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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 271 records · Page 15
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NASA NTRS2001

Entry Debris Field Estimation Methods and Application to Compton Gamma Ray Observatory Disposal

For public safety reasons, the Compton Gamma Ray Observatory (CGRO) was intentionally deorbited on June 4, 2000. This deorbit was NASA's first intentional controlled deorbit of a satellite, and more will come including the eventual deorbit of the International Space Station. To maximize public safety, satellite deorbit planning requires conservative estimates of the debris footprint size and location. These estimates are needed to properly design a deorbit sequence that places the debris footprint over unpopulated areas, including protection for deorbit contingencies. This paper details a method for estimating the length (range), width (crossrange), and location of entry and breakup debris footprints. This method utilizes a three degree-of-freedom Monte Carlo simulation incorporating uncertainties in all aspects of the problem, including vehicle and environment uncertainties. The method incorporates a range of debris characteristics based on historical data in addition to any vehicle-specific debris catalog information. This paper describes the method in detail, and presents results of its application as used in planning the deorbit of the CGRO.

Mrozinski, Richard B.↗
NASA NTRS2001

Quantifying and Improving International Space Station Survivability Following Orbital Debris Penetration

The increase of the orbital debris environment in low-earth orbit has prompted NASA to develop analytical tools for quantifying and lowering the likelihood of crew loss following orbital debris penetration of the International Space Station (ISS). NASA uses the Manned Spacecraft and Crew Survivability (MSCSurv) computer program to simulate the events that may cause crew loss following orbital debris penetration of ISS manned modules, including: (1) critical cracking (explosive decompression) of the module; (2) critical external equipment penetration (such as hydrazine and high pressure tanks); (3) critical internal system penetration (guidance, control, and other vital components); (4) hazardous payload penetration (furnaces, pressure bottles, and toxic substances); (5) crew injury (from fragments, overpressure, light flash, and temperature rise); (6) hypoxia from loss of cabin pressure; and (7) thrust from module hole causing high angular velocity (occurring only when key Guidance, Navigation, and Control (GN&C) equipment is damaged) and, thus, preventing safe escape vehicle (EV) departure. MSCSurv is also capable of quantifying the 'end effects' of orbital debris penetration, such as the likelihood of crew escape, the probability of each module depressurizing, and late loss of station control. By quantifying these effects (and their associated uncertainties), NASA is able to improve the likelihood of crew survivability following orbital debris penetration due to improved crew operations and internal designs.

Williamsen, Joel↗
NASA NTRS2002

Tethers as Debris: Hydrocode Simulation of Impacts of Tether Fragments on Planar Aerospace Materials

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.

Evans, Steven W.↗
NASA NTRS2006

NASA's Program to Monitor Orbital Debris in the GEO Belt and the General Problem of Measuring Near-Earth Object Orbits: Similarities and Differences

One of the goals for NASA s Orbital Debris Program Office has been to accurately characterize the population of debris in the geosynchronous Earth orbit (GEO) environment. Most objects larger than about 1 meter in size are regularly tracked and catalogued by the US Space Surveillance System in the GEO regime. The consequence has been that most large intact GEO objects are tracked, but the vast majority of GEO debris fragments are not. Only in recent years have observations been dedicated to characterize the GEO debris population. NASA s efforts have concentrated on using wide field-of-view telescopes to make complete surveys of the GEO regime to better our statistical understanding of the GEO debris population. These telescopes operate in a staring mode, and only make limited short-arc measurements of the orbits. This information, while limited, allows the possibility of debiasing the observations and constructing statistical distributions of orbits in inclination and ascending node. Recent work suggests that we may be able to use statistical methods to estimate better orbit parameters despite the limited data. Both of these types of studies estimating statistical orbit distributions, and estimating accurate orbits using limited short-arc data have direct analogues in ongoing studies of near-Earth objects (NEO) such as asteroids and comets. This talk will describe the GEO study methods in use and being developed at NASA, and will discuss how such methods may or may not be applicable for NEO studies as well.

Matney, Mark↗
NASA NTRS2007

Space Shuttle and Launch Pad Lift-Off Debris Transport Analysis: SRB Plume-Driven

This paper discusses the Space Shuttle Lift-Off model developed for potential Lift-Off Debris transport. A critical Lift-Off portion of the flight is defined from approximately 1.5 sec after SRB Ignition up to 'Tower Clear', where exhaust plume interactions with the Launch Pad occur. A CFD model containing the Space Shuttle and Launch Pad geometry has been constructed and executed. The CFD model works in conjunction with a debris particle transport model and a debris particle impact damage tolerance model. These models have been used to assess the effects of the Space Shuttle plumes, the wind environment, their interactions with the Launch Pad, and their ultimate effect on potential debris during Lift-Off. Emphasis in this paper is on potential debris that might be caught by the SRB plumes.

West, Jeff↗
NASA NTRS2008

Optical Studies of Orbital Debris at GEO Using Two Telescopes

Beginning in March, 2007, optical observations of debris at geosynchronous orbit (GEO) were commenced using two telescopes simultaneously at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. The University of Michigan's 0.6/0.9-m Schmidt telescope MODEST (for Michigan Orbital DEbris Survey Telescope) was used in survey mode to find objects that potentially could be at GEO. Because GEO objects only appear in this telescope's field of view for an average of 5 minutes, a full six-parameter orbit can not be determined. Interrupting the survey for follow-up observations leads to incompleteness in the survey results. Instead, as objects are detected on MODEST, initial predictions assuming a circular orbit are done for where the object will be for the next hour, and the objects are reacquired as quickly as possible on the CTIO 0.9-m telescope. This second telescope then follows-up during the first night and, if possible, over several more nights to obtain the maximum time arc possible, and the best six parameter orbit. Our goal is to obtain an initial orbit for all detected objects fainter than R = 15th in order to estimate the orbital distribution of objects selected on the basis of two observational criteria: magnitude and angular rate. Objects fainter than 15th are largely uncataloged and have a completely different angular rate distribution than brighter objects. Combining the information obtained for both faint and bright objects yields a more complete picture of the debris environment rather than just concentrating on the faint debris. One objective is to estimate what fraction of objects selected on the basis of angular rate are not at GEO. A second objective is to obtain magnitudes and colors in standard astronomical filters (BVRI) for comparison with reflectance spectra of likely spacecraft materials. This paper reports on results from two 14 night runs with both telescopes: in March and November 2007: (1) A significant fraction of objects fainter than R = 15th have eccentric orbits (e > 0.1) (2) Virtually all objects selected on the basis of angular rate are in the GEO and GTO regimes. (3) Calibrated magnitudes and colors in BVRI were obtained for many objects fainter than R = 15th magnitude. This work is supported by NASA's Orbital Debris Program Office, Johnson Space Center, Houston, Texas, USA.

Seitzer, P.↗
NASA NTRS2008

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

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.

Roberg, A.↗
NASA NTRS2009

An Assessment of GEO Orbital Debris Photometric Properties Derived from Laboratory-Based Measurements

Optical observations of orbital debris offer insights that differ from radar measurements (specifically the size parameter and wavelength regime). For example, time-dependent photometric data yield lightcurves in multiple bandpasses that aid in material identification and possible periodic orientations. This data can also be used to help identify shapes and optical properties at multiple phase angles. Capitalizing on optical data products and applying them to generate a more complete understanding of orbital space objects, is a key objective of NASA s Optical Measurement Program, and a primary driver for creation of the Optical Measurements Center (OMC). The OMC attempts to emulate space-based illumination conditions using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. The OMC uses a 300 Watt Xenon arc lamp as a solar simulator, a CCD camera with Johnson/Bessel colored filters, and a robotic arm to orientate/rotate objects to simulate an object's orbit/rotational period. A high-resolution, high bandwidth (350nm-2500nm) Analytical Spectral Devices (ASD) spectrometer is also employed to baseline various material types. Since observation of GEO targets are generally restricted to the optical regime (due to radar range limitations), analysis of their properties is tailored to those revealed by optical data products. In this connection, much attention has been directed towards understanding the lightcurves of orbital debris with high area-to-mass (A/m) ratios (greater than 0.9 square meters per kilogram). A small population of GEO debris was recently identified, which exhibits the properties of high A/m objects, such as variable eccentricities and inclinations a dynamical characteristic generally resulting from varying solar radiation pressure on high A/m objects. Materials such as multi-layered insulation (MLI) and solar panels are two examples of materials with high area-to mass ratios. Lightcurves for such objects can vary greatly (even for the same object under different illumination conditions). For example, specular reflections from multiple facets of the target surface (e.g. Mylar or Aluminized Kapton) can lead to erratic, orientation-dependent light curves. This paper will investigate published color photometric data for a series of orbital debris targets and compare it to the empirical photometric measurements generated in the OMC. The specific materials investigated (known to exist in GEO) are: an intact piece of MLI, separated layers of MLI, and multiple solar cells materials. Using the data acquired over specific rotational angles through different filters (B, V, R, I), a color index is acquired (B-R, R-I). As a secondary check, the spectrometer is used to define color indexes for the same material. Using these values and their associated lightcurves, this laboratory data is compared to observational data obtained on the 1m telescope of the Astronomical Institute of the University of Bern (AUIB) and the 0.9 m Small and Moderate Aperture Research Telescope System (SMARTS) telescope at Cerro Tololo Inter-American Observatory (CTIO). We will present laboratory generated lightcurves with color indexes of the high A/m materials alongside telescopic data of targets with high A/m values. We will discuss the relationship of laboratory to telescope data in the context of classification of GEO debris objects.

Rodriquez-Cowardin, H.↗
NASA NTRS2009

Reading the Signatures of Extrasolar Planets in Debris Disks

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.

Kuchner, Marc J.↗
NASA NTRS2009

Best Mitigation Paths To Effectively Reduce Earth's Orbital Debris

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.

Wiegman, Bruce M.↗
NASA NTRS2010

Characterization of Orbital Debris Photometric Properties Derived from Laboratory-Based Measurements

To better characterize and model optical data acquired from ground-based telescopes, the Optical Measurements Center (OMC) at NASA/JSC attempts to emulate illumination conditions seen in space using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. The OMC uses a 75 Watt Xenon arc lamp as a solar simulator, an SBIG CCD camera with standard Johnson/Bessel filters, and a robotic arm to simulate an object's position and rotation. The laboratory uses known shapes, materials suspected to be consistent with the orbital debris population, and three phase angles to best match the lighting conditions of the telescope based data. The fourteen objects studied in the laboratory are fragments or materials acquired through ground-tests of scaled-model satellites/rocket bodies as well as material samples in more/less "flight-ready" condition. All fragments were measured at 10 increments in a full 360 rotation at 6 , 36 , and 60 phase angles. This paper will investigate published color photometric data for a series of orbital debris targets and compare it to the empirical photometric measurements generated in the OMC. Using the data acquired over specific rotational angles through different filters (B, V, R, I), a color index is acquired (B-R, R-I). Using these values and their associated lightcurves, this laboratory data is compared to observational data obtained on the 1 m telescope of the Astronomical Institute of the University of Bern (AUIB), the 0.9 m operated by the Small- and Medium-Aperture Research Telescope System (SMARTS) Consortium and the Curtis-Schmidt 0.6 m Michigan Orbital Debris Space Debris Telescope both located at Cerro Tololo Inter-American Observatory (CTIO). An empirical based optical characterization model will be presented to provide preliminary correlations between laboratory based and telescope-based data in the context of classification of GEO debris objects.

Cowardin, H.↗
NASA NTRS2010

Orbital Debris: Quarterly News, Volume 14, Issue 2

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.

Liou, J. C.↗
NASA NTRS2010

Jupiter After the 2009 Impact: Hubble Space Telescope Imaging of the Impact-Generated Debris and Its Temporal Evolution

We report Hubble Space Telescope images of Jupiter during the aftermath of an impact by an unknown object in 2009 July, The 2009 impact-created debris field evolved more slowly than those created in 1994 by the collision of the tidally disrupted comet D/Shoemaker-Levy 9 (SL9). The slower evolution, in conjunction with the isolated nature of this single impact, permits a more detailed assessment of the altitudes and meridional motion of the debris than was possible with SL9. The color of the 2009 debris was markedly similar to that seen in 1994, thus this dark debris is likely to be Jovian material that is highly thermally processed. The 2009 impact site differed from the 1994 SL9 sites in UV morphology and contrast lifetime; both are suggestive of the impacting body being asteroidal rather than cometary. Transport of the 2009 Jovian debris as imaged by Hubble shared similarities with transport of volcanic aerosols in Earth's atmosphere after major eruptions.

Hammel, H. B.↗
NASA NTRS2010

Sensitivity Analysis of Launch Vehicle Debris Risk Model

As part of an analysis of the loss of crew risk associated with an ascent abort system for a manned launch vehicle, a model was developed to predict the impact risk of the debris resulting from an explosion of the launch vehicle on the crew module. The model consisted of a debris catalog describing the number, size and imparted velocity of each piece of debris, a method to compute the trajectories of the debris and a method to calculate the impact risk given the abort trajectory of the crew module. The model provided a point estimate of the strike probability as a function of the debris catalog, the time of abort and the delay time between the abort and destruction of the launch vehicle. A study was conducted to determine the sensitivity of the strike probability to the various model input parameters and to develop a response surface model for use in the sensitivity analysis of the overall ascent abort risk model. The results of the sensitivity analysis and the response surface model are presented in this paper.

Gee, Ken↗
NASA NTRS2010

Space Shuttle Debris Transport

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.

Gomez, Reynaldo J., III↗
NASA NTRS2010

Gas and Dustin Debris Disks: Clues to the Late Stages of Planet Formation

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.

Roberge, Aki↗
NASA NTRS2011

Spitzer IRS Spectroscopy of the 10 Myr-Old EF Cha Debris Disk: Evidence for Phyllosilicate-Rich Dust in the Terrestrial Zone

We describe Spitzer IRS spectroscopic observations of the approx. 10 Myr-old star, EF Chao Compositional modeling of the spectra from 5 micron to 35 micron confirms that it is surrounded by a luminous debris disk with L(sub D)/L(sub *) approx. 10(exp -3), containing dust with temperatures between 225 K and 430 K characteristic of the terrestrial zone. The EF Cha spectrum shows evidence for many solid-state features, unlike most cold, low-luminosity debris disks but like some other 10-20 Myr-old luminous, warm debris disks (e.g. HD 113766A). The EF Cha debris disk is unusually rich in a species or combination of species whose emissivities resemble that of finely-powdered, laboratory-measured phyllosilicate species (talc, saponite, and smectite), which are likely produced by aqueous alteration of primordial anhydrous rocky materials. The dust and, by inference, the parent bodies of the debris also contain abundant amorphous silicates and metal sulfides, and possibly water ice. The dust's total olivine to pyroxene ratio of approx. 2 also provides evidence of aqueous alteration. The large mass volume of grains with sizes comparable to or below the radiation blow-out limit implies that planetesimals may be colliding at a rate high enough to yield the emitting dust but not so high as to devolatize the planetesimals via impact processing. Because phyllosilicates are produced by the interactions between anhydrous rock and warm, reactive water, EF Cha's disk is a likely signpost for water delivery to the terrestrial zone of a young planetary system.

Currie, Thayne↗
NASA NTRS2012

The Challenge of Orbital Debris

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.

Matney, Mark↗