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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Overview of Proposed ISRU Technology Development

ISRU involves any hardware or operation that harnesses and utilizes in-situ resources (natural and discarded) to create products and services for robotic and human exploration: Assessment of physical, mineral chemical, and volatile water resources, terrain, geology, and environment (orbital and local). Production of replacement parts, complex products, machines, and integrated systems from feedstock derived from one or more processed resources. Civil engineering, infrastructure emplacement, and structure construction using materials produced from in situ resources. Radiation shields, landing pads, roads, berms, habitats, etc. Generation and storage of electrical, thermal, and chemical energy with in situ derived materials. Solar arrays, thermal wadis, chemical batteries, etc. ISRU is a disruptive capability: Enables more affordable exploration than todays paradigm. Allows more sustainable architectures to be developed. Understand the ripple effect in the other Exploration Elements: MAV: propellant selection, higher rendezvous altitude (higher DV capable with ISRU propellants). EDL: significantly reduces required landed mass. Life Support: reduce amount of ECLSS closure, reduce trash mass carried through propulsive maneuvers. Power: ISRU drives electrical requirements, reactant and regeneration for fuel cells for landers, rovers, and habitat backup. Every Exploration Element except ISRU has some flight heritage (power, propulsion, habitats, landers, life support, etc.) ISRU will require a flight demonstration mission on Mars before it will be included in the critical path. Mission needs to be concluded at least 10 years before first human landed mission to ensure lessons learned can be incorporated into final design. ISRU Formulation team has generated a (still incomplete) list of over 75 technical questions on more than 40 components and subsystems that need to be answered before the right ISRU system will be ready for this flight demo.

Mars exploration↗
NASA NTRS2020

A Mercury Lander Mission Concept Study for the Next Decadal Survey

Mariner 10 provided our first closeup reconnaissance of Mercury during its three flybys in 1974 and 1975. MESSENGER’s 2011–2015 orbital investigation enabled numerous discoveries, several of which led to substantial or complete changes in our fundamental understanding of the planet. Among these were the unanticipated, widespread presence of volatile elements (e.g., Na, K, S); a surface with extremely low Fe abundance whose darkening agent is likely C; a previously unknown landform—hollows— that may form by volatile sublimation from within rocks exposed to the harsh conditions on the surface; a history of expansive effusive and explosive volcanism; substantial radial contraction of the planet from interior cooling; offset of the dipole moment of the internal magnetic field northward from the geographic equator by ~20% of the planet’s radius; crustal magnetization, attributed at least in part to an ancient field; unexpected seasonal variability and relationships among exospheric species and processes; and the presence in permanently shadowed polar terrain of water ice and other volatile materials, likely to include complex organic compounds. Mercury’s highly chemically reduced and unexpectedly volatile-rich composition is unique among the terrestrial planets and was not predicted by earlier hypotheses for the planet’s origin. As an end-member of terrestrial planet formation, Mercury holds unique clues about the original distribution of elements in the earliest stages of the Solar System and how planets (and exoplanets) form and evolve in close proximity to their host stars. The BepiColombo mission promises to expand our knowledge of this planet and to shed light on some of the mysteries revealed by the MESSENGER mission. However, several fundamental science questions raised by MESSENGER’s pioneering exploration of Mercury can only be answered with in situ measurements from the planet’s surface.

Ernst, C. M.↗
DOE OSTI2020

Computing water flow through complex landscapes – Part 2: Finding hierarchies in depressions and morphological segmentations

Depressions – inwardly draining regions of digital elevation models – present difficulties for terrain analysis and hydrological modeling. Analogous “depressions” also arise in image processing and morphological segmentation, where they may represent noise, features of interest, or both. Here we provide a new data structure – the depression hierarchy – that captures the full topologic and topographic complexity of depressions in a region. We treat depressions as networks in a way that is analogous to surface-water flow paths, in which individual sub-depressions merge together to form meta-depressions in a process that continues until they begin to drain externally. This hierarchy can be used to selectively fill or breach depressions or to accelerate dynamic models of hydrological flow. Complete, well-commented, open-source code and correctness tests are available on GitHub and Zenodo.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1985

Radio phase characteristics of terrain from multipolarized synthetic aperture radar data

Recent advances in digital data acquisition and signal processing technology permit simultaneous measurement of the complex (amplitude and phase) radar backscatter from several polarization-diverse antennas. While absolute phase mesurements remain to be analyzed in detail. The differential phase of signals polarized parallel and perpendicular to the plane of incidence provide information on the scattering mechanisms that dominate the interaction of the radio waves with the terrain. Analysis of phase backscatter maps from a typical urban area yields a bimodal distribution with the two peaks separated by approximately 180 degrees, highly indicative of a dominant simple geometric one bounce-two bounce mechanism. Some maps of agricultural areas exhibit a similar distribution, however, other agricultural areas yield a distribution that, while still bimodal, consists of two peaks separated by about 110 deg. Still other agricultural areas exhibit a more complex distribution. All of the observed phase shifts appear to be independent of incidence angle from at least 20 deg to 55 deg, therefore the 110 degree shifts are inconsistent with both the geometric model used for the urban area and with common dielectric slab models.

Zebker, H. A.↗
NASA NTRS1979

Cockpit displays of traffic information: Airline pilots opinions about content, symbology, and format

A number of candidate computer-generated cockpit displays of traffic information (CDTI) displays and display options were simulated statically and were shown to 23 airline pilots who were asked to respond to more than 250 questions about them. The pilots indicated that the amount and complexity of navigation information displayed should increase with altitude and map scale. Terrain information should appear automatically if a pilot's own aircraft descends below the minimum safe altitude and should include only those obstruction within 2,000 ft or less. Few pilots that weather information should be displayed on a CDTI, but if it was, it should be at pilot request only. A chevron-shaped symbol, located so that the majority of the map area was ahead was preferred. The position, altitude, ground speed, ground track, weight class, and flightpath history of other aircraft should be presented graphically by coding the shape of the symbol for other aircraft or presented digitally in data tags displayed at pilot request. All pilots thought that color coding was necessary to recognize different categories of information quickly and accurately. The majority of pilots felt that a CDTI would provide useful information even though its presence might increase their workload somewhat particularly during its introductory stages.

Hart, S. G.↗
NASA NTRSDate not supplied

Implementation of a Six Degree of Freedom Precision Lunar Landing Algorithm Using Dual Quaternion Representation

In this study, a powered descent guidance algorithm using a unit dual quaternion represen- tation of the vehicle dynamics is implemented in a high-fidelity simulation and on representative flight hardware. This Dual-Quaternion Guidance (DQG) algorithm is applied to the precision lunar landing problem which levies complex constraints upon the trajectory, including state triggered attitude constraints to enable terrain-relative navigation and hazard detection as well as real-time requirements for landing site re-designation. The investigation explores DQG’s usefulness as a mission design tool as well as a real-time guidance algorithm and defines real-time performance requirements for the hazard detection and avoidance (HDA) re-targeting phase of precision lunar landing. The experiment is presented in two parts. First, DQG is implemented within a high-fidelity Monte Carlo simulation to tune the algorithm’s parameters for the simulated vehicle, to refine the mission design, and to develop guidance update timing requirements to perform the HDA maneuver. DQG generates trajectories online for the divert which are tracked by the vehicle’s inner-loop controllers to the targeted landing site. Second, DQG is run on representative hardware to demonstrate real-time operation through a divert maneuver. These results allow for rapid, flexible, optimal mission design satisfying complex constraints, and for the definition of real-time performance requirements for the HDA operations inherent in precision lunar landing. The HDA divert maneuver is found to require guidance trajectory updates in less than three seconds. DQG is found to be too slow to meet this update timing on the descent and landing computer (DLC) in its current implementation. DQG running on alternative hardware can meet the update rate requirement. Algorithm implementation improvements are also recommended which are expected to speed up computation sufficiently to meet requirements on the DLC.

GN&C↗
NASA NTRS2016

The Geology of Pluto and Charon Through the Eyes of New Horizons

NASA's New Horizons spacecraft has revealed the complex geology of Pluto and Charon. Pluto shows ongoing surface geological activity centered on a vast basin containing a thick layer of volatile ices that is involved in convection and advection, with a crater retention age no greater than 10 Ma. Surrounding terrains show active glacial flow, apparent transport and rotation of large buoyant water-ice crustal blocks, and pitting by sublimation erosion and/or collapse. More enigmatic features include tall mounds with central depressions that are conceivably cryovolcanic, and ridges with complex bladed textures. Pluto also has ancient cratered terrains up to 4 Ga old that are extensionally fractured and extensively mantled and eroded by glacial or other processes. Charon is not currently active, but experienced major extensional tectonism and resurfacing (probably cryovolcanic) nearly 4 billion years ago. Impact crater populations on Pluto and Charon are not consistent with the steepest proposed impactor size-frequency distributions.

New Horizons spacecraft↗
NASA NTRS2016

The Geology of Pluto and Charon Through the Eyes of New Horizons

NASA's New Horizons spacecraft has revealed the complex geology of Pluto and Charon. Pluto's encounter hemisphere shows ongoing surface geological activity centered on a vast basin containing a thick layer of volatile ices that appears to be involved in convection and advection, with a crater retention age no greater than approximately 10 million years. Surrounding terrains show active glacial flow, apparent transport and rotation of large buoyant water-ice crustal blocks, and pitting, the latter likely caused by sublimation erosion and/or collapse. More enigmatic features include tall mounds with central depressions that are conceivably cryovolcanic and ridges with complex bladed textures. Pluto also has ancient cratered terrains up to approximately 4 billion years old that are extensionally faulted and extensively mantled and perhaps eroded by glacial or other processes. Charon does not appear to be currently active, but experienced major extensional tectonism and resurfacing (probably cryovolcanic) nearly 4 billion years ago. Impact crater populations on Pluto and Charon are not consistent with the steepest impactor size-frequency distributions proposed for the Kuiper belt.

Moore, Jeffrey M.↗
NASA NTRS1994

Synthetic vision display evaluation studies

The goal of this research was to help us understand the display requirements for a synthetic vision system for the High Speed Civil Transport (HSCT). Four experiments were conducted to examine the effects of different levels of perceptual cue complexity in displays used by pilots in a flare and landing task. Increased levels of texture mapping of terrain and runway produced mixed results, including harder but shorter landings and a lower flare initiation altitude. Under higher workload conditions, increased texture resulted in an improvement in performance. An increase in familiar size cues did not result in improved performance. Only a small difference was found between displays using two patterns of high resolution texture mapping. The effects of increased perceptual cue complexity on performance was not as strong as would be predicted from the pilot's subjective reports or from related literature. A description of the role of a synthetic vision system in the High Speed Civil Transport is provide along with a literature review covering applied research related to perceptual cue usage in aircraft displays.

Regal, David M.↗
NASA NTRS2004

Architecting a Simulation Framework for Model Rehosting

The utility of vehicle math models extends beyond human-in-the-loop simulation. It is desirable to deploy a given model across a multitude of applications that target design, analysis, and research. However, the vehicle model alone represents an incomplete simulation. One must also replicate the environment models (e.g., atmosphere, gravity, terrain) to achieve identical vehicle behavior across all applications. Environment models are increasing in complexity and represent a substantial investment to re-engineer for a new application. A software component that can be rehosted in each application is one solution to the deployment problem. The component must encapsulate both the vehicle and environment models. The component must have a well-defined interface that abstracts the bulk of the logic to operate the models. This paper examines the characteristics of a rehostable modeling component from the perspective of a human-in-the-loop simulation framework. The Langley Standard Real-Time Simulation in C++ (LaSRS++) is used as an example. LaSRS++ was recently redesigned to transform its modeling package into a rehostable component.

Madden, Michael M.↗
NASA NTRS1985

A Silicic Shield Volcano in Bolivia

Volcan Quemado and its environs provides an excellent site to study the radar signature of a silicic volcanic construct. This feature differs from basaltic terrains primarily by the evidence of explosive eruptions associated with silica-rich magmas. These explosions produced a complex of distinctive craters that are visible on radar because of their steep inner walls and exposed bedrock units. Explosive events also generated surface deposits of fine (1 mm to 10 cm) material that mantles the region around the volcano to a distance of 20 to 30 km from its center. These features are very different from those observed on basaltic flows, which typically lack violet, explosive events. In these terrains, the surface is dominated by radar-rough flows with steep, lobate flow fronts. Craters are less common, although maars are found in some regions. These comparisons suggest that spaceborne radar may be able to distinguish surface characteristics that can be used to identify volcanic eruptive styles on Venus, Mars, and other solar-system bodies.

Christensen, P. R.↗
NASA NTRS1983

The geology of dione

Dione is one of the more geologically complex of Saturn's satellites. Several geologic units have been identified including ancient heavily cratered terrain; two plains units: cratered plains and lightly cratered plains; lobate deposits; crater rim deposits; and bright wispy material. The only structural features observed are a series of troughs which cross portions of th surface and subtle northeast and northwest trending lineaments. The troughs are associated with volcanic deposits and are interpreted to be the vents through which material was erupted. Correlations exist between telescopically observed albedo patterns and the distribution of geologic units.

Plescia, J. B.↗
NASA NTRS1986

Archaean megacrystic plagioclase units and the tectonic setting of greenstones

Large (up to 20 cm), equidimensional, commonly euhedral, plagioclase megacrysts of highly calcic composition (An sub 80-90) occur commonly in all Archean cratons in one or more of three distinct associations: (1) as cumulate crystal segregations of anorthosite or as megacrysts in basaltic dikes, sills, and flows in greenstone belts that vary in metamorphic grade from greenschist to granulite. Throughout 100's of thousands of square kilometers of northwestern Ontario and Manitoba the plagioclase megacrysts occur in pillowed and massive flows, sills, dikes, large inclusions in dikes, and intrusive anorthositic complexes with areas of up to a few 100 sq km and spanning a period of at least 100 m.y. in the 2.7 to 2.8 b.y. time frame; (2) as basaltic dike swarms in stable cratonic areas forming parallel to subparallel patterns over hundreds of thousands of square kilometers intruding both granitic gneisses and supracrustal belts including greenstones. These swams include the Ameralik-Saglek system at 3.1 to 3.4 b.y., the Matachewan system at 2.5 to 2.6 b.y., and the Beartooth-Bighorn system at 2.2 to 2.3 b.y.; and, (3) as anorthositic complexes associated with marbles and quartzites (Sittampundi, India and Messina, South Africa) in granulite grade terrains. Initial attempts to correlate tectonic settings of similar modern crystbearing units with their Archean counterparts were only partially successful.

Phinney, W. C.↗
NASA NTRS1988

Bayes classification of terrain cover using normalized polarimetric data

The normalized polarimetric classifier (NPC) which uses only the relative magnitudes and phases of the polarimetric data is proposed for discrimination of terrain elements. The probability density functions (PDFs) of polarimetric data are assumed to have a complex Gaussian distribution, and the marginal PDF of the normalized polarimetric data is derived by adopting the Euclidean norm as the normalization function. The general form of the distance measure for the NPC is also obtained. It is demonstrated that for polarimetric data with an arbitrary PDF, the distance measure of NPC will be independent of the normalization function selected even when the classifier is mistrained. A complex Gaussian distribution is assumed for the polarimetric data consisting of grass and tree regions. The probability of error for the NPC is compared with those of several other single-feature classifiers. The classification error of NPCs is shown to be independent of the normalization function.

Yueh, H. A.↗
NASA NTRS1989

Synthetic perspective optical flow: Influence on pilot control tasks

One approach used to better understand the impact of visual flow on control tasks has been to use synthetic perspective flow patterns. Such patterns are the result of apparent motion across a grid or random dot display. Unfortunately, the optical flow so generated is based on a subset of the flow information that exists in the real world. The danger is that the resulting optical motions may not generate the visual flow patterns useful for actual flight control. Researchers conducted a series of studies directed at understanding the characteristics of synthetic perspective flow that support various pilot tasks. In the first of these, they examined the control of altitude over various perspective grid textures (Johnson et al., 1987). Another set of studies was directed at studying the head tracking of targets moving in a 3-D coordinate system. These studies, parametric in nature, utilized both impoverished and complex virtual worlds represented by simple perspective grids at one extreme, and computer-generated terrain at the other. These studies are part of an applied visual research program directed at understanding the design principles required for the development of instruments displaying spatial orientation information. The experiments also highlight the need for modeling the impact of spatial displays on pilot control tasks.

Bennett, C. Thomas↗
NASA NTRS2009

Enceladus: An Active Cryovolcanic Satellite

Enceladus is one of the most remarkable satellites in the solar system, as revealed by Cassini's detection of active plumes erupting from warm fractures near its south pole. This discovery makes Enceladus the only icy satellite known to exhibit ongoing internally driven geological activity. The activity is presumably powered by tidal heating maintained by Enceladus 2:1 mean-motion resonance with Dione, but many questions remain. For instance, it appears difficult or impossible to maintain the currently observed radiated power (probably at least 6 GW) in steady state. It is also not clear how Enceladus first entered its current self-maintaining warm and dissipative state initial heating from non-tidal sources is probably required. There are also many unanswered questions about Enceladus interior. The silicate fraction inferred from its density of 1.68 g per cubic centimeter is probably differentiated into a core, though we have only indirect evidence for differentiation. Above the core there is probably a global or regional water layer, inferred from several models of tidal heating, and an ice shell thick enough to support the ~1 kilometer amplitude topography seen on Enceladus. It is possible that dissipation is largely localized beneath the south polar region. Enceladus surface geology, ranging from moderately cratered terrain to the virtually crater-free active south polar region, is highly diverse, tectonically complex, and remarkably symmetrical about the rotation axis and the direction to Saturn. South polar activity is concentrated along the four tiger stripe fractures, which radiate heat at temperatures up to at least 167 K and are the source of multiple plumes ejecting ~200 kilograms per second of H2O vapor along with significant N2 (or C2H4), CO2, CH4, NH3, and higher-mass hydrocarbons. The escaping gas maintains Saturn's neutral gas torus, and the plumes also eject a large number of micron-sized H2O ice grains that populate Saturn's E-ring. The mechanism that powers the plumes is not well understood, and whether liquid water is involved is a subject of active debate (but likely nonetheless). Enceladus provides a promising potential habitat for life in the outer solar system, and the active plumes allow the unique opportunity for direct sampling of that zone. Enceladus is thus a prime target for Cassini's continued exploration of the Saturn system, and will be a tempting target for future missions.

Spencer, J. R.↗
NASA NTRS2020

Basaltic Fissure Types on Earth: Suitable Analogs to Evaluate the Origins of Volcanic Terrains on the Moon and Mars?

Basaltic eruptive fissures of the Great Rift and surroundings on the eastern Snake River Plain of Idaho, USA, and selected volcanic features in Hawai`i, Iceland and northern Africa were surveyed for their relevancy as planetary analogs. Evaluated during field investigations and in satellite imagery for structures, physiography, and geologic setting, fissures were categorized into four broad types: (1) simple, monogenetic fissures with obvious volcanic constructs or deposits, (2) monogenetic fissures now obscured by low shields or relatively large cones, (3) polygenetic volcanic rift zones with multiple vents and deposits, and (4) compound regional fissure systems or dike swarms that comprise major rift zones or large volcanic terrains. Using this classification as an initial base, we surveyed imagery of volcanic features for likely fissure vents in two major geologic settings on the Moon: floor-fractured craters (FFCs) and mare and cryptomare provinces. Two major regions on Mars, the volcanic plains around Alba Mons and the greater Tharsis region, were also surveyed for fissure types and volcanic associations of fissure-like features. The planetary surveys suggest that the proposed classification provides a suitable analog starting point to interpret structures associated with fissure systems on the Moon and Mars. With few exceptions, our survey indicates that each of the studied terrains exhibits a dominant fissure type. Type 1 fissures, most with pyroclastic deposits, prevail in lunar FFCs and mare-like regions; whereas type 2 fissures are ubiquitous in the Tharsis region of Mars and a few exist on the Moon as low shields. Type 3 volcanic rift zones are not common on either the Moon or Mars, although they might become evident in future work on chemically evolved terrains. Type 4 fissures are inferred in mare terrains, often represented as the extensions of major linear rille networks or rimae, with possibly complex dike swarms that were buried beneath voluminous mare basalt lava flows. Likewise, numerous flood lavas on Mars are possibly associated with now-obscured or difficult to define type 4 fissure systems.

Scott S. Hughes↗
NASA NTRSDate not supplied

DLES Unreal Simulation Tool (DUST)

NASA’s future Artemis missions to the Moon seek to explore areas around the Lunar South Pole. Though humans have previously set foot on the lunar surface, the proposed region provides unique and challenging environments that require insight and investigation prior to arrival. Several teams throughout the agency are performing this site and mission planning, design, and analysis to support areas like the Human Landing System (HLS), surface mobility, habitation elements, and scientific exploration. The NASA Exploration Systems Simulation (NExSyS) team at Johnson Space Center is developing a graphical environment of the Lunar South Pole region. Lunar terrain information collected from the Lunar Reconnaissance Orbiter (LRO) is compiled and made available through Johnson Space Center’s Digital Lunar Exploration Sites (DLES) data sets. The DLES data is used to build this graphic environment. The process of ingesting and accurately modeling this information in a meaningful way for analysis creates its own challenges such as generating a performant model from the source data and the application of curvature. Additionally, the area around the Lunar South Pole experiences different lighting conditions than those observed from the Apollo missions. The need to use the lunar environmental data products provided by DLES combined with the capability to calculate date specific ephemerides in real-time has given rise to the development of the DLES Unreal Simulation Tool (DUST). DUST incorporates augmented terrain from the DLES product into a desktop application that allows exploration of the Lunar South Pole region and its complex lighting conditions. DUST leverages advanced capabilities in the recently released Unreal Engine 5 renderer by Epic Games such as double precision for positioning of planetary bodies and surface elements, multiple infinite light sources to represent the Sun and eventually Earthshine, high resolution shadow maps for dynamic shadow accuracy, real-time software ray-tracing for multi-surface bounce lighting to render sunlight reflected off surface elements and terrain features, and performance optimized level of detail shifting as the eyepoint changes in a scene. This paper details the DUST application, the technologies of the engine platform that enable scientific and engineering analysis, the unique techniques and processes developed to consume the DLES data sets, and how the tool is being used to support the Artemis program.

Lunar Visualization↗