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NASA NTRS2017

Ecological Forecasting Project Management with Examples

Once scientists publish results of their projects and studies, all too often they end up on the shelf and are not otherwise used. The NASA Earth Science Division established its Applied Sciences Program (ASP) to apply research findings to help solve and manage real-world problems and needs. ASP-funded projects generally produce decision support systems for operational applications which are expected to last beyond the end of the NASA funding. Because of NASAs unique perspective of looking down on the Earth from space, ASP studies involve the use of remotely sensed information consisting of satellite data and imagery as well as information from sub-orbital platforms. ASP regularly solicits Earth science proposals that address one or more focus areas; disasters mitigation, ecological forecasting, health and air quality, and water resources. Reporting requirements for ASP-funded projects are different from those typical for research grants from NASA and other granting agencies, requiring management approaches different from other programs. This presentation will address the foregoing in some detail and give examples of three ASP-funded ecological forecasting projects that include: 1) the detection and survey of chimpanzee habitat in Africa from space, 2) harmful algal blooms (HABs) in the California Current System affecting aquaculture facilities and marine mammal populations, and 3) a call for the public to identify North America wildlife in Wisconsin using trail camera photos. Contact information to propose to ASP solicitations for those PIs interested is also provided.

Management↗
NASA NTRS1995

Effects of the LDEF orbital environment on the reflectance of optical mirror materials

Specimens of eight different optical mirror materials were flown in low earth orbit as part of the Long Duration Exposure Facility (LDEF) manifest to determine their ability to withstand exposure to the residual atomic oxygen and other environmental effects at those altitudes. Optical thin films of aluminum, gold, iridium, osmium, platinum, magnesium fluoride-overcoated aluminum and reactively deposited, silicon monoxide-protected aluminum, all of which were vacuum deposited on polished fused silica substrates, were included as part of Experiment S0010, Exposure of Spacecraft Coatings. Two specimens of polished, chemical vapor deposited (CVD) silicon carbide were installed in sites available in Experiment A0114, Interaction of Atomic Oxygen with Solid Surfaces at Orbital Altitudes, which included trays in two of the spacecraft bays, one on the leading edge and the other on the trailing edge. One of the silicon carbide samples was located in each of these trays. This paper will compare specular reflectance data from the preflight and postflight measurements made on each of these samples and attempt to explain the changes in light of the specific environments to which the experiments were exposed.

Herzig, Howard↗
NASA NTRS2011

Space Weathering Impact on Solar System Surfaces and Planetary Mission Science

We often look "through a glass, darkly" at solar system bodies with tenuous atmospheres and direct surface exposure to the local space environment. Space weathering exposure acts via universal space-surface interaction processes to produce a thin patina of outer material covering, potentially obscuring endogenic surface materials of greatest interest for understanding origins and interior evolution. Examples of obscuring exogenic layers are radiation crusts on cometary nuclei and iogenic components of sulfate hydrate deposits on the trailing hemisphere of Europa. Weathering processes include plasma ion implantation into surfaces, sputtering by charged particles and solar ultraviolet photons, photolytic chemistry driven by UV irradiation, and radiolytic chemistry evolving from products of charged particle irradiation. Regolith structure from impacts, and underlying deeper structures from internal evolution, affects efficacy of certain surface interactions, e.g. sputtering as affected by porosity and surface irradiation dosage as partly attenuated by local topographic shielding. These processes should be regarded for mission science planning as potentially enabling, e.g. since direct surface sputtering, and resultant surface-bound exospheres, can provide in-situ samples of surface composition to ion and neutral mass spectrometers on orbital spacecraft. Sample return for highest sensitivity compOSitional and structural analyses at Earth will usually be precluded by limited range of surface sampling, long times for return, and high cost. Targeted advancements in instrument technology would be more cost efficient for local remote and in-situ sample analysis. More realistic laboratory simulations, e.g. for bulk samples, are needed to interpret mission science observations of weathered surfaces. Space environment effects on mission spacecraft and science operations must also be specified and mitigated from the hourly to monthly changes in space weather and from longer term (e.g., solar cycle) evolution of space climate. Capable instrumentation on planetary missions can and should be planned to contribute to knowledge of interplanetary space environments. Evolving data system technologies such as virtual observatories should be explored for more interdisciplinary application to the science of planetary surface, atmospheric, magnetospheric, and interplanetary interactions.

Cooper, John F.↗
NASA NTRS1995

Micrometeoroids and debris on LDEF comparison with MIR data

Part of the LDEF tray allocated to French experiments (FRECOPA) has been devoted to the study of dust particles. The tray was located on the face of LDEF directly opposed to the velocity vector. Crater size distributions have made possible the evaluation of the incident microparticle flux in the near-Earth environment. Comparisons are made with measurements obtained on the other faces of LDEF (tray clamps), on the leading edge (MAP) and with results of a similar experiment flown on the MIR space station. The geometry of impact craters, depth in particular, provides useful information on the nature of impacting particles and the correlation of geometry with the chemical analysis of projectile remnants inside craters make possible a discrimination between meteoroids and orbital debris. Emphasis has been laid on the size distribution of small craters in order to assess a cut-off in the distribution of particles in LEO. Special attention has been paid to the phenomenon of secondary impacts. A comparison of flight data with current models of meteoroids and space debris shows a fair agreement for LDEF, except for the smaller particles: the possible contribution of orbital debris in GTO orbits to the LDEF trailing edge flux is discussed. For MIR, flight results show differences with current modeling: the possible enhancement of orbital debris could be due to the contaminating presence of a permanently manned space station.

Mandeville, Jean-Claude↗
NASA NTRS2013

Conceptual Design of a Flight Validation Mission for a Hypervelocity Asteroid Intercept Vehicle

Near-Earth Objects (NEOs) are asteroids and comets whose orbits approach or cross Earth s orbit. NEOs have collided with our planet in the past, sometimes to devastating effect, and continue to do so today. Collisions with NEOs large enough to do significant damage to the ground are fortunately infrequent, but such events can occur at any time and we therefore need to develop and validate the techniques and technologies necessary to prevent the Earth impact of an incoming NEO. In this paper we provide background on the hazard posed to Earth by NEOs and present the results of a recent study performed by the NASA/Goddard Space Flight Center s Mission Design Lab (MDL) in collaboration with Iowa State University s Asteroid Deflection Research Center (ADRC) to design a flight validation mission for a Hypervelocity Asteroid Intercept Vehicle (HAIV) as part of a Phase 2 NASA Innovative Advanced Concepts (NIAC) research project. The HAIV is a two-body vehicle consisting of a leading kinetic impactor and trailing follower carrying a Nuclear Explosive Device (NED) payload. The HAIV detonates the NED inside the crater in the NEO s surface created by the lead kinetic impactor portion of the vehicle, effecting a powerful subsurface detonation to disrupt the NEO. For the flight validation mission, only a simple mass proxy for the NED is carried in the HAIV. Ongoing and future research topics are discussed following the presentation of the detailed flight validation mission design results produced in the MDL.

Barbee, Brent W.↗
NASA NTRS1995

Organic matrix composite protective coatings for space applications

Successful use of composites in low earth orbit (LEO) depends on their ability to survive long-term exposure to atomic oxygen (AO), ultraviolet radiation, charged particle radiation, thermal cycling, and micrometeoroid and space debris. The AO environment is especially severe for unprotected organic matrix composites surfaces in LEO. Ram facing unprotected graphite/epoxy flown on the 69-month Long Duration Exposure Facility (LDEF) mission lost up to one ply of thickness (5 mils) resulting in decreased mechanical properties. The expected AO fluence of the 30 year Space Station Alpha mission is approximately 20 times that seen on LDEF. This exposure would result in significant material loss of unprotected ram facing organic matrix composites. Several protective coatings for composites were flown on LDEF including anodized aluminum, vacuum deposited coatings, a variety of thermal control coatings, metalized Teflon, and leafing aluminum. Results from the testing and analysis of the coated and uncoated composite specimens flown on LDEF's leading and trailing edges provide the baseline for determining the effectiveness of protectively coated composites in LEO. In addition to LDEF results, results from shuttle flight experiments and ground based testing will be discussed.

Dursch, Harry W.↗
NASA NTRS2005

Lunar and Planetary Science XXXVI, Part 6

Contents include the following: A Model for Multiple Populations of Presolar Diamonds. Characterization of Martian North Polar Geologic Units Using Mars Odyssey THEMIS Data. Effect of Flow on the Internal Structure of the Martian North Polar Layered Deposits. Elemental Abundance Distributions in Basalt Clays and Meteorites: Is It a Biosignature? Early Results on the Saturn System from the Composite Infrared Spectrometer. NanoSIMS D/H Imaging of Isotopically Primitive Interplanetary Dust Particles. Presolar (Circumstellar and Interstellar) Phases in Renazzo: The Effects of Parent Body Processing. Catastrophic Disruption of Hydrated Targets: Implications for the Hydrated Asteroids and for the Production of Interplanetary Dust Particles. Chemical and Mineralogical Analyses of Particles from the Stratospheric Collections Coinciding with the 2002 Leonid Storm and the 2003 Comet Grigg-Skjellerup Trail Passage. An Analysis of the Solvus in the CaS-MnS System. ESA s SMART-1 Mission at the Moon: First Results, Status and Next Steps. Europa Analog Ice-splitting Measurements and Experiments with Ice-Hunveyor on the Frozen Balaton-Lake, Hungary. Chromium on Eros: Further Evidence of Ordinary Chondrite Composition. Dust Devil Tracks on Mars: Observation and Analysis from Orbit and the Surface. Spatial Variation of Methane and Other Trace Gases Detected on Mars: Interpretation with a General Circulation Model. Mars Water Ice and Carbon Dioxide Seasonal Polar Caps: GCM Modeling and Comparison with Mars Express Omega Observations. Component Separation of OMEGA Spectra with ICA. Clathrate Formation in the Near-Surface Environment of Titan. Space Weathering: A Proposed Laboratory Approach to Explaining the Sulfur Depletion on Eros. Sample Collection from Small Airless Bodies: Examination of Temperature Constraints for the TGIP. Sample Collector for the Hera Near-Earth Asteroid Sample Return Mission. A Rugged Miniature Mass-Spectrometer for Measuring Aqueous Geochemistry on Mars. Martian and Lunar Pyroxene Microstructures Studied by Single-Crystal X-Ray Diffraction.

Source record↗
NASA NTRS1994

Supersonic aerodynamic characteristics of a circular body Earth-to-Orbit vehicle

The circular body configuration is a generic single- or multi-stage reusable Earth-to-orbit transport. A thick clipped-delta wing is the major lifting surface. For directional control, three different vertical fin arrangements were investigated: a conventional aft-mounted center fin, wingtip fins, and a nose-mounted fin. The tests were conducted in the Langley Unitary Plan Wind Tunnel. The configuration is longitudinally stable about the estimated center of gravity of 0.72 body length up to a Mach number of about 3.0. Above Mach 3.0, the model is longitudinally unstable at low angles of attack but has a stable secondary trim point at angles of attack above 30 deg. The model has sufficient pitch control authority with elevator and body flap to produce stable trim over the test range. The model with the center fin is directionally stable at low angles of attack up to a Mach number of 3.90. The rudder-like surfaces on the tip fins and the all-movable nose fin are designed as active controls to produce artificial directional stability and are effective in producing yawing moment. The wing trailing-edge aileron surfaces are effective in producing rolling moment, but they also produce large adverse yawing moment.

Ware, George M.↗
NASA NTRS2006

Aerocapture Benefits to Future Science Missions

NASA's In-Space Propulsion Technology (ISPT) Program is investing in technologies to revolutionize the robotic exploration of deep space. One of these technologies is Aerocapture, the most promising of the "aeroassist" techniques used to maneuver a space vehicle within an atmosphere, using aerodynamic forces in lieu of propellant. (Other aeroassist techniques include aeroentry and aerobraking.) Aerocapture relies on drag atmospheric drag to decelerate an incoming spacecraft and capture it into orbit. This technique is very attractive since it permits spacecraft to be launched from Earth at higher velocities, providing shorter trip times and saving mass and overall cost on future missions. Recent aerocapture systems analysis studies quantify the benefits of aerocapture to future exploration. The 2002 Titan aerocapture study showed that using aerocapture at Titan instead of conventional propulsive capture results in over twice as much payload delivered to Titan. Aerocapture at Venus results in almost twice the payload delivered to Venus as with aerobraking, and over six times more mass delivered into orbit than all-propulsive capture. Aerocapture at Mars shows significant benefits as the payload sizes increase and as missions become more complex. Recent Neptune aerocapture studies show that aerocapture opens up entirely new classes of missions at Neptune. Current aerocapture technology development is advancing the maturity of each subsystem technology needed for successful implementation of aerocapture on future missions. Recent development has focused on both rigid aeroshell and inflatable aerocapture systems. Rigid aeroshell systems development includes new ablative and non-ablative thermal protection systems, advanced aeroshell performance sensors, lightweight structures and higher temperature adhesives. Inflatable systems such as trailing tethered and clamped "ballutes" and inflatable aeroshells are also under development. Computational tools required to support future aerocapture missions are an integral part of aerocapture development. Tools include engineering reference atmosphere models, guidance and navigation algorithms, aerothermodynamic modeling, and flight simulation.

Artis, Gwen↗
NASA NTRS1993

LDEF Space Plasma-High Voltage Drainage Experiment post-flight results

The Space Plasma-High Voltage Drainage Experiment (SP-HVDE) was comprised of two identical experimental trays. With one tray located on the leading (ram facing, B10) edge and the other located on the trailing (wake facing, D4) edge of the Long Duration Exposure Facility (LDEF), it was possible to directly compare the effects of ram and wake spacecraft environments on charged dielectric materials. Six arrays of Kapton dielectric samples of 2 mil, 3 mil, and 5 mil thicknesses maintained at +/- 300, +/- 500, and +/- 1000 voltage bias formed the experimental matrix of each tray. In addition, each tray carried two solar cell strings, one biased at +300 volts and the other at -300 volts, to study current leakage from High Voltage Solar Arrays (HVSA). The SP-HVDE provides the first direct, long-term, in-flight measurements of average leakage current through dielectric materials under electric stress. The experiment also yields information on the long term stability of the bulk dielectric properties of such materials. Data and findings of the SP-HVDE are an extension of those from shorter term flight experiments such as the PIX-1 (Plasma Interaction Experiment) and PIX-2 and are therefore valuable in the design and evaluation of long-lived space systems with high voltage systems exposed to the low earth orbital environment. A summary of the SP-HVDE post flight analysis final report delivered to the LDEF Project Office under contract to the National Aeronautics and Space Administration is presented.

Yaung, J. Y.↗
NASA NTRS2010

Orbital Debris Detection and Tracking Strategies for the NASA/AFRL Meter Class Autonomous Telescope (MCAT)

MCAT (Meter-Class Autonomous Telescope) is a 1.3m f/4 Ritchey-Chr tien on a double horseshoe equatorial mount that will be deployed in early 2011 to the western pacific island of Legan in the Kwajalein Atoll to perform orbital debris observations. MCAT will be capable of tracking earth orbital objects at all inclinations and at altitudes from 200 km to geosynchronous. MCAT s primary objective is the detection of new orbital debris in both low-inclination low-earth orbits (LEO) and at geosynchronous earth orbit (GEO). MCAT was thus designed with a fast focal ratio and a large unvignetted image circle able to accommodate a detector sized to yield a large field of view. The selected primary detector is a close-cycle cooled 4Kx4K 15um pixel CCD camera that yields a 0.9 degree diagonal field. For orbital debris detection in widely spaced angular rate regimes, the camera must offer low read-noise performance over a wide range of framing rates. MCAT s 4-port camera operates from 100 kHz to 1.5 MHz per port at 2 e- and 10 e- read noise respectively. This enables low-noise multi-second exposures for GEO observations as well as rapid (several frames per second) exposures for LEO. GEO observations will be performed using a counter-sidereal time delay integration (TDI) technique which NASA has used successfully in the past. For MCAT the GEO survey, detection, and follow-up prediction algorithms will be automated. These algorithms will be detailed herein. For LEO observations two methods will be employed. The first, Orbit Survey Mode (OSM), will scan specific orbital inclination and altitude regimes, detect new orbital debris objects against trailed background stars, and adjust the telescope track to follow the detected object. The second, Stare and Chase Mode (SCM), will perform a stare, then detect and track objects that enter the field of view which satisfy specific rate and brightness criteria. As with GEO, the LEO operational modes will be fully automated and will be described herein. The automation of photometric and astrometric processing (thus streamlining data collection for environmental modeling) will also be discussed.

Mulrooney, M.↗
NASA NTRS2012

Dark Material at the Surface of Polar Crater Deposits on Mercury

Earth-based radar measurements [1-3] have yielded images of radar-bright material at the poles of Mercury postulated to be near-surface water ice residing in cold traps on the permanently shadowed floors of polar impact craters. The Mercury Laser Altimeter (MLA) on board the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft has now mapped much of the north polar region of Mercury [4] (Fig. 1). Radar-bright zones lie within polar craters or along poleward-facing scarps lying mainly in shadow. Calculations of illumination with respect to solid-body motion [5] show that at least 0.5% of the surface area north of 75deg N lies in permanent shadow, and that most such permanently shadowed regions (PSRs) coincide with radar-bright regions. MLA transmits a 1064-nm-wavelength laser pulse at 8 Hz, timing the leading and trailing edges of the return pulse. MLA can in some cases infer energy and thereby surface reflectance at the laser wavelength from the returned pulses. Surficial exposures of water ice would be optically brighter than the surroundings, but persistent surface water ice would require temperatures over all seasons to remain extremely low (<110 K). Thermal models [6,7] incorporating direct and scattered radiation, Mercury s eccentric orbit, 3:2 spin-orbit resonance, and near-zero obliquity generally do not support such conditions in all permanently shadowed craters but suggest that water ice buried near the surface (<0.5 m depth) could survive for > 1 Gy. We describe measurements of reflectivity derived from MLA pulse returns. These reflectivity data show that surface materials in the shadowed regions are darker than their surroundings, enough to strongly attenuate or extinguish laser returns. Such measurements appear to rule out widespread surface exposures of water ice. We consider explanations for the apparent low reflectivity of these regions involving other types of volatile deposit.

Neumann, Gregory A.↗
NASA NTRS2007

Earth's 2006 Encounter with Comet 73P/Schwassmann-Wachmann: Products of Nucleus Fragmentation Seen in Closeup

The large numbers of nucleus fragments observed are a spectacular illustration of the process of cascading fragmentation in progress, a concept introduced to interpret the properties of the Kreutz system of sungrazers and comet D/1993 F2. The objective is to describe the fragmentation sequence and hierarchy of comet 73P, the nature of the fragmentation process and observed events, and the expected future evolution of this comet. The orbital arc populated by the fragments refers to an interval of 3.74 days in the perihelion time. This result suggests that they all could be products (but not necessarily first-generation fragments) of two 1995 events, in early September (involving an enormous outburst) and at the beginning of November. The interval of perihelion times is equivalent to a range of about 2.5 m/s in separation velocity or 0.00012 the Sun's attraction in nongravitational deceleration. Their combined effect suggests minor orbital momentum changes acquired during fragmentation and decelerations compatible with survival over two revolutions about the Sun. Fragment B is a likely first-generation product of one of the 1995 events. From the behavior of the primary fragment C, 73P is not a dying comet, even though fragment B and others were episodically breaking up into many pieces. Each episode began with the sudden appearance of a starlike nucleus condensation and a rapidly expanding outburst, followed by a development of jets, and a gradual tailward extension of the fading condensation, until the discrete masses embedded in it could be resolved. In April-May, this debris traveled first to the southwest, but models show their eventual motion toward the projected orbit. Fainter fragments were imaged over limited time, apparently because of their erratic activity (interspersed with periods of dormancy) rather than improptu disintegration. A dust trail joining the fragments and reminiscent of comet 141P/Machholz suggests that cascading fragmentation exerts itself profoundly over an extremely broad mass range of particulate debris.

daya analysis↗