.

  3. Matched Template Signal Processing for Continuous Wave Laser Tracking of Space Debris

    NASA Astrophysics Data System (ADS)

    Raj, S.; Ward, R.; Roberts, L.; Fleddermann, R.; Francis, S.; McClellend, D.; Shaddock, D.; Smith, C.

    2016-09-01

    The build up of space junk in Earth's orbit space is a growing concern as it shares the same orbit as many currently active satellites. As the number of objects increase in these orbits, the likelihood of collisions between satellites and debris will increase [1]. The eventual goal is to be able to maneuver space debris to avoid such collisions. We at SERC aim to accomplish this by using ground based laser facilities that are already being used to track space debris orbit. One potential method to maneuver space debris is using continuous wave lasers and applying photon pressure on the debris and attempt to change the orbit. However most current laser ranging facilities operates using pulsed lasers where a pulse of light is sent out and the time taken for the pulse to return back to the telescope is measured after being reflected by the target. If space debris maneuvering is carried out with a continuous wave laser then two laser sources need to be used for ranging and maneuvering. The aim of this research is to develop a laser ranging system that is compatible with the continuous wave laser; using the same laser source to simultaneously track and maneuver space debris. We aim to accomplish this by modulating the outgoing laser light with pseudo random noise (PRN) codes, time tagging the outgoing light, and utilising a matched filter at the receiver end to extract the various orbital information of the debris.

  4. MODELING COLLISIONAL CASCADES IN DEBRIS DISKS: THE NUMERICAL METHOD

    SciTech Connect

    Gaspar, Andras; Psaltis, Dimitrios; Oezel, Feryal; Rieke, George H.; Cooney, Alan E-mail: dpsaltis@as.arizona.edu E-mail: grieke@as.arizona.edu

    2012-04-10

    We develop a new numerical algorithm to model collisional cascades in debris disks. Because of the large dynamical range in particle masses, we solve the integro-differential equations describing erosive and catastrophic collisions in a particle-in-a-box approach, while treating the orbital dynamics of the particles in an approximate fashion. We employ a new scheme for describing erosive (cratering) collisions that yields a continuous set of outcomes as a function of colliding masses. We demonstrate the stability and convergence characteristics of our algorithm and compare it with other treatments. We show that incorporating the effects of erosive collisions results in a decay of the particle distribution that is significantly faster than with purely catastrophic collisions.

  5. Space debris: Assessing risk and responsibility

    NASA Astrophysics Data System (ADS)

    Bradley, Andrew M.; Wein, Lawrence M.

    2009-05-01

    We model the orbital debris environment by a set of differential equations with parameter values that capture many of the complexities of existing three-dimensional simulation models. We compute the probability that a spacecraft gets destroyed in a collision during its operational lifetime, and then define the sustainable risk level as the maximum of this probability over all future time. Focusing on the 900- to 1000-km altitude region, which is the most congested portion of low Earth orbit, we find that - despite the initial rise in the level of fragments - the sustainable risk remains below 10-3 if there is high (>98%) compliance to the existing 25-year postmission deorbiting guideline. We quantify the damage (via the number of future destroyed operational spacecraft) generated by past and future space activities. We estimate that the 2007 FengYun 1C antisatellite weapon test represents ≈1% of the legacy damage due to space objects having a characteristic size of ⩾10 cm, and causes the same damage as failing to deorbit 2.6 spacecraft after their operational life. Although the political and economic issues are daunting, these damage estimates can be used to help determine one-time legacy fees and fees on future activities (including deorbit noncompliance), which can deter future debris generation, compensate operational spacecraft that are destroyed in future collisions, and partially fund research and development into space debris mitigation technologies. Our results need to be confirmed with a high-fidelity three-dimensional model before they can provide the basis for any major decisions made by the space community.

  6. Handling sharps and needles

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000444.htm Handling sharps and needles To use the sharing features ... Health Administration. OSHA fact sheet: protecting yourself when handling contaminated sharps. Updated January 2011. Available at: www. ...

  7. An efficient algorithm for orbital evolution of space debris

    NASA Astrophysics Data System (ADS)

    Abdel-Aziz, Y.; Abd El-Salam, F.

    More than four decades of space exploration have led to accumulation of significant quantities of debris around the Earth. These objects range in size from a tiny piece of junk to a large inoperable satellite, although these objects that have small size they have high are-to-mass ratios, and consequently their orbits are strongly influenced by solar radiation pressure and atmospheric drag. So the increasing population of space debris object in the LEO, MEO and GEO present growing with time, serious hazard for the survival of operating spacecrafts, particularly satellites and astronomical observatories. Since the average collision velocity between any spacecraft orbiting in the LOE and debris objects is about 10 km/s and about 3 km/s in the GEO. Space debris may significantly disturb any satellite operations or cause catastrophic damage to a spacecraft itself. Applying different shielding techniques spacecraft my be protected against impacts of space debris with diameters smaller than 1 cm. For larger debris objects, only one effective method to avoid catastrophic consequence of collision is a manoeuvre that will change the spacecraft orbit. The necessary conditions in this case is to evaluate and predict future positions of the spacecraft and space debris with sufficient accuray. Numerical integration of equations of motion are used until now. Existing analytical methods can solve this problem only with low accuracy. Difficulties are caused mainly by the lack of satisfying analytical solution of the resonance problem for geosynchronous orbit as well as from the lack of efficient analytical theory combining luni-solar perturbation and solar radiation pressure with geopotential attraction. Numerical integration is time consuming in some cases, and then for qualitative analysis of the satellite's and debris's motion it is necessary to apply analytical solution. This is the reason for searching for an accurate model to evaluate the orbital position of the operating

  8. Space Debris Mitigation Guidelines

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2011-01-01

    The purpose of national and international space debris mitigation guides is to promote the preservation of near-Earth space for applications and exploration missions far into the future. To accomplish this objective, the accumulation of objects, particularly in long-lived orbits, must be eliminated or curtailed.

  9. Earth Satellite Population Instability: Underscoring the Need for Debris Mitigation

    NASA Technical Reports Server (NTRS)

    Liou, Jer-chyi; Johnson, N. L.

    2006-01-01

    A recent study by NASA indicates that the implementation of international orbital debris mitigation measures alone will not prevent a significant increase in the artificial Earth satellite population, beginning in the second half of this century. Whereas the focus of the aerospace community for the past 25 years has been on the curtailment of the generation of long-lived orbital debris, active remediation of the current orbital debris population should now be reconsidered to help preserve near-Earth space for future generations. In particular, we show in this paper that even if launch operations were to cease today, the population of space debris would continue to grow. Further, proposed remediation techniques do not appear to offer a viable solution. We therefore recommend that, while the aerospace community maintains the current debris-limiting mission regulations and postmission disposal procedures, future emphasis should be placed on finding new remediation technologies for solving this growing problem. Since the launch of Sputnik 1, space activities have created an orbital debris environment that poses increasing impact risks to existing space systems, including human space flight and robotic missions (1, 2). Currently, more than 9,000 Earth orbiting man-made objects (including many breakup fragments), with a combined mass exceeding 5 million kilograms, are tracked by the US Space Surveillance Network and maintained in the US satellite catalog (3-5). Three accidental collisions between cataloged satellites during the period from late 1991 to early 2005 have already been documented (6), although fortunately none resulted in the creation of large, trackable debris clouds. Several studies conducted during 1991-2001 demonstrated, with assumed future launch rates, the unintended growth potential of the Earth satellite population, resulting from random, accidental collisions among resident space objects (7-13). In some low Earth orbit (LEO) altitude regimes where

  10. Erosive Hit-and-Run Impact Events: Debris Unbound

    NASA Astrophysics Data System (ADS)

    Sarid, Gal; Stewart, Sarah T.; Leinhardt, Zoë M.

    2016-01-01

    Erosive collisions among planetary embryos in the inner solar system can lead to multiple remnant bodies, varied in mass, composition and residual velocity. Some of the smaller, unbound debris may become available to seed the main asteroid belt. The makeup of these collisionally produced bodies is different from the canonical chondritic composition, in terms of rock/iron ratio and may contain further shock-processed material. Having some of the material in the asteroid belt owe its origin from collisions of larger planetary bodies may help in explaining some of the diversity and oddities in composition of different asteroid groups.

  11. Tethers as Debris: Hydrocode Simulation of Impacts of Polymer Tether Fragments on Aluminum Plates

    NASA Technical Reports Server (NTRS)

    Evans, Steven W.

    2003-01-01

    Tethers promise to find use in a variety of space applications. Despite being narrow objects, their great lengths result in them having large total areas. Consequently, tethers are very susceptible to being severed by orbital debris. Extensive work has been done designing tethers that resist severs by small debris objects, in order to lengthen their working lives. It is from this perspective that most recent work has considered the tether - debris question. The potential of intact tethers, or severed tether fragments, as debris, to pose a significant collision risk to other spacecraft has been less well studied. Understanding the consequences of such collisions is important in assessing the risks tethers pose to other spacecraft. This paper discusses the damage that polymer tethers may produce on aluminum plates, as revealed by hypervelocity impact simulations using the SPHC hydrodynamic code.

  12. Essential Properties of New Debris Disks

    NASA Astrophysics Data System (ADS)

    Weinberger, Alycia

    We propose to use HAWC+ at 53 microns to measure fundamental attributes of newly discovered debris disks - their temperatures (and hence sizes) and dust contents. Circumstellar debris disks are generated by the collisions and evaporation of planetesimals, the leftover building blocks of planets. Their structures and compositions provide clues to planet formation and planetary system architectures. Their dust may also impede our ability to detect Earth-sized planets. Our 33 A and F-type targets are drawn from recent studies that have used the Wide-field Infrared Survey Explorer (WISE) catalog to detected hundreds of hitherto unknown disks. It's amazing and exciting that despite years of work with IRAS, Spitzer, and Herschel space telescopes, our knowledge of debris disks within the solar neighborhood (<100 pc) was still vastly incomplete. While exciting, the detection of excess at a single wavelength reveals very little about a disk's basic properties. While a detection with WISE's longest wavelength band (22 micron) is sufficient to find a disk, it reveals nothing about the disk's temperature or total dust content. Most of the dust in debris disks is cold, <70 K, which is why the 60 micron band of IRAS was essential to discovering them. So, WISE's 22 micron is likely the Wien side of the iceberg. These disks around luminous stars could be ideal targets for follow-up studies to learn about their dust composition (scattered light observations with HST and JWST, infrared spectroscopy with JWST) and in which to search for planets with adaptive optics on large telescopes. The first step upon which all future work will depend is to characterize these disks in the far-infrared with SOFIA.

  13. Protecting and manoeuvring of spacecraft in space debris environment

    NASA Astrophysics Data System (ADS)

    Rex, D.; Bendisch, J.; Eichler, P.; Zhang, J.

    The paper gives an overview on the fields of debris research performed at the TUBS. The orbital debris flux of all objects larger than 1cm has been established and simulated by a mathematical model in the past mainly on the basis of simulating explosion fragments. However the flux in the millimeter and submillimeter size range seems to be largely influenced by collisions and their ejecta on high circular or on eccentric orbits. The angular distribution of the impact flux on targets at various altitudes and on various inclinations are presented. This angular distribution has also influence on the surface impact flux on a space station, where also the self shielding has to be considered. Results for the ISS are presented. The risk of impacts of larger not shieldable objects on a space station may become too high, so that collision avoidance manoeuvres must be envisaged, the feasibility of which using onboard detectors is discussed.

  14. Evolution of gas in debris discs

    NASA Astrophysics Data System (ADS)

    Kral, Quentin; Wyatt, Mark; Pringle, Jim

    2015-12-01

    A non negligible quantity of gas has been discovered in an increasing number of debris disc systems. ALMA high sensitivity and high resolution is changing our perception of the gaseous component of debris discs as CO is discovered in systems where it should be rapidly photodissociated. It implies that there is a replenishment mechanism and that the observed gas is secondary. Past missions such as Herschel probed the atomic part of the gas through O I and C II emission lines. Gas science in debris discs is still in its infancy, and these new observations raise a handful of questions concerning the mechanisms to create the gas and about its evolution in the planetary system when it is released. The latter question will be addressed in this talk as a self-consistent gas evolution scenario is proposed and is compared to observations for the peculiar case of β Pictoris.Our model proposes that carbon and oxygen within debris discs are created due to photodissociation of CO which is itself created from the debris disc dust (due to grain-grain collisions or photodesorption). The evolution of the carbon atoms is modelled as viscous spreading, with viscosity parameterised using an α model. The temperature, ionisation fraction and population levels of carbon are followed with a PDR model called Cloudy, which is coupled to the dynamical viscous α model. Only carbon gets ionised due to its lower ionisation potential than oxygen. The carbon gas disc can end up with a high ionisation fraction due to strong FUV radiation field. A high ionisation fraction means that the magnetorotational instability (MRI) is very active, so that α is very high. Gas density profiles can be worked out for different input parameters such as the α value, the CO input rate, the location of the input and the incoming radiation field. Observability predictions can be made for future observations, and our model is tested on β Pictoris observations. This new gas evolution model fits the carbon and CO

  15. Molecular gas clumps from the destruction of icy bodies in the β Pictoris debris disk.

    PubMed

    Dent, W R F; Wyatt, M C; Roberge, A; Augereau, J-C; Casassus, S; Corder, S; Greaves, J S; de Gregorio-Monsalvo, I; Hales, A; Jackson, A P; Hughes, A Meredith; Lagrange, A-M; Matthews, B; Wilner, D

    2014-03-28

    Many stars are surrounded by disks of dusty debris formed in the collisions of asteroids, comets, and dwarf planets, but is gas also released in such events? Observations at submillimeter wavelengths of the archetypal debris disk around β Pictoris show that 0.3% of a Moon mass of carbon monoxide orbits in its debris belt. The gas distribution is highly asymmetric, with 30% found in a single clump 85 astronomical units from the star, in a plane closely aligned with the orbit of the inner planet, β Pictoris b. This gas clump delineates a region of enhanced collisions, either from a mean motion resonance with an unseen giant planet or from the remnants of a collision of Mars-mass planets.

  16. Molecular Gas Clumps from the Destruction of Icy Bodies in the beta Pictoris Debris Disk

    NASA Technical Reports Server (NTRS)

    Dent, W. R. F.; Wyatt, M. C.; Roberge, A.; Augereau, J. -C.; Casassus, S.; Corder, S.; Greaves, J. S.; DeGregorio-Monsalvo, I.; Hales, A.; Jackson, A. P.; Hughes, A. Meredith; Lagrange, A. -M.; Matthews, B.; Wilner, D.

    2014-01-01

    Many stars are surrounded by disks of dusty debris formed in the collisions of asteroids, comets and dwarf planets. But is gas also released in such events? Observations at sub-mm wavelengths of the archetypal debris disk around ß Pictoris show that 0.3% of a Moon mass of carbon monoxide orbits in its debris belt. The gas distribution is highly asymmetric, with 30% found in a single clump 85 AU from the star, in a plane closely aligned with the orbit of the inner planet, beta Pic b. This gas clump delineates a region of enhanced collisions, either from a mean motion resonance with an unseen giant planet, or from the remnants of a collision of Mars-mass planets.

  17. Coronagraphic Imaging of Debris Disks from a High-Altitude Balloon Platform

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen C.; Traub, Wesley A.; Trauger, John T.; Bryden, Geoffrey; Krist, John; Stuchlik, David W.; Lillie, Charles F.

    2012-01-01

    Debris disks are rings of micron-size dust orbiting in the outer regions of planetary systems. Asteroid and comet collisions are the probable sources of the dust. Radiation pressure and Poynting-Robertson drag. Planets shepherd and sculpt the dust into a ring. The dust ring is bright enough to be imaged, brighter than the planets themselves. So debris disk images are our connection to as-yet unseen planets, comets, and asteroids.

  18. Coronagraphic Imaging of Debris Disks from a High-Altitude Balloon Platform

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen C.; Traub, Wesley A.; Trauger, John T.; Bryden, Geoffrey; Krist, John; Stuchlik, David W.; Lillie, Charles F.

    2012-01-01

    Debris disks are rings of micron-size dust orbiting in the outer regions of planetary systems. Asteroid and comet collisions are the probable sources of the dust. Radiation pressure and Poynting-Robertson drag. Planets shepherd and sculpt the dust into a ring. The dust ring is bright enough to be imaged, brighter than the planets themselves. So debris disk images are our connection to as-yet unseen planets, comets, and asteroids.

  19. An active debris removal parametric study for LEO environment remediation

    NASA Astrophysics Data System (ADS)

    Liou, J.-C.

    2011-06-01

    Recent analyses on the instability of the orbital debris population in the low Earth orbit (LEO) region and the collision between Iridium 33 and Cosmos 2251 have reignited interest in using active debris removal (ADR) to remediate the environment. There are, however, monumental technical, resource, operational, legal, and political challenges in making economically viable ADR a reality. Before a consensus on the need for ADR can be reached, a careful analysis of its effectiveness must be conducted. The goal is to demonstrate the need and feasibility of using ADR to better preserve the future environment and to explore different operational options to maximize the benefit-to-cost ratio. This paper describes a new sensitivity study on using ADR to stabilize the future LEO debris environment. The NASA long-term orbital debris evolutionary model, LEGEND, is used to quantify the effects of several key parameters, including target selection criteria/constraints and the starting epoch of ADR implementation. Additional analyses on potential ADR targets among the existing satellites and the benefits of collision avoidance maneuvers are also included.

  20. A Method and a Tool for Assessing In-Orbit Debris-Related Risk for Space Systems

    NASA Astrophysics Data System (ADS)

    Elie, Andre; Kervarc, Romain; Carle, Patrice; Prudhomme, Stephanie; Kempf, Scott; Schaefer, Frank; Donath, Therese

    2013-08-01

    This paper addresses a methodology taking space-debris-related risk for Low, Medium and Geostationary Earth Orbit space missions into account, and aims at assessing the collision risk not only as a physical threat supported by a physical spacecraft, but as a hazardous effect on the space system mission. The goal is to develop a tool exploiting such physical simulation results (i.e. effects of sustainable impacts on the spacecraft in case of small debris, cost of the spacecraft avoidance manoeuvres in case of large debris) in a given debris scenario, to compute the repercussion of these effects on the space mission, and to perform comparisons between possible debris scenarios. This work is part of the PÇ-ROTECT (Prediction, Protection & Reduction of OrbiTal Exposure to Collision Threats) project, initiated in March 2011.

  1. Collision tectonics

    SciTech Connect

    Coward, M.P.; Ries, A.C.

    1985-01-01

    The motions of lithospheric plates have produced most existing mountain ranges, but structures produced as a result of, and following the collision of continental plates need to be distinguished from those produced before by subduction. If subduction is normally only stopped when collision occurs, then most geologically ancient fold belts must be collisional, so it is essential to recognize and understand the effects of the collision process. This book consists of papers that review collision tectonics, covering tectonics, structure, geochemistry, paleomagnetism, metamorphism, and magmatism.

  2. A Numerical Approach to Estimate the Ballistic Coefficient of Space Debris from TLE Orbital Data

    NASA Technical Reports Server (NTRS)

    Narkeliunas, Jonas

    2016-01-01

    Low Earth Orbit (LEO) is full of space debris, which consist of spent rocket stages, old satellites and fragments from explosions and collisions. As of 2009, more than 21,000 orbital debris larger than 10 cm are known to exist], and while it is hard to track anything smaller than that, the estimated population of particles between 1 and 10 cm in diameter is approximately 500,000, whereas small as 1 cm exceeds 100 million. These objects orbit Earth with huge kinetic energies speeds usually exceed 7 kms. The shape of their orbit varies from almost circular to highly elliptical and covers all LEO, a region in space between 160 and 2,000 km above sea level. Unfortunately, LEO is also the place where most of our active satellites are situated, as well as, International Space Station (ISS) and Hubble Space Telescope, whose orbits are around 400 and 550 km above sea level, respectively.This poses a real threat as debris can collide with satellites and deal substantial damage or even destroy them.Collisions between two or more debris create clouds of smaller debris, which are harder to track and increase overall object density and collision probability. At some point, the debris density couldthen reach a critical value, which would start a chain reaction and the number of space debris would grow exponentially. This phenomenon was first described by Kessler in 1978 and he concluded that it would lead to creation of debris belt, which would vastly complicate satellite operations in LEO. The debris density is already relatively high, as seen from several necessary debris avoidance maneuvers done by Shuttle, before it was discontinued, and ISS. But not all satellites have a propulsion system to avoid collision, hence different methods need to be applied. One of the proposed collision avoidance concepts is called LightForce and it suggests using photon pressure to induce small orbital corrections to deflect debris from colliding. This method is very efficient as seen from

  3. Study of pore fluid effect on the mobility of granular debris flows

    NASA Astrophysics Data System (ADS)

    Zhou, Gordon G. D.; Sun, Q. C.

    2017-06-01

    Granular debris flows in nature are composed of a wide range of solids and viscous pore fluids, moving at high velocities down sloping channels. The pore fluids in a granular debris flow affect the interactions between the solid and fluid phases and thus govern the debris-flow mobility. Study of the pore fluid effect (i.e., excess pore water pressures correlated to solid structures, and the viscous shearing and dragging) is essential for understanding the high flow mobility of granular debris flows. This study critically reviews two dimensionless numbers with clear physical meanings, then demonstrates a new application of field monitoring data for identifying natural debris flows on large scales (i.e., surge and continuous debris-flows, respectively). This study illustrates that, the pore fluid viscous shearing stress dominates solid inertial stress due to solids collision. It is also found that different to continuous debris-flows, the high pore fluid pressures generated in surge debris-flow body dissipate quite slowly and mostly influence particle contact behaviour significantly. A new scientific criterion for identification of continuous and surge debris flow in nature can be given by this study.

  4. Gas in Debris Disks: Clues to the Late Stages of Planet Formation

    NASA Technical Reports Server (NTRS)

    Roberg, A.

    2008-01-01

    The basic character of debris disks was established soon after their discovery in the mid-80's. These disks around nearby main sequence stars are composed of material produced by collisions and/or evaporation of extrasolar asteroids and comets. Debris disks appear to be largely composed of dust, though little is known about its typical composition. Nonetheless, at least some debris disks have detectable gas, which has very different characteristics from the gas in younger protoplanetary disks. The gas component has resisted observation, but appears to hold important clues to the composition of extrasolar planetesimals during the late-stages of planetary system formation and the formation of terrestrial planet atmospheres. In this talk, I will explain our current understanding of the place of debris disks in the planet formation process and describe what is known about the gas component. Finally, I will outline upcoming opportunities for sensitive new studies of gas in debris disks.

  5. ORDEM 3.0 and the Risk of High-Density Debris

    NASA Technical Reports Server (NTRS)

    Matney, Mark; Anz-Meador, Philip

    2014-01-01

    NASA’s Orbital Debris Engineering Model was designed to calculate orbital debris fluxes on spacecraft in order to assess collision risk. The newest of these models, ORDEM 3.0, has a number of features not present in previous models. One of the most important is that the populations and fluxes are now broken out into material density groups. Previous models concentrated on debris size alone, but a particle’s mass and density also determine the amount of damage it can cause. ORDEM 3.0 includes a high-density component, primarily consisting of iron/steel particles that drive much of the risk to spacecraft. This paper will outline the methods that were used to separate and identify the different densities of debris, and how these new densities affect the overall debris flux and risk.

  6. Gas in Debris Disks: Clues to the Late Stages of Planet Formation

    NASA Technical Reports Server (NTRS)

    Roberg, A.

    2008-01-01

    The basic character of debris disks was established soon after their discovery in the mid-80's. These disks around nearby main sequence stars are composed of material produced by collisions and/or evaporation of extrasolar asteroids and comets. Debris disks appear to be largely composed of dust, though little is known about its typical composition. Nonetheless, at least some debris disks have detectable gas, which has very different characteristics from the gas in younger protoplanetary disks. The gas component has resisted observation, but appears to hold important clues to the composition of extrasolar planetesimals during the late-stages of planetary system formation and the formation of terrestrial planet atmospheres. In this talk, I will explain our current understanding of the place of debris disks in the planet formation process and describe what is known about the gas component. Finally, I will outline upcoming opportunities for sensitive new studies of gas in debris disks.

  7. Active Debris Removal - A Grand Engineering Challenge for the Twenty-First Century

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.

    2011-01-01

    The collision between Iridium 33 and Cosmos 2251 in 2009 has reignited interest in using active debris removal to remediate the near-Earth orbital debris environment. A recent NASA study shows that, in order to stabilize the environment in the low Earth orbit (LEO) region for the next 200 years, active debris removal of about five large and massive (1 to more than 8 metric tons) objects per year is needed. To develop the capability to remove five of those objects per year in a cost-effective manner truly represents a grand challenge in engineering and technology development.

  8. STS-125 Orbital Debris

    NASA Image and Video Library

    2009-07-02

    JSC2010-E-054445 (2 July 2009) --- Members of the Orbital Debris Program Office and the Hypervelocity Impact Technology Facility at JSC record images of impact craters and other surface data on the returned Wide Field and Planetary Camera (WFPC-2) of the Hubble Space Telescope. Inspection took place at the Goddard Space Flight Center during the summer of 2009. Photo credit: NASA or National Aeronautics and Space Administration

  9. Debris - Onboard GT-10

    NASA Image and Video Library

    1966-07-18

    S66-46241 (18 July 1966) --- Debris on spacecraft window in picture taken from inside the Gemini-10 spacecraft. At this time Gemini-10 was docked with the Agena Target Docking Vehicle 5005. Taken with a modified 70mm Hasselblad camera, using Eastman Kodak, Ektachrome, MS (S.O. 217) color film. The Gemini-10 crew is astronaut John W. Young, command pilot, and Michael Collins, pilot. Photo credit: NASA

  10. Laser/space material uncooperative propulsion for orbital debris removal and asteroid, meteoroid, and comet deflection

    NASA Astrophysics Data System (ADS)

    Campbell, Jonathan W.; Taylor, Charles R.; Smalley, Larry L.; Dickerson, Thomas

    1999-01-01

    Orbital debris in low-Earth orbit in the size range from 1 to 10 cm in diameter can be detected but not tracked reliably enough to be avoided by spacecraft. It can cause catastrophic damage even to a shielded spacecraft. With adaptive optics, a ground-based pulsed laser ablating the debris surface can produce enough propulsion in several hundred pulses to cause such debris to reenter the atmosphere. A single laser station could remove all of the 1-10 cm debris in three years or less. A technology demonstration of laser space propulsion is proposed which would pave the way for the implementation of such a debris removal system. The cost of the proposed demonstration is comparable with the estimated annual cost of spacecraft operations in the present orbital debris environment. Orbital debris is not the only space junk that is deleterious to the Earth's environment. Collisions with asteroids have caused major havoc to the Earth's biosphere many times in the ancient past. Since the possibility still exists for major impacts, it is shown that it is possible to scale up the systems to prevent these catastrophic collisions given sufficient early warning.

  11. Space Debris Modeling at NASA

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2001-01-01

    Since the Second European Conference on Space Debris in 1997, the Orbital Debris Program Office at the NASA Johnson Space Center has undertaken a major effort to update and improve the principal software tools employed to model the space debris environment and to evaluate mission risks. NASA's orbital debris engineering model, ORDEM, represents the current and near-term Earth orbital debris population from the largest spacecraft to the smallest debris in a manner which permits spacecraft engineers and experimenters to estimate the frequency and velocity with which a satellite may be struck by debris of different sizes. Using expanded databases and a new program design, ORDEM2000 provides a more accurate environment definition combined with a much broader array of output products in comparison with its predecessor, ORDEM96. Studies of the potential long-term space debris environment are now conducted with EVOLVE 4.0, which incorporates significant advances in debris characterization and breakup modeling. An adjunct to EVOLVE 4.0, GEO EVOLVE has been created to examine debris issues near the geosynchronous orbital regime. In support of NASA Safety Standard 1740.14, which establishes debris mitigation guidelines for all NASA space programs, a set of evaluation tools called the Debris Assessment Software (DAS) is specifically designed for program offices to determine whether they are in compliance with NASA debris mitigation guidelines. DAS 1.5 has recently been released with improved WINDOWS compatibility and graphics functions. DAS 2.0 will incorporate guideline changes in a forthcoming revision to NASA Safety Standard 1740.14. Whereas DAS contains a simplified model to calculate possible risks associated with satellite reentries, NASA's higher fidelity Object Reentry Survival Analysis Tool (ORSAT) has been upgraded to Version 5.0. With the growing awareness of the potential risks posed by uncontrolled satellite reentries to people and property on Earth, the

  12. Mission concept and autonomy considerations for active Debris removal

    NASA Astrophysics Data System (ADS)

    Peters, Susanne; Pirzkall, Christoph; Fiedler, Hauke; Förstner, Roger

    2016-12-01

    Over the last 60 years, Space Debris has become one of the main challenges for the safe operation of satellites in low Earth orbit. To address this threat, guidelines that include a limited debris release during normal operations, minimization of the potential for on-orbit break-ups and post mission disposal have begun to be implemented. However, for the long-term, the amount of debris will still increase due to fragments created by collisions of objects in space. The active removal of space debris of at least five large objects per years is therefore recommended, but not yet included in those guidelines. Even though various technical concepts have been developed over the last years, the question on how to make them reliable and safe or how to finance such mission has not been answered. This paper addresses the first two topics. With Space Debris representing an uncooperative and possibly tumbling target, close proximity becomes absolutely critical, especially when an uninterrupted connection to the ground station is not ensured. This paper therefore defines firstly a mission to remove at least five large objects and secondly introduces a preliminary autonomy concept fitted for this mission.

  13. Handling and restraint.

    PubMed

    Donovan, John; Brown, Patricia

    2004-09-01

    For the safety of the handler and the animal, proper methods for handling and restraining laboratory animals should be followed. Improper handling can result in increased stress and injury to the animal. In addition, the handler risks injury from bite wounds or scratches inflicted when the animal becomes fearful or anxious. By using sure, direct movements with a determined attitude, the animal can be easily handled and restrained. Animals can be restrained either manually or in a plastic restrainer. The protocols in this unit describe handling and manual restraint of mice, rats, hamsters, and rabbits. Alternate protocols describe restraint using the plastic restrainer.

  14. Handling and restraint.

    PubMed

    Donovan, John; Brown, Patricia

    2006-07-01

    For the safety of the handler and the animal, proper methods for handling and restraining laboratory animals should be followed. Improper handling can result in increased stress and injury to the animal. In addition, the handler risks injury from bite wounds or scratches inflicted when the animal becomes fearful or anxious. By using sure, direct movements with a determined attitude, the animal can be easily handled and restrained. Animals can be restrained either manually or in a plastic restrainer. The protocols in this unit describe handling and manual restraint of mice, rats, hamsters, and rabbits. Alternate protocols describe restraint using the plastic restrainer.

  15. Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime

    NASA Astrophysics Data System (ADS)

    Anderson, Paul V.

    The geosynchronous orbit (GEO) is a unique commodity of the satellite industry that is becoming increasingly contaminated with orbital debris, but is heavily populated with high-value assets from the civil, commercial, and defense sectors. The GEO arena is home to hundreds of communications, data transmission, and intelligence satellites collectively insured for an estimated 18.3 billion USD. As the lack of natural cleansing mechanisms at the GEO altitude renders the lifetimes of GEO debris essentially infinite, conjunction and risk assessment must be performed to safeguard operational assets from debris collisions. In this thesis, longitude-dependent debris congestion is characterized by predicting the number of near-miss events per day for every longitude slot at GEO, using custom debris propagation tools and a torus intersection metric. Near-miss events with the present-day debris population are assigned risk levels based on GEO-relative position and speed, and this risk information is used to prioritize the population for debris removal target selection. Long-term projections of debris growth under nominal launch traffic, mitigation practices, and fragmentation events are also discussed, and latitudinal synchronization of the GEO debris population is explained via node variations arising from luni-solar gravity. In addition to characterizing localized debris congestion in the GEO ring, this thesis further investigates the conjunction risk to operational satellites or debris removal systems applying low-thrust propulsion to raise orbit altitude at end-of-life to a super-synchronous disposal orbit. Conjunction risks as a function of thrust level, miss distance, longitude, and semi-major axis are evaluated, and a guidance method for evading conjuncting debris with continuous thrust by means of a thrust heading change via single-shooting is developed.

  16. External tank space debris considerations

    NASA Technical Reports Server (NTRS)

    Elfer, N.; Baillif, F.; Robinson, J.

    1992-01-01

    Orbital debris issues associated with maintaining a Space Shuttle External Tank (ET) on orbit are presented. The first issue is to ensure that the ET does not become a danger to other spacecraft by generating space debris, and the second is to protect the pressurized ET from penetration by space debris or meteoroids. Tests on shield designs for penetration resistance showed that when utilized with an adequate bumper, thermal protection system foam on the ET is effective in preventing penetration.

  17. DEBRIS FLOWS AND HYPERCONCENTRATED STREAMFLOWS.

    USGS Publications Warehouse

    Wieczorek, Gerald F.

    1986-01-01

    Examination of recent debris-flow and hyperconcentrated-streamflow events in the western United States reveals (1) the topographic, geologic, hydrologic, and vegetative conditions that affect initiation of debris flows and (2) the wide ranging climatic conditions that can trigger debris flows. Recognition of these physiographic and climatic conditions has aided development of preliminary methods for hazard evaluation. Recent developments in the application of electronic data gathering, transmitting, and processing systems shows potential for real-time hazard warning.

  18. Active debris removal of multiple priority targets

    NASA Astrophysics Data System (ADS)

    Braun, Vitali; Lüpken, A.; Flegel, S.; Gelhaus, J.; Möckel, M.; Kebschull, C.; Wiedemann, C.; Vörsmann, P.

    2013-05-01

    Today's space debris environment shows major concentrations of objects within distinct orbital regions for nearly all size regimes. The most critical region is found at orbital altitudes near 800 km with high declinations. Within this region many satellites are operated in so called sun-synchronous orbits (SSO). Among those, there are Earth observation, communication and weather satellites. Due to the orbital geometry in SSO, head-on encounters with relative velocities of about 15 km/s are most probable and would thus result in highly energetic collisions, which are often referred to as catastrophic collisions, leading to the complete fragmentation of the participating objects. So called feedback collisions can then be triggered by the newly generated fragments, thus leading to a further population increase in the affected orbital region. This effect is known as the Kessler syndrome.Current studies show that catastrophic collisions are not a major problem today, but will become the main process for debris generation within the SSO region in the near future, even without any further launches. In order to avoid this effect, objects with a major impact on collisional cascading have to be actively removed from the critical region after their end of life. Not having the capability to perform an end-of-life maneuver in order to transfer to a graveyard orbit or to de-orbit, many satellites and rocket bodies would have to be de-orbited within a dedicated mission. In such a mission, a service satellite would perform a de-orbit maneuver, after having docked to a specific target.In this paper, chemical and electric propulsion systems were analysed with the main focus on removing multiple targets within one single mission. The targets were chosen from a previously defined priority list in order to enhance the mission efficiency. Total mission time, ΔV and system mass were identified as key parameters to allow for an evaluation of the different concepts. It was shown that it

  19. Grain Handling and Storage.

    ERIC Educational Resources Information Center

    Harris, Troy G.; Minor, John

    This text for a secondary- or postecondary-level course in grain handling and storage contains ten chapters. Chapter titles are (1) Introduction to Grain Handling and Storage, (2) Elevator Safety, (3) Grain Grading and Seed Identification, (4) Moisture Control, (5) Insect and Rodent Control, (6) Grain Inventory Control, (7) Elevator Maintenance,…

  20. Data Handling and Citizenship

    ERIC Educational Resources Information Center

    Tresidder, Gwen

    2006-01-01

    When marking GCSE data handling coursework, the author was repeatedly reminded just how poor the level of statistical understanding is among students. In response to a feeling that the teaching of handling data topics was limited, the author and her colleague designed a project with Y8 students to try to teach statistics for a deeper…

  1. Feature test report for the Small Debris Collection and Packaging System

    SciTech Connect

    Brisbin, S.A.

    1995-03-17

    The Spent Nuclear Fuel Equipment Engineering group performed feature testing of the Small Debris Collection and Packaging System (SDCPS) in the 305 Cold Test Facility from January 30, 1995, to February 1, 1995. Feature testing of the Small Debris Collection and Packaging System (SDCPS) was performed for the following reasons: To assess the feasibility of using ``drop-out`` vessels to collect small debris (<2.5 cm) in MK-II fuel canisters while transferring sludge to the Weasel Pit. To evaluate system performance under conditions similar to those in the K-Basins (e.g. submerged under 4.9 meters of water and operated with long handled tools) while using a surrogate sludge mixed with debris. To determine if canister weight could be used to predict the volume of sludge and/or debris contained within the canisters during system operation.

  2. Current Issues in Orbital Debris

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2011-01-01

    During the past two decades, great strides have been made in the international community regarding orbital debris mitigation. The majority of space-faring nations have reached a consensus on an initial set of orbital debris mitigation measures. Implementation of and compliance with the IADC and UN space debris mitigation guidelines should remain a high priority. Improvements of the IADC and UN space debris mitigation guidelines should continue as technical consensus permits. The remediation of the near-Earth space environment will require a significant and long-term undertaking.

  3. The Mystery of Herschel's ``Cold Debris Disks''

    NASA Astrophysics Data System (ADS)

    Krivov, A. V.; Löhne, T.; Eiroa, C.; Marshall, J. P.

    2012-03-01

    An important result of the Herschel Open Times Key Program DUNES is a discovery of a new class of ``cold debris disks''. These are tenuous disks that show little or no infrared excess at 100μm, but a significant one at 160μm and possibly longer wavelengths. A comparison of the dust temperatures inferred from the SEDs to the disk radii estimated from resolved images suggests that the dust is colder than a black body at the dust location. This requires the grains to be large (compared to far-infrared wavelengths) and to have low absorption in the visible. While the latter can be achieved, for instance if the dust is rich in ices, the absence of small grains is puzzling, since collisional models of debris disks predict the grains of all sizes down to several times the radiation pressure blowout limit to be present. We will discuss several scenarios proposed to explain depletion of small grains: transport-dominated disks, disks with dynamically cold dust-producing planetesimals, and the disks of unstirred primordial millimeter-sized grains. While the first two scenarios encounter problems, the last one looks more promising. Our collisional simulations show that, at least for some collision outcome prescriptions, such disks can indeed survive for gigayears, largely preserving the primordial size distribution. The modeled thermal emission appears to be roughly consistent with the observed one.

  4. 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.

  5. Space Debris Hazard Evaluation

    NASA Technical Reports Server (NTRS)

    Davison, Elmer H.; Winslow, Paul C., Jr.

    1961-01-01

    The hazard to space vehicles from natural space debris has been explored. A survey of the available information pertinent to this problem is presented. The hope is that this presentation gives a coherent picture of the knowledge to date in terms of the topic covered. The conclusion reached is that a definite hazard exists but that it can only be poorly assessed on the basis of present information. The need for direct measurement of this hazard is obvious, and some of the problems involved in making these direct measurements have been explored.

  6. Removal of orbital debris

    NASA Astrophysics Data System (ADS)

    Petro, Andrew J.; Talent, David L.

    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.

  7. 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.

  8. Microplastic debris in sandhoppers

    NASA Astrophysics Data System (ADS)

    Ugolini, A.; Ungherese, G.; Ciofini, M.; Lapucci, A.; Camaiti, M.

    2013-09-01

    Adults of the sandhopper Talitrus saltator were fed with dry fish food mixed with polyethylene microspheres (diameter 10-45 μm). Observations of homogenized guts revealed the presence of microspheres independently of their dimensions. The gut resident time (GRT) was recorded and most of the microspheres are expelled in 24 h. Microspheres are totally expelled in one week. Preliminary investigations did not show any consequence of microsphere ingestion on the survival capacity in the laboratory. FT-IR analyses carried out on faeces of freshly collected individuals revealed the presence of polyethylene and polypropylene. This confirms that microplastic debris could be swallowed by T. saltator in natural conditions.

  9. Recent Measurements of the Orbital Debris Environment at NASA Johnson Space Center

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    Space debris presents many challenges to current space operations. Although, the probability of collision between an operational spacecraft and a piece of space debris is quite small, the potential losses can be quite high. Prior to 1990, characterization of the orbital debris environment was divided into two categories. Objects larger than 10 cm are monitored by the United States Space Surveillance Network (SSN) and documented in the U.S. Space Command (USSPACECOM) catalog. Knowledge of debris smaller than 0.1 cm has come from the analyses of returned surfaces. The lack of information about the debris environment in the size range from 0.1 to 1 0 cm led to a joint NASA-DOD effort for orbital debris measurements using the Haystack radar and the unbuilt Haystack Auxiliary (HAX) radars. The data from these radars have been critical to the design of shielding for the International Space Station and have been extensively used in the creation of recent models describing the orbital debris environment. Recent debris campaigns have been conducted to verify and validate through comparative measurements, the results and conclusions drawn from the Haystack/HAX measurements. The Haystack/HAX measurements and results will be described as well as the results of the recent measurement campaigns.

  10. Future of remote handling

    SciTech Connect

    Grisham, D.L.; Lambert, J.E.

    1986-01-01

    The field of remote handling started in the late 1940's and early 1950's with the invention of mechanical master-slave and electromechanical manipulators. That field now consists of three major divisions: (1) conventional remote handling in fixed facilities with shielding windows and mechanical manipulators; (2) large area remote handling using portable equipment, electric master-slave manipulators, and television for viewing; and (3) the field of robotics which is beginning to be applied to repetitive operations on toxic and dangerous materials. All three divisions will continue to develop and evolve over the next decade.

  11. CHR -- Character Handling Routines

    NASA Astrophysics Data System (ADS)

    Charles, A. C.; Rees, P. C. T.; Chipperfield, A. J.; Jenness, T.

    This document describes the Character Handling Routine library, CHR, and its use. The CHR library augments the limited character handling facilities provided by the Fortran 77 standard. It offers a range of character handling facilities: from formatting Fortran data types into text strings and the reverse, to higher level functions such as wild card matching, string sorting, paragraph reformatting and justification. The library may be used simply for building text strings for interactive applications or as a basis for more complex text processing applications.

  12. Space Station: Delays in dealing with space debris may reduce safety and increase costs

    NASA Astrophysics Data System (ADS)

    1992-06-01

    The majority of NASA's current designs for protecting the space station and crew from debris are outdated and its overall debris protection strategy is insufficient. NASA's contractors have designed the station using a 1984 model of the space environment that is obsolete, significantly underestimating the increasing amount of debris that the station will encounter during its 30-year lifetime. In February 1992, NASA directed its space centers to incorporate an updated 1991 model into their designs. However, the agency has not yet made critical decisions on how to implement this change. Preliminary evaluations show that incorporating the 1991 model using currently established safety criteria could entail a major redesign of some components, with significant cost impact and schedule delays. NASA's overall protection strategy for space debris is insufficient. While NASA has concentrated its protection on shielding the space station from small debris and plans to augment this initial shielding in orbit, it has not yet developed designs or studied the cost and operational impact of augmenting its protection with additional shielding. Further, current designs do not provide the capability of warning or protecting the crew from imminent collision with mid-size debris. Finally, although some capabilities exist for maneuvering the station away from large debris, the agency lacks collision-avoidance plans and debris-tracking equipment. In developing a comprehensive strategy to protect the station from the more severe debris environment, NASA cannot avoid some difficult decisions. These decisions involve tradeoffs between how much the agency is willing to pay to protect the station, the schedule delays it may incur, and the risk to station safety it is willing to accept. It is important that these decisions be made before NASA completes its critical design reviews in early 1993. At that time key designs will be made final and manufacturing will begin. Without a comprehensive

  13. Review of uncertainty sources affecting the long-term predictions of space debris evolutionary models

    NASA Astrophysics Data System (ADS)

    Dolado-Perez, J. C.; Pardini, Carmen; Anselmo, Luciano

    2015-08-01

    Since the launch of Sputnik-I in 1957, the amount of space debris in Earth's orbit has increased continuously. Historically, besides abandoned intact objects (spacecraft and orbital stages), the primary sources of space debris in Earth's orbit were (i) accidental and intentional break-ups which produced long-lasting debris and (ii) debris released intentionally during the operation of launch vehicle orbital stages and spacecraft. In the future, fragments generated by collisions are expected to become a significant source as well. In this context, and from a purely mathematical point of view, the orbital debris population in Low Earth Orbit (LEO) should be intrinsically unstable, due to the physics of mutual collisions and the relative ineffectiveness of natural sink mechanisms above~700 km. Therefore, the real question should not be "if", but "when" the exponential growth of the space debris population is supposed to start. From a practical point of view, and in order to answer the previous question, since the end of the 1980's several sophisticated long-term debris evolutionary models have been developed. Unfortunately, the predictions performed with such models, in particular beyond a few decades, are affected by considerable uncertainty. Such uncertainty comes from a relative important number of variables that being either under the partial control or completely out of the control of modellers, introduce a variability on the long-term simulation of the space debris population which cannot be captured with standard Monte Carlo statistics. The objective of this paper is to present and discuss many of the uncertainty sources affecting the long-term predictions done with evolutionary models, in order to serve as a roadmap for the uncertainty and the statistical robustness analysis of the long-term evolution of the space debris population.

  14. Treatability Variance for Containerised Liquids in Mixed Debris Waste - 12101

    SciTech Connect

    Alstatt, Catherine M.

    2012-07-01

    The TRU Waste Processing Center (TWPC) is a Department of Energy facility whose mission is to receive and process for appropriate disposal legacy Contact Handled (CH) and Remote Handled (RH) waste, including debris waste stored at various DOE Oak Ridge facilities. Acceptable Knowledge (AK) prepared for the waste characterizes the waste as mixed waste, meaning it is both radioactive and regulated under the Resource Conservation and Recovery Act (RCRA). The AK also indicates that a number of the debris waste packages contain small amounts of containerised liquids. The documentation indicates liquid wastes generated in routine lab operations were typically collected for potential recovery of valuable isotopes. However, during activities associated with decontamination and decommissioning (D and D), some containers with small amounts of liquids were placed into the waste containers with debris waste. Many of these containers now hold from 2.5 milliliters (ml) to 237 ml of liquid; a few contain larger volumes. At least some of these containers were likely empty at the time of generation, but documentation of this condition is lacking. Since WIPP compliant AK is developed on a waste stream basis, rather than an individual container basis, and includes every potential RCRA hazardous constituent within the waste stream, it is insufficient for the purpose of characterizing individual containers of liquid. Debris waste is defined in 40 CFR 268.2(g) as 'solid material exceeding a 60 mm particle size that is intended for disposal and that is: a manufactured object; or plant or animal matter; or natural geologic material'. The definition further states that intact containers of hazardous waste that are not ruptured and that retain at least 75% of their original volume are not debris. The prescribed treatment is removal of intact containers from the debris waste, and treatment of their contents to meet specific Land Disposal Restrictions (LDR) standards. This is true for

  15. High energy particle collisions near black holes

    NASA Astrophysics Data System (ADS)

    Zaslavskii, O. B.

    2016-10-01

    If two geodesic particles collide near a rotating black hole, their energy in the centre of mass frame Ec.m. can become unbound under certain conditions (the so-called BSW effect). The special role is played here by so-called critical geodesics when one of particles has fine-tuned energy and angular momentum. The nature of geodesics reveals itself also in fate of the debris after collisions. One of particles moving to a remote observer is necessarily near-critical. We discuss, when such a collision can give rise not only unboud Ec.m. but also unbound Killing energy E (so-called super-Penrose process).

  16. Space debris modeling at NASA

    NASA Astrophysics Data System (ADS)

    Johnson, Nicholas L.

    2001-10-01

    Since the Second European Conference on Space Debris in 1997, the Orbital Debris Program Office at the NASA Johnson Space Center has undertaken a major effort to update and improve the principal software tools employed to model the space debris environment and to evaluate mission risks. NASA's orbital debris engineering model, ORDEM, represents the current and near-term Earth orbital debris population from the largest spacecraft to the smallest debris in a manner which permits spacecraft engineers and experimenters to estimate the frequency and velocity with which a satellite may be struck by debris of different sizes. Using expanded databases and a new program design, ORDEM2000 provides a more accurate environment definition combined with a much broader array of output products in comparison with its predecessor, ORDEM96. Studies of the potential long-term space debris environment are now conducted with EVOVLE 4.0, which incorporates significant advances in debris characterization and breakup modeling. An adjunct to EVOLVE 4.0, GEO EVOLVE has been created to examine debris issues near the geosynchronous orbital regime. In support of NASA Safety Standard (NSS) 1740.14, which establishes debris mitigation guidelines for all NASA space programs, a set of evaluation tools called the Debris Assessment Software (DAS) is specifically designed for program offices to determine whether they are in compliance with NASA debris mitigation guidelines. DAS 1.5 has recently been completed with improved WINDOWS compatibility and graphics functions. DAS 2.0 will incorporate guideline changes in a forthcoming revision to NSS 1740.14. Whereas DAS contains a simplified model to calculate possible risks associated with satellite reentries, NASA's higher fidelity Object Reentry Survival Analysis Tool (ORSAT) has been upgraded to Version 5.0. With the growing awareness of the potential risks posed by uncontrolled satellite reentries to people and property on Earth, the application of

  17. Remote Sensing of Plastic Debris

    NASA Astrophysics Data System (ADS)

    Garaba, S. P.; Dierssen, H. M.

    2016-02-01

    Plastic debris is becoming a nuisance in the environment and as a result there has been a dire need to synoptically detect and quantify them in the ocean and on land. We investigate the possible utility of spectral information determined from hand held, airborne and satellite remote sensing tools in the detection and identification polymer source of plastic debris. Sampled debris will be compared to our derived spectral library of typical raw polymer sources found at sea and in household waste. Additional work will be to determine ways to estimate the abundance of plastic debris in target areas. Implications of successful remote detection, tracking and quantification of plastic debris will be towards validating field observations over large areas and at repeated time intervals both on land and at sea.

  18. 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.

  19. Autonomous space processor for orbital debris

    NASA Technical Reports Server (NTRS)

    Ramohalli, Kumar; Campbell, David; Brockman, Jeff P.; Carter, Bruce; Donelson, Leslie; John, Lawrence E.; Marine, Micky C.; Rodina, Dan D.

    1989-01-01

    This work continues to develop advanced designs toward the ultimate goal of a GETAWAY SPECIAL to demonstrate economical removal of orbital debris utilizing local resources in orbit. The fundamental technical feasibility was demonstrated last year through theoretical calculations, quantitative computer animation, a solar focal point cutter, a robotic arm design and a subscale model. During this reporting period, several improvements are made in the solar cutter, such as auto track capabilities, better quality reflectors and a more versatile framework. The major advance has been in the design, fabrication and working demonstration of a ROBOTIC ARM that has several degrees of freedom. The functions were specifically tailored for the orbital debris handling. These advances are discussed here. Also a small fraction of the resources were allocated towards research in flame augmentation in SCRAMJETS for the NASP. Here, the fundamental advance was the attainment of Mach numbers up to 0.6 in the flame zone and a vastly improved injection system; the current work is expected to achieve supersonic combustion in the laboratory and an advanced monitoring system.

  20. Handle-shaped Prominence

    NASA Image and Video Library

    2001-02-17

    NASA Extreme Ultraviolet Imaging Telescope aboard ESA’s SOHO spacecraft took this image of a huge, handle-shaped prominence in 1999. Prominences are huge clouds of relatively cool dense plasma suspended in the Sun hot, thin corona.

  1. Handling Pyrophoric Reagents

    SciTech Connect

    Alnajjar, Mikhail S.; Haynie, Todd O.

    2009-08-14

    Pyrophoric reagents are extremely hazardous. Special handling techniques are required to prevent contact with air and the resulting fire. This document provides several methods for working with pyrophoric reagents outside of an inert atmosphere.

  2. Variability in the terrestrial zone of an extreme debris disk

    NASA Astrophysics Data System (ADS)

    Moor, Attila; Cataldi, Gianni; Kospal, Agnes; Abraham, Peter; Vida, Krisztian; Szabo, Gyula

    2017-04-01

    The origin of the high fractional luminosity 'extreme debris disks', discovered by Spitzer as a new class, is thought to be related to recent giant collisions in the innermost 1-2 AU of the debris disk. Previous monitoring data revealed that the infrared emission is often variable, suggesting changes in the dust distribution on orbital timescales, but long continuous multi-epoch data sets are still missing. Our group recently discovered the most extreme debris disk so far around a young solar-analog star, and here we propose to scrutinize it with Spitzer. Sparse data from the NEOWISE mission shows that the disk is variable at 3.4 and 4.6 micrometer. The proposed long gap-free Spitzer monitoring at an ecliptic latitude of 87 deg will reveal brightening/fading timescales, which determine the minimum mass of the released dust, constrain the size of fragmented bodies, and point to probable dust formation mechanisms. The observations will provide the highest value dataset to detect and understand those huge collisions which probably occurred also in the early solar system, being responsible for the formation of the Moon.

  3. Charging of space debris in the LEO and GEO regions

    NASA Astrophysics Data System (ADS)

    Sen, Abhijit; Tiwari, Sanat Kumar

    The near exponential rise of space debris at the satellite orbital altitudes (particularly in the low earth orbit (LEO) region) and the risk they pose for space assets is a source of major concern for all nations engaged in space activities. Considerable efforts are therefore being expended into accurate modeling and tracking of these objects and various ideas for the safe removal of these debris are being explored. The debris objects are likely to acquire a large amount of charge since they are typically found in a plasma environment - such as the earth’s ionospheric plasma in the LEO region (100 kms to 1000 kms) and the radiation belts in the geosynchronous orbit (GEO) region. The consequent flow of electron and ion currents on them lead to the accumulation of a large amount of surface charge and the development of a surface potential on these objects. The influence of the plasma environment on the dynamics and charging of the debris is a relatively unexplored area of Space Situational Awareness (SSA) and Space Debris (SD) research and can be potentially important for the accurate prediction of the long-term evolution of debris orbits and their collision probabilities with other space objects. In this paper we will report on the charging of space debris under a variety of orbital conditions in the LEO and GEO regions using both analytic and particle-in-cell (PIC) modeling. The analytic estimates are obtained using refined Orbit Motion Limited (OML) modeling while the simulation studies are carried out using the SPIS code [1]. In the GEO region account is taken of charging due to photoemission processes as well as energetic beam charging. The PIC approach enables us to study charging of irregularly shaped debris objects as well as differential charging on objects that are composed of patches of conducting and insulated regions. The dynamical consequences of the debris charging on their orbital trajectories and rotational characteristics will be discussed. [1] J

  4. Helicopter Handling Qualities

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Helicopters are used by the military and civilian communities for a variety of tasks and must be capable of operating in poor weather conditions and at night. Accompanying extended helicopter operations is a significant increase in pilot workload and a need for better handling qualities. An overview of the status and problems in the development and specification of helicopter handling-qualities criteria is presented. Topics for future research efforts by government and industry are highlighted.

  5. 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.

  6. Young Debris Disks With Newly Discovered Emission Features

    NASA Astrophysics Data System (ADS)

    Ballering, N.

    2014-04-01

    We analyzed the Spitzer/IRS spectra of young A and F stars that host debris disks with previously unidentified silicate emission features. Such features probe small, warm dust grains in the inner regions of these young systems where terrestrial planet formation may be proceeding (Lisse et al. 2009). For most systems, these regions are too near their host star to be directly seen with high-contrast imaging and too warm to be imaged with submillimeter interferometers. Mid-infrared excess spectra - originating from the thermal emission of the debris disk dust - remain the best data to constrain the properties of the debris in these regions. For each target, we fit physically-motivated model spectra to the data. Typical spectra of unresolved debris disks are featureless and suffer severe degeneracies between the dust location and the grain properties; however, spectra with solid-state emission features provide significantly more information, allowing for a more accurate determination of the dust size, composition, and location (e.g. Chen et al. 2006; Olofsson et al. 2012). Our results shed light on the dynamic properties occurring in the terrestrial regions of these systems. For instance, the sizes of the smallest grains and the nature of the grain size distribution reveal whether the dust originates from steady-state collisional cascades or from stochastic collisions. The properties of the dust grains - such as their crystalline or amorphous structure - can inform us of grain processing mechanisms in the disk. The location of this debris illuminates where terrestrial planet forming activity is occurring. We used results from the Beta Pictoris - which has a well-resolved debris disk with emission features (Li et al. 2012) - to place our results in context. References: Chen et al. 2006, ApJS, 166, 351 Li et al. 2012, ApJ, 759, 81 Lisse et al. 2009, ApJ, 701, 2019 Olofsson et al. 2012, A&A, 542, A90

  7. Collisionless Coupling between Explosive Debris Plasma and Magnetized Ambient Plasma

    NASA Astrophysics Data System (ADS)

    Bondarenko, Anton

    2016-10-01

    The explosive expansion of a dense debris plasma cloud into relatively tenuous, magnetized, ambient plasma characterizes a wide variety of astrophysical and space phenomena, including supernova remnants, interplanetary coronal mass ejections, and ionospheric explosions. In these rarified environments, collective electromagnetic processes rather than Coulomb collisions typically mediate the transfer of momentum and energy from the debris plasma to the ambient plasma. In an effort to better understand the detailed physics of collisionless coupling mechanisms in a reproducible laboratory setting, the present research jointly utilizes the Large Plasma Device (LAPD) and the Phoenix laser facility at UCLA to study the super-Alfvénic, quasi-perpendicular expansion of laser-produced carbon (C) and hydrogen (H) debris plasma through preformed, magnetized helium (He) ambient plasma via a variety of diagnostics, including emission spectroscopy, wavelength-filtered imaging, and magnetic field induction probes. Large Doppler shifts detected in a He II ion spectral line directly indicate initial ambient ion acceleration transverse to both the debris plasma flow and the background magnetic field, indicative of a fundamental process known as Larmor coupling. Characterization of the laser-produced debris plasma via a radiation-hydrodynamics code permits an explicit calculation of the laminar electric field in the framework of a ``hybrid'' model (kinetic ions, charge-neutralizing massless fluid electrons), thus allowing for a simulation of the initial response of a distribution of He II test ions. A synthetic Doppler-shifted spectrum constructed from the simulated velocity distribution of the accelerated test ions excellently reproduces the spectroscopic measurements, confirming the role of Larmor coupling in the debris-ambient interaction.

  8. A Comparison of Catastrophic On-Orbit Collisions

    NASA Astrophysics Data System (ADS)

    Stansbery, G.; Matney, M.; Liou, J.; Whitlock, D.

    Orbital debris environment models, such as NASA's LEGEND model, show that accidental collisions between satellites will begin to be the dominant cause for future debris population growth within the foreseeable future. The collisional breakup models employed are obviously a critical component of the environment models. The Chinese Anti-Satellite (ASAT) test which destroyed the Fengyun-1C weather satellite provided a rare, but not unique, chance to compare the breakup models against an actual on-orbit collision. Measurements from the U.S. Space Surveillance Network (SSN), for debris larger than 10-cm, and from Haystack, for debris larger than 1-cm, show that the number of fragments created from Fengyun significantly exceeds model predictions using the NASA Standard Collision Breakup Model. However, it may not be appropriate to alter the model to match this one, individual case. At least three other on-orbit collisions have occurred which have produced significant numbers of debris fragments. In September 1985, the U.S. conducted an ASAT test against the Solwind P-78 spacecraft at an altitude of approximately 525 km. A year later, in September 1986, the Delta 180 payload was struck by its Delta II rocket body in a planned collision at 220 km altitude. And, in February 2008, the USA-193 satellite was destroyed by a ship launched missile in order to eliminate risk to humans on the ground from an on-board tank of frozen hydrazine. Although no Haystack data was available in 1985-6 and very few debris pieces were cataloged from Delta 180 due to its low altitude, measurements were collected sensors in the days after each test. This paper will examine the available data from each test and compare and contrast the results with model predictions and with the results from the more recent Fengyun ASAT test.

  9. Signatures of planets in circumstellar debris disks

    NASA Astrophysics Data System (ADS)

    Moro-Martin, Maria Amaya

    2004-12-01

    Main sequence stars are commonly surrounded by debris disks, composed of cold dust continuously replenished by a reservoir of undetected dust-producing planetesimals. In the outer Solar System, Kuiper Belt (KB) objects produce dust by mutual or interstellar grain collisions. The orbital evolution of KB dust has been numerically modeled. Its equilibrium radial density distribution can be accurately estimated even though there are inherent uncertainties in the prediction of structure, owing to the chaotic dynamics of dust orbital evolution imposed by resonant gravitational perturbations of the planets. The particle size distribution of dust is greatly changed from the distribution at production, as a result of radiation forces and the perturbations of the planets. The contribution of KB dust to the population of interplanetary dust particles collected at Earth may be as low as a few percent. Gravitational scattering by giant planets creates an outflow of large grains. We quantify the characteristics of this large-particle outflow in different planetary architectures, discuss its implications for exo-planetary debris disks, and for the interpretation of in-situ dust detection experiments in space probes traveling in the outer Solar System. These outflows may contribute to the clearing of circumstellar debris in planetary systems, affecting the particle size distribution of their local ISM. In anticipation of future observations of unresolved debris disks with Spitzer , we are interested in studying how the structure carved by planets affects the shape of the disk's spectral energy distribution (SED), and consequently if the SED can be used to infer the presence of planets. We numerically calculate the equilibrium spatial density distributions and SEDs of dust disks originated by an outer belt of planetesimals (35-50 AU) in the presence of different planetary configurations, and for a representative sample of chemical compositions. The dynamical models are needed to

  10. Implementation of the hazardous debris rule

    SciTech Connect

    Sailer, J.E.

    1993-01-05

    Hazardous debris includes objects contaminated with hazardous waste. Examples of debris include tree stumps, timbers, boulders, tanks, piping, crushed drums, personal protective clothing, etc. Most of the hazardous debris encountered comes from Superfund sites and other facility remediation, although generators and treaters of hazardous waste also generate hazardous debris. Major problems associated with disposal of debris includes: Inappropriateness of many waste treatments to debris; Difficulties in obtaining representative samples; Costs associated with applying waste specific treatments to debris; Subtitle C landfill space was being used for many low hazard debris types. These factors brought about the need for debris treatment technologies and regulations that addressed these issues. The goal of such regulation was to provide treatment to destroy or remove the contamination if possible and, if this is achieved, to dispose of the cleaned debris as a nonhazardous waste. EPA has accomplished this goal through promulgation of the Hazardous Debris Rule, August 18, 1992.

  11. Brute Force Modeling of the Orbital Debris Evolution

    NASA Astrophysics Data System (ADS)

    Nikolaev, S.; Phillion, D.; Horsley, M.; Johnson, N.

    2012-09-01

    The Kessler Syndrome (runaway increase in the number of orbiting debris fragments through cascading collisions) presents a serious danger to future space missions. To understand its implications and study the effectiveness of various proposed debris mitigation strategies, long-term evolutionary models for near-Earth space environment (e.g. NASA's LEGEND, ESA's MASTER-2009) are used. Because of the long timescales involved, existing models represent the orbiting population by some average spatial density functions, resulting in a limited spatial and temporal resolution of such models. Here, we present the brute force approach to evolutionary debris modeling, by propagating and monitoring every object in orbit for the length of the simulation (100+ years). The approach involved designing a custom, efficient orbital propagator, coupled with a fast conjunction analysis module. The resulting highly parallel simulation code was run on LLNL's supercomputers, due to the extremely demanding computing power requirements. Here we present some of the results of these high-fidelity simulations. This approach allows unprecedented, high-resolution view of the evolution of orbiting populations, and establishes new state of the art in evolutionary debris modeling.

  12. Carbon Monoxide Emissions in Middle Aged Debris Disks

    NASA Astrophysics Data System (ADS)

    Henderson, Morgan; Gorti, Uma; Hales, Antonio; Carpenter, John M.; Hughes, A. Meredith

    2017-01-01

    Circumstellar disks greater than 10 Myr old, referred to as debris disks, are expected to be gas poor. The original gas and dust in these disks is thought to be accreted onto the host stars, used up in the formation of planets and other bodies, or blown out of the disks via stellar radiation. However, recent ALMA observations at millimeter wavelengths have led to the detection of carbon monoxide (J=2-1) emission in a few debris disks, prompting further investigation.Using ALMA data, two separate models of gas genesis were tested against observations of the CO emissions in the disks around HIP 73145, HIP 76310, and HIP 84881 in the Upper Sco association. One of these models was built on the hypothesis that the gas in these debris disks is left over from stellar formation and has persisted over uncommonly long periods of time. The other model is built on the hypothesis that this gas is of secondary nature, produced by collisions between planetary bodies in the debris disks. Model emissions were calculated using the Line Modeling Engine (LIME) radiative transfer code and were compared with observational data to infer gas masses under both production scenarios. The implications of the masses of carbon monoxide in the disks suggested by each of the two models are discussed.

  13. Detection Of Exocomets Within Edge-on Debris Disks

    NASA Astrophysics Data System (ADS)

    Montgomery, Sharon Lynn; Welsh, B.

    2011-01-01

    The youngest circumstellar debris disks in orbit around main sequence stars are thought to represent the last stage in the formation of a planetary system. Dust and gas continues to be replenished in these systems when planetesimals reach sizes of around 2000 km. Dynamical instabilities can "stir" the population of smaller planetesimals such that they undergo violent dust-generating collisions with each other. The same instabilities may send comets on highly eccentric orbits toward the star in these debris disk systems. Four stars, including the protypical debris disk star Beta Pic, have already been shown to exhibit short-term (i.e., night-to-night) variability in Ca II, which is widely believed to be due to infalling evaporating bodies (FEBs or exocomets). We have collected moderately high-resolution spectra of ten young, A-type, rapidly-rotating stars with excess infrared continuum emission using the Cassegrain-Echelle spectrograph of the 2.1m Otto Struve Telescope. Here, we report the detection of two new gas disk systems with short-term variability in CaII: 5 Vul and 49 Cet. While the circumstellar disks of both stars have been previously described in the literature, this is the first report of night-to-night variability within the debris disk gas. Velocity arguments have allowed us to place some constraints on the dynamics of the absorbing gas.

  14. Comprehensive Census and Complete Characterization of Nearby Debris Disk Stars

    NASA Astrophysics Data System (ADS)

    Cotten, Tara H.; Song, Inseok

    2016-01-01

    Debris disks are intimately linked to planetary system evolution since the rocky material surrounding the host stars is believed to be due to secondary generation from the collisions of planetesimals. With the conclusion and lack of future large scale infrared excess survey missions, it is time to summarize the history of using excess emission in the infrared as a tracer of debris and exploit all available data as well as provide a comprehensive study of the parameters of these important objects. We have compiled a catalog of infrared excess stars from peer-reviewed articles and performed an extensive search for new debris disks by cross-correlating the Tycho-2 and AllWISE catalogs. This study will conclude following the thorough examination of each debris disk star's parameters obtained through high-resolution spectroscopy at various facilities which is currently ongoing. We will maintain a webpage (www.debrisdisks.org) devoted to these infrared excess sources and provide various resources related to our catalog creation, SED fitting, and data reduction.

  15. Methodology of design and analysis of external walls of space station for hypervelocity impacts by meteoroids and space debris

    NASA Technical Reports Server (NTRS)

    Batla, F. A.

    1986-01-01

    The development of criteria and methodology for the design and analysis of Space Station wall elements for collisions with meteoroids and space debris at hypervelocities is discussed. These collisions will occur at velocities of 10 km/s or more and can be damaging to the external wall elements of the Space Station. The wall elements need to be designed to protect the pressurized modules of the Space Station from functional or structural failure due to these collisions at hypervelocities for a given environment and population of meteoroids and space debris. The design and analysis approach and the associated computer program presented is to achieve this objective, including the optimization of the design for a required overall probability of no penetration. The approach is based on the presently available experimental and actual data on meteoroids and space debris flux and damage assessments and the empirical relationships resulting from the hypervelocity impact studies in laboratories.

  16. GAP CLEARING BY PLANETS IN A COLLISIONAL DEBRIS DISK

    SciTech Connect

    Nesvold, Erika R.; Kuchner, Marc J. E-mail: Marc.Kuchner@nasa.gov

    2015-01-10

    We apply our 3D debris disk model, SMACK, to simulate a planet on a circular orbit near a ring of planetesimals that are experiencing destructive collisions. Previous simulations of a planet opening a gap in a collisionless debris disk have found that the width of the gap scales as the planet mass to the 2/7th power (α = 2/7). We find that gap sizes in a collisional disk still obey a power law scaling with planet mass, but that the index α of the power law depends on the age of the system t relative to the collisional timescale t {sub coll} of the disk by α = 0.32(t/t {sub coll}){sup –0.04}, with inferred planet masses up to five times smaller than those predicted by the classical gap law. The increased gap sizes likely stem from the interaction between collisions and the mean motion resonances near the chaotic zone. We investigate the effects of the initial eccentricity distribution of the disk particles and find a negligible effect on the gap size at Jovian planet masses, since collisions tend to erase memory of the initial particle eccentricity distributions. Finally, we find that the presence of Trojan analogs is a potentially powerful diagnostic of planets in the mass range ∼1-10 M {sub Jup}. We apply our model to place new upper limits on planets around Fomalhaut, HR 4796 A, HD 202628, HD 181327, and β Pictoris.

  17. Observing orbital debris using space-based telescopes. I - Mission orbit considerations

    NASA Technical Reports Server (NTRS)

    Reynolds, Robert C.; Talent, David L.; Vilas, Faith

    1989-01-01

    In this paper, mission orbit considerations are addressed for using the Space Shuttle as a telescope platform for observing man-made orbital debris. Computer modeling of various electrooptical systems predicts that such a space-borne system will be able to detect particles as small as 1-mm diameter. The research is meant to support the development of debris- collision warning sensors through the acquisition of spatial distribution and spectral characteristics for debris and testing of detector combinations on a shuttle-borne telescopic experiment. The technique can also be applied to low-earth-orbit-debris environment monitoring systems. It is shown how the choice of mission orbit, season of launch, and time of day of launch may be employed to provide extended periods of favorable observing conditions.

  18. A computational model for assessing high-velocity debris impact in space applications

    NASA Astrophysics Data System (ADS)

    Bergh, M.; Garcia, V.

    2017-07-01

    Man-made space debris is dominating the background meteorite environment with a growing debris population leading to increased collision risks for satellites, especially in the low Earth orbit and geostationary orbit protected environments. Here we present a computational model for estimating the effect of hypervelocity impact from debris particles on non-shielded propellant and pressurant tanks. Eulerian hydrocode simulation is utilised to model firstly penetration and shock wave formation in the propellant and secondly subsequent detonation wave propagation and interaction with the tank wall. Furthermore, reactive molecular dynamics is used to estimate the risk of detonation in a liquid hydrazine layer. We present simulations of a 3.5 mm aluminium spherical debris particle at a velocity of 14 km/s relative to a hydrazine tank. We find that the degree of damage is strongly dependent on tank temperature and hence on the satellite thermal configuration at its end of life.

  19. A computational model for assessing high-velocity debris impact in space applications

    NASA Astrophysics Data System (ADS)

    Bergh, M.; Garcia, V.

    2017-01-01

    Man-made space debris is dominating the background meteorite environment with a growing debris population leading to increased collision risks for satellites, especially in the low Earth orbit and geostationary orbit protected environments. Here we present a computational model for estimating the effect of hypervelocity impact from debris particles on non-shielded propellant and pressurant tanks. Eulerian hydrocode simulation is utilised to model firstly penetration and shock wave formation in the propellant and secondly subsequent detonation wave propagation and interaction with the tank wall. Furthermore, reactive molecular dynamics is used to estimate the risk of detonation in a liquid hydrazine layer. We present simulations of a 3.5 mm aluminium spherical debris particle at a velocity of 14 km/s relative to a hydrazine tank. We find that the degree of damage is strongly dependent on tank temperature and hence on the satellite thermal configuration at its end of life.

  20. LIDT-DD: A new self-consistent debris disc model that includes radiation pressure and couples dynamical and collisional evolution

    NASA Astrophysics Data System (ADS)

    Kral, Q.; Thébault, P.; Charnoz, S.

    2013-10-01

    Context. In most current debris disc models, the dynamical and the collisional evolutions are studied separately with N-body and statistical codes, respectively, because of stringent computational constraints. In particular, incorporating collisional effects (especially destructive collisions) into an N-body scheme has proven a very arduous task because of the exponential increase of particles it would imply. Aims: We present here LIDT-DD, the first code able to mix both approaches in a fully self-consistent way. Our aim is for it to be generic enough to be applied to any astrophysical case where we expect dynamics and collisions to be deeply interlocked with one another: planets in discs, violent massive breakups, destabilized planetesimal belts, bright exozodiacal discs, etc. Methods: The code takes its basic architecture from the LIDT3D algorithm for protoplanetary discs, but has been strongly modified and updated to handle the very constraining specificities of debris disc physics: high-velocity fragmenting collisions, radiation-pressure affected orbits, absence of gas that never relaxes initial conditions, etc. It has a 3D Lagrangian-Eulerian structure, where grains of a given size at a given location in a disc are grouped into super-particles or tracers whose orbits are evolved with an N-body code and whose mutual collisions are individually tracked and treated using a particle-in-a-box prescription designed to handle fragmenting impacts. To cope with the wide range of possible dynamics for same-sized particles at any given location in the disc, and in order not to lose important dynamical information, tracers are sorted and regrouped into dynamical families depending on their orbits. A complex reassignment routine that searches for redundant tracers in each family and reassignes them where they are needed, prevents the number of tracers from diverging. Results: The LIDT-DD code has been successfully tested on simplified cases for which robust results have

  1. Is the Sky Really Falling? An Overview of Orbital Debris

    NASA Technical Reports Server (NTRS)

    Hull, Scott M.

    2015-01-01

    Orbital debris has been a prominent topic for a while, even before the movie Gravity came out. An anti-satellite test and a collision with an operational satellite both produced large highly-publicized debris clouds within recent years. While large objects like abandoned satellites and rocket bodies may be the most recognizable and identifiable concerns, a majority of the daily threat comes from the much more numerous smaller particles. In fact, small particle penetration continues to rank among the leading risks for manned space missions to the International Space Station and beyond. How much 'stuff' is up there, where did it come from, what harm can it do, and what is being done about it? These questions and more will be discussed.

  2. Laser-reactive protection of spacecraft from fine debris

    SciTech Connect

    Kuznetsov, L I; Savichev, V Yu; Tikhonov, N N

    1998-04-30

    An analysis is made of the optimal conditions for laser irradiation and of typical paths of man-made debris in laser-reactive protection of spacecraft. Protection is provided by the recoil momentum resulting from laser evaporation of the surface layers of a debris particle, which can change its path, thus avoiding an collision with a spacecraft. Estimates are obtained of changes in the paths of particles with a characteristic size 1 cm when they are irradiated by radiation from a laser located on the protected spacecraft moving along one of the circular orbits at altitudes of 200, 400, or 700 km above the Earth's surface. (laser applications and other topics in quantum electronics)

  3. Conjunction challenges of low-thrust geosynchronous debris removal maneuvers

    NASA Astrophysics Data System (ADS)

    Anderson, Paul V.; Schaub, Hanspeter

    2016-06-01

    The conjunction challenges of low-thrust engines for continuous thrust re-orbiting of geosynchronous (GEO) objects to super-synchronous disposal orbits are investigated, with applications to end-of-life mitigation and active debris removal (ADR) technologies. In particular, the low maneuverability of low-thrust systems renders collision avoidance a challenging task. This study investigates the number of conjunction events a low-thrust system could encounter with the current GEO debris population during a typical re-orbit to 300 km above the GEO ring. Sensitivities to thrust level and initial longitude and inclination are evaluated, and the impact of delaying the start time for a re-orbiting maneuver is assessed. Results demonstrate that the mean number of conjunctions increases hyperbolically as thrust level decreases, but timing the start of the maneuver appropriately can reduce the average conjunction rate when lower thrust levels are applied.

  4. Herschel DEBRIS survey of debris discs around A stars

    NASA Astrophysics Data System (ADS)

    Thureau, N.

    2014-11-01

    The Herschel DEBRIS survey (Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre) brings a unique perspective to the study of debris discs around main-sequence A-type stars. We have observed a sample of 89 A-stars with the Photodetector Array Camera and Spectrometer (PACS) on the Herschel space telescope at 100 and 160 μm. A statistical analysis of the data shows a lower debris disc rate than has previously been found. The drop is due in part to the fact that some excess sources were resolved as background objects by the superior angular resolution (a factor of 2.5) of PACS-100 relative to that of Spitzer (MIPS-70). We found a 3-σ detection rate of 23 myblue which is similar to the the detection rate around main-sequence F, G and K stars. Most of the debris discs were detected around the youngest and hottest stars in our sample. The incidence of discs in single and multiple systems was similar. The debris discs in multiple systems ware found either in tight binary systems (<1 AU) or wide ones (>100 AU). Debris discs in both tight and wide binary systems have physical properties that are statistically similar to those of discs around single stars. We did not detect any debris discs in binary systems with intermediate separation, in which the orbit and the debris disc would be on the same scale. One possible explanation is that discs in intermediate systems have evolved much faster owing to the disc-companion interactions and they are now undetectable.

  5. DebriSat - A Planned Laboratory-Based Satellite Impact Experiment for Breakup Fragment Characterization

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.; Fitz-Coy, N.; Werremeyer, M.; Huynh, T.; Voelker, M.; Opiela, J.

    2012-01-01

    DebriSat is a planned laboratory ]based satellite hypervelocity impact experiment. The goal of the project is to characterize the orbital debris that would be generated by a hypervelocity collision involving a modern satellite in low Earth orbit (LEO). The DebriSat project will update and expand upon the information obtained in the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT), which characterized the breakup of a 1960 's US Navy Transit satellite. There are three phases to this project: the design and fabrication of an engineering model representing a modern, 50-cm/50-kg class LEO satellite known as DebriSat; conduction of a laboratory-based hypervelocity impact to catastrophically break up the satellite; and characterization of the properties of breakup fragments down to 2 mm in size. The data obtained, including fragment size, area ]to ]mass ratio, density, shape, material composition, optical properties, and radar cross ]section distributions, will be used to supplement the DoD fs and NASA fs satellite breakup models to better describe the breakup outcome of a modern satellite. Updated breakup models will improve mission planning, environmental models, and event response. The DebriSat project is sponsored by the Air Force fs Space and Missile Systems Center and the NASA Orbital Debris Program Office. The design and fabrication of DebriSat is led by University of Florida with subject matter experts f support from The Aerospace Corporation. The major milestones of the project include the complete fabrication of DebriSat by September 2013, the hypervelocity impact of DebriSat at the Air Force fs Arnold Engineering Development Complex in early 2014, and fragment characterization and data analyses in late 2014.

  6. ElectroDynamic Debris Eliminator (EDDE): Design, Operation, and Ground Support

    NASA Astrophysics Data System (ADS)

    Pearson, J.; Levin, E.; Oldson, J.; Carroll, J.

    2010-09-01

    The ElectroDynamic Debris Eliminator (EDDE) is a low-cost solution for LEO space debris removal. EDDE can affordably remove nearly all the 2,465 objects of more than 2 kg that are now in 500-2000 km orbits. That is more than 99% of the total mass, collision area, and debris-generation potential in LEO. EDDE is a propellantless vehicle that reacts against the Earth's magnetic field. EDDE can climb about 200 km/day and change orbit plane at 1.5°/day, even in polar orbit. No other electric vehicle can match these rates, much less sustain them for years. After catching and releasing one object, EDDE can climb and change its orbit to reach another object within days, while actively avoiding other catalog objects. Binocular imaging allows accurate relative orbit determination from a distance. Capture uses lightweight expendable nets and real-time man-in-the-loop control. After capture, EDDE drags the debris down and releases it and the net into a short-lived orbit safely below ISS, or takes it to a recycling facility for reuse. EDDE can also sling debris into controlled reentry, or can include an adjustable drag device with the net before release, to allow later adjustment of payload reentry location. A dozen 100-kg EDDE vehicles could remove nearly all 2166 tons of LEO orbital debris in 7 years. The estimated cost per kilogram of debris removed is on the order of a few percent of typical launch costs per kilogram. This supports shifting the focus on debris from simply maintaining the status quo by limiting the introduction of new debris to active, wholesale removal of all large debris objects in LEO with EDDE.

  7. 44 CFR 206.224 - Debris removal.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Debris removal. 206.224... Debris removal. (a) Public interest. Upon determination that debris removal is in the public interest, the Regional Administrator may provide assistance for the removal of debris and wreckage from publicly...

  8. 44 CFR 206.224 - Debris removal.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Debris removal. 206.224... Debris removal. (a) Public interest. Upon determination that debris removal is in the public interest, the Regional Administrator may provide assistance for the removal of debris and wreckage from publicly...

  9. 44 CFR 206.224 - Debris removal.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Debris removal. 206.224... Debris removal. (a) Public interest. Upon determination that debris removal is in the public interest, the Regional Administrator may provide assistance for the removal of debris and wreckage from publicly...

  10. 44 CFR 206.224 - Debris removal.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Debris removal. 206.224... Debris removal. (a) Public interest. Upon determination that debris removal is in the public interest, the Regional Administrator may provide assistance for the removal of debris and wreckage from publicly...

  11. SPAR data handling utilities

    NASA Technical Reports Server (NTRS)

    Giles, G. L.; Haftka, R. T.

    1978-01-01

    The SPAR computer software system is a collection of processors that perform particular steps in the finite-element structural analysis procedure. The data generated by each processor are stored on a data base complex residing on an auxiliary storage device, and these data are then used by subsequent processors. The SPAR data handling utilities use routines to transfer data between the processors and the data base complex. A detailed description of the data base complex organization is presented. A discussion of how these SPAR data handling utilities are used in an application program to perform desired user functions is given with the steps necessary to convert an existing program to a SPAR processor by incorporating these utilities. Finally, a sample SPAR processor is included to illustrate the use of the data handling utilities.

  12. The New NASA Orbital Debris Engineering Model ORDEM 3.0

    NASA Technical Reports Server (NTRS)

    Krisko, P. H.

    2014-01-01

    The NASA Orbital Debris Program Office (ODPO) has released its latest Orbital Debris Engineering Model, ORDEM 3.0. It supersedes ORDEM 2.0. This newer model encompasses the Earth satellite and debris flux environment from altitudes of low Earth orbit (LEO) through geosynchronous orbit (GEO). Debris sizes of 10 microns through 1 m in non-GEO and 10 cm through 1 m in GEO are modeled. The inclusive years are 2010 through 2035. The ORDEM model series has always been data driven. ORDEM 3.0 has the benefit of many more hours from existing data sources and from new sources that weren't available to past versions. Returned surfaces, ground tests, and remote sensors all contribute data. The returned surface and ground test data reveal material characteristics of small particles. Densities of fragmentation debris particles smaller than 10 cm are grouped in ORDEM 3.0 in terms of high-, medium-, and lowdensities, along with RORSAT sodium-potassium droplets. Supporting models have advanced significantly. The LEO-to-GEO ENvironment Debris model (LEGEND) includes an historical and a future projection component with yearly populations that include launched and maneuvered intacts, mission related debris (MRD), and explosion and collision fragments. LEGEND propagates objects with ephemerides and physical characteristics down to 1 mm in size. The full LEGEND yearly population acts as an a priori condition for a Bayesian statistical model. Specific, well defined populations are added like the Radar Ocean Reconnaissance Satellite (RORSAT) sodium-potassium (NaK) droplets, recent major accidental and deliberate collision fragments, and known anomalous debris event fragments. For microdebris of sizes 10 microns to 1 mm the ODPO uses an in-house Degradation/Ejecta model in which a MLE technique is used with returned surface data to estimate populations. This paper elaborates on the upgrades of this model over previous versions highlighting the material density splits and consequences of

  13. System engineering analysis of derelict collision prevention options

    NASA Astrophysics Data System (ADS)

    McKnight, Darren S.; Di Pentino, Frank; Kaczmarek, Adam; Dingman, Patrick

    2013-08-01

    Sensitivities to the future growth of orbital debris and the resulting hazard to operational satellites due to collisional breakups of large derelict objects are being studied extensively. However, little work has been done to quantify the technical and operational tradeoffs between options for minimizing future derelict fragmentations that act as the primary source for future debris hazard growth. The two general categories of debris mitigation examined for prevention of collisions involving large derelict objects (rocket bodies and payloads) are active debris removal (ADR) and just-in-time collision avoidance (JCA). Timing, cost, and effectiveness are compared for ADR and JCA solutions highlighting the required enhancements in uncooperative element set accuracy, rapid ballistic launch, despin/grappling systems, removal technologies, and remote impulsive devices. The primary metrics are (1) the number of derelict objects moved/removed per the number of catastrophic collisions prevented and (2) cost per collision event prevented. A response strategy that contains five different activities, including selective JCA and ADR, is proposed as the best approach going forward.

  14. Active Debris Removal System Based on Polyurethane Foam

    NASA Astrophysics Data System (ADS)

    Rizzitelli, Federico; Valdatta, Marcelo; Bellini, Niccolo; Candini Gian, Paolo; Rastelli, Davide; Romei, Fedrico; Locarini, Alfredo; Spadanuda, Antonio; Bagassi, Sara

    2013-08-01

    Space debris is an increasing problem. The exponential increase of satellite launches in the last 50 years has determined the problem of space debris especially in LEO. The remains of past missions are dangerous for both operative satellites and human activity in space. But not only: it has been shown that uncontrolled impacts between space objects can lead to a potentially dangerous situation for civil people on Earth. It is possible to reach a situation of instability where the big amount of debris could cause a cascade of collisions, the so called Kessler syndrome, resulting in the infeasibility of new space missions for many generations. Currently new technologies for the mitigation of space debris are under study: for what concerning the removal of debris the use of laser to give a little impulse to the object and push it in a graveyard orbit or to be destroyed in the atmosphere. Another solution is the use of a satellite to rendezvous with the space junk and then use a net to capture it and destroy it in the reentry phase. In a parallel way the research is addressed to the study of deorbiting solutions to prevent the formation of new space junk. The project presented in this paper faces the problem of how to deorbit an existing debris, applying the studies about the use of polyurethane foam developed by Space Robotic Group of University of Bologna. The research is started with the Redemption experiment part of last ESA Rexus program. The foam is composed by two liquid components that, once properly mixed, trig an expansive reaction leading to an increase of volume whose entity depends on the chemical composition of the two starting components. It is possible to perform two kind of mission: 1) Not controlled removal: the two components are designed to react producing a low density, high expanded, spongy foam that incorporates the debris. The A/m ratio of the debris is increased and in this way also the ballistic parameter. As a consequence, the effect of

  15. Effects of basal debris on glacier flow.

    PubMed

    Iverson, Neal R; Cohen, Denis; Hooyer, Thomas S; Fischer, Urs H; Jackson, Miriam; Moore, Peter L; Lappegard, Gaute; Kohler, Jack

    2003-07-04

    Glacier movement is resisted partially by debris, either within glaciers or under glaciers in water-saturated layers. In experiments beneath a thick, sliding glacier, ice containing 2 to 11% debris exerted shear traction of 60 to 200 kilopascals on a smooth rock bed, comparable to the total shear traction beneath glaciers and contrary to the usual assumption that debris-bed friction is negligible. Imposed pore-water pressure that was 60 to 100% of the normal stress in a subglacial debris layer reduced shear traction on the debris sufficiently to halt its deformation and cause slip of ice over the debris. Slip resistance was thus less than debris shearing resistance.

  16. Safe Handling Practices

    NASA Technical Reports Server (NTRS)

    1980-01-01

    In 1977 Compugraphic Corporation was experiencing an unacceptable failure rate on microelectronic chips. Company engineers suspected that static electricity was causing the trouble because some electronic components are highly susceptible to damage by electrostatic charge. From a NASA Tech Brief, they learned that Rockwell International had prepared a report on safe handling practices for electronic components. NASA provided a Technical Support Package detailing 50 safe handling procedures affecting workers, work areas, equipment and packaging materials. Where poor practices were discovered, re-education of employees and other corrective measures were undertaken.

  17. FUEL HANDLING MECHANISM

    DOEpatents

    Koch, L.J.; Hutter, E.

    1960-02-01

    A remotely operable handling device specifically adapted for the handling of vertically disposed fuel rods in a nuclear reactor was developed. The device consists essentially of an elongated tubular member having a gripping device at the lower end of the pivoted jaw type adapted to grip an enlarged head on the upper end of the workpiece. The device includes a sensing element which engages the enlarged head and is displaced to remotely indicate when the workpiece is in the proper position to be engaged by the jaws.

  18. SLUG HANDLING DEVICES

    DOEpatents

    Gentry, J.R.

    1958-09-16

    A device is described for handling fuel elements of a neutronic reactor. The device consists of two concentric telescoped contalners that may fit about the fuel element. A number of ratchet members, equally spaced about the entrance to the containers, are pivoted on the inner container and spring biased to the outer container so thnt they are forced to hear against and hold the fuel element, the weight of which tends to force the ratchets tighter against the fuel element. The ratchets are released from their hold by raising the inner container relative to the outer memeber. This device reduces the radiation hazard to the personnel handling the fuel elements.

  19. A laser-optical system to re-enter or lower low Earth orbit space debris

    NASA Astrophysics Data System (ADS)

    Phipps, Claude R.

    2014-01-01

    Collisions among existing Low Earth Orbit (LEO) debris are now a main source of new debris, threatening future use of LEO space. Due to their greater number, small (1-10 cm) debris are the main threat, while large (>10 cm) objects are the main source of new debris. Flying up and interacting with each large object is inefficient due to the energy cost of orbit plane changes, and quite expensive per object removed. Strategically, it is imperative to remove both small and large debris. Laser-Orbital-Debris-Removal (LODR), is the only solution that can address both large and small debris. In this paper, we briefly review ground-based LODR, and discuss how a polar location can dramatically increase its effectiveness for the important class of sun-synchronous orbit (SSO) objects. With 20% clear weather, a laser-optical system at either pole could lower the 8-ton ENVISAT by 40 km in about 8 weeks, reducing the hazard it represents by a factor of four. We also discuss the advantages and disadvantages of a space-based LODR system. We estimate cost per object removed for these systems. International cooperation is essential for designing, building and operating any such system.

  20. NASA Orbital Debris Large-Object Baseline Population in ORDEM 3.0

    NASA Technical Reports Server (NTRS)

    Krisco, Paula H.; Vavrin, A. B.; Anz-Meador, P. D.

    2013-01-01

    The NASA Orbital Debris Program Office (ODPO) has created and validated high fidelity populations of the debris environment for the latest Orbital Debris Engineering Model (ORDEM 3.0). Though the model includes fluxes of objects 10 um and larger, this paper considers particle fluxes for 1 cm and larger debris objects from low Earth orbit (LEO) through Geosynchronous Transfer Orbit (GTO). These are validated by several reliable radar observations through the Space Surveillance Network (SSN), Haystack, and HAX radars. ORDEM 3.0 populations were designed for the purpose of assisting, debris researchers and sensor developers in planning and testing. This environment includes a background derived from the LEO-to-GEO ENvironment Debris evolutionary model (LEGEND) with a Bayesian rescaling as well as specific events such as the FY-1C anti-satellite test, the Iridium 33/Cosmos 2251 accidental collision, and the Soviet/Russian Radar Ocean Reconnaissance Satellite (RORSAT) sodium-potassium droplet releases. The environment described in this paper is the most realistic orbital debris population larger than 1 cm, to date. We describe derivations of the background population and added specific populations. We present sample validation charts of our 1 cm and larger LEO population against Space Surveillance Network (SSN), Haystack, and HAX radar measurements.

  1. Galaxy collisions.

    NASA Astrophysics Data System (ADS)

    Struck, C.

    Theories of how galaxies, the fundamental constituents of large-scale structure, form and evolve have undergone a dramatic paradigm shift in the last few decades. Earlier views were of rapid, early collapse and formation of basic structures, followed by slow evolution of the stellar populations and steady buildup of the chemical elements. Current theories emphasize hierarchical buildup via recurrent collisions and mergers, separated by long periods of relaxation and secular restructuring. Thus, collisions between galaxies are now seen as a primary process in their evolution. This article begins with a brief history of how this once peripheral subject found its way to center stage. The author then tours parts of the vast array of collisional forms that have been discovered to date. Many examples are provided to illustrate how detailed numerical models and multiwaveband observations have allowed the general chronological sequence of collisional morphologies to be deciphered, and how these forms are produced by the processes of tidal kinematics, hypersonic gas dynamics, collective dynamical friction and violent relaxation. Galaxy collisions may trigger the formation of a large fraction of all the stars ever formed, and play a key role in fueling active galactic nuclei. Current understanding of the processes involved is reviewed. The last decade has seen exciting new discoveries about how collisions are orchestrated by their environment, how collisional processes depend on environment, and how these environments depend on redshift or cosmological time. These discoveries and prospects for the future are summarized in the final sections.

  2. Imaging Debris Disks with CCAT

    NASA Astrophysics Data System (ADS)

    Carpenter, John M.; Bryden, G.; Matthews, B. C.; Isella, A.; Ricci, L.; Swift, J.

    2013-01-01

    Debris disks are sustained by the collisional grinding of planetesimals down to micron-sized particles. The mechanisms by which the planetesimals are perturbed include stirring by planetary mass bodies, which interact gravitationally to sculpt the disk by scattering dust particles out of the disk, and capturing dust in mean motion resonances as particles drift inwards from Poynting-Robertson drag or as planets migrate. Thus the location of the debris dust can trace where planetesimals have formed, as well as the dynamical history of the disk. With high angular resolution and high sensitivity at submillimeter wavelengths, CCAT will be a powerful telescope to discover and image the structure of debris disks around nearby stars. This poster will describe various surveys that CCAT will conduct to search for new debris disks.

  3. Lightweight Shield Against Space Debris

    NASA Technical Reports Server (NTRS)

    Redmon, John W., Jr.; Lawson, Bobby E.; Miller, Andre E.; Cobb, W. E.

    1992-01-01

    Report presents concept for lightweight, deployable shield protecting orbiting spacecraft against meteoroids and debris, and functions as barrier to conductive and radiative losses of heat. Shield made in four segments providing 360 degree coverage of cylindrical space-station module.

  4. Lightweight Shield Against Space Debris

    NASA Technical Reports Server (NTRS)

    Redmon, John W., Jr.; Lawson, Bobby E.; Miller, Andre E.; Cobb, W. E.

    1992-01-01

    Report presents concept for lightweight, deployable shield protecting orbiting spacecraft against meteoroids and debris, and functions as barrier to conductive and radiative losses of heat. Shield made in four segments providing 360 degree coverage of cylindrical space-station module.

  5. Hydraulic System Wear Debris Analysis.

    DTIC Science & Technology

    1982-08-03

    drawn. Each one-=L sample was drawn with a clean plastic pipette of one-mL capacity. The samples were placed in clean Ferrogram preparation bottles ...and from cavities in a block which held linear seals into sampling bottles . Several photographs of this debris , which was deposited on Ferro- grams...silicon in the glass overshadowed the elements of the wear debris . To overcome this difficulty, the Ferrogram should be pre- pared on a carbon-filled

  6. DebriSat Laboratory Analyses

    DTIC Science & Technology

    2015-01-05

    thomas.huynh@us.af.mil Jesse Edwards SMC/ENC jesse.edwards.4@us.af.mil J.-C. Liou NASA-JSC jer -chyi.l iou-1 @nasa.gov John Opiela NASA-JSC...DebriSat Team Members: J.-C. Liou : NASA Space Debris Program Office, NASA JSC AEDC Range G Light Gas Gun Staff Charles Griffice: Aerospace Marlon

  7. Backwater development by woody debris

    NASA Astrophysics Data System (ADS)

    Geertsema, Tjitske; Torfs, Paul; Teuling, Ryan; Hoitink, Ton

    2017-04-01

    Placement of woody debris is a common method for increasing ecological values in river and stream restoration, and is thus widely used in natural environments. Water managers, however, are afraid to introduce wood in channels draining agricultural and urban areas. Upstream, it may create backwater, depending on hydrodynamic characteristics including the obstruction ratio, the Froude number and the surface level gradient. Patches of wood may trigger or counter morphological activity, both laterally, through bank erosion and protection, and vertically, with pool and riffle formation. Also, a permeable construction composed of wood will weather over time. Both morphodynamic activity and weathering cause backwater effects to change in time. The purpose of this study is to quantify the time development of backwater effects caused by woody debris. Hourly water levels gauged upstream and downstream of patches and discharge are collected for five streams in the Netherlands. The water level drop over the woody debris patch relates to discharge in the streams. This relation is characterized by an increasing water level difference for an increasing discharge, up to a maximum. If the discharge increases beyond this level, the water level difference reduces to the value that may represent the situation without woody debris. This reduction depends primarily on the obstruction ratio of the woody debris in the channel cross-section. Morphologic adjustments in the stream and reorientation of the woody material reduce the water level drop over the patches in time. Our results demonstrate that backwater effects can be reduced by optimizing the location where woody debris is placed and manipulating the obstruction ratio. Current efforts are focussed on representing woody debris in a one-dimensional numerical model, aiming to obtain a generic tool to achieve a stream design with woody debris that minimizes backwater.

  8. 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

  9. Decision time on orbital debris

    NASA Technical Reports Server (NTRS)

    Loftus, Joseph P.; Tilton, Lee E.; Temple, L. Parker, III

    1988-01-01

    The problem of orbital debris, especially in LEO is discussed, stressing ways to minimize hazards caused by debris. There are over 7,000 objects making up 2.4 X 10 to the 6th kg of debris in LEO with velocities up to 7 km/sec. The least costly way of minimizing hazards from debris is to make spent rocket stages inert, to preclude failures after their useful life, by insuring that all residual propellants and pressurant gases are vented while the stage is still subject to command. A more costly option is the actively controlled deorbit of spent stages and spacecraft at the end of their useful mission life. The removal of inert stages or spacecraft is too costly to be practical. The least expensive methods of removal are deorbit for altitudes below 25,000 km and placing the object in earth-escape trajectory for objects at higher altitudes. NASA is developing a special radar to measure the existing small-particle debris and its changes over time, and international agreements are expected to set standards of operational practices to minimize debris.

  10. Modeling, simulation, and characterization of space debris in low-Earth orbit

    NASA Astrophysics Data System (ADS)

    McCall, Paul David

    Every space launch increases the overall amount of space debris. Satellites have limited awareness of nearby objects that might pose a collision hazard. Astrometric, radiometric, and thermal models for the study of space debris in low-Earth orbit have been developed. This modeled approach proposes analysis methods that provide increased Local Area Awareness for satellites in low-Earth and geostationary orbit. Local Area Awareness is defined as the ability to detect, characterize, and extract useful information regarding resident space objects as they move through the space environment surrounding a spacecraft. The study of space debris is of critical importance to all space-faring nations. Characterization efforts are proposed using long-wave infrared sensors for space-based observations of debris objects in low-Earth orbit. Long-wave infrared sensors are commercially available and do not require solar illumination to be observed, as their received signal is temperature dependent. The characterization of debris objects through means of passive imaging techniques allows for further studies into the origination, specifications, and future trajectory of debris objects. Conclusions are made regarding the aforementioned thermal analysis as a function of debris orbit, geometry, orientation with respect to time, and material properties. Development of a thermal model permits the characterization of debris objects based upon their received long-wave infrared signals. Information regarding the material type, size, and tumble-rate of the observed debris objects are extracted. This investigation proposes the utilization of long-wave infrared radiometric models of typical debris to develop techniques for the detection and characterization of debris objects via signal analysis of unresolved imagery. Knowledge regarding the orbital type and semi-major axis of the observed debris object are extracted via astrometric analysis. This knowledge may aid in the constraint of the

  11. Active debris removal: Recent progress and current trends

    NASA Astrophysics Data System (ADS)

    Bonnal, Christophe; Ruault, Jean-Marc; Desjean, Marie-Christine

    2013-04-01

    According to all available findings at international level, the Kessler syndrome, increase of the number of space debris in Low Earth Orbits due to mutual collisions, appears now to be a fact, triggered mainly by several major break-ups in orbit which occurred since 2007. The time may have come to study how to clean this fundamentally useful orbital region in an active way. CNES has studied potential solutions for more than 12 years! The paper aims at reviewing the current status of these activities. The high level requirements are fundamental, and have to be properly justified. The working basis, as confirmed through IADC studies consists in the removal of 5-10 integer objects from the overcrowded orbits, spent upper stages or old satellites, as identified by NASA. The logic of CNES activities consider a stepped approach aiming at progressively gaining the required Technological Readiness Level on the features required for Active Debris Removal which have not yet been demonstrated in orbit. The rendezvous with a non-cooperative, un-prepared, tumbling debris is essential. Following maturation gained with Research and Technology programs, a set of small orbital demonstrators could enable a confidence high enough to perform a full end to end demonstration performing the de-orbiting of a large debris and paving the way for the development of a first generation operational de-orbiter. The internal CNES studies, led together by the Toulouse Space Centre and the Paris Launcher Directorate, have started in 2008 and led to a detailed System Requirements Document used for the Industrial studies. Three industrial teams did work under CNES contract during 2011, led by Thales Alenia Space, Bertin Technologies and Astrium Space Transportation, with numerous sub-contractors. Their approaches were very rich, complementary, and innovative. The second phase of studies began mid-2012. Some key questions nevertheless have to be resolved, and correspond generally to current IADC

  12. A Comparison of Three Catastrophic On-Orbit Collisions

    NASA Technical Reports Server (NTRS)

    Stansbery, Gene; Matney, Mark; Liou, J. C.; Whitlock, Dave

    2007-01-01

    Orbital debris environment models, such as NASA's LEGEND model, show that accidental collisions between satellites will begin to be the dominant cause for future debris population growth within the foreseeable future. The collisional breakup models employed are obviously a critical component of the environment models. The Chinese Anti-Satellite (ASAT) test which destroyed the Fengyun-1C weather satellite provided a rare, but not unique, chance to compare the breakup models against an actual on-orbit collision. Measurements from the U.S. Space Surveillance Network (SSN), for debris larger than 10-cm, and from Haystack, for debris larger than 1-cm, show that the number of fragments created from Fengyun significantly exceeds model predictions using the NASA Standard Collisional Breakup Model. However, it may not be appropriate to alter the model to match this one, individual case. Two other on-orbit collisions have occurred in the past which have produced significant numbers of debris fragments. In September 1985, the U.S. conducted an ASAT test against the Solwind P-78 spacecraft at an altitude of approximately 525 km. A year later, in September 1986, the Delta 180 payload was struck by its Delta II rocket body in a planned collision at 220 km altitude. Although no Haystack data is available in 1985-6 and very few debris pieces were cataloged from Delta 180 due to its low altitude, measurements were collected in dedicated tests by phased array radars in the SSN in the days after each test. This paper will examine the available radar data from each test and compare and contrast the results with model predictions and with the results from the more recent Fengyun ASAT test.

  13. Grain Grading and Handling.

    ERIC Educational Resources Information Center

    Rendleman, Matt; Legacy, James

    This publication provides an introduction to grain grading and handling for adult students in vocational and technical education programs. Organized in five chapters, the booklet provides a brief overview of the jobs performed at a grain elevator and of the techniques used to grade grain. The first chapter introduces the grain industry and…

  14. Microforms in Information Handling.

    ERIC Educational Resources Information Center

    Williams, B. J. S.

    In an attempt to identify some of the factors which influence the utility of microforms as a medium for information handling, this report first traces some of the landmarks in the evolution of microforms since their invention in 1893. It next provides a factual account of current microform media and formats. The last section of the report contains…

  15. Changes of Space Debris Orbits After LDR Operation

    NASA Astrophysics Data System (ADS)

    Wnuk, E.; Golebiewska, J.; Jacquelard, C.; Haag, H.

    2013-09-01

    A lot of technical studies are currently developing concepts of active removal of space debris to protect space assets from on orbit collision. For small objects, such concepts include the use of ground-based lasers to remove or reduce the momentum of the objects thereby lowering their orbit in order to facilitate their decay by re-entry into the Earth's atmosphere. The concept of the Laser Debris Removal (LDR) system is the main subject of the CLEANSPACE project. One of the CLEANSPACE objectives is to define a global architecture (including surveillance, identification and tracking) for an innovative ground-based laser solution, which can remove hazardous medium debris around selected space assets. The CLEANSPACE project is realized by a European consortium in the frame of the European Commission Seventh Framework Programme (FP7), Space topic. The use of sequence of laser operations to remove space debris, needs very precise predictions of future space debris orbital positions, on a level even better than 1 meter. Orbit determination, tracking (radar, optical and laser) and orbit prediction have to be performed with accuracy much better than so far. For that, the applied prediction tools have to take into account all perturbation factors that influence object orbit. The expected object's trajectory after the LDR operation is a lowering of its perigee. To prevent the debris with this new trajectory to collide with another object, a precise trajectory prediction after the LDR sequence is therefore the main task allowing also to estimate re-entry parameters. The LDR laser pulses change the debris object velocity v. The future orbit and re-entry parameters of the space debris after the LDR engagement can be calculated if the resulting ?v vector is known with the sufficient accuracy. The value of the ?v may be estimated from the parameters of the LDR station and from the characteristics of the orbital debris. However, usually due to the poor knowledge of the debris

  16. Debris about asteroids: Where and how much?

    NASA Technical Reports Server (NTRS)

    Burns, Joseph A.; Hamilton, Douglas P.

    1992-01-01

    We summarize several recent findings on the size and shape of the region within which material can stably orbit an asteroid. If the asteroid (with assumed density 2.38 g/cu cm) circles the Sun at 2.55 AU, co-planar prograde material will remain trapped whenever started on unperturbed circular orbits at less than about 220 R(sub A) (asteroid radii); co-planar retrograde particles are stable out twice as far. Our 3-D stability surface, which encloses several hundred numerically calculated orbits that start with various inclinations, is shaped like a sphere with its top and bottom sliced off; its dimensions scale like the Hill radius =(mu/3)(exp 1/3)R, where mu is the asteroid-to-solar mass ratio and R is the asteroid's orbital radius. If the asteroid moves along an elliptical orbit, a fairly reliable indicator of the dimensions of the hazard zone is the size of its Hill sphere at the orbit's pericenter. Grains with radii less than a few mm will be lost through the action of radiation forces which can induce escape or cause collisions with the asteroid on times scales of a few years; interplanetary micrometeoroids produce collisional break-up of these particles in approximately 10(exp 4) yrs. The effects of Jupiter and of asteroids that pass close to the target asteroid allow particles to diffuse from the system, again shrinking the hazard zone. None of the considered sources-primordial formation, debris spalled off the asteroid during micrometeoroid impact, captured interplanetary particles, feeder satellites, etc., seem capable of densely populating distant orbits from the asteroid. No certain detections of debris clouds or of binary asteroids have been made. Thus, it seems highly unlikely that a spacecraft fly-by targeted at 100 R(sub A) from the asteroid over its orbital pole would encounter any material.

  17. Collisional dust avalanches in debris discs

    NASA Astrophysics Data System (ADS)

    Grigorieva, A.; Artymowicz, P.; Thébault, Ph.

    2007-01-01

    We quantitatively investigate how collisional avalanches may develop in debris discs as the result of the initial breakup of a planetesimal or comet-like object, triggering a collisional chain reaction due to outward escaping small dust grains. We use a specifically developed numerical code that follows both the spatial distribution of the dust grains and the evolution of their size-frequency distribution due to collisions. We investigate how strongly avalanche propagation depends on different parameters (e.g., amount of dust released in the initial breakup, collisional properties of dust grains, and their distribution in the disc). Our simulations show that avalanches evolve on timescales of ~1000 years, propagating outwards following a spiral-like pattern, and that their amplitude exponentially depends on the number density of dust grains in the system. We estimate the probability of witnessing an avalanche event as a function of disc densities, for a gas-free case around an A-type star, and find that features created by avalanche propagation can lead to observable asymmetries for dusty systems with a β Pictoris-like dust content or higher. Characteristic observable features include: (i) a brightness asymmetry of the two sides for a disc viewed edge-on, and (ii) a one-armed open spiral or a lumpy structure in the case of face-on orientation. A possible system in which avalanche-induced structures might have been observed is the edge-on seen debris disc around HD 32297, which displays a strong luminosity difference between its two sides.

  18. The fate of debris in the Pluto-Charon system

    NASA Astrophysics Data System (ADS)

    Smullen, Rachel A.; Kratter, Kaitlin M.

    2017-04-01

    The Pluto-Charon system has come into sharper focus following the flyby of New Horizons. We use N-body simulations to probe the unique dynamical history of this binary dwarf planet system. We follow the evolution of the debris disc that might have formed during the Charon-forming giant impact. First, we note that in situ formation of the four circumbinary moons is extremely difficult if Charon undergoes eccentric tidal evolution. We track collisions of disc debris with Charon, estimating that hundreds to hundreds of thousands of visible craters might arise from 0.3-5 km radius bodies. New Horizons data suggesting a dearth of these small craters may place constraints on the disc properties. While tidal heating will erase some of the cratering history, both tidal and radiogenic heating may also make it possible to differentiate disc debris craters from Kuiper belt object craters. We also track the debris ejected from the Pluto-Charon system into the Solar system; while most of this debris is ultimately lost from the Solar system, a few tens of 10-30 km radius bodies could survive as a Pluto-Charon collisional family. Most are plutinos in the 3:2 resonance with Neptune, while a small number populate nearby resonances. We show that migration of the giant planets early in the Solar system's history would not destroy this collisional family. Finally, we suggest that identification of such a family would likely need to be based on composition as they show minimal clustering in relevant orbital parameters.

  19. The Fate of Debris in the Pluto-Charon System

    NASA Astrophysics Data System (ADS)

    Smullen, Rachel A.; Kratter, Kaitlin M.

    2017-01-01

    The Pluto-Charon system has come into sharper focus following the fly by of New Horizons. We use N-body simulations to probe the unique dynamical history of this binary dwarf planet system. We follow the evolution of the debris disc that might have formed during the Charon-forming giant impact. First, we note that in-situ formation of the four circumbinary moons is extremely difficult if Charon undergoes eccentric tidal evolution. We track collisions of disc debris with Charon, estimating that hundreds to hundreds of thousands of visible craters might arise from 0.3-5 km radius bodies. New Horizons data suggesting a dearth of these small craters may place constraints on the disc properties. While tidal heating will erase some of the cratering history, both tidal and radiogenic heating may also make it possible to differentiate disc debris craters from Kuiper belt object craters. We also track the debris ejected from the Pluto-Charon system into the Solar System; while most of this debris is ultimately lost from the Solar System, a few tens of 10-30 km radius bodies could survive as a Pluto-Charon collisional family. Most are plutinos in the 3:2 resonance with Neptune, while a small number populate nearby resonances. We show that migration of the giant planets early in the Solar System's history would not destroy this collisional family. Finally, we suggest that identification of such a family would likely need to be based on composition as they show minimal clustering in relevant orbital parameters.

  20. Mantle Debris in Giant Impacts: Parameter-Space Study and Scaling Laws

    NASA Astrophysics Data System (ADS)

    Gabriel, Travis; Reufer, Andreas; Jackson, Alan P.; Asphaug, Erik

    2016-10-01

    Collisions between similar-sized planetesimals are prevalent throughout the early stages of the formation of the Solar System. N-body dynamics simulations commonly employed to understand planetary evolution depend on parameterized disruption/accretion criteria in order to consider the diversity of outcomes of these collisions. Additionally, understanding the debris from collisions is essential in tracing the source regions of volatiles, placing constraints on collisional grinding, and explaining the formation of small solar system bodies. We describe the transport of mantle material through debris production in giant impacts using a large database of SPH hydrocode simulations. We then develop new scaling laws that accurately capture the production of diverse debris products found in giant impacts with a range of relative velocities up to a few times the mutual escape velocity and a complete range of impact geometries. At typical impact angles it is found that giant impacts are significantly less erosive than suggested by existing scaling laws. This discrepancy grows with impact velocity and the impactor-to-target mass ratio, and thus it grows with the kinetic energy of the system. Our database spans a wide parameter space of pre-impact initial conditions, and includes chondritic and icy, chondritic material representative of the bulk abundances in the inner and outer solar system respectively. Implications for this new understanding in debris production through giant impacts are discussed.

  1. The Near-Earth Orbital Debris Problem and the Challenges for Environment Remediation

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi

    2012-01-01

    The near-Earth space environment has been gradually polluted with orbital debris (OD) since the beginning of space activities 55 years ago. Although this problem has been known to the research community for decades, the public was, in general, unaware of the issue until the anti-satellite test conducted by China in 2007 and the collision between Cosmos 2251 and the operational Iridium 33 in 2009. The latter also underlined the potential of an ongoing collision cascade effect (the "Kessler Syndrome") in the low Earth orbit (LEO, the region below 2000 km altitude). Recent modeling results have indicated that mitigation measures commonly adopted by the international space community will be insufficient to stabilize the LEO debris population. To better limit the OD population increase, more aggressive actions must be considered. There are three options for OD environment remediation-removal of large/massive intact objects to address the root cause of the OD population growth problem, removal of 5-mm-to-1 cm debris to mitigate the main mission-ending threats for the majority of operational spacecraft, and prevention of major debris-generating collisions as a temporary means to slow down the OD population increase. The technology, engineering, and cost challenges to carry out any of these three options are monumental. It will require innovative ideas, game-changing technologies, and major collaborations at the international level to address the OD problem and preserve the near-Earth environment for future generations.

  2. Estimation of the annual production and composition of C&D Debris in Galicia (Spain).

    PubMed

    Martínez Lage, Isabel; Martínez Abella, Fernando; Herrero, Cristina Vázquez; Ordóñez, Juan Luis Pérez

    2010-04-01

    One of the key aspects that must be taken into consideration within the framework of Sustainable Construction is the management of Construction and Demolition (C&D) Debris. As for other types of waste, specific handling procedures are required to manage C&D Debris; these include reduction, reuse, recycling, and if all other possibilities fail, recovery or disposal. For public planning strategies aimed at the management of C&D Debris to be effective, it is first necessary to have specific knowledge of the type of waste materials generated in a particular region. After verifying that the methods available to determine the production and composition of C&D Debris are limited, this paper presents a procedure to ascertain the production and composition of C&D Debris, in any region. The procedure utilizes data on the surface areas of newly constructed buildings, renovations and demolitions, which are estimated from available data for recent years, as well as information on the quantity of debris generated per surface area in any type of construction site, which is obtained from recently executed constructions or from the ground plans of older buildings. The method proposed here has been applied to Galicia, one of Spain's autonomous communities, for which the quantity and composition of C&D Debris have been estimated for the horizon year 2011.

  3. Optical Observations of Space Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Abercromby, Kira; Rodriquez, Heather; Barker, Edwin S.; Kelecy, Thomas

    2008-01-01

    This viewgraph presentation reviews the use of optical telescopes to observe space debris. .It will present a brief review of how the survey is conducted, and what some of the significant results encompass. The goal is to characterize the population of debris objects at GEO, with emphasis on the faint object population. Because the survey observations extend over a very short arc (5 minutes), a full six parameter orbit can not be determined. Recently we have begun to use a second telescope, the 0.9-m at CTIO, as a chase telescope to do follow-up observations of potential GEO debris candidates found by MODEST. With a long enough sequence of observations, a full six-parameter orbit including eccentricity can be determined. The project has used STK since inception for planning observing sessions based on the distribution of bright cataloged objects and the anti-solar point (to avoid eclipse). Recently, AGI's Orbit Determination Tool Kit (ODTK) has been used to determine orbits, including the effects of solar radiation pressure. Since an unknown fraction of the faint debris at GEO has a high area-to-mass ratio (A/M), the orbits are perturbed significantly by solar radiation. The ODTK analysis results indicate that temporal variations in the solar perturbations, possibly due to debris orientation dynamics, can be estimated in the OD process. Additionally, the best results appear to be achieved when solar forces orthogonal to the object-Sun line are considered. Determining the A/M of individual objects and the distribution of A/M values of a large sample of debris is important to understanding the total population of debris at GEO

  4. Active Space Debris Removal using European Modified Launch Vehicle Upper Stages Equipped with Electrodynamic Tethers

    NASA Astrophysics Data System (ADS)

    Nasseri, Ali S.; Emanuelli, Matteo; Raval, Siddharth; Turconi, Andrea; Becker, Cristoph

    2013-08-01

    During the past few years, several research programs have assessed the current state and future evolution of the Low Earth Orbit region. These studies indicate that space debris density could reach a critical level such that there will be a continuous increase in the number of debris objects, primarily driven by debris-debris collision activity known as the Kessler effect. This cascade effect can be even more significant when intact objects as dismissed rocket bodies are involved in the collision. The majority of the studies until now have highlighted the urgency for active debris removal in the next years. An Active Debris Removal System (ADRS) is a system capable of approaching the debris object through a close-range rendezvous, establishing physical connection, stabilizing its attitude and finally de-orbiting the debris object using a type of propulsion system in a controlled manoeuvre. In its previous work, this group showed that a modified Fregat (Soyuz FG's 4th stage) or Breeze-M upper stage (Proton-M) launched from Plesetsk (Russian Federation) and equipped with an electro-dynamic tether (EDT) system can be used, after an opportune inclination's change, to de-orbit a Kosmos-3M second stage rocket body while also delivering an acceptable payload to orbit. In this paper, we continue our work on the aforementioned concept, presented at the 2012 Beijing Space Sustainability Conference, by comparing its performance to ADR missions using only chemical propulsion from the upper stage for the far approach and the de-orbiting phase. We will also update the EDT model used in our previous work and highlight some of the methods for creating physical contact with the object. Moreover, we will assess this concept also with European launch vehicles (Vega and Soyuz 2-1A) to remove space debris from space. In addition, the paper will cover some economic aspects, like the cost for the launches' operator in term of payload mass' loss at the launch. The entire debris removal

  5. Risk assessment reveals high exposure of sea turtles to marine debris in French Mediterranean and metropolitan Atlantic waters

    NASA Astrophysics Data System (ADS)

    Darmon, Gaëlle; Miaud, Claude; Claro, Françoise; Doremus, Ghislain; Galgani, François

    2017-07-01

    Debris impact on marine wildlife has become a major issue of concern. Mainy species have been identified as being threatened by collision, entanglement or ingestion of debris, generally plastics, which constitute the predominant part of the recorded marine debris. Assessing sensitive areas, where exposure to debris are high, is thus crucial, in particular for sea turtles which have been proposed as sentinels of debris levels for the Marine Strategy Framework Directive and for the Unep-MedPol convention. Our objective here was to assess sea turtle exposure to marine debris in the 3 metropolitan French fronts. Using aerial surveys performed in the Channel, the Atlantic and the Mediterranean regions in winter and summer 2011-2012, we evaluated exposure areas and magnitude in terms of spatial overlap, encounter probability and density of surrounding debris at various spatial scales. Major overlapping areas appeared in the Atlantic and Mediterranean fronts, concerning mostly the leatherback and the loggerhead turtles respectively. The probability for individuals to be in contact with debris (around 90% of individuals within a radius of 2 km) and the density of debris surrounding individuals (up to 16 items with a radius of 2 km, 88 items within a radius of 10 km) were very high, whatever the considered spatial scale, especially in the Mediterranean region and during the summer season. The comparison of the observed mean debris density with random distribution suggested that turtles selected debris areas. This may occur if both debris and turtles drift to the same areas due to currents, if turtles meet debris accidentally by selecting high food concentration areas, and/or if turtles actively seek debris out, confounding them with their preys. Various factors such as species-specific foraging strategies or oceanic features which condition the passive diffusion of debris, and sea turtles in part, may explain spatio-temporal variations in sensitive areas. Further research

  6. 77 FR 11112 - Proposed Approval of the Central Characterization Project's Remote-Handled Transuranic Waste...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... radioactive, remote-handled (RH), transuranic (TRU) waste characterization program implemented by the Central... Compliance Criteria, EPA evaluated the characterization of RH TRU debris waste from SRS-CCP during an... Office (CBFO) program, EPA verified whether DOE could adequately characterize RH TRU waste...

  7. 76 FR 62062 - Proposed Approval of the Central Characterization Project's Remote-Handled Transuranic Waste...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-06

    ... addition, RH containers with different AK pedigree and new or different radionuclide scaling factors that... radioactive, remote-handled (RH), transuranic (TRU) waste characterization program implemented by the Central... Compliance Criteria, EPA evaluated the characterization of RH TRU debris waste from SNL-CCP during...

  8. Solid waste handling

    SciTech Connect

    Parazin, R.J.

    1995-05-31

    This study presents estimates of the solid radioactive waste quantities that will be generated in the Separations, Low-Level Waste Vitrification and High-Level Waste Vitrification facilities, collectively called the Tank Waste Remediation System Treatment Complex, over the life of these facilities. This study then considers previous estimates from other 200 Area generators and compares alternative methods of handling (segregation, packaging, assaying, shipping, etc.).

  9. Space shuttle handling qualities

    NASA Technical Reports Server (NTRS)

    Gilbert, D. W.

    1985-01-01

    The initial Orbiter handling qualities requirements, their effect on the vehicle design, and how it all turned out through the first six orbital missions are reviewed. Specific areas consisting of hand controller considerations and the wheelie problem are discussed. The requirements for the pitch axis subsonic flight control system are reviewed. Results of recent simulator evaluations to compare the existing system at landing with several other configurations are presented.

  10. Renal phosphate handling: Physiology

    PubMed Central

    Prasad, Narayan; Bhadauria, Dharmendra

    2013-01-01

    Phosphorus is a common anion. It plays an important role in energy generation. Renal phosphate handling is regulated by three organs parathyroid, kidney and bone through feedback loops. These counter regulatory loops also regulate intestinal absorption and thus maintain serum phosphorus concentration in physiologic range. The parathyroid hormone, vitamin D, Fibrogenic growth factor 23 (FGF23) and klotho coreceptor are the key regulators of phosphorus balance in body. PMID:23961477

  11. Close Approach Prediction Analysis of the Earth Science Constellation with the Fengyun-1C Debris

    NASA Technical Reports Server (NTRS)

    Duncan, Matthew; Rand, David K.

    2008-01-01

    Routine satellite operations for the Earth Science Constellation (ESC) include collision risk assessment between members of the constellation and other orbiting space objects. Each day, close approach predictions are generated by a U.S. Department of Defense Joint Space Operations Center Orbital Safety Analyst using the high accuracy Space Object Catalog maintained by the Air Force's 1" Space Control Squadron. Prediction results and other ancillary data such as state vector information are sent to NASAJGoddard Space Flight Center's (GSFC's) Collision Risk Assessment analysis team for review. Collision analysis is performed and the GSFC team works with the ESC member missions to develop risk reduction strategies as necessary. This paper presents various close approach statistics for the ESC. The ESC missions have been affected by debris from the recent anti-satellite test which destroyed the Chinese Fengyun- 1 C satellite. The paper also presents the percentage of close approach events induced by the Fengyun-1C debris, and presents analysis results which predict the future effects on the ESC caused by this event. Specifically, the Fengyun-1C debris is propagated for twenty years using high-performance computing technology and close approach predictions are generated for the ESC. The percent increase in the total number of conjunction events is considered to be an estimate of the collision risk due to the Fengyun-1C break- UP.

  12. Uranium hexafluoride handling. Proceedings

    SciTech Connect

    Not Available

    1991-12-31

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF{sub 6} from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

  13. Biological response to prosthetic debris

    PubMed Central

    Bitar, Diana; Parvizi, Javad

    2015-01-01

    Joint arthroplasty had revolutionized the outcome of orthopaedic surgery. Extensive and collaborative work of many innovator surgeons had led to the development of durable bearing surfaces, yet no single material is considered absolutely perfect. Generation of wear debris from any part of the prosthesis is unavoidable. Implant loosening secondary to osteolysis is the most common mode of failure of arthroplasty. Osteolysis is the resultant of complex contribution of the generated wear debris and the mechanical instability of the prosthetic components. Roughly speaking, all orthopedic biomaterials may induce a universal biologic host response to generated wear débris with little specific characteristics for each material; but some debris has been shown to be more cytotoxic than others. Prosthetic wear debris induces an extensive biological cascade of adverse cellular responses, where macrophages are the main cellular type involved in this hostile inflammatory process. Macrophages cause osteolysis indirectly by releasing numerous chemotactic inflammatory mediators, and directly by resorbing bone with their membrane microstructures. The bio-reactivity of wear particles depends on two major elements: particle characteristics (size, concentration and composition) and host characteristics. While any particle type may enhance hostile cellular reaction, cytological examination demonstrated that more than 70% of the debris burden is constituted of polyethylene particles. Comprehensive understanding of the intricate process of osteolysis is of utmost importance for future development of therapeutic modalities that may delay or prevent the disease progression. PMID:25793158

  14. 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.

  15. Modeling UHMWPE wear debris generation.

    PubMed

    Baudriller, H; Chabrand, P; Moukoko, D

    2007-02-01

    It is widely recognized that polyethylene wear debris is one of the main causes of long-term prosthesis loosening. The noxious bioreactivity associated with this debris is determined by its size, shape, and quantity. The aim of this study was to develop a numerical tool that can be used to investigate the primary polyethylene wear mechanisms involved. This model illustrates the formation of varying flow of polyethylene debris with various shapes and sizes caused by elementary mechanical processes. Instead of using the classical continuum mechanics formulation for this purpose, we used a divided materials approach to simulate debris production and release. This approach involves complex nonlinear bulk behaviors, frictional adhesive contact, and characterizes material damage as a loss of adhesion. All the associated models were validated with various benchmark tests. The examples given show the ability of the numerical model to generate debris of various shapes and sizes such as those observed in implant retrieval studies. Most of wear mechanisms such as abrasion, adhesion, and the shearing off of micro-asperities can be described using this approach. Furthermore, it could be applied to study the effects of friction couples, macroscopic geometries, and material processing (e.g. irradiation) on wear. (c) 2006 Wiley Periodicals, Inc.

  16. Hydroplaning and submarine debris flows

    NASA Astrophysics Data System (ADS)

    de Blasio, Fabio V.; Engvik, Lars; Harbitz, Carl B.; ElverhøI, Anders

    2004-01-01

    Examination of submarine clastic deposits along the continental margins reveals the remnants of holocenic or older debris flows with run-out distances up to hundreds of kilometers. Laboratory experiments on subaqueous debris flows, where typically one tenth of a cubic meter of material is dropped down a flume, also show high velocities and long run-out distances compared to subaerial debris flows. Moreover, they show the tendency of the head of the flow to run out ahead of the rest of the body. The experiments reveal the possible clue to the mechanism of long run-out. This mechanism, called hydroplaning, begins as the dynamic pressure at the front of the debris flow becomes of the order of the pressure exerted by the weight of the sediment. In such conditions a layer of water can intrude under the sediment with a lubrication effect and a decrease in the resistance forces between the sediment and the seabed. A physical-mathematical model of hydroplaning is presented and investigated numerically. The model is applied to both laboratory- and field-scale debris flows. Agreement with laboratory experiments makes us confident in the extrapolation of our model to natural flows and shows that long run-out distances can be naturally attained.

  17. Geosynchronous Earth orbital debris campaign

    NASA Astrophysics Data System (ADS)

    Africano, John L.; Sydney, Paul F.; Talent, David L.; Stansbery, Eugene G.; Jarvis, Kandy S.; Monet, David G.; Seitzer, Patrick

    2000-10-01

    The National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) is conducting systematic searches of the Geosynchronous Earth Orbit (GEO) environment as part of an international measurement campaign under the auspices of the Inter-Agency Space Debris Coordination Committee (IADC). The objectives for this survey are to determine the extent and character of debris in GEO, buy obtaining distributions for the brightness, inclination, Right Ascension of Ascending Node (RAAN), and mean motion of the debris. The Charged Coupled Device (CCD) Debris Telescope (CDT), an automated 0.32 meter aperture, transportable Schmidt telescope presently located at Cloudcroft, New Mexico, is used nightly to monitor the GEO debris environment. The CDT is equipped with a CCD camera capable of detecting 17th magnitude objects in a 20 second exposure. This corresponds to a 0.6 meter diameter object having a 0.2 albedo at 36000 km. Two other larger telescopes have been used for this purpose, the United States Naval Observatory's new 1.3 meter telescope located in Flagstaff Arizona and a 0.6 m Schmidt telescope located at Cerro Tololo Inter-American Observatory (CTIO) near La Serena Chile. Data reduction and analysis software used to reduce this data exploit tools developed by both the astronomical and DoD communities. These tools and data results are presented.

  18. Optical surveys for space debris

    NASA Astrophysics Data System (ADS)

    Schildknecht, Thomas

    2007-01-01

    Space debris—man-made non-functional objects of all sizes in near-Earth space—has been recognized as an increasing threat for current and future space operations. The debris population in near-Earth space has therefore been extensively studied during the last decade. Information on objects at altitudes higher than about 2,000 km is, however, still comparatively sparse. Debris in this region is best detected by surveys utilizing optical telescopes. Moreover, the instruments and the applied observation techniques, as well as the processing methods, have many similarities with those used in optical surveys for ‘astronomical’ objects like near-Earth objects (NEOs). The present article gives a general introduction to the problem of space debris, presents the used observation and processing techniques emphasizing the similarities and differences compared to optical surveys for NEOs, and reviews the results from optical surveys for space debris in high-altitude Earth orbits. Predictions on the influence of space debris on the future of space research and space astronomy in particular are reported as well.

  19. A Sensitivity Study on the Effectiveness of Active Debris Removal in LEO

    NASA Technical Reports Server (NTRS)

    Liou, J. C.; Johnson, Nicholas L.

    2007-01-01

    The near-Earth orbital debris population will continue to increase in the future due to ongoing space activities, on-orbit explosions, and accidental collisions among resident space objects. Commonly adopted mitigation measures, such as limiting postmission orbital lifetimes of satellites to less than 25 years, will slow down the population growth, but may be insufficient to stabilize the environment. The nature of the growth, in the low Earth orbit (LEO) region, is further demonstrated by a recent study where no future space launches were conducted in the environment projection simulations. The results indicate that, even with no new launches, the LEO debris population would remain relatively constant for only the next 50 years. Beyond that, the debris population would begin to increase noticeably, due to the production of collisional debris. Therefore, to better limit the growth of future debris population to protect the environment, remediation option, i.e., removing existing large and massive objects from orbit, needs to be considered. This paper does not intend to address the technical or economical issues for active debris removal. Rather, the objective is to provide a sensitivity study to quantify the effectiveness of various remediation options. A removal criterion based upon mass and collision probability is developed to rank objects at the beginning of each projection year. This study includes simulations with removal rates ranging from 2 to 20 objects per year, starting in the year 2020. The outcome of each simulation is analyzed, and compared with others. The summary of the study serves as a general guideline for future debris removal consideration.

  20. The New NASA Orbital Debris Engineering Model ORDEM 3.0

    NASA Technical Reports Server (NTRS)

    Krisko, P. H.

    2014-01-01

    The NASA Orbital Debris Program Office (ODPO) has released its latest Orbital Debris Engineering Model, ORDEM 3.0. It supersedes ORDEM 2000, now referred to as ORDEM 2.0. This newer model encompasses the Earth satellite and debris flux environment from altitudes of low Earth orbit (LEO) through geosynchronous orbit (GEO). Debris sizes of 10 micron through larger than 1 m in non-GEO and 10 cm through larger than 1 m in GEO are available. The inclusive years are 2010 through 2035. The ORDEM model series has always been data driven. ORDEM 3.0 has the benefit of many more hours of data from existing sources and from new sources than past ORDEM versions. The object data range in size from 10 µm to larger than 1 m, and include in situ and remote measurements. The in situ data reveals material characteristics of small particles. Mass densities are grouped in ORDEM 3.0 in terms of 'high-density', represented by 7.9 g/cc, 'medium-density' represented by 2.8 g/cc and 'low-density' represented by 1.4 g/cc. Supporting models have also advanced significantly. The LEO-to-GEO ENvironment Debris model (LEGEND) includes an historical and a future projection component with yearly populations that include launched and maneuvered intact spacecraft and rocket bodies, mission related debris, and explosion and collision event fragments. LEGEND propagates objects with ephemerides and physical characteristics down to 1 mm in size. The full LEGEND yearly population acts as an a priori condition for a Bayesian statistical model. Specific populations are added from sodium potassium droplet releases, recent major accidental and deliberate collisions, and known anomalous debris events. This paper elaborates on the upgrades of this model over previous versions. Sample validation results with remote and in situ measurements are shown, and the consequences of including material density are discussed as it relates to heightened risks to crewed and robotic spacecraft

  1. Disaster Debris Recovery Database - Recovery

    EPA Pesticide Factsheets

    The US EPA Region 5 Disaster Debris Recovery Database includes public datasets of over 6,000 composting facilities, demolition contractors, transfer stations, landfills and recycling facilities for construction and demolition materials, electronics, household hazardous waste, metals, tires, and vehicles in the states of Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Ohio, Pennsylvania, South Dakota, West Virginia and Wisconsin.In this update, facilities in the 7 states that border the EPA Region 5 states were added to assist interstate disaster debris management. Also, the datasets for composters, construction and demolition recyclers, demolition contractors, and metals recyclers were verified and source information added for each record using these sources: AGC, Biocycle, BMRA, CDRA, ISRI, NDA, USCC, FEMA Debris Removal Contractor Registry, EPA Facility Registry System, and State and local listings.

  2. Disaster Debris Recovery Database - Landfills

    EPA Pesticide Factsheets

    The US EPA Region 5 Disaster Debris Recovery Database includes public datasets of over 6,000 composting facilities, demolition contractors, transfer stations, landfills and recycling facilities for construction and demolition materials, electronics, household hazardous waste, metals, tires, and vehicles in the states of Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Ohio, Pennsylvania, South Dakota, West Virginia and Wisconsin.In this update, facilities in the 7 states that border the EPA Region 5 states were added to assist interstate disaster debris management. Also, the datasets for composters, construction and demolition recyclers, demolition contractors, and metals recyclers were verified and source information added for each record using these sources: AGC, Biocycle, BMRA, CDRA, ISRI, NDA, USCC, FEMA Debris Removal Contractor Registry, EPA Facility Registry System, and State and local listings.

  3. Summary of Orbital Debris Workshop

    NASA Technical Reports Server (NTRS)

    Kessler, D. J.

    1982-01-01

    An Orbital Debris Workshop was conducted in July 1982. The working groups established were related to measurements of large particles, modeling of large particles, measurements of small particles, spacecraft hazard and shielding requirements, and space object management. The results of the Orbital Debris Workshop reaffirm the need for research to better understand the character of orbital debris, its effects on future spacecraft, and the related requirements for policy. A clear charter is required for this research to receive the necessary support, focus, and coordination. It was recommended that NASA assume the role of lead agency. The first task is to develop an overall plan with both Department of Defense and the North American Aerospace Defense Command participation.

  4. Atomic gas in debris discs

    NASA Astrophysics Data System (ADS)

    Hales, Antonio S.; Barlow, M. J.; Crawford, I. A.; Casassus, S.

    2017-04-01

    We have conducted a search for optical circumstellar absorption lines in the spectra of 16 debris disc host stars. None of the stars in our sample showed signs of emission line activity in either Hα, Ca II or Na I, confirming their more evolved nature. Four stars were found to exhibit narrow absorption features near the cores of the photospheric Ca II and Na I D lines (when Na I D data were available). We analyse the characteristics of these spectral features to determine whether they are of circumstellar or interstellar origins. The strongest evidence for circumstellar gas is seen in the spectrum of HD 110058, which is known to host a debris disc observed close to edge-on. This is consistent with a recent ALMA detection of molecular gas in this debris disc, which shows many similarities to the β Pictoris system.

  5. Fate of debris from the Borealis basin impact on Mars and from the formation of the Earth-Moon system

    NASA Astrophysics Data System (ADS)

    Asphaug, Erik; Jackson, Alan P.; Gabriel, Travis; Minton, David A.; Hesselbrock, Andrew

    2016-10-01

    Giant planet-forming collisions can inject significant amounts of debris into the inner solar system. Dynamically the fate of this debris is primarily to re-impact the target body and the other terrestrial planets, defining a post-giant-impact epoch. Giant impact debris leave signatures on the surfaces of terrestrial bodies, influencing and perhaps dominating their early cratering record, and for the largest giant impacts, to intensive surface evolution and even changes in bulk crustal material composition. We use high-resolution N-body simulations to study the fate of debris released by specific giant impacts suggested to have formed the Borealis basin on Mars, and compare it to the fate of debris released by giant impact scenarios for Earth's Moon. We consider how the velocity dependence of Earth-Moon accretion leads to differing velocity distributions of debris-impactors for Earth and Moon, and thus different crater distributions, and study how different assumptions on the size distribution of debris effects these results. We also investigate the influence of collisional grinding within the debris distribution, and the possibility of trapped populations.

  6. Looking inside a debris flow

    NASA Astrophysics Data System (ADS)

    Bowman, Elisabeth; Sanvitale, Nicoletta; Bird, Joshua

    2014-05-01

    Debris flows, masses of saturated, channelized, granular materials that flow at high speeds downslope, present a hazard to lives and infrastructure in regions of high relief and runoff. They also present a challenge to modelling due to the heterogeneous, multi-phase, nature of the constituent materials, with particles ranging from boulder-size to silt-size and fluid viscosity being altered by the presence of fine particles and clay. As a debris flow travels on its flow path, it will tend to segregate, with larger particles being focused to the flow front and fluid being concentrated in the tail - resulting in different rheological behaviour in time and space. It will also tend to erode and deposit material as it moves through different channel segments or reaches, with this behaviour influenced by the confinement of the channel and the angle of the slope within each reach. Flume studies offer the potential to examine in detail the behaviour of model debris flows within the penultimate and final (deposit fan area) reaches - zones which are generally of most interest in terms of human risk. Flume studies which are conducted using transparent debris offer additional benefits to more traditional methods that use opaque materials, enabling insights to the flow behaviour that are inaccessible via other physical methods. We present flume model work which has been designed to capture some essential aspects of debris flow behaviour using well graded (polydisperse) transparent debris, albeit at reduced scale. These aspects include the final deposit spread or runout increasing for a lower concentration of solids and a higher penultimate reach slope angle, and observable particle size segregation during downslope motion. We present time-varying measurements made internally and externally at a point in the channel via Plane Laser Induced Fluorescence and Particle Image Velocimetry, PIV. The measurements enable velocity distributions of the segregating flows over time to be

  7. Momentum distribution in debris cloud during hypervelocity impact

    NASA Technical Reports Server (NTRS)

    Lemaster, P.; Mount, A.; Zee, R. H.

    1992-01-01

    The long term operation of the Space Station Freedom requires a scheme to protect it from high velocity impacts by both man-made particles and micrometeor fragments. One such scheme is the use of metal plates to serve as shields against such orbital debris. These 'bumper' plates, as they are referred to, serve to break up any incident particle and redistribute its momentum over a larger area. It is therefore necessary to determine the momentum distribution within the debris cloud produced by such collisions in order to evaluate a materials effectiveness at accomplishing this task. This paper details the design and development of an innovative device which has made this possible. Momentum profiles were obtained for a series of test conditions. Total momentum values in the debris cloud were then calculated from these profiles. These results indicated that a momentum amplification exists with a multiplication factor of between 2 and 3. Thus the role of the bumper to serve as a means for momentum redistribution and not reduction was verified.

  8. Orbital Debris Assesment Tesing in the AEDC Range G

    NASA Technical Reports Server (NTRS)

    Polk, Marshall; Woods, David; Roebuck, Brian; Opiela, John; Sheaffer, Patti; Liou, J.-C.

    2015-01-01

    The space environment presents many hazards for satellites and spacecraft. One of the major hazards is hypervelocity impacts from uncontrolled man-made space debris. Arnold Engineering Development Complex (AEDC), The National Aeronautics and Space Administration (NASA), The United States Air Force Space and Missile Systems Center (SMC), the University of Florida, and The Aerospace Corporation configured a large ballistic range to perform a series of hypervelocity destructive impact tests in order to better understand the effects of space collisions. The test utilized AEDC's Range G light gas launcher, which is capable of firing projectiles up to 7 km/s. A non-functional full-scale representation of a modern satellite called the DebriSat was destroyed in the enclosed range enviroment. Several modifications to the range facility were made to ensure quality data was obtained from the impact events. The facility modifcations were intended to provide a high impact energy to target mass ratio (>200 J/g), a non-damaging method of debris collection, and an instrumentation suite capable of providing information on the physics of the entire imapct event.

  9. What Sets the Radial Locations of Warm Debris Disks?

    NASA Astrophysics Data System (ADS)

    Ballering, Nicholas P.; Rieke, George H.; Su, Kate Y. L.; Gáspár, András

    2017-08-01

    The architectures of debris disks encode the history of planet formation in these systems. Studies of debris disks via their spectral energy distributions (SEDs) have found infrared excesses arising from cold dust, warm dust, or a combination of the two. The cold outer belts of many systems have been imaged, facilitating their study in great detail. Far less is known about the warm components, including the origin of the dust. The regularity of the disk temperatures indicates an underlying structure that may be linked to the water snow line. If the dust is generated from collisions in an exo-asteroid belt, the dust will likely trace the location of the water snow line in the primordial protoplanetary disk where planetesimal growth was enhanced. If instead the warm dust arises from the inward transport from a reservoir of icy material farther out in the system, the dust location is expected to be set by the current snow line. We analyze the SEDs of a large sample of debris disks with warm components. We find that warm components in single-component systems (those without detectable cold components) follow the primordial snow line rather than the current snow line, so they likely arise from exo-asteroid belts. While the locations of many warm components in two-component systems are also consistent with the primordial snow line, there is more diversity among these systems, suggesting additional effects play a role.

  10. Laboratory study of the underground sound generated by debris flows

    NASA Astrophysics Data System (ADS)

    Huang, Ching-Jer; Shieh, Chieng-Lun; Yin, Hsiao-Yuan

    2004-03-01

    This experimental study investigates the underground sound generated by different kinds of rock motions that occur in debris flows. The experiments were divided into two parts. The first part consisted of measuring the main characteristics of the underground sound caused by friction of a rock rubbed against a bed of gravel and of that caused by a free-falling rock hitting a similar bed of gravel. In the second part a hydrophone was installed at the bottom of a laboratory channel to measure the underground sound of debris flows in that channel. The sound signals were analyzed using both the fast Fourier transform and the Gabor transform to represent the signals in both the frequency and time-frequency domains. The measurement results reveal that the frequency of the sound generated by the rock-gravel bed friction is relatively low, being mostly between 20 and 80 Hz. In contrast, the frequency range of the collision sound is relatively higher, between 10 and 500 Hz. Finally, the frequency of the underground sound caused by the debris flows in the flume is in the range of 20-300 Hz.

  11. PLANETESIMALS IN DEBRIS DISKS OF SUN-LIKE STARS

    SciTech Connect

    Shannon, Andrew; Wu Yanqin

    2011-09-20

    Observations of dusty debris disks can be used to test theories of planetesimal coagulation. Planetesimals of sizes up to a couple of thousand kilometers are embedded in these disks and their mutual collisions generate the small dust grains that are observed. The dust luminosities, when combined with information on the dust spatial extent and the system age, can be used to infer initial masses in the planetesimal belts. Carrying out such a procedure for a sample of debris disks around Sun-like stars, we reach the following two conclusions. First, if we assume that colliding planetesimals satisfy a primordial size spectrum of the form dn/ds{proportional_to}s{sup -q}, observed disks strongly favor a value of q between 3.5 and 4, while both current theoretical expectations and statistics of Kuiper belt objects favor a somewhat larger value. Second, number densities of planetesimals are two to three orders of magnitude higher in detected disks than in the Kuiper belt, for comparably sized objects. This is a surprise for the coagulation models. It would require a similar increase in the disk surface density over that of the Minimum Mass Solar Nebula, which is unreasonable. Both of our conclusions are driven by the need to explain the presence of bright debris disks at a few gigayears of age.

  12. Hydraulic characteristics of debris flows in a drainage channel with stepped dissipater

    NASA Astrophysics Data System (ADS)

    Chen, Huayong; Chen, Xiaoqing; Zhao, Wanyu

    2017-04-01

    Sichuan-Tibet railway started from Chengdu, via Pujiang, Ya'an, Kangding, Litang, Zuogong, Bomi, nyingchi, and lhasa, which covers a distance of 1,629 km. The Sichuan-Tibet railway cuts through the alpine region that has the feature of large elevation difference, active tectonics, and obvious space differentiation. Debris flows with high density, low viscosity, and high speed are one of the most common geo-hazards in these regions. A new type of drainage channel with stepped dissipater was proposed to apply to mitigate the debris flow disaster in the alpine region. The debris flow patterns, debris flow velocity, energy dissipation along the drainage channel were analyzed under different structures of the drainage channels based on the experiments. The roughness coefficient calculated by the Manning formula was also investigated along the flow depth for both rectangular channel and the channel with stepped dissipater. The results indicated that compared with the traditional rectangular drainage channel, the channel with stepped dissipater has more efficiency to decrease the flow velocity, Reduce the abrasion along drainage channel, and improve the energy dissipation rate due to the Intense collision, friction between debris flows and the solid boundary. The maximum energy dissipation rate reaches approximately 61%. Based on the theory of particle projectile, the relation between the step length and the debris flow velocity, step height was proposed..

  13. Laser Solutions for Reducing the Environmental Risks Associated with Orbital Debris and Near Earth Objects

    NASA Technical Reports Server (NTRS)

    Campbell, Jonathan W.; Howell, Joe T. (Technical Monitor)

    2001-01-01

    Increasing activity in space is gradually increasing the amount of orbital debris in low earth orbit. As the debris increases, the environmental risk (hypervelocity collisions) associated with spaceflight also increases. Debris larger than 10 cm can typically be detected and tracked sufficiently to allow risk avoidance to be achieved by maneuvering to safe distances. Risk reduction for objects smaller than I cm may be accomplished through shielding. However, intermediate sized debris remains a problem. A convenient risk reduction solution has been identified using modem laser technology. In this approach, a relatively low energy laser facility operating near e equator may significantly reduce the amount of intermediate sized debris (1 - 10 cm) in a few years of operation. A sufficiently intense laser pulse arriving at a debris objects surface will ablate a micro-thin layer of material. As this hot gas rapidly expands away from the object, a small change in momentum is imparted. The momentum change for one pulse is insignificant. However, since the laser can provide 10-1000 pulses per second over several minutes, the cumulative effect is substantive. The object's perigee may be lowered in this manner into atmosphere where it will be vaporized. This same technique may be employed on a larger scale for risk reduction in asteroids, meteoroids, and comets colliding with the Earth at hypervelocities.

  14. Active Debris Removal - A Grand Engineering Challenge for the Twenty-First Century

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi

    2010-01-01

    The collision between Iridium 33 and Cosmos 2251 in 2009 underlined the potential of an ongoing collision cascade effect (the Kessler Syndrome ) in the near-Earth orbital debris environment. A 2006 NASA analysis of the instability of the debris population in the low Earth orbit (LEO, the region below 2000 km altitude) shows that the environment has reached a point where the debris population will continue to increase in the next 200 years, even without any future launches. The increase is driven by fragments generated via collisions among existing objects in LEO. In reality, the situation will be worse than this prediction because satellite launches will continue and unexpected major breakups may continue to occur. Mitigation measures commonly adopted by the international space community (such as the 25-year rule) will help, but will be insufficient to stop the population growth. To better preserve the near-Earth space environment for future generations, active debris removal (ADR) should be considered. The idea of active debris removal is not new. However, due to the monumental technical, resource, operational, legal, and political challenges associated with removing objects from orbit, it has not yet been widely considered feasible. The recent major breakup events and the environment modeling efforts have certainly reignited the interest in using active debris removal to remediate the environment. This trend is further highlighted by the National Space Policy of the United States of America, released by the White House in June 2010, where the President explicitly directs NASA and the Department of Defense to pursue research and development of technology and techniques, to mitigate and remove on-orbit debris, reduce hazards, and increase understanding of the current and future debris environment. A 2009 modeling study by the NASA Orbital Debris Program Office has shown that, in order to maintain the LEO debris population at a constant level for the next 200 years

  15. The Effect of a Potentially Low Solar Cycle #24 on Orbital Lifetimes of Fengyun 1-C Debris

    NASA Technical Reports Server (NTRS)

    Whitlock, David; Johnson, Nicholas; Matney, Mark; Krisko, Paula

    2008-01-01

    The magnitude of Solar Cycle #24 will have a non-trivial impact on the lifetimes of debris pieces that resulted from the intentional hypervelocity impact of the Fengyun 1-C satellite in January 2007. Recent solar flux measurements indicate Solar Cycle #24 has begun in the last few months, and will continue until approximately 2019. While there have been differing opinions on whether the intensity of this solar cycle will be higher or lower than usual, the Space Weather Prediction Center within the National Oceanic Atmospheric Administration (NOAA/SWPC) has recently forecast unusually low solar activity, which would result in longer orbital lifetimes. Using models for both the breakup of Fengyun 1-C and the propagation of the resultant debris cloud, the Orbital Debris Program Office at NASA Johnson Space Center conducted a study to better understand the impact of the solar cycle on lifetimes for pieces as small as 1 mm. Using a modified collision breakup model and PROP3D propagation software, the orbits of nearly 2 million objects 1 mm and larger were propagated for up to 200 years. By comparing a normal solar cycle with that of the NOAA/SWPC forecast low cycle, the effect of the solar flux on the lifetimes of the debris pieces is evaluated. The modeling of the low solar cycle shows an additional debris count of 12% for pieces larger than 10 cm by 2019 when compared to the resultant debris count using a normal cycle. The difference becomes more exaggerated (over 15%) for debris count in the smaller size regimes. However, in 50 years, the models predict the differences in debris count from differing models of Solar Cycle #24 to be less than 10% for all size regimes, with less variance in the smaller sizes. Understanding the longevity of the debris cloud will affect collision probabilities for both operational spacecraft and large derelict objects over the next century and beyond.

  16. DebriSat Project Update and Planning

    NASA Technical Reports Server (NTRS)

    Sorge, M.; Krisko, P. H.

    2016-01-01

    DebriSat Reporting Topics: DebriSat Fragment Analysis Calendar; Near-term Fragment Extraction Strategy; Fragment Characterization and Database; HVI (High-Velocity Impact) Considerations; Requirements Document.

  17. Physical Properties of Supraglacial Debris on Mars

    NASA Astrophysics Data System (ADS)

    Baker, D. M. H.; Carter, L. M.

    2016-09-01

    The thickness and physical properties of surface debris preserving glacial ice in the mid-latitudes of Mars is assessed using crater morphology and radar sounding data. We suggest that this debris layer is much thicker than has been hypothesized.

  18. NASA Orbital Debris Requirements and Best Practices

    NASA Technical Reports Server (NTRS)

    Hull, Scott

    2014-01-01

    Limitation of orbital debris accumulation is an international and national concern, reflectedin NASA debris limitation requirements. These requirements will be reviewed, along with some practices that can be employed to achieve the requirements.

  19. Solid handling valve

    DOEpatents

    Williams, William R.

    1979-01-01

    The present invention is directed to a solids handling valve for use in combination with lock hoppers utilized for conveying pulverized coal to a coal gasifier. The valve comprises a fluid-actuated flow control piston disposed within a housing and provided with a tapered primary seal having a recessed seat on the housing and a radially expandable fluid-actuated secondary seal. The valve seals are highly resistive to corrosion, erosion and abrasion by the solids, liquids, and gases associated with the gasification process so as to minimize valve failure.

  20. Debris disks as seen by Herschel/DUNES

    NASA Astrophysics Data System (ADS)

    Löhne, T.; Eiroa, C.; Augereau, J.-C.; Ertel, S.; Marshall, J. P.; Mora, A.; Absil, O.; Stapelfeldt, K.; Thébault, P.; Bayo, A.; del Burgo, C.; Danchi, W.; Krivov, A. V.; Lebreton, J.; Letawe, G.; Magain, P.; Maldonado, J.; Montesinos, B.; Pilbratt, G. L.; White, G. J.; Wolf, S.

    2012-06-01

    The far-infrared excesses produced by debris disks are common features of stellar systems. These disks are thought to contain solids ranging from micron-sized dust to planetesimals. Naturally, their formation and evolution are linked to those of potential planets. With this motivation, the Herschel open time key programme DUNES (DUst around NEarby Stars) aims at further characterising known debris disks and discovering new ones in the regime explored by the Herschel space observatory. On the one hand, in their survey of 133 nearby FGK stars, DUNES discovered a class of extremely cold and faint debris disks, different from well-known disks such as the one around Vega in that their inferred typical grain sizes are rather large, indicating low dynamical excitation and low collision rates. On the other hand, for the more massive disk around the sun-like star HD 207129, well-resolved PACS images confirmed the ring-liked structure seen in HST images and provided valuable information for an in-depth study and benchmark for models. Employing both models for power-law fitting and collisional evolution we found the disk around HD 207129 to feature low collision rates and large grains, as well. Transport by means of Poynting-Robertson drag likely plays a role in replenishing the dust seen closer to the star, inside of the ring. The inner edge is therefore rather smooth and the contribution from the extended halo of barely bound grains is small. Both slowly self-stirring and planetary perturbations could potentially have formed and shaped this disk. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  1. Students' Strategies for Exception Handling

    ERIC Educational Resources Information Center

    Rashkovits, Rami; Lavy, Ilana

    2011-01-01

    This study discusses and presents various strategies employed by novice programmers concerning exception handling. The main contributions of this paper are as follows: we provide an analysis tool to measure the level of assimilation of exception handling mechanism; we present and analyse strategies to handle exceptions; we present and analyse…

  2. Students' Strategies for Exception Handling

    ERIC Educational Resources Information Center

    Rashkovits, Rami; Lavy, Ilana

    2011-01-01

    This study discusses and presents various strategies employed by novice programmers concerning exception handling. The main contributions of this paper are as follows: we provide an analysis tool to measure the level of assimilation of exception handling mechanism; we present and analyse strategies to handle exceptions; we present and analyse…

  3. The International Space Station and the Space Debris Environment: 10 Years On

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas; Klinkrad, Heiner

    2009-01-01

    tracked and cataloged have also been generated, but normally with even shorter orbital lifetimes. Finally, eight collision avoidance maneuvers have been performed to avoid potential collisions between ISS and large, tracked space debris. The most recent such maneuver was accomplished by ESA's Automated Transfer Vehicle, the Jules Verne, just three months before the 10th anniversary of the launch of ISS's first element.

  4. Space Debris: Its Causes and Management

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2002-01-01

    Orbital debris is internationally recognized as an environmental issue which needs to be addressed today to preserve near-Earth space for future generations. All major space agencies are committed to mitigating the growth of the debris environment. Many commercial space system operators have responded positively to orbital debris mitigation principles and recommendations. Orbital debris mitigation measures are most cost-effective if included in the design development phase.

  5. A Search for Optically Faint GEO Debris

    DTIC Science & Technology

    2011-09-01

    similar filter with the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American...Examples are the results from the European Space Debris Facility in the Canary Islands, MODEST (the Michigan orbital DEbris Survey Telescope at Cerro ...filter with the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American

  6. 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

  7. Puck collisions

    NASA Astrophysics Data System (ADS)

    Hauge, E. H.

    2012-09-01

    Collisions between two ice hockey pucks sliding on frictionless ice are studied, with both inelasticity and frictional contact between the colliding surfaces of the two pucks taken into account. The latter couples translational and rotational motion. The full solution depends on the sign and magnitude of the initial mismatch between the surface velocities at the point of contact. The initial state defines two physically distinct regimes for the friction coefficient. To illustrate the complexities, we discuss at length the typical situation (well known from curling) when puck number 1 is initially at rest, and is hit by puck number 2 with an arbitrary impact parameter, velocity and angular velocity. We find that the total outgoing angle between the pucks exceeds \\frac{1}{2}\\pi if and only if the collision leads to a net increase in the translational part of the kinetic energy. The conditions for this to happen are scrutinized, and the results are presented both analytically and numerically by a set of representative curves. This paper is written with an ambitious undergraduate, and her teacher, in mind.

  8. Applying Knowledge from Terrestrial Debris-Covered Glaciers to Constrain the Evolution of Martian Debris-Covered Ice

    NASA Astrophysics Data System (ADS)

    Koutnik, M. R.; Pathare, A. V.; Todd, C.; Waddington, E.; Christian, J. E.

    2016-09-01

    We will discuss the application of terrestrial knowledge on debris emplacement, the effects of debris on glacier-surface topography, debris transport by ice flow, deformation of debris-laden ice, and atmosphere-glacier feedbacks to Mars ice.

  9. LightForce: Orbital collision avoidance using ground-based laser induced photon pressure

    NASA Astrophysics Data System (ADS)

    Stupl, Jan; Mason, James; Marshall, William; Levit, Creon; Smith, Craig; Olivier, Scot; Pertica, Alex; De Vries, Wim

    2012-07-01

    We propose to employ small orbit perturbations, induced by photon pressure from ground-based laser illumination, for collision avoidance in space. Possible applications would be a) protecting space assets from impacts with debris and b) stabilizing the orbital debris environment. In comparison to schemes aimed at de-orbiting debris using laser ablation, collision avoidance requires much less force and hence needs less sophisticated laser/telescope systems. In earlier research we concluded that a system consisting of a 10kW class laser, directed by a 1.5m telescope with adaptive optics, could avoid a significant fraction of collisions in low earth orbit. This paper describes our recent efforts which include refining our original analysis, employing higher fidelity simulations and presenting our planned experimental approach.

  10. Sectional device handling tool

    DOEpatents

    Candee, Clark B.

    1988-07-12

    Apparatus for remotely handling a device in an irradiated underwater environment includes a plurality of tubular sections interconnected end-to-end to form a handling structure, the bottom section being adapted for connection to the device. A support section is connected to the top tubular section and is adapted to be suspended from an overhead crane. Each section is flanged at its opposite ends. Axially retractable bolts in each bottom flange are threadedly engageable with holes in the top flange of an adjacent section, each bolt being biased to its retracted position and retained in place on the bottom flange. Guide pins on each top flange cooperate with mating holes on adjacent bottom flanges to guide movement of the parts to the proper interconnection orientation. Each section carries two hydraulic line segments provided with quick-connect/disconnect fittings at their opposite ends for connection to the segments of adjacent tubular sections upon interconnection thereof to form control lines which are connectable to the device and to an associated control console.

  11. Orbital Debris and Future Environment Remediation

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi

    2011-01-01

    This slide presentation is an overview of the historical and current orbital debris environment. Included is information about: Projected growth of the future debris population, The need for active debris removal (ADR), A grand challenge for the 21st century and The forward path

  12. Microchemical Analysis Of Space Operation Debris

    NASA Technical Reports Server (NTRS)

    Cummings, Virginia J.; Kim, Hae Soo

    1995-01-01

    Report discusses techniques used in analyzing debris relative to space shuttle operations. Debris collected from space shuttle, expendable launch vehicles, payloads carried by space shuttle, and payloads carried by expendable launch vehicles. Optical microscopy, scanning electron microscopy with energy-dispersive spectrometry, analytical electron microscopy with wavelength-dispersive spectrometry, and X-ray diffraction chosen as techniques used in examining samples of debris.

  13. Simulations of SSLV Ascent and Debris Transport

    NASA Technical Reports Server (NTRS)

    Rogers, Stuart; Aftosmis, Michael; Murman, Scott; Chan, William; Gomez, Ray; Gomez, Ray; Vicker, Darby; Stuart, Phil

    2006-01-01

    A viewgraph presentation on Computational Fluid Dynamic (CFD) Simulation of Space Shuttle Launch Vehicle (SSLV) ascent and debris transport analysis is shown. The topics include: 1) CFD simulations of the Space Shuttle Launch Vehicle ascent; 2) Debris transport analysis; 3) Debris aerodynamic modeling; and 4) Other applications.

  14. RTF Analysis-Shuttle Debris Transport

    NASA Technical Reports Server (NTRS)

    Aftosmis, Michael

    2004-01-01

    This demo will rewew the findings of the Shuttle's Debris Transport analysis. The demo focuses on aero analysis of the entlre vehicle in ascent (orbiter, SRB and ET together at low Mach number) for debris transoort and determining maximum allowable debris sizes from various sources. We will present analysis results along with performance data of the simulation runs on Supercomputers such as Columbia.

  15. Analysis and Consequences of the Iridium 33-Cosmos 2251 Collision

    NASA Technical Reports Server (NTRS)

    Anz-Meador, P. D.; Liou, Jer-Chi

    2010-01-01

    The collision of Iridium 33 and Cosmos 2251, on 10 February 2009, was the first known unintentional hypervelocity collision in space of intact satellites. Iridium 33 was an active commercial telecommunications satellite, while Cosmos 2251 was a derelict communication satellite of the Strela-2M class. The collision occurred at a relative velocity of 11.6 km/s at an altitude of approximately 790 km over the Great Siberian Plain and near the northern apex of Cosmos 2251 s orbit. This paper describes the physical and orbital characteristics of the relevant spacecraft classes and reports upon our analysis of the resulting debris clouds size, mass, area-to-mass ratio, and relative velocity/directionality distributions. We compare these distributions to those predicted by the NASA breakup model and notable recent fragmentation events; in particular, we compare the area-to-mass ratio distribution for each spacecraft to that exhibited by the FY-1C debris cloud for the purpose of assessing the relative contribution of modern aerospace materials to debris clouds resulting from energetic collisions. In addition, we examine the long-term consequences of this event for the low Earth orbit (LEO) environment. Finally, we discuss "lessons learned", which may be incorporated into NASA s environmental models.

  16. Space Debris Detection and Analysis

    DTIC Science & Technology

    1994-02-28

    7F AD-A282 012 PL.-TR-94-206 Space Debris Detection and Analysis Robert H. Eather Ron Siewert Keo Consultants 27 Irving St. Brookline MA 02146 28...PERFORMING ORGANIZATION REPORT NUMBER Keo Consultants 27 Irving St. Brookline MA 02146 9. SPONSORINGI MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING

  17. A Passive Nuclear Debris Collector.

    ERIC Educational Resources Information Center

    Griffin, John J.; And Others

    1979-01-01

    Describes a nuclear debris collector which removes trace substances from the lower atmosphere during rainfall. Suggests that the collector could be implemented into courses at various educational levels and could result in developing a network for monitoring the geographical extent of nuclear contamination. (Author/SA)

  18. A Passive Nuclear Debris Collector.

    ERIC Educational Resources Information Center

    Griffin, John J.; And Others

    1979-01-01

    Describes a nuclear debris collector which removes trace substances from the lower atmosphere during rainfall. Suggests that the collector could be implemented into courses at various educational levels and could result in developing a network for monitoring the geographical extent of nuclear contamination. (Author/SA)

  19. Mass and Size Frequency Distribution of the Impact Debris from Disruption of Chondritic Meteorites

    NASA Technical Reports Server (NTRS)

    VanVeghten, T. W.; Flynn, G. J.; Durda, D. D.; Hart, S.; Asphaug, E.

    2003-01-01

    Since direct observation of the collision of asteroids in space is not always convenient for earthbound observers, we have undertaken simulations of these collisions using the NASA Ames Vertical Gun Range (AVGR). To simulate the collision of asteroids in space, and aluminum projectiles with velocities ranging from approx.1 to approx.6 km/sec were fired at 70g to approx.200 g fragments of chondritic meteorites. The target meteorite was placed in an evacuated chamber at the AVGR. Detectors, usually four, were set up around the target meteorite. These detectors consisted of aerogel and aluminum foil of varying thickness. The aerogel's purpose was to catch debris after the collision, and the aluminum foil.s purpose was to show the size of the debris particles through the size of the holes in the aluminum foil. Outside the chamber, a camera was set up to record high-speed film of the collision. This camera recorded at either 500 frames per second or 1000 frames per second. Three different types of targets were used for these tests. The first were actual meteorites, which varied in mineralogical composition, density, and porosity. The second type of target was a Hawaiian basalt, consisting of olivine phenocrysts in a porous matrix, which we thought might be similar to the chondritic meteorites, thus providing data for comparison. The final type was made out of Styrofoam. The Styrofoam was thought to simulate very low-density asteroids and comets.

  20. Photometric Studies of GEO Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Cowardin, Heather M.; Barker, Edwin; Abercromby, Kira J.; Foreman, Gary; Horstman, Matt

    2009-01-01

    The photometric signature of a debris object can be useful in determining what the physical characteristics of a piece of debris are. We report on optical observations in multiple filters of debris at geosynchronous Earth orbit (GEO). Our sample is taken from GEO objects discovered in a survey with the University of Michigan's 0.6-m aperture Schmidt telescope MODEST (for Michigan Orbital DEbris Survey Telescope), and then followed up in real-time with the SMARTS (Small and Medium Aperture Research Telescope System) 0.9-m at CTIO for orbits and photometry. Our goal is to determine 6 parameter orbits and measure colors for all objects fainter than R = 15 th magnitude that are discovered in the MODEST survey. At this magnitude the distribution of observed angular rates changes significantly from that of brighter objects. There are two objectives: 1. Estimate the orbital distribution of objects selected on the basis of two observational criteria: brightness (magnitude) and angular rates. 2. Obtain magnitudes and colors in standard astronomical filters (BVRI) for comparison with reflectance spectra of likely spacecraft materials. What is the faint debris likely to be? In this paper we report on the photometric results. For a sample of 50 objects, more than 90 calibrated sequences of R-B-V-I-R magnitudes have been obtained with the CTIO 0.9-m. For objects that do not show large brightness variations, the colors are largely redder than solar in both B-R and R-I. The width of the color distribution may be intrinsic to the nature of the surfaces, but also could be that we are seeing irregularly shaped objects and measuring the colors at different times with just one telescope. For a smaller sample of objects we have observed with synchronized CCD cameras on the two telescopes. The CTIO 0.9-m observes in B, and MODEST in R. The CCD cameras are electronically linked together so that the start time and duration of observations are the same to better than 50 milliseconds. Thus

  1. 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.

  2. Study the Space Debris Impact in the Early Stages of the Nano-Satellite Design

    NASA Astrophysics Data System (ADS)

    Mahdi, Mohammed Chessab

    2016-12-01

    The probability of KufaSat collisions with different sizes of orbital debris and with other satellites which operating in the same orbit during orbital lifetime was determined. Apogee/Perigee Altitude History was used to graph apogee and perigee altitudes over KufaSat lifetime. The required change in velocity for maneuvers necessary to reentry atmospheric within 25 years was calculated. The prediction of orbital lifetime of KufaSat using orbital parameters and engineering specifications as inputs to the Debris Assessment Software (DAS) was done, it has been verified that the orbital lifetime will not be more than 25 years after end of mission which is compatible with recommendation of Inter-Agency Space Debris Coordination Committee (IADC).

  3. Detecting debris flows using ground vibrations

    USGS Publications Warehouse

    LaHusen, Richard G.

    1998-01-01

    Debris flows are rapidly flowing mixtures of rock debris, mud, and water that originate on steep slopes. During and following volcanic eruptions, debris flows are among the most destructive and persistent hazards. Debris flows threaten lives and property not only on volcanoes but far downstream in valleys that drain volcanoes where they arrive suddenly and inundate entire valley bottoms. Debris flows can destroy vegetation and structures in their path, including bridges and buildings. Their deposits can cover roads and railways, smother crops, and fill stream channels, thereby reducing their flood-carrying capacity and navigability.

  4. Orbital Debris Research in the United States

    NASA Technical Reports Server (NTRS)

    Stansbery, Gene

    2009-01-01

    The presentation includes information about growth of the satellite population, the U.S. Space Surveillance Network, tracking and catalog maintenance, Haystack and HAX radar observation, Goldstone radar, the Michigan Orbital Debris Survey Telescope (MODEST), spacecraft surface examinations and sample of space shuttle impacts. GEO/LEO observations from Kwajalein Atoll, NASA s Orbital Debris Engineering Model (ORDEM2008), a LEO-to-GEO Environment Debris Model (LEGEND), Debris Assessment Software (DAS) 2.0, the NASA/JSC BUMPER-II meteoroid/debris threat assessment code, satellite reentry risk assessment, optical size and shape determination, work on more complicated fragments, and spectral studies.

  5. An optimal trajectory design for debris deorbiting

    NASA Astrophysics Data System (ADS)

    Ouyang, Gaoxiang; Dong, Xin; Li, Xin; Zhang, Yang

    2016-01-01

    The problem of deorbiting debris is studied in this paper. As a feasible measure, a disposable satellite would be launched, attach to debris, and deorbit the space debris using a technology named electrodynamic tether (EDT). In order to deorbit multiple debris as many as possible, a suboptimal but feasible and efficient trajectory set has been designed to allow a deorbiter satellite tour the LEO small bodies per one mission. Finally a simulation given by this paper showed that a 600 kg satellite is capable of deorbiting 6 debris objects in about 230 days.

  6. High-Performance Computer Modeling of the Cosmos-Iridium Collision

    SciTech Connect

    Olivier, S; Cook, K; Fasenfest, B; Jefferson, D; Jiang, M; Leek, J; Levatin, J; Nikolaev, S; Pertica, A; Phillion, D; Springer, K; De Vries, W

    2009-08-28

    This paper describes the application of a new, integrated modeling and simulation framework, encompassing the space situational awareness (SSA) enterprise, to the recent Cosmos-Iridium collision. This framework is based on a flexible, scalable architecture to enable efficient simulation of the current SSA enterprise, and to accommodate future advancements in SSA systems. In particular, the code is designed to take advantage of massively parallel, high-performance computer systems available, for example, at Lawrence Livermore National Laboratory. We will describe the application of this framework to the recent collision of the Cosmos and Iridium satellites, including (1) detailed hydrodynamic modeling of the satellite collision and resulting debris generation, (2) orbital propagation of the simulated debris and analysis of the increased risk to other satellites (3) calculation of the radar and optical signatures of the simulated debris and modeling of debris detection with space surveillance radar and optical systems (4) determination of simulated debris orbits from modeled space surveillance observations and analysis of the resulting orbital accuracy, (5) comparison of these modeling and simulation results with Space Surveillance Network observations. We will also discuss the use of this integrated modeling and simulation framework to analyze the risks and consequences of future satellite collisions and to assess strategies for mitigating or avoiding future incidents, including the addition of new sensor systems, used in conjunction with the Space Surveillance Network, for improving space situational awareness.

  7. Bulk material handling system

    DOEpatents

    Kleysteuber, William K.; Mayercheck, William D.

    1979-01-01

    This disclosure relates to a bulk material handling system particularly adapted for underground mining and includes a monorail supported overhead and carrying a plurality of conveyors each having input and output end portions with the output end portion of a first of the conveyors positioned above an input end portion of a second of the conveyors, a device for imparting motion to the conveyors to move the material from the input end portions toward the output end portions thereof, a device for supporting at least one of the input and output end portions of the first and second conveyors from the monorail, and the supporting device including a plurality of trolleys rollingly supported by the monorail whereby the conveyors can be readily moved therealong.

  8. A Critical Examination of Current On-Orbit Satellite Collision Risk Analysis Under Constraints of Public Data

    NASA Astrophysics Data System (ADS)

    Whitworth, Brandon; Moon, Mark; Pace, William; Baker, Robert

    2010-09-01

    The collision of Cosmos 2251 and Iridium 33 on 10 February 2009, made real the dangers of space operations without accurate situational awareness. A critical examination of the state of the art in collision risk assessment for on-orbit assets quickly reveals that it is inadequate to have provided satellite operators the opportunity to prevent the Cosmos-Iridium collision. Satellite operators need reliable information in a timely manner in order to take appropriate action. The shortfalls of publicly available orbit information place all spacecraft and missions at risk. The accuracy limitations of the General Perturbations(GP) catalog and orbit model(SGP-4) limit the effectiveness of current open source efforts. Beyond the accuracy limits, the relatively low frequency of updates for debris included in the catalog increases the uncertainty in time-space for inactive space objects such as Cosmos 2251. The current state of the art collision risk assessment includes advanced techniques such as expanding the GP model with covariance information which will allow uncertainty in the model to be accounted for in the on-orbit risk calculations. Covariance information can be estimated from consecutively published element sets for the same orbital object. A challenge to covariance estimation is that maneuvers or long periods of time between updates can skew the computed data. Once reliable covariance information is known and an efficient algorithm can be applied to find all of the close approaches between all cataloged objects then it is possible to estimate the collision risk for each close encounter with the tri-variate normal distribution. Unknown covariance will need to be handled in an appropriate way for a complete solution. Covariance information alone cannot solve the problem due to the relatively slow rate of update for all objects by the Space Surveillance Network(SSN) and there is no centralized source for planned and executed orbit changes for powered spacecraft. The

  9. Platelets: handle with care.

    PubMed

    Thomas, S

    2016-10-01

    Platelets are delicate cells that require careful handling between collection, preparation and transfusion. This review addresses practical questions relating to platelet concentration, resting time after collection, total time and number of periods without agitation and temperature. The bags in which platelets are stored are made from gas-permeable plastic to allow sufficient oxygen for the platelets to maintain aerobic respiration. Manufacturers have assigned limits for platelet content and concentration, and these must not be exceeded. There is no strong evidence for or against the resting of platelets post-collection and pre-agitation, but platelets should not be over-wrapped during this period as this compromises gas exchange; a short rest period of up to 1 h may allow the separation of minor aggregates. It is necessary to transport platelet concentrates (e.g. from manufacturing site to hospital), but these periods without gas exchange must be limited to avoid excessive damage to the platelets. Current data support a total of 24 h of transportation per component but with no individual period lasting more than 8 h. Platelets need to be stored at 20-24 °C based on evidence that colder storage leads to irreversible changes on the platelet membrane, resulting in phagocytosis of the platelets following transfusion. Storage at warmer temperatures may lead to an increase in bacterial risk. On the basis of this review, the UK Guidelines for Blood Transfusion Services have been updated to ensure that platelets are handled in the most appropriate way to ensure that efficacious components are provided for patients.

  10. Tracking Low Earth Orbit Small Debris with GPS Satellites as Bistatic Radar

    NASA Astrophysics Data System (ADS)

    Mahmud, M.; Qaisar, S.; Benson, C.

    2016-09-01

    Space debris is a growing problem and collisions are potentially lethal to satellites. Trajectories for small objects are predicted based on infrequent measurements, and the scale and therefore cost of maneuver required to avoid collisions is a function of trajectory accuracy. Frequent and precise observations will improve trajectory accuracy. In this paper, we extend on aspects of the feasibility of tracking space debris in Low Earth Orbit using emissions from GNSS satellites as bistatic radar illuminators. The wavelengths of GNSS signals are of order 20 cm and our primary focus is to track debris smaller than this, thereby maintaining phase stability of the scattered signals, enabling very long coherent processing intervals. However, the signals scattered by debris will be very weak at a terrestrial receiver, requiring the computationally expensive integration of a large number of signals, over an extended duration and with a large phased array. Detection of such weak signals in the presence of relatively strong direct-arrival signals requires extremely high cross-correlation protection. We show that sufficient cross-correlation protection can be obtained due to the large and varying Doppler shift, and also illustrate a novel processing approach utilizing downshifting of the collected signal to audio frequency. This technique dramatically reduces the cost and complexity of updating debris trajectories. The processing cost of preserving an uncertainty volume of many hundreds of meters around the predicted debris track is very modest, and searching within that uncertainty volume is undertaken at audio sampling rates. Moreover, we explore techniques that further lower the already modest cost of the non-linear search within the preserved uncertainty volume. We conclude with an outline of a system using these techniques that could provide centimetre level tracking of large quantities of small orbital objects at a modest cost.

  11. 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

  12. A Parametric Study on Using Active Debris Removal for LEO Environment Remediation

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Recent analyses on the instability of the orbital debris population in the low Earth orbit (LEO) region and the collision between Iridium 33 and Cosmos 2251 have reignited the interest in using active debris removal (ADR) to remediate the environment. There are; however, monumental technical, resource, operational, legal, and political challenges in making economically viable ADR a reality. Before a consensus on the need for ADR can be reached, a careful analysis of its effectiveness must be conducted. The goal is to demonstrate the need and feasibility of using ADR to better preserve the future environment and to guide its implementation to maximize the benefit-to-cost ratio. This paper describes a new sensitivity study on using ADR to stabilize the future LEO debris environment. The NASA long-term orbital debris evolutionary model, LEGEND, is used to quantify the effects of several key parameters, including target selection criteria/constraints and the starting epoch of ADR implementation. Additional analyses on potential ADR targets among the currently existing satellites and the benefits of collision avoidance maneuvers are also included.

  13. COLLISIONAL AND LUMINOSITY EVOLUTION OF A DEBRIS DISK: THE CASE OF HD 12039

    SciTech Connect

    Weidenschilling, S. J.

    2010-10-20

    Extrasolar debris disks that are bright enough to be observed are dense enough to be collision-dominated; i.e., the small grains that produce their infrared excess have collisional lifetimes shorter than their Poynting-Robertson decay times. This paper describes a numerical code for the modeling of such disks, including accretion and gravitational stirring as well as disruptive collisions. A constraint relating the mass of a debris disk and the sizes of the largest embedded bodies to its luminosity is demonstrated. The collisional code is applied to the debris disk around HD 12039, which has been intensively observed by the Spitzer Space Telescope. The evolution in time of the disk's luminosity is computed for a range of initial disk masses and planetesimal sizes. The luminosity at a given age depends on both the initial disk mass and the initial size of the planetesimals. Luminosity decays more rapidly for massive disks due to the combination of collisional depletion of small bodies and their accretion by bodies too large to contribute to dust production. Disks with low initial masses evolve slowly and can maintain their luminosities for {approx} Gyr timescales. This behavior may explain the lack of correlation between stellar metallicity and the abundance of debris disks.

  14. Evolution of the Debris Cloud Generated by the Fengyun-1C Fragmentation Event

    NASA Technical Reports Server (NTRS)

    Pardini, Carmen; Anselmo, Luciano

    2007-01-01

    The cloud of cataloged debris produced in low earth orbit by the fragmentation of the Fengyun-1C spacecraft was propagated for 15 years, taking into account all relevant perturbations. Unfortunately, the cloud resulted to be very stable, not suffering substantial debris decay during the time span considered. The only significant short term evolution was the differential spreading of the orbital planes of the fragments, leading to the formation of a debris shell around the earth approximately 7-8 months after the breakup, and the perigee precession of the elliptical orbits. Both effects will render the shell more "isotropic" in the coming years. The immediate consequence of the Chinese anti-satellite test, carried out in an orbital regime populated by many important operational satellites, was to increase significantly the probability of collision with man-made debris. For the two Italian spacecraft launched in the first half of 2007, the collision probability with cataloged objects increased by 12% for AGILE, in equatorial orbit, and by 38% for COSMO-SkyMed 1, in sun-synchronous orbit.

  15. Collision Avoidance Short Course Part I: Theory

    NASA Technical Reports Server (NTRS)

    Hejduk, Matthew D.

    2017-01-01

    Satellite conjunction assessment is perhaps the fastest-growing area in space situational awareness and protection, with military, civil, and commercial satellite owner operators embracing more and more sophisticated processes to avoid the avoidable namely collisions between high-value space assets and orbital debris. NASA and CNES have collaborated to offer an introductory short course on all the major aspects of the conjunction assessment problem. This half-day course will cover satellite conjunction dynamics and theory, JSpOC conjunction data products, major risk assessment parameters and plots, conjunction remediation decision support, and present and future challenges. This briefing represents the NASA portion of the course.

  16. Flexible Electrostatic Technologies for Capture and Handling, Phase 1

    NASA Technical Reports Server (NTRS)

    Bryan, Thomas

    2015-01-01

    Fundamental to many of NASA's in-space transportation missions is the capture and handling of various objects and vehicles in various orbits for servicing, debris disposal, sample retrieval, and assembly without the benefit of sufficient grapple fixtures and docking ports. To perform similar material handling tasks on Earth, pincher grippers, suction grippers, or magnetic chucks are used, but are unable to reliably grip aluminum and composite spacecraft, insulation, radiators, solar arrays, or extra-terrestrial objects in the vacuum of outer space without dedicated handles in the right places. The electronic Flexible Electrostatic Technologies for space Capture and Handling (FETCH) will enable reliable and compliant gripping (soft dock) of practically any object in various orbits or surfaces without dedicated mechanical features, very low impact capture, and built-in proximity sensing without any conventional actuators. Originally developed to handle semiconductor and glass wafers during vacuum chamber processing without contamination, the normal rigid wafer handling chucks are replaced with thin metal foil segments laminated in flexible insulation driven by commercial off-the-shelf solid state, high-voltage power supplies. Preliminary testing in NASA Marshall Space Flight Center's (MSFC's) Flat Floor Robotics Lab demonstrated compliant alignment and gripping with a full-sized, 150-lb microsat mockup and translation before a clean release with a flip of a switch. The flexible electrostatic gripper pads can be adapted to various space applications with different sizes, shapes, and foil electrode layouts even with openings through the gripper pads for addition of guidance sensors or injection of permanent adhesives. With gripping forces estimated between 0.5 and 2.5 lb/in2 or 70-300 lb/ft2 of surface contact, the FETCH can turn on and off rapidly and repeatedly to enable sample handling, soft docking, in-space assembly, precision relocation, and surface translation

  17. THE COLLISIONAL EVOLUTION OF DEBRIS DISKS

    SciTech Connect

    Gaspar, Andras; Rieke, George H.; Balog, Zoltan E-mail: grieke@as.arizona.edu

    2013-05-01

    We explore the collisional decay of disk mass and infrared emission in debris disks. With models, we show that the rate of the decay varies throughout the evolution of the disks, increasing its rate up to a certain point, which is followed by a leveling off to a slower value. The total disk mass falls off {proportional_to}t {sup -0.35} at its fastest point (where t is time) for our reference model, while the dust mass and its proxy-the infrared excess emission-fades significantly faster ({proportional_to}t {sup -0.8}). These later level off to a decay rate of M{sub tot}(t){proportional_to}t {sup -0.08} and M{sub dust}(t) or L{sub ir}(t){proportional_to}t {sup -0.6}. This is slower than the {proportional_to}t {sup -1} decay given for all three system parameters by traditional analytic models. We also compile an extensive catalog of Spitzer and Herschel 24, 70, and 100 {mu}m observations. Assuming a log-normal distribution of initial disk masses, we generate model population decay curves for the fraction of stars harboring debris disks detected at 24 {mu}m. We also model the distribution of measured excesses at the far-IR wavelengths (70-100 {mu}m) at certain age regimes. We show general agreement at 24 {mu}m between the decay of our numerical collisional population synthesis model and observations up to a Gyr. We associate offsets above a Gyr to stochastic events in a few select systems. We cannot fit the decay in the far-infrared convincingly with grain strength properties appropriate for silicates, but those of water ice give fits more consistent with the observations (other relatively weak grain materials would presumably also be successful). The oldest disks have a higher incidence of large excesses than predicted by the model; again, a plausible explanation is very late phases of high dynamical activity around a small number of stars. Finally, we constrain the variables of our numerical model by comparing the evolutionary trends generated from the exploration

  18. 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

  19. Developing Insights into Debris Disk Composition from Dust Scattering

    NASA Astrophysics Data System (ADS)

    Weinberger, Alycia

    Science Goals: To enable interpretation of visible to near-IR spectrophotometric imaging of debris disks, we propose realistic modeling of scattering of light by small aggregate dust grains and new laboratory measurements of meteoritic organic analogs. We will determine if disk colors, phase functions, and polarizations place unique constraints on the composition of debris dust. Ongoing collisions of planetesimals generate dust; therefore, the dust provides unique information on compositions of the parent bodies. These exosolar analogs of asteroids and comets bear clues to the history of a planetary system including migration and thermal processing. In the solar system, small bodies delivered volatiles to Earth, and they presumably play the same role for exoplanets. Because directly imaged debris disks are cold, they have no solid-state emission features. Grain scattering properties as a function of wavelength are our only tool to reveal their compositions. Hubble Space Telescope (HST) imaging showed debris disks to be populated with small grains, a few tenths of a micron and larger. Radiation pressure and blasting by the interstellar medium sweep the dust away. New work from HST and ground-based adaptive optics systems reveal the color and polarization of the scattered light at wavelengths from visible to near-IR, with two dozen disks imaged at some subset of wavelengths. Far-IR and submm images from Herschel and ALMA show that the same disks also contain large, i.e. mm-sized, grains. Our goal is to develop dust calculations so that spectrophotometry of disks can determine dust compositions. Solar system interplanetary dust particles are fluffy aggregates, but most previous work on debris disk composition relied on Mie theory, i.e. assumed compact spherical grains. Mie calculations do not reproduce the observed colors and phase functions observed from debris disks. The few more complex calculations that exist do not explore the range of compositions and sizes

  20. The Predicted Growth of the Low Earth Orbit Space Debris Environment: An Assessment of Future Risk for Spacecraft

    NASA Technical Reports Server (NTRS)

    Krisko, Paula H.

    2007-01-01

    Space debris is a worldwide-recognized issue concerning the safety of commercial, military, and exploration spacecraft. The space debris environment includes both naturally occuring meteoroids and objects in Earth orbit that are generated by human activity, termed orbital debris. Space agencies around the world are addressing the dangers of debris collisions to both crewed and robotic spacecraft. In the United States, the Orbital Debris Program Office at the NASA Johnson Space Center leads the effort to categorize debris, predict its growth, and formulate mitigation policy for the environment from low Earth orbit (LEO) through geosynchronous orbit (GEO). This paper presents recent results derived from the NASA long-term debris environment model, LEGEND. It includes the revised NASA sodium potassium droplet model, newly corrected for a factor of two over-estimation of the droplet population. The study indicates a LEO environment that is already highly collisionally active among orbital debris larger than 1 cm in size. Most of the modeled collision events are non-catastrophic (i.e., They lead to a cratering of the target, but no large scale fragmentation.). But they are potentially mission-ending, and take place between impactors smaller than 10 cm and targets larger than 10 cm. Given the small size of the impactor these events would likely be undetectable by present-day measurement means. The activity continues into the future as would be expected. Impact rates of about four per year are predicted by the current study within the next 30 years, with the majority of targets being abandoned intacts (spent upper stages and spacecraft). Still, operational spacecraft do show a small collisional activity, one that increases over time as the small fragment population increases.

  1. Collisions in space: A retrospective overview of ISAS studies

    NASA Astrophysics Data System (ADS)

    Uesugi, K.

    A chronological review of studies in ISAS concerning collisions in space is presented. The collision probability in space with artificial orbiting bodies was estimated, and a Space Traffic Control System was proposed, in 1971. The design of a space station for safety against collision hazards was discussed in 1972. A trajectory optimization technique for low-thrust multiple rendezvous mission in order ti sweep space debris around the earth was developed in 1977. In 1984, the collision probability was reestimated using space bedris data accumulated for more than a decade. Several experimental projects in ISAS, such as hypervelocity impact experiments using a railgun system, sampling and measuring of alumina particles in exhaust plume of solid-propellant propellant rocket motors, and a result of analysis on the behavior of such alumina particles in orbit are also introduced.

  2. Analysis of the effect of attachment point bias during large space debris removal using a tethered space tug

    NASA Astrophysics Data System (ADS)

    Chu, Zhongyi; Di, Jingnan; Cui, Jing

    2017-10-01

    Space debris occupies a valuable orbital resource and is an inevitable and urgent problem, especially for large space debris because of its high risk and the possible crippling effects of a collision. Space debris has attracted much attention in recent years. A tethered system used in an active debris removal scenario is a promising method to de-orbit large debris in a safe manner. In a tethered system, the flexibility of the tether used in debris removal can possibly induce tangling, which is dangerous and should be avoided. In particular, attachment point bias due to capture error can significantly affect the motion of debris relative to the tether and increase the tangling risk. Hence, in this paper, the effect of attachment point bias on the tethered system is studied based on a dynamic model established based on a Newtonian approach. Next, a safety metric of avoiding a tangle when a tether is tensioned with attachment point bias is designed to analyse the tangling risk of the tethered system. Finally, several numerical cases are established and simulated to validate the effects of attachment point bias on a space tethered system.

  3. Effects of Y-type spillway lateral contraction ratios on debris-flowpatterns and scour features downriver of a check dam

    NASA Astrophysics Data System (ADS)

    Chen, Huayong; Liu, Jinfeng; Zhao, Wanyu

    2016-11-01

    Debris flows often cause devastating damage to property and can injure or kill residents in mountainous areas. The construction of check dams in debris-flow valleys is considered a useful strategy for mitigating the damages downstream. In this paper, a new type of spillway structure with lateral contraction was proposed to distribute debris flows after the check dam storage filled up. Four different lateral contraction ratios of the spillway were considered in experiments that investigated debris-flow patterns, scour characteristics, and energy dissipation rates when debris flows passed through the spillway. The results indicated that lateral contraction considerably influenced the extension of debris-flow nappes. The drop length of the nappe at η = 0.7 (η means lateral contraction ratio) was approximately 1.4 times larger than at η = 0.4. The collision, friction, and mixing forces between the debris-flow nappes and debris flows in downstream plunge pools dissipated much of the debris-flow kinetic energy, ranging from 42.03 to 78.08 % at different contraction ratios. Additionally, based on a dimensionless analysis, an empirical model was proposed to predict the maximum scour depth downriver of a check dam. It indicated that the results calculated by the model exhibited good agreement with the experimental results.

  4. Handling of injectable antineoplastic agents.

    PubMed Central

    Knowles, R S; Virden, J E

    1980-01-01

    Although the clinical toxicity of antineoplastic drugs has been well documented there is little or no information on the problems that may arise on the handling and mishandling of such agents. This paper attempts to highlight the importance of taking precautions to prevent adverse effects resulting from contact with cytotoxic drugs during handling and to suggest a practical guide for the handling of such agents. PMID:7427382

  5. Debris flow study in Malaysia

    NASA Astrophysics Data System (ADS)

    Bahrin Jaafar, Kamal

    2016-04-01

    The phenomenon of debris flow occurs in Malaysia occasionally. The topography of Peningsular Malysia is characterized by the central mountain ranges running from south to north. Several parts of hilly areas with steep slopes, combined with high saturation of soil strata that deliberately increase the pore water pressure underneath the hill slope. As a tropical country Malaysia has very high intensity rainfall which is triggered the landslide. In the study area where the debris flow are bound to occur, there are a few factors that contribute to this phenomenon such as high rainfall intensity, very steep slope which an inclination more than 35 degree and sandy clay soil type which is easily change to liquidity soil. This paper will discuss the study of rainfall, mechanism, modeling and design of mitigation measure to avoid repeated failure in future in same area.

  6. Debris Disks and Hidden Planets

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2008-01-01

    When a planet orbits inside a debris disk like the disk around Vega or Beta Pictoris, the planet may be invisible, but the patterns it creates in the disk may give it away. Observing and decoding these patterns may be the only way we can detect exo-Neptunes orbiting more than 20 AU from their stars, and the only way we can spot planets in systems undergoing the late stages of planet formation. Fortunately, every few months, a new image of a debris disk appears with curious structures begging for explanation. I'll describe some new ideas in the theory of these planet-disk interactions and provide a buyers guide to the latest models (and the planets they predict).

  7. Workers Search for Columbia's Debris

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Members of a US Forest Service search team walk a grid during a Columbia recovery search near the Hemphill, Texas site. The group is accompanied by a space program worker able to identify potential hazards of Shuttle parts. Workers from every NASA Center and numerous federal, state, and local agencies searched for Columbia's debris in the recovery effort. For more information on STS-107, please see GRIN Columbia General Explanation

  8. Net Catches Debris From Explosion

    NASA Technical Reports Server (NTRS)

    Kahn, Jon B.; Schneider, William C.

    1992-01-01

    Device restrains fragments and absorbs their kinetic energy. Net of stitched webbing folds compactly over honeycomb plug. Attaches to frame mounted on wall around rectangular area to be cut out by explosion. Honeycomb panel absorbs debris from explosion and crumples into net. Dissipates energy by ripping about 9 in. of stitched net. Developed for emergency escape system in Space Shuttle, adaptable to restraint belts for vehicles; subjecting passengers to more gradual deceleration and less shock.

  9. Fate of Basin-forming Impact Debris from the Moon

    NASA Astrophysics Data System (ADS)

    Schultz, P. H.; Bruck Syal, M.; Raskin, C.; Owen, J. M.

    2016-12-01

    Recent work shows that projectile sizes for basin-forming impacts at the Moon are larger than previously estimated [1]. This finding has implications for the source regions of Late Heavy Bombardment impactors as well as added contributions from debris generated by similar basin-forming collisions. At such large scales, portions of the projectile fragment survive without interactions with the surface and continue downrange along the original trajectory. Such a process most likely occurs for oblique collisions (< 35° from the surface tangent) by bodies larger than 10% of the diameter of the Moon. For the SPA collision, more than 20% of the impacting body survives as newly generated Earth/Moon-crossing objects [2]. Over time some of this debris may have contributed to a spike in impact craters 20-50 km in diameter. Here we model lunar impact basin formation using Spheral, an adaptive Smoothed Particle Hydrodynamics code [3,4], focusing on the dynamical fate of basin ejecta and projectile fragments. Models employ self-gravity for the Moon and impactor and include the Earth's gravitational potential. Large impactors and the Moon are each assigned a two-layer, iron core and forsterite mantle structure. The problem is initialized using hydrostatic equlibrium profiles for pressure and density in both the impactor and target. We begin by modeling debris (target and impactor fragments) ejected from the South Pole-Aitken basin impact and extend the analysis to the Imbrium, Orientale, and Crisium basin formation. [1] Schultz, P.H., Crawford, D.A. Origin and implications of non-radial Imbrium Sculpture on the Moon, Nature 535, 391-394(2016). [2] Schultz, P.H., Crawford, D.A. Origin of nearside structural and geochemical anomalies on the Moon. GSA Special Papers 477, 141-159 (2011). [3] Owen, J. M. ASPH modeling of material damage and failure, in: Proceedings of the Fifth International SPHERIC Workshop, 297-304 (2010). [4] Owen, J. M. A compatibly differenced total energy

  10. Conjunctions and Collision Avoidance with Electrodynamic Tethers

    NASA Astrophysics Data System (ADS)

    Levin, E.

    2013-09-01

    Electrodynamic propulsion technology is currently in development by NASA, ESA, and JAXA for the purpose of affordable removal of large debris objects from LEO. At the same time, the Naval Research Laboratory is preparing a 3U CubeSat with a 1-km electrodynamic tether for a flight demonstration of electrodynamic propulsion. This type of propulsion does not require fuel. The electrodynamic thrust is the Lorentz force acting on the electric current in a long conductor (tether) in the geomagnetic field. Electrons are collected from the ambient plasma on one end and emitted back into the plasma from the other end. The electric current loop is closed through the ionosphere, as demonstrated in two previous flights. The vehicle is solar powered. To support safe navigation of electrodynamic tethers, proper conjunction analysis and collision avoidance strategies are needed. The typical lengths of electrodynamic tethers for near-term applications are measured in kilometers, and the conjunction geometry is very different from the geometry of conjunctions between compact objects. It is commonly thought that the collision cross-section in a conjunction between a tether and a compact object is represented by the product of the tether length and the size of the object. However, rigorous analysis shows that this is not the case, and that the above assumption leads to grossly overestimated collision probabilities. The paper will present the results of a detailed mathematical analysis of the conjunction geometry and collision probabilities in close approaches between electrodynamic tethers and compact objects, such as satellites, rocket bodies, and debris fragments. Electrodynamic spacecraft will not require fuel, and therefore, can thrust constantly. Their orbit transfers can take many days, but can result in major orbit changes, including large rotations of the orbital plane, both in the inclination and the node. During these orbit transfers, the electrodynamic spacecraft will

  11. Comparison of debris flux models

    NASA Astrophysics Data System (ADS)

    Sdunnus, H.; Beltrami, P.; Klinkrad, H.; Matney, M.; Nazarenko, A.; Wegener, P.

    The availability of models to estimate the impact risk from the man-made space debris and the natural meteoroid environment is essential for both, manned and unmanned satellite missions. Various independent tools based on different approaches have been developed in the past years. Due to an increased knowledge of the debris environment and its sources e.g. from improved measurement capabilities, these models could be updated regularly, providing more detailed and more reliable simulations. This paper addresses an in-depth, quantitative comparison of widely distributed debris flux models which were recently updated, namely ESA's MASTER 2001 model, NASA's ORDEM 2000 and the Russian SDPA 2000 model. The comparison was performed in the frame of the work of the 20t h Interagency Debris Coordination (IADC) meeting held in Surrey, UK. ORDEM 2000ORDEM 2000 uses careful empirical estimates of the orbit populations based onthree primary data sources - the US Space Command Catalog, the H ystackaRadar, and the Long Duration Exposure Facility spacecraft returned surfaces.Further data (e.g. HAX and Goldstone radars, impacts on Shuttle windows andradiators, and others) were used to adjust these populations for regions in time,size, and space not covered by the primary data sets. Some interpolation andextrapolation to regions with no data (such as projections into the future) wasprovided by the EVOLVE model. MASTER 2001The ESA MASTER model offers a full three dimensional description of theterrestrial debris distribution reaching from LEO up to the GEO region. Fluxresults relative to an orbiting target or to an inertial volume can be resolved intosource terms, impactor characteristics and orbit, as well as impact velocity anddirection. All relevant debris source terms are considered by the MASTERmodel. For each simulated source, a corresponding debris generation model interms of mass/diameter distribution, additional velocities, and directionalspreading has been developed. A

  12. BINARIES AMONG DEBRIS DISK STARS

    SciTech Connect

    Rodriguez, David R.; Zuckerman, B.

    2012-02-01

    We have gathered a sample of 112 main-sequence stars with known debris disks. We collected published information and performed adaptive optics observations at Lick Observatory to determine if these debris disks are associated with binary or multiple stars. We discovered a previously unknown M-star companion to HD 1051 at a projected separation of 628 AU. We found that 25% {+-} 4% of our debris disk systems are binary or triple star systems, substantially less than the expected {approx}50%. The period distribution for these suggests a relative lack of systems with 1-100 AU separations. Only a few systems have blackbody disk radii comparable to the binary/triple separation. Together, these two characteristics suggest that binaries with intermediate separations of 1-100 AU readily clear out their disks. We find that the fractional disk luminosity, as a proxy for disk mass, is generally lower for multiple systems than for single stars at any given age. Hence, for a binary to possess a disk (or form planets) it must either be a very widely separated binary with disk particles orbiting a single star or it must be a small separation binary with a circumbinary disk.

  13. 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.

  14. REMOTE HANDLING ARRANGEMENTS

    DOEpatents

    Ginns, D.W.

    1958-04-01

    A means for handling remotely a sample pellet to be irradiated in a nuclear reactor is proposed. It is comprised essentially of an inlet tube extending through the outer shield of the reactor and being inclined so that its outer end is at a higher elevation than its inner end, an outlet tube extending through the outer shield being inclined so that its inner end is at a higher elevation than its outer end, the inner ends of these two tubes being interconnected, and a straight tube extending through the outer shield and into the reactor core between the inlet and outlet tubes and passing through the juncture of said inner ends. A rod-like member is rotatably and slidely operated within the central straight tube and has a receptacle on its inner end for receiving a sample pellet from the inlet tube. The rod member is operated to pick up a sample pellet from the inlet tube, carry the sample pellet into the irradiating position within the core, and return to the receiving position where it is rotated to dump the irradiated pellet into the outlet tube by which it is conveyed by gravity to the outside of the reactor. Stop members are provided in the inlet tube, and electrical operating devices are provided to control the sequence of the operation automatically.

  15. Space Shuttle Solid Rocket Booster Debris Assessment

    NASA Technical Reports Server (NTRS)

    Kendall, Kristin; Kanner, Howard; Yu, Weiping

    2006-01-01

    The Space Shuttle Columbia Accident revealed a fundamental problem of the Space Shuttle Program regarding debris. Prior to the tragedy, the Space Shuttle requirement stated that no debris should be liberated that would jeopardize the flight crew and/or mission success. When the accident investigation determined that a large piece of foam debris was the primary cause of the loss of the shuttle and crew, it became apparent that the risk and scope of - damage that could be caused by certain types of debris, especially - ice and foam, were not fully understood. There was no clear understanding of the materials that could become debris, the path the debris might take during flight, the structures the debris might impact or the damage the impact might cause. In addition to supporting the primary NASA and USA goal of returning the Space Shuttle to flight by understanding the SRB debris environment and capability to withstand that environment, the SRB debris assessment project was divided into four primary tasks that were required to be completed to support the RTF goal. These tasks were (1) debris environment definition, (2) impact testing, (3) model correlation and (4) hardware evaluation. Additionally, the project aligned with USA's corporate goals of safety, customer satisfaction, professional development and fiscal accountability.

  16. What Children Tell Us about Their Parents: From Visible Dust to Invisible Planetesimals in Debris Disks

    NASA Astrophysics Data System (ADS)

    Mueller, Sebastian; Krivov, A. V.; Loehne, T.; Mutschke, H.

    2008-09-01

    Various small body families in the solar system, together with dust they produce through mutual collisions and cometary activity, exemplify a non-planetary component of a planetary system, usually referred to as a "debris disk". Debris disks have been found to be a common phenomenon for main-sequence stars and, similar to the solar system, are believed to comprise planetesimal populations that have accreted at early epochs and survived possible planet formation. However, in contrast to the solar system, observations of extrasolar debris disks only show their dusty portion, whereas the dust-producing planetesimals remain invisible. We show how collisional models of debris disks can be used to "climb up" the ladder of the collisional cascade, from dust towards parent bodies, representing the main mass reservoir of the disks. Applying our approach to five sun-like stars known to harbor dust, we find that the observed excess emission in far-IR to sub-mm is compatible with debris disks collisionally sustained by "large Kuiper belts" of 0.2-50 earth masses (in the bodies up to 100 km in size) with radii of 100-200 AU, larger than thought before. This research has been funded by the Deutsche Forschungsgemeinschaft (DFG), projects Kr 2164/5-1 and Mu 1164/6-1, by the Deutscher Akademischer Austauschdienst (DAAD), project D/0707543, and by the International Space Science Institute (Bern).

  17. Gas and Dust in Debris Disks: Clues to the Late Stages of Planet Formation

    NASA Technical Reports Server (NTRS)

    Roberge, Aki

    2012-01-01

    The basic character of debris disks was established soon after their discovery in the mid- 1980's. These disks around nearby main sequence stars are composed of material (mostly dust) produced by collisions and/or evaporation of extrasolar asteroids and comets. However, fundamental observational questions about debris disks remain unanswered. How much material do debris disks typically contain and how does it evolve with time? What is the composition of their dust and gas? Are planets present or forming in the disks? Answers to these questions will provide insights into the late stages of planetary system formation and the origins of terrestrial planet atmospheres. In this talk, I will explain our current understanding of the place of debris disks in the planet formation process. Progress toward addressing the questions given above will be discussed, with emphasis on recent studies of the small but important gas component. Finally, I will outline the implications of debris dust for future efforts to directly image and characterize extrasolar terrestrial planets.

  18. Gas and Dustin Debris Disks: Clues to the Late Stages of Planet Formation

    NASA Technical Reports Server (NTRS)

    Roberge, Aki

    2010-01-01

    The basic character of debris disks was established soon after their discovery in the mid- 1980's. These disks around nearby main sequence stars are composed of material (mostly dust) produced by collisions and/or evaporation of extrasolar asteroids and comets. However, fundamental observational questions about debris disks remain unanswered. How much material do debris disks typically contain and how does it evolve with time? What is the composition of their dust and gas? Are planets present or forming in the disks? Answers to these questions will provide insights into the late-stages of planetary system formation and the origins of terrestrial planet atmospheres. In this talk, I will explain our current understanding of the place of debris disks in the planet formation process. Progress toward addressing the questions given above will be discussed, with emphasis on recent studies of the small but important gas component. Finally, I will outline the implications of debris dust for future efforts to directly image and characterize extrasolar terrestrial planets.

  19. Tethers as Debris: Hydrocode Simulation of Impacts of Tether Fragments on Planar Aerospace Materials

    NASA Technical Reports Server (NTRS)

    Evans, Steven W.; Parker, Nelson C. (Technical Monitor)

    2002-01-01

    Tethers promise to find use in a variety of space applications. Despite being narrow objects, their great lengths result in them having large total areas, and so tethers are quite susceptible to being severed by orbital debris. Extensive work has been done designing tethers that resist severs by small debris objects, and hence have longer working lives. It is from this perspective that most recent work has considered the tether - debris question. The potential of intact tethers, or severed tether fragments, as debris to pose a significant collision risk to other spacecraft has been less well studied. Understanding the consequences of such encounters is important in assessing the risks to other spacecraft posed by tethers. In this paper I discuss the damage that two types of tethers may produce on planar aerospace materials, as revealed by hyper- velocity impact simulations using the SPHC hydrodynamic code. Tether types considered include a single nylon line and a complex design including metal wires. Target materials considered include the aluminum plates typically used in debris shielding, and solar panels.

  20. Total Probability of Collision as a Metric for Finite Conjunction Assessment and Collision Risk Management

    NASA Astrophysics Data System (ADS)

    Frigm, R.; Johnson, L.

    The Probability of Collision (Pc) has become a universal metric and statement of on-orbit collision risk. Although several flavors of the computation exist and are well-documented in the literature, the basic calculation requires the same input: estimates for the position, position uncertainty, and sizes of the two objects involved. The Pc is used operationally to make decisions on whether a given conjunction poses significant collision risk to the primary object (or space asset of concern). It is also used to determine necessity and degree of mitigative action (typically in the form of an orbital maneuver) to be performed. The predicted post-maneuver Pc also informs the maneuver planning process into regarding the timing, direction, and magnitude of the maneuver needed to mitigate the collision risk. Although the data sources, techniques, decision calculus, and workflows vary for different agencies and organizations, they all have a common thread. The standard conjunction assessment and collision risk concept of operations (CONOPS) predicts conjunctions, assesses the collision risk (typically, via the Pc), and plans and executes avoidance activities for conjunctions as a discrete events. As the space debris environment continues to increase and improvements are made to remote sensing capabilities and sensitivities to detect, track, and predict smaller debris objects, the number of conjunctions will in turn continue to increase. The expected order-of-magnitude increase in the number of predicted conjunctions will challenge the paradigm of treating each conjunction as a discrete event. The challenge will not be limited to workload issues, such as manpower and computing performance, but also the ability for satellite owner/operators to successfully execute their mission while also managing on-orbit collision risk. Executing a propulsive maneuver occasionally can easily be absorbed into the mission planning and operations tempo; whereas, continuously planning evasive

  1. Debris Flow Distributed Propagation Model

    NASA Astrophysics Data System (ADS)

    Gregoretti, C.

    The debris flow distributed propagation model is a DEM-based model. The fan is dis- cretized by square cells and each cell is assigned an altitude on the sea level. The cells of the catchment are distinguished in two categories: the source cells and the stripe cells. The source cells receive the input hydograph: the cells close to the torrent which are flooded by the debris flow overflowing the torrent embankment are source cells. The stripes cells are the cells flooded by debris flow coming from the surrounding cells. At the first time step only the source cells are flooded by debris flow coming from the torrent. At the second time step a certain number of cells are flooded by de- bris flow coming from the source cells. These cells constitute a stripe of cells and are assigned order two. At the third time step another group of cells are flooded by the debris flow coming from the cells whose order is two. These cells constitute another stripe and are assigned order three. The cell order of a stripe is the time step number corresponding to the transition from dry to flooded state. The mass transfer or mo- mentum exchange between cells is governed by two different mechanisms. The mass transfer is allowed only by a positive or equal to zero flow level difference between the drained cell and the receiving cell. The mass transfer is limited by a not negative final flow level difference between the drained cell and the receiving cells. This limitation excludes the case of possible oscillations in the mass transfer. Another limitation is that the mass drained by a cell should be less than the available mass in that cell. This last condition provides the respect of mass conservation. The first mechanism of mass transfer is the gravity. The mass in a cell is transferred to the neighbouring cells with lower altitude and flow level according to an uniform flow law: The second mecha- nism of mass transfer is the broad crested weir. The mass in a cell is transferred to the

  2. Location and origin of dust in circumstellar debris disks: A mid-infrared imaging study

    NASA Astrophysics Data System (ADS)

    Moerchen, Margaret Marie

    Approximately one third of A-type stars host dusty disks beyond the expected timescales for dissipation of the primordial disk material. The primordial dust particles may either be blown out by radiation pressure from the star or they may experience destructive collisions that generate smaller particles that are then blown out of the system. We infer from the sustained presence of the dust that it must be resupplied through collisions of already-formed planets and planetesimals or through the sublimation of cometary bodies, and systems with such dust are called debris disks. Since the 1984 discovery of the debris disk Vega, observations of circumstellar debris disks have revealed the presence planetary systems that would otherwise have remained unknown. In this work, we set out to find asymmetric structures in debris disks that would indicate a physical process sculpting the disk, such as a catastrophic planetesimal collision that generates a bright region of newly-formed dust, or a clumpy pattern comprised of dust that is trapped in an orbital resonance with a giant planet. We obtained high spatial resolution ([Special characters omitted.] 0.5") images of the thermally emitting dust in 21 debris disk candidates (some of which are now known not to be debris disks), and in most cases we did not detect any brightness asymmetry nor was the source even spatially resolved. However, among the resolved disks, we have discovered several structures that may be analogous to those in our own solar system, such as a potential asteroid belts (in z Lep) and a snow line (in HD 32297). One brightness asymmetry is seen, in the disk of 16 HR 4796A, and we have determined that the bright side of the disk is also hotter than the opposite side. We review the possible origins of such a temperature asymmetry in the dust disk, such as pericenter glow and resonant trapping, and this investigation is ongoing. More generally, two disk archetypes are observed among all of the disks in this

  3. Target selection and comparison of mission design for space debris removal by DLR's advanced study group

    NASA Astrophysics Data System (ADS)

    van der Pas, Niels; Lousada, Joao; Terhes, Claudia; Bernabeu, Marc; Bauer, Waldemar

    2014-09-01

    Space debris is a growing problem. Models show that the Kessler syndrome, the exponential growth of debris due to collisions, has become unavoidable unless an active debris removal program is initiated. The debris population in LEO with inclination between 60° and 95° is considered as the most critical zone. In order to stabilize the debris population in orbit, especially in LEO, 5 to 10 objects will need to be removed every year. The unique circumstances of such a mission could require that several objects are removed with a single launch. This will require a mission to rendezvous with a multitude of objects orbiting on different altitudes, inclinations and planes. Removal models have assumed that the top priority targets will be removed first. However this will lead to a suboptimal mission design and increase the ΔV-budget. Since there is a multitude of targets to choose from, the targets can be selected for an optimal mission design. In order to select a group of targets for a removal mission the orbital parameters and political constraints should also be taken into account. Within this paper a number of the target selection criteria are presented. The possible mission targets and their order of retrieval is dependent on the mission architecture. A comparison between several global mission architectures is given. Under consideration are 3 global missions of which a number of parameters are varied. The first mission launches multiple separate deorbit kits. The second launches a mother craft with deorbit kits. The third launches an orbital tug which pulls the debris in a lower orbit, after which a deorbit kit performs the final deorbit burn. A RoM mass and cost comparison is presented. The research described in this paper has been conducted as part of an active debris removal study by the Advanced Study Group (ASG). The ASG is an interdisciplinary student group working at the DLR, analyzing existing technologies and developing new ideas into preliminary

  4. Super-Penrose process due to collisions inside ergosphere

    NASA Astrophysics Data System (ADS)

    Zaslavskii, O. B.

    If two particles collide inside the ergosphere, the energy in the center of mass frame can be made unbound provided at least one of particles has a large negative angular momentum [A. A. Grib and Yu. V. Pavlov, Europhys. Lett. 101 (2013) 20004]. We show that the same condition can give rise to unbounded Killing energy of debris at infinity, i.e. super-Penrose process. Proximity of the point of collision to the black hole horizon is not required.

  5. Simulation of the space debris environment in LEO using a simplified approach

    NASA Astrophysics Data System (ADS)

    Kebschull, Christopher; Scheidemann, Philipp; Hesselbach, Sebastian; Radtke, Jonas; Braun, Vitali; Krag, H.; Stoll, Enrico

    2017-01-01

    Several numerical approaches exist to simulate the evolution of the space debris environment. These simulations usually rely on the propagation of a large population of objects in order to determine the collision probability for each object. Explosion and collision events are triggered randomly using a Monte-Carlo (MC) approach. So in many different scenarios different objects are fragmented and contribute to a different version of the space debris environment. The results of the single Monte-Carlo runs therefore represent the whole spectrum of possible evolutions of the space debris environment. For the comparison of different scenarios, in general the average of all MC runs together with its standard deviation is used. This method is computationally very expensive due to the propagation of thousands of objects over long timeframes and the application of the MC method. At the Institute of Space Systems (IRAS) a model capable of describing the evolution of the space debris environment has been developed and implemented. The model is based on source and sink mechanisms, where yearly launches as well as collisions and explosions are considered as sources. The natural decay and post mission disposal measures are the only sink mechanisms. This method reduces the computational costs tremendously. In order to achieve this benefit a few simplifications have been applied. The approach of the model partitions the Low Earth Orbit (LEO) region into altitude shells. Only two kinds of objects are considered, intact bodies and fragments, which are also divided into diameter bins. As an extension to a previously presented model the eccentricity has additionally been taken into account with 67 eccentricity bins. While a set of differential equations has been implemented in a generic manner, the Euler method was chosen to integrate the equations for a given time span. For this paper parameters have been derived so that the model is able to reflect the results of the numerical MC

  6. ADIFOR exception handling

    SciTech Connect

    Bischof, C.; Corliss, G.; Griewank, A.

    1992-01-01

    Automatic differentiation uses recurrence relations based on the rules of calculus. Consequently, the results are guaranteed to be correct only in the relevant mathematical assumptions are satisfied at least in a neighborhood of the current argument. Computer programs may violate these conditions by branching or by calling intrinsic functions such as abs, max, sqrt, and asin at point where their derivative is undefined or infinite. The resulting dependence between the program's input and output variables may still be differentiable, because branch vales fit together smoothly or nondifferentiabilities cancel each other out. We have two objectives. First, we would like to assure the user that the function being evaluated is indeed locally differentiable because all intrinsics are evaluated at smooth arguments and none of the branching tests are critical. Second, the derivative program should run even when the assumptions of the chain rule are not strictly satisfied. In this case, the numerical results represent at least generalized derivations under reasonable (but usually unverifiable) regularity assumptions. To achieve these two goals, we must take into account the effects of finite-precision arithmetic. This paper addresses the detection and handling of exceptions. It is an exception in the ADIFOR-generated code to evaluate a function at a point at which the function may not be mathematically differentiable. When an exception is detected by tests written into the ADIFOR-generated code, an error handler is called. The error handler prints an error message (optionally), halts execution (optionally), and returns a value that allows the user's client program to detect that a requested derivative is not available. Code is included for all of the necessary Fortran intrinsic functions and for the error handler.

  7. Sedimentology, Behavior, and Hazards of Debris Flows at Mount Rainier, Washington

    USGS Publications Warehouse

    Scott, K.M.; Vallance, J.W.; Pringle, P.T.

    1995-01-01

    Mount Rainier is potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes, active hydrothermal system, and extensive glacier mantle. Many debris flows and their distal phases have inundated areas far from the volcano during postglacial time. Two types of debris flows, cohesive and noncohesive, have radically different origins and behavior that relate empirically to clay content. The two types are the major subpopulations of debris flows at Mount Rainier. The behavior of cohesive flows is affected by the cohesion and adhesion of particles; noncohesive flows are dominated by particle collisions to the extent that particle cataclasis becomes common during near-boundary shear. Cohesive debris flows contain more than 3 to 5 percent of clay-size sediment. The composition of these flows changed little as they traveled more than 100 kilometers from Mount Rainier to inundate parts of the now-populated Puget Sound lowland. They originate as deep-seated failures of sectors of the volcanic edifice, and such failures are sufficiently frequent that they are the major destructional process of Mount Rainier's morphologic evolution. In several deposits of large cohesive flows, a lateral, megaclast-bearing facies (with a mounded or hummocky surface) contrasts with a more clay-rich facies in the center of valleys and downstream. Cohesive flows at Mount Rainier do not correlate strongly with volcanic activity and thus can recur without warning, possibly triggered by non-magmatic earthquakes or by changes in the hydrothermal system. Noncohesive debris flows contain less than 3 to 5 percent clay-size sediment. They form most commonly by bulking of sediment in water surges, but some originate directly or indirectly from shallow slope failures that do not penetrate the hydrothermally altered core of the volcano. In contrast with cohesive flows, most noncohesive flows transform both from and to other flow types and are, therefore, the

  8. Fluid handling equipment: A compilation

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Devices and techniques used in fluid-handling and vacuum systems are described. Section 1 presents several articles on fluid lines and tubing. Section 2 describes a number of components such as valves, filters, and regulators. The last section contains descriptions of a number of innovative fluid-handling systems.

  9. 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.

  10. 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.

  11. Evaluating tsunami hazards from debris flows

    USGS Publications Warehouse

    Watts, P.; Walder, J.S.; ,

    2003-01-01

    Debris flows that enter water bodies may have significant kinetic energy, some of which is transferred to water motion or waves that can impact shorelines and structures. The associated hazards depend on the location of the affected area relative to the point at which the debris flow enters the water. Three distinct regions (splash zone, near field, and far field) may be identified. Experiments demonstrate that characteristics of the near field water wave, which is the only coherent wave to emerge from the splash zone, depend primarily on debris flow volume, debris flow submerged time of motion, and water depth at the point where debris flow motion stops. Near field wave characteristics commonly may be used as & proxy source for computational tsunami propagation. This result is used to assess hazards associated with potential debris flows entering a reservoir in the northwestern USA. ?? 2003 Millpress,.

  12. The impact of debris on marine life.

    PubMed

    Gall, S C; Thompson, R C

    2015-03-15

    Marine debris is listed among the major perceived threats to biodiversity, and is cause for particular concern due to its abundance, durability and persistence in the marine environment. An extensive literature search reviewed the current state of knowledge on the effects of marine debris on marine organisms. 340 original publications reported encounters between organisms and marine debris and 693 species. Plastic debris accounted for 92% of encounters between debris and individuals. Numerous direct and indirect consequences were recorded, with the potential for sublethal effects of ingestion an area of considerable uncertainty and concern. Comparison to the IUCN Red List highlighted that at least 17% of species affected by entanglement and ingestion were listed as threatened or near threatened. Hence where marine debris combines with other anthropogenic stressors it may affect populations, trophic interactions and assemblages. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Determination of electron-nucleus collisions geometry with forward neutrons

    DOE PAGES

    Zheng, L.; Aschenauer, E.; Lee, J. H.

    2014-12-29

    There are a large number of physics programs one can explore in electron-nucleus collisions at a future electron-ion collider. Collision geometry is very important in these studies, while the measurement for an event-by-event geometric control is rarely discussed in the prior deep-inelastic scattering experiments off a nucleus. This paper seeks to provide some detailed studies on the potential of tagging collision geometries through forward neutron multiplicity measurements with a zero degree calorimeter. As a result, this type of geometry handle, if achieved, can be extremely beneficial in constraining nuclear effects for the electron-nucleus program at an electron-ion collider.

  14. Debris Removal: An Opportunity for Cooperative Research?

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2007-01-01

    Space debris mitigation practices will be insufficient to prevent the continued growth of the Earth satellite population. Removal of orbital debris can improve the reliability of present and future space systems. The challenges of developing an effective, affordable debris removal capability are considerable. The time is right for a new look at space remediation concepts. In concert with or following the current IAA study An international approach to the remediation of the near-Earth space environment will likely be required.

  15. Debris dams and the relief of headwater streams.

    Treesearch

    S.T. Lancaster; G.E. Grant

    2005-01-01

    In forested, mountain landscapes where debris flows are common, valley-spanning debris dams formed by debris-flow deposition are a common feature of headwater valleys. In this paper, we examine how wood and boulder steps, i.e., debris dams, affect longitudinal profile relief and gradient at the debris-flow-fluvial transition in three sites in the Oregon Coast Range,...

  16. Best Mitigation Paths To Effectively Reduce Earth's Orbital Debris

    NASA Technical Reports Server (NTRS)

    Wiegman, Bruce M.

    2009-01-01

    This slide presentation reviews some ways to reduce the problem posed by debris in orbit around the Earth. It reviews the orbital debris environment, the near-term needs to minimize the Kessler syndrome, also known as collisional cascading, a survey of active orbital debris mitigation strategies, the best paths to actively remove orbital debris, and technologies that are required for active debris mitigation.

  17. Variations in debris distribution and thickness on Himalayan debris-covered glaciers

    NASA Astrophysics Data System (ADS)

    Gibson, Morgan; Rowan, Ann; Irvine-Fynn, Tristram; Quincey, Duncan; Glasser, Neil

    2016-04-01

    Many Himalayan glaciers are characterised by extensive supraglacial debris coverage; in Nepal 33% of glaciers exhibit a continuous layer of debris covering their ablation areas. The presence of such a debris layer modulates a glacier's response to climatic change. However, the impact of this modulation is poorly constrained due to inadequate quantification of the impact of supraglacial debris on glacier surface energy balance. Few data exist to describe spatial and temporal variations in parameters such as debris thickness, albedo and surface roughness in energy balance calculations. Consequently, improved understanding of how debris affects Himalayan glacier ablation requires the assessment of surface energy balance model sensitivity to spatial and temporal variability in these parameters. Measurements of debris thickness, surface temperature, reflectance and roughness were collected across Khumbu Glacier during the pre- and post-monsoon seasons of 2014 and 2015. The extent of the spatial variation in each of these parameters are currently being incorporated into a point-based glacier surface energy balance model (CMB-RES, Collier et al., 2014, The Cryosphere), applied on a pixel-by-pixel basis to the glacier surface, to ascertain the sensitivity of glacier surface energy balance and ablation values to these debris parameters. A time series of debris thickness maps have been produced for Khumbu Glacier over a 15-year period (2000-2015) using Mihalcea et al.'s (2008, Cold Reg. Sci. Technol.) method, which utilised multi-temporal ASTER thermal imagery and our in situ debris surface temperature and thickness measurements. Change detection between these maps allowed the identification of variations in debris thickness that could be compared to discrete measurements, glacier surface velocity and morphology of the debris-covered area. Debris thickness was found to vary spatially between 0.1 and 4 metres within each debris thickness map, and temporally on the order of 1

  18. Mechanical aggregation of enstatite chondrites from an inhomogeneous debris cloud

    NASA Astrophysics Data System (ADS)

    Leitch, C. A.; Smith, J. V.

    1981-03-01

    Enstatite chondrites have oxygen isotope ratios closer to those of the earth and moon than other meteorites. Their minerals are chemically reduced; metal contains Si, and some Ca, Ti, Mg and Mn are incorporated in sulphides rather than silicates. Clinoenstatite and olivine are virtually Fe-free. Two types of clinoenstatite in the Indarch enstatite chondrite have been reported, one luminescing blue and one red. Similar clinoenstatites in the Kota-Kota enstatite chondrite are associated with two distinct types of forsteritic olivine, one luminescing orange and the other blue. The textural relations and differences in chemical composition cannot be explained by progressive condensation from the solar nebula and require the mechanical mixing of material from at least two sources. It is suggested here that enstatite chondrites result from mechanical and chemical processes during aerodynamic sorting and gravitational settling of debris from a hot cloud of dust, liquid and gas produced during collision of planetesimals.

  19. Implementation of an open-scenario, long-term space debris simulation approach

    NASA Astrophysics Data System (ADS)

    Stupl, J.; Nelson, B.; Faber, N.; Perez, A.; Carlino, R.; Yang, F.; Henze, C.; Karacalioglu, A.; O'Toole, C.; Swenson, J.

    This paper provides a status update on the implementation of a flexible, long-term space debris simulation approach. The motivation is to build a tool that can assess the long-term impact of various options for debris-remediation, including the LightForce space debris collision avoidance scheme. State-of-the-art simulation approaches that assess the long-term development of the debris environment use either completely statistical approaches, or they rely on large time steps in the order of several (5-15) days if they simulate the positions of single objects over time. They cannot be easily adapted to investigate the impact of specific collision avoidance schemes or de-orbit schemes, because the efficiency of a collision avoidance maneuver can depend on various input parameters, including ground station positions, space object parameters and orbital parameters of the conjunctions and take place in much smaller timeframes than 5-15 days. For example, LightForce only changes the orbit of a certain object (aiming to reduce the probability of collision), but it does not remove entire objects or groups of objects. In the same sense, it is also not straightforward to compare specific de-orbit methods in regard to potential collision risks during a de-orbit maneuver. To gain flexibility in assessing interactions with objects, we implement a simulation that includes every tracked space object in LEO, propagates all objects with high precision, and advances with variable-sized time-steps as small as one second. It allows the assessment of the (potential) impact of changes to any object. The final goal is to employ a Monte Carlo approach to assess the debris evolution during the simulation time-frame of 100 years and to compare a baseline scenario to debris remediation scenarios or other scenarios of interest. To populate the initial simulation, we use the entire space-track object catalog in LEO. We then use a high precision propagator to propagate all objects over the

  20. Implementation of an Open-Scenario, Long-Term Space Debris Simulation Approach

    NASA Technical Reports Server (NTRS)

    Nelson, Bron; Yang Yang, Fan; Carlino, Roberto; Dono Perez, Andres; Faber, Nicolas; Henze, Chris; Karacalioglu, Arif Goktug; O'Toole, Conor; Swenson, Jason; Stupl, Jan

    2015-01-01

    This paper provides a status update on the implementation of a flexible, long-term space debris simulation approach. The motivation is to build a tool that can assess the long-term impact of various options for debris-remediation, including the LightForce space debris collision avoidance concept that diverts objects using photon pressure [9]. State-of-the-art simulation approaches that assess the long-term development of the debris environment use either completely statistical approaches, or they rely on large time steps on the order of several days if they simulate the positions of single objects over time. They cannot be easily adapted to investigate the impact of specific collision avoidance schemes or de-orbit schemes, because the efficiency of a collision avoidance maneuver can depend on various input parameters, including ground station positions and orbital and physical parameters of the objects involved in close encounters (conjunctions). Furthermore, maneuvers take place on timescales much smaller than days. For example, LightForce only changes the orbit of a certain object (aiming to reduce the probability of collision), but it does not remove entire objects or groups of objects. In the same sense, it is also not straightforward to compare specific de-orbit methods in regard to potential collision risks during a de-orbit maneuver. To gain flexibility in assessing interactions with objects, we implement a simulation that includes every tracked space object in Low Earth Orbit (LEO) and propagates all objects with high precision and variable time-steps as small as one second. It allows the assessment of the (potential) impact of physical or orbital changes to any object. The final goal is to employ a Monte Carlo approach to assess the debris evolution during the simulation time-frame of 100 years and to compare a baseline scenario to debris remediation scenarios or other scenarios of interest. To populate the initial simulation, we use the entire space

  1. Primary dispersal of supraglacial debris and debris cover formation on alpine glaciers

    NASA Astrophysics Data System (ADS)

    Kirkbride, M. P.; Deline, P.

    2009-04-01

    Debris-covered glaciers are receiving increased attention due to the modulation of runoff by supraglacial covers, and to the lake outburst flood hazard at many covered glacier termini. Observed increases in debris cover extents cannot presently be explained in terms of glaciological influences. The supply of englacial debris to the supraglacial zone has previously been understood only in terms of local dispersal due to differential ablation between covered and uncovered ice, for example on medial moraines. Here, we introduce the term primary dispersal to describe the process of migration of the outcrops of angled debris septa across melting, thinning ablation zones. Understanding primary debris dispersal is an essential step to understanding how supraglacial debris cover is controlled by glaciological variables, and hence is sensitive to climatically-induced fluctuation. Three measures of a glacier's ability to evacuate supraglacial debris are outlined: (1) a concentration factor describing the focussing of englacial debris into specific supraglacial mass loads; (2) the rate of migration of a septum outcrop relative to the local ice surface; and (3) a downstream velocity differential between a septum outcrop and the ice surface. (1) and (2) are inversely related, while (3) increases downglacier to explain why slow-moving, thinning ice rapidly becomes debris covered. Data from Glacier d'Estelette (Italian Alps) illustrate primary dispersal processes at a site where debris cover is increasing in common with many other shrinking alpine glaciers. We develop a model of the potential for debris cover formation and growth in different glaciological environments. This explains why glaciers whose termini are obstructed often have steep debris septa feeding debris covers which vary slowly in response to mass balance change. In contrast, at glaciers with gently-dipping debris-bearing foliation, the debris cover extent is sensitive to glaciological change. These findings

  2. Debris Selection and Optimal Path Planning for Debris Removal on the SSO: Impulsive-Thrust Option

    NASA Astrophysics Data System (ADS)

    Olympio, J. T.; Frouvelle, N.

    2013-08-01

    The current paper deals with the mission design of a generic active space debris removal spacecraft. Considered debris are all on a sun-synchronous orbit. A perturbed Lambert's problem, modelling the transfer between two debris, is devised to take into account J2 perturbation, and to quickly evaluate mission scenarios. A robust approach, using techniques of global optimisation, is followed to find optimal debris sequence and mission strategy. Manoeuvres optimization is then performed to refine the selected trajectory scenarii.

  3. Space debris measurement program at Phillips Laboratory

    NASA Technical Reports Server (NTRS)

    Dao, Phan D.; Mcnutt, Ross T.

    1992-01-01

    Ground-based optical sensing was identified as a technique for measuring space debris complementary to radar in the critical debris size range of 1 to 10 cm. The Phillips Laboratory is building a staring optical sensor for space debris measurement and considering search and track optical measurement at additional sites. The staring sensor is implemented in collaboration with Wright Laboratory using the 2.5 m telescope at Wright Patterson AFB, Dayton, Ohio. The search and track sensor is designed to detect and track orbital debris in tasked orbits. A progress report and a discussion of sensor performance and search and track strategies will be given.

  4. Space debris mitigation measures in India

    NASA Astrophysics Data System (ADS)

    Adimurthy, V.; Ganeshan, A. S.

    2006-02-01

    The Indian Space Research Organization (ISRO) recognizes the importance of the current space debris scenario, and the impact it has on the effective utilization of space technology for the improvement in the quality of life on the Earth. ISRO is committed to effective management of the threats due to space debris. Towards this commitment ISRO works on different aspects of space debris, including the debris mitigation measures. This paper highlights the activities and achievements in the implementation of the mitigation measures. ISRO successfully designed and developed a propellant venting system for implementation in the existing upper stage of India's Polar Satellite Launch Vehicle (PSLV), which uses Earth-storable liquid propellants. GSLV also employs passivation of the Cryogenic Upper Stage at the end of its useful mission. ISRO's communication satellites in GSO are designed with adequate propellant margins for re-orbiting at the end of their useful life to a higher graveyard orbit. A typical successful operation in connection with INSAT-2C is described. ISRO developed its debris environmental models and software to predict the close approach of any of the debris to the functional satellites. The software are regularly used for the debris risk management of the orbiting spacecraft and launch vehicles. ISRO recognizes the role of international cooperation in the debris mitigation measures and actively contributes to the efforts of the Inter-Agency Space Debris Coordination Committee (IADC) and United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS).

  5. An investigation of collisions between fiber positioning units in LAMOST

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Jie; Wang, Gang

    2016-04-01

    The arrangement of fiber positioning units in the LAMOST focal plane may lead to collisions during the fiber allocation process. To avoid these collisions, a software-based protection system has to abandon some targets located in the overlapping field of adjacent fiber units. In this paper, we first analyze the probability of collisions between fibers and infer their possible reasons. It is useful to solve the problem of collisions among fiber positioning units so as to improve the efficiency of LAMOST. Based on this, a collision handling system is designed by using a master-slave control structure between the micro control unit and microcomputer. Simulated experiments validate that the system can provide real-time inspection and swap information between the fiber unit controllers and the main controller.

  6. Space Debris End to End Service - presentation of the DLR work plan

    NASA Astrophysics Data System (ADS)

    Alwes, D.

    2001-10-01

    Resulting from the present effort on international regulations and the compilation of guidelines to handle the space debris problem in the future, the need consists to advise spacecraft manufacturer, suppliers and operators ideally in the form of a commercially useful End to End Service. The competence of German institutions incl. research institutes and companies in the field of the space debris research and risk analyses is widely recognized and very well suitable to deal with all the corresponding aspects in Germany but also Europe-wide. It is the intention of DLR to concentrate and link all expertises and competences, available in Germany, in one coherent project. The space industry should contribute to risk analyses, reviews of guidelines and to proposals for space debris minimising design and operations of spacecraft. Preliminary proposals by several institutes and companies have been prepared and have been compiled to a consolidated work plan for a project named 'Space Debris End to End Service'. 'End to End' means the consideration of space debris mitigation aspects from begin of the design over the operational phase of a spacecraft up to the end of the mission and the following phase of the initiation of space debris avoidance measures (e.g. passivation, de- or re-orbiting). The effectiveness of such an End to End Service shall be demonstrated on a satellite project. The work packages of the project shall cover in principle the following activities: Conception of an End to End Service - Identification of national needs, the state of knowledge and information - Spacecraft requirements and mitigation measures - Re-entry analyses - Application on a pilot project, incl. system review, meteoroid and space debris modelling, hazard analyses, recommendations of measures and a cost to benefit analysis. This paper reports about the work plan and the status of the project.

  7. Debris Mitigation as a Component of Space Traffic Management

    NASA Astrophysics Data System (ADS)

    Kemper Force, M.

    2012-01-01

    The necessity of a traffic management in space is a consequence of our "free use" of it over the past fifty years, during which certain orbits have accumulated a significant amount of debris that may, in the future, threaten the feasibility of their use. This paper encapsulates the primary issues involved in the concept of space traffic management through basic questions, using as a case study the recent alarm caused by two close-misses of the ISS in one week, in order to guide the reader to an understanding of the current need for a space traffic management regime. The paper will describe the fundamental elements of space traffic management, including the tracking of objects, conjunction assessment, collision avoidance and orbital mechanics to understand why Earth-bound systems cannot be extrapolated to space. The paper will then focus on the primary concern of space debris, the acceptance and use of current guidelines in light of the existing corpus juris spatialis and international law, positing that the guidelines may soon develop into a customary norm. The paper will conclude that the latest close calls with the ISS demonstrate we cannot count on the mere vastness of space to reduce the probability of collisions with space objects. Despite the significant political, technical and economic challenges recognized by the International Space University Final Report of 2007, the International Academy of Astronautics' Cosmic Study of 2006 and the IAASS An ICAO for Space?, there is a need for a system to obviate the looming peril before governments and investors will sign on to a comprehensive program which limits their "free" use of space.

  8. Modelling the inner debris disc of HR 8799

    NASA Astrophysics Data System (ADS)

    Contro, B.; Horner, J.; Wittenmyer, R. A.; Marshall, J. P.; Hinse, T. C.

    2016-11-01

    In many ways, the HR 8799 planetary system strongly resembles our own. It features four giant planets and two debris belts, analogues to the Asteroid and Edgeworth-Kuiper belts. Here, we present the results of dynamical simulations of HR8799's inner debris belt, to study its structure and collisional environment. Our results suggest that HR 8799's inner belt is highly structured, with gaps between regions of dynamical stability. The belt is likely constrained between sharp inner and outer edges, located at ˜6 and ˜8 au, respectively. Its inner edge coincides with a broad gap cleared by the 4:1 mean-motion resonance with HR 8799e. Within the belt, planetesimals are undergoing a process of collisional attrition like that observed in the Asteroid belt. However, whilst the mean collision velocity in the Asteroid belt exceeds 5 km s-1, the majority of collisions within HR 8799's inner belt occur with velocities of order 1.2 km s-1, or less. Despite this, they remain sufficiently energetic to be destructive - giving a source for the warm dust detected in the system. Interior to the inner belt, test particles remain dynamically unstirred, aside from narrow bands excited by distant high-order resonances with HR 8799e. This lack of stirring is consistent with earlier thermal modelling of HR 8799's infrared excess, which predicted little dust inside 6 au. The inner system is sufficiently stable and unstirred that the formation of telluric planets is feasible, although such planets would doubtless be subject to a punitive impact regime, given the intense collisional grinding required in the inner belt to generate the observed infrared excess.

  9. Active Debris Removal mission design in Low Earth Orbit

    NASA Astrophysics Data System (ADS)

    Martin, Th.; Pérot, E.; Desjean, M.-Ch.; Bitetti, L.

    2013-03-01

    Active Debris Removal (ADR) aims at removing large sized intact objects ― defunct satellites, rocket upper-stages ― from space crowded regions. Why? Because they constitute the main source of the long-term debris environment deterioration caused by possible future collisions with fragments and worse still with other intact but uncontrolled objects. In order to limit the growth of the orbital debris population in the future (referred to as the Kessler syndrome), it is now highly recommended to carry out such ADR missions, together with the mitigation measures already adopted by national agencies (such as postmission disposal). At the French Space Agency, CNES, and in the frame of advanced studies, the design of such an ADR mission in Low Earth Orbit (LEO) is under evaluation. A two-step preliminary approach has been envisaged. First, a reconnaissance mission based on a small demonstrator (˜500 kg) rendezvousing with several targets (observation and in-flight qualification testing). Secondly, an ADR mission based on a larger vehicle (inherited from the Orbital Transfer Vehicle (OTV) concept) being able to capture and deorbit several preselected targets by attaching a propulsive kit to these targets. This paper presents a flight dynamics level tradeoff analysis between different vehicle and mission concepts as well as target disposal options. The delta-velocity, times, and masses required to transfer, rendezvous with targets and deorbit are assessed for some propelled systems and propellant less options. Total mass budgets are then derived for two end-to-end study cases corresponding to the reconnaissance and ADR missions mentioned above.

  10. Development of in-situ Space Debris Detector

    NASA Astrophysics Data System (ADS)

    Bauer, Waldemar; Romberg, O.; Wiedemann, C.; Drolshagen, G.; Vörsmann, P.

    2014-11-01

    Due to high relative velocities, collisions of spacecraft in orbit with Space Debris (SD) or Micrometeoroids (MM) can lead to payload degradation, anomalies as well as failures in spacecraft operation, or even loss of mission. Flux models and impact risk assessment tools, such as MASTER (Meteoroid and Space Debris Terrestrial Environment Reference) or ORDEM (Orbital Debris Engineering Model), and ESABASE2 or BUMPER II are used to analyse mission risk associated with these hazards. Validation of flux models is based on measured data. Currently, as most of the SD and MM objects are too small (millimeter down to micron sized) for ground-based observations (e.g. radar, optical), the only available data for model validation is based upon retrieved hardware investigations e.g. Long Duration Exposure Facility (LDEF), Hubble Space Telescope (HST), European Retrievable Carrier (EURECA). Since existing data sets are insufficient, further in-situ experimental investigation of the SD and MM populations are required. This paper provides an overview and assessment of existing and planned SD and MM impact detectors. The detection area of the described detectors is too small to adequately provide the missing data sets. Therefore an innovative detection concept is proposed that utilises existing spacecraft components for detection purposes. In general, solar panels of a spacecraft provide a large area that can be utilised for in-situ impact detection. By using this method on several spacecraft in different orbits the detection area can be increased significantly and allow the detection of SD and MM objects with diameters as low as 100 μm. The design of the detector is based on damage equations from HST and EURECA solar panels. An extensive investigation of those panels was performed by ESA and is summarized within this paper. Furthermore, an estimate of the expected sensitivity of the patented detector concept as well as examples for its implementation into large and small

  11. 33 CFR 151.3000 - Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the purposes of the Marine Debris Research, Prevention, and Reduction Act. 151.3000 Section 151.3000... Definition of Marine Debris for the Purposes of the Marine Debris Research, Prevention, and Reduction Act § 151.3000 Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and...

  12. 33 CFR 151.3000 - Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the purposes of the Marine Debris Research, Prevention, and Reduction Act. 151.3000 Section 151.3000... Definition of Marine Debris for the Purposes of the Marine Debris Research, Prevention, and Reduction Act § 151.3000 Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and...

  13. 33 CFR 151.3000 - Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the purposes of the Marine Debris Research, Prevention, and Reduction Act. 151.3000 Section 151.3000... Definition of Marine Debris for the Purposes of the Marine Debris Research, Prevention, and Reduction Act § 151.3000 Definition of marine debris for the purposes of the Marine Debris Research, Prevention,...

  14. 33 CFR 151.3000 - Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the purposes of the Marine Debris Research, Prevention, and Reduction Act. 151.3000 Section 151.3000... Definition of Marine Debris for the Purposes of the Marine Debris Research, Prevention, and Reduction Act § 151.3000 Definition of marine debris for the purposes of the Marine Debris Research, Prevention,...

  15. Debris flow rheology: Experimental analysis of fine-grained slurries

    USGS Publications Warehouse

    Major, Jon J.; Pierson, Thomas C.

    1992-01-01

    The rheology of slurries consisting of ≤2-mm sediment from a natural debris flow deposit was measured using a wide-gap concentric-cylinder viscometer. The influence of sediment concentration and size and distribution of grains on the bulk rheological behavior of the slurries was evaluated at concentrations ranging from 0.44 to 0.66. The slurries exhibit diverse rheological behavior. At shear rates above 5 s−1 the behavior approaches that of a Bingham material; below 5 s−1, sand exerts more influence and slurry behavior deviates from the Bingham idealization. Sand grain interactions dominate the mechanical behavior when sand concentration exceeds 0.2; transient fluctuations in measured torque, time-dependent decay of torque, and hysteresis effects are observed. Grain rubbing, interlocking, and collision cause changes in packing density, particle distribution, grain orientation, and formation and destruction of grain clusters, which may explain the observed behavior. Yield strength and plastic viscosity exhibit order-of-magnitude variation when sediment concentration changes as little as 2–4%. Owing to these complexities, it is unlikely that debris flows can be characterized by a single rheological model.

  16. Space debris tracking at San Fernando laser station

    NASA Astrophysics Data System (ADS)

    Catalán, M.; Quijano, M.; Pazos, A.; Martín Davila, J.; Cortina, L. M.

    2016-12-01

    For years to come space debris will be a major issue for society. It has a negative impact on active artificial satellites, having implications for future missions. Tracking space debris as accurately as possible is the first step towards controlling this problem, yet it presents a challenge for science. The main limitation is the relatively low accuracy of the methods used to date for tracking these objects. Clearly, improving the predicted orbit accuracy is crucial (avoiding unnecessary anti-collision maneuvers). A new field of research was recently instituted by our satellite laser ranging station: tracking decommissioned artificial satellites equipped with retroreflectors. To this end we work in conjunction with international space agencies which provide increasing attention to this problem. We thus proposed to share our time-schedule of use of the satellite laser ranging station for obtaining data that would make orbital element predictions far more accurate (meter accuracy), whilst maintaining our tracking routines for active satellites. This manuscript reports on the actions carried out so far.

  17. Columbia Debris - Congressman Dave Weldon

    NASA Image and Video Library

    2003-02-20

    Congressman Dave Weldon (second from right) looks over the pieces of Columbia debris stored in the RLV Hangar. At right is Steve Altemus, Space Shuttle test director . Accompanying Weldon are (left toright) Greg Katnick, Grant Case, J.B. Kump and Center Director Roy Bridges. Workers will attempt to reconstruct the orbiter as part of the ongoing investigation of the accident that destroyed the Columbia and claimed the lives of seven astronauts as they returned to Earth after a 16-day research mission, STS-107.

  18. Improved Quantitative Debris Monitoring Capability

    DTIC Science & Technology

    1987-04-01

    voltage increase. A rate increase of the output was expected. The results were inconclusive because the oil contained 12 - r b a large amount of the 10...34ME%7A= - %ZT.ATQf This research was partially funded by the in-house 1 rdt )eri (lent research fund. 𔃻 CCSATI CODIES a S%.9jECT bE~,ohq. n~f...q.-bwrI This report describes the operation and performance evaluation results of a QDmi Mark TI prototype fine ferrous debris monitoring system

  19. Collision Repair Campaign

    EPA Pesticide Factsheets

    The Collision Repair Campaign targets meaningful risk reduction in the Collision Repair source category to reduce air toxic emissions in their communities. The Campaign also helps shops to work towards early compliance with the Auto Body Rule.

  20. HAND TRUCK FOR HANDLING EQUIPMENT

    DOEpatents

    King, D.W.

    1959-02-24

    A truck is described for the handling of large and relatively heavy pieces of equipment and particularly for the handling of ion source units for use in calutrons. The truck includes a chassis and a frame pivoted to the chassis so as to be operable to swing in the manner of a boom. The frame has spaced members so arranged that the device to be handled can be suspended between or passed between these spaced members and also rotated with respect to the frame when the device is secured to the spaced members.