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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 505 records · Page 28
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NASA NTRS1976

Structure of the lunar interior from magnetic field measurements

A network of lunar surface and orbiting magnetometers was used to obtain measurements of electrical conductivity and magnetic permeability of the lunar interior. An exceptionally large solar transient event, when the moon was in a geomagnetic tail lobe, enabled the most accurate lunar electromagnetic sounding information to date to be obtained. A new analytical technique using a network of two surface magnetometers and a satellite magnetometer superimposes many time series measurements to improve the signal-to-noise ratio and uses both the amplitude and phase information of all three vector components of the magnetic field data. Size constraints on a hypothetical highly conducting lunar core are investigated with the aid of the permeability results.

Dyal, P.↗
NASA NTRS2009

Synergistic Development, Test, and Qualification Approaches for the Ares I and V Launch Vehicles

The U.S. National Aeronautics and Space Administration is designing and developing the Ares I and Ares V launch vehicles for access to the International Space Station (ISS) and human exploration of the Moon. The Ares I consists of a first stage reusable five-segment solid rocket booster, a upper stage using a J-2X engine derived from heritage experience (Saturn and Space Shuttle External Tank programs), and the Orion crew exploration vehicle (CEV). The Ares V is designed to minimize the development and overall life-cycle costs by leveraging off of the Ares I design. The Ares V consists of two boosters, a core stage, an earth departure stage (EDS), and a shroud. The core stage and EDS use LH2/LO2 propellants, metallic propellant tanks, and composite dry structures. The core stage has six RS-68B upgraded Delta IV engines while the EDS uses a J-2X engine for second stage ascent and trans-lunar injection (TLI) burn. System and propulsion tests and qualification approaches for Ares V elements are being considered as follow-on extensions of the Ares I development program. Following Ares I IOC, testing will be conducted to verify the J-2X engine's orbital restart and TLI burn capability. The Ares I upper stage operation will be demonstrated through integrated stage development and acceptance testing. The EDS will undergo similar development and acceptance testing with additional testing to verify aspects of cryogenic propellant management, operation of sub-systems in a space simulation environment, and orbital re-start of the main propulsion system. RS-68B certification testing will be conducted along with integrated core stage development and acceptance testing. Structural testing of the Ares V EDS and core stage propellant tanks will be conducted similar to the Ares I upper stage. The structural qualification testing may be accomplished with separate propellant tank test articles. Structural development and qualification testing of the dry structure will be pursued as part of the design and development process. Especially critical is the development test program for the composite structures. The Ares V payload shroud will undergo acoustic, vibration, structural qualification, and deployment testing in a space simulation environment. Similar to Ares I, requirements for full-scale structural dynamic testing are being studied. Both Ares I and Ares V include validation flight testing as part of the qualification programs.

Cockrell, Charles E.↗
NASA NTRS1977

A lunar density model consistent with topographic, gravitational, librational, and seismic data

A series of models of the lunar interior are derived from topographic, gravitational, librational, and seismic data. The librational parameters and low-degree gravity harmonics result primarily from surface height variations and only secondarily from lateral density variations. The moon departs from isostasy, even for the low-degree harmonics, with a maximum superisostatic stress of 200 bars under the major mascon basins. The mean crustal thicknesses under different physiographic regions are: mascons, 30-35 km; irregular maria, 50-60 km; and highlands, 90-110 km. A possible composition consistent with our model is an anorthositic crust, underlain by a predominantly forsterite upper mantle which grades into a refractory rich lower mantle surrounding a pyrrhotite core.

Bills, B. G.↗
NASA NTRS1993

US/CIS integrated NTRE

The paper describes the Nuclear Thermal Energy (NTRE) engine, developed by taking advantage of mature fuel technology developed in the former Soviet Union, thus shortening the development schedule of this engine for moon and Mars explorations. The near-term NTRE engine has a number of features that provide safety, mission performance, cost, and risk benefits. These include: (1) high-temperature long-life CIS fuel, (2) high-pressure recuperated expander cycle, (3) assured restart, (4) long-life cooled nozzle with thin inner wall, (5) long-life turbopumps, (6) heat radiation and electrical power generation, and (7) component integration synergy. Diagrams of the reactor core, the recuperated bottoming cycle flow schematic, and the recuperated bottoming cycle engine schematic are presented.

Bulman, M. J.↗
NASA NTRSDate not supplied

Autonomous Navigation, Guidance, and Control Software in a Low SWaP Box

Onboard autonomy is a necessity for responsive space operations. Autonomous navigation, guidance, and control (NGC) enables space missions to reduce their dependence on high demand ground assets and costly ground personnel. It also allows for in-situ decision making and higher return on mission data. A flight software and hardware system providing this capability, called “autoNGC,” is currently being developed at NASA Goddard Space Flight Center for infusion into multiple future missions. The autoNGC flight software is built on the plug-and-play architecture of the core Flight System (cFS) consisting of the standard cFS apps and newly developed autoNGC interface apps and libraries. The various apps cooperate through communication over the message-based software bus. With the plug-and-play architecture of autoNGC, cFS apps can easily be added and replaced to meet the needs of different missions, even after launch. The first flight software release of autoNGC is targeted for Summer 2024 to provide autonomous navigation at the Moon and beyond. It can perform sensor fusion of multiple measurement types including pseudo-range from a Global Navigation Satellite System (GNSS) receiver (including weak signal), 1-way and 2-way range and Doppler from ground stations (i.e., direct to Earth (DTE)), bearing and range from optical camera images, and accelerometer data. Accurate onboard navigation and timing is obtained through the Goddard Enhanced Onboard Navigation System (GEONS) software library which fuses different measurement types through an extended Kalman filter (EKF) framework. Optical measurements that are ingested in GEONS are first extracted from optical images by the cFS Goddard Image Analysis and Navigation Tool (cGIANT) app. If the imaged body is far enough away that it appears as a pixel or cluster of pixels, then bearing angles to the body centroid can be provided. If the body is close enough and the shape is known coarsely, then bearing angles and range to the body centroid can be derived from the limb. Bearing angles to individual surface features can also be extracted (i.e., terrain relative navigation (TRN)). Onboard guidance and control capabilities are being developed for a future release to perform autonomous station-keeping and trajectory correction maneuvers in multiple orbital regimes. Capabilities to enable distributed systems missions and constellations, such as crosslink measurements, and onboard time management are being developed as well. The first hardware implementation of autoNGC is a minimal size, weight, and power (SWaP) design allowing for inclusion into CubeSats and SmallSat-size buses. Advancements in miniaturized space processors, such as the SpaceCube 3.0 Mini and the SpaceCube Mini-Z are utilized for low SWaP while maintaining a high level of performance. The current enclosure design is 12 cm x 17 cm x 13.5 cm. The box mass is expected to be less than 2 kg, and the nominal power is 21 W. In order to accommodate a wide range of missions, the hardware interfaces are designed for flexibility with a variety of sensor inputs. Through comprehensive testing in the software-in-the-loop, processor-in-the-loop, and hardware-in-the-loop test beds that are concurrently being developed, autoNGC is expected to achieve TRL 6 by late 2024.

Sun Hur-Diaz↗
NASA NTRS1982

The intercrater plains of Mercury and the Moon: Their nature, origin and role in terrestrial planet evolution. Chronology of surface history of Mercury

Phases in the history of the planet Mercury include: (1) condensation and accretion; (2) heating; (3) planetary expansion during heavy bombardment; (4) tidal spin-down and lineament formation; (5) P5 plains emplacement; (6) P4 plains emplacement; (7) peak planetary volume in P3 period; (8) scarp formation; (9) Caloris Basin formation, late class 3; (10) scarp formation and P2 plains formation; (11) smooth plains formation in and around large basins; (12) late or local tectonic stress; and (13) quiescent class 1 period. Although the cooling and contraction of the lithosphere are complete, the core remains molten as an active dynamo, producing the magnetic fields detected by Mariner 10. Plains produced since core formation (P3 to P-1) should record its magnetic activity. Cratering during the Class 2 and Class 1 periods is probably not enough to distribute ballistic materials and homogenize any color differences.

Leake, M. A.↗
NASA NTRS2017

NASA's Space Launch System: A Transformative Capability for Deep Space Missions

Already making substantial progress toward its first launches, NASA’s Space Launch System (SLS) exploration-class launch vehicle presents game-changing new opportunities in spaceflight, enabling human exploration of deep space, as well as a variety of missions and mission profiles that are currently impossible. Today, the initial configuration of SLS, able to deliver more than 70 metric tons of payload to low Earth orbit (LEO), is well into final production and testing ahead of its planned first flight, which will send NASA’s new Orion crew vehicle around the moon and will deploy 13 CubeSats, representing multiple disciplines, into deep space. At the same time, production work is already underway toward the more-capable Block 1B configuration, planned to debut on the second flight of SLS, and capable of lofting 105 tons to LEO or of co-manifesting large exploration systems with Orion on launches to the lunar vicinity. Progress being made on the vehicle for that second flight includes initial welding of its core stage and testing of one of its engines, as well as development of new elements such as the powerful Exploration Upper Stage and the Universal Stage Adapter “payload bay.” Ultimately, SLS will evolve to a configuration capable of delivering more than 130 tons to LEO to support humans missions to Mars. In order to enable human deep-space exploration, SLS provides unrivaled mass, volume, and departure energy for payloads, offering numerous benefits for a variety of other missions. For robotic science probes to the outer solar system, for example, SLS can cut transit times to less than half that of currently available vehicles or substantially increased spacecraft mass. In the field of astrophysics, SLS’ high payload volume, in the form of payload fairings with a diameter of up to 10 meters, creates the opportunity for launch of large-aperture telescopes providing an unprecedented look at our universe. This presentation will give an overview of SLS’ capabilities and its current status, and discuss the vehicle’s potential for human exploration of deep space and other game-changing utilization opportunities.

Creech, Stephen D.↗
NASA NTRSDate not supplied

NASA Space Launch System Completes Key Hot Fire Test and Begins Vehicle Integration

The Moon is again in reach. NASA and its commercial and international partners are on the way back. The team is working to land the first woman and the first person of color on the planetary body. NASA and its partners made significant progress towards that goal in the latter half of 2020 and the first half of 2021, including on the agency’s Space Launch System (SLS) rocket – a key part of the Artemis program. The SLS core stage for the Artemis I mission – the first launch of SLS and an uncrewed Orion capsule – completed the Green Run test series and was successfully mated with the SLS twin solid rocket boosters on the mobile launcher at Kennedy Space Center (KSC). All of the major systems for Artemis I are at KSC for assembly, integration, and launch, targeted for late 2021. Work also continued on SLS hardware for Artemis II, which will be the first flight of crew on Orion and SLS. Work progressed on core stage components, booster segments, and other hardware for Artemis III and future missions. This paper will detail the progress made.

John Honeycutt↗
NASA NTRS1978

Luna 24 - Lateral heterogeneity in the lunar crust

Results of petrological investigations of Luna 24 soil samples are compared with data from Apollo and other Luna missions in order to determine the large scale composition of the lunar surface and crust. Modal analysis of the 90 to 150 micron soil fraction and electron microprobe analysis of glass spheres and fragments of the Luna 24 core sample are presented. High and low MgO mare basalt compositional clusters are found, suggesting the derivation of southern Mare Crisium basalts from two magmas. A model of Luna 24 soils as being composed of a mixture of glass-poor mare material and glass-rich highland material is found to be consistent with glass and agglutinate modal abundances. Comparisons show that potassium, and by inference all lithophile trace elements, are depleted on the eastern limb of the moon relative to the central nearside. The observed depletion is interpreted to be characteristic of the underlying crust and mantle as well as the surface.

Warner, J. L.↗
NASA NTRSDate not supplied

NASA’s Space Launch System: Progress Toward Launch

The Space Launch System (SLS), NASA’s cornerstone launch capability for a new generation of deep space exploration, has begun assembly at Kennedy Space Center (KSC) in preparation for launch in 2021. SLS will provide an unparalleled launch capability for human and robotic deep space exploration missions. Its proven propulsion system, upgrade path to more powerful vehicles, and high-volume payload fairings make it the foundation for ambitious and demanding as part of the Artemis program. Artemis is NASA’s 21st-century plan to put boots on the Moon and to perform sustainable, long-term science in deep space, with eyes toward sending explorers to Mars. The initial SLS vehicle to fly, Block 1 in the crew configuration – with the new Orion spacecraft – is scheduled to lift off from revitalized launch facilities at KSC in 2021 for an uncrewed test flight known as Artemis I. Manufacturing is complete on the vehicle and all elements have been delivered to the Exploration Ground Systems (EGS) Program, except the core stage. The program’s all-new development, the core stage is currently in the midst of a “Green Run” test campaign at Stennis Space Center (SSC). Eight progressively more challenging tests in the Green Run series will culminate in a hot-fire of four flight-proven liquid hydrogen/liquid oxygen (LH2/LOX) RS25 engines. Following the Green Run hotfiring, the core stage will ship to KSC. Already at KSC, aft sections of the fivesegment solid rocket boosters are being assembled. Previously delivered elements, including the upper stage, are undergoing final checkouts in preparation for stacking. An exciting 2021 will include such milestones as stacking SLS and Orion in KSC’s Vehicle Assembly Building (VAB), modal testing, roll out to Launch Pad 39B, Wet Dress Rehearsal (WDR), and launch. Teams across the country are preparing for launch by finalizing procedures, defining launch constraints and flight rules, training console operators, performing simulations, and more. With the SLS Block 1 vehicle for Artemis I nearing integration and launch, the second Block 1 vehicle in the crew configuration, which will carry astronauts on an Artemis II hybrid lunar flyby mission, has several elements manufactured. In fact, the solid rocket motor segments and RS-25 engines are complete. Those program elements are processing hardware for the third flight and working toward manufacturing the second SLS variant to fly, Block 1B, which will onramp a powerful new upper stage, the Exploration Upper Stage (EUS).

John Honeycutt↗
NASA NTRS1971

Lunar magnetic field measurements, electrical conductivity calculations and thermal profile inferences

Steady magnetic field measurements of magnitude 30 to 100 gamma on the lunar surface impose problems of interpretation when coupled with the nondetectability of a lunar field at 0.4 lunar radius altitude and the limb induced perturbations of the solar wind at the Explorer orbit. The lunar time-varying magnetic field clearly indicates the presence of eddy currents in the lunar interior and permits calculation of an electrical conductivity profile. The problem is complicated by the day-night asymmetry of the moon's electromagnetic environment, the possible presence of the transverse magnetic mode, and the variable wave directions of the driving function. The electrical conductivity is calculated to be low near the surface, rising to a peak of .006/ohm meter at 250 km, dropping steeply inwards to a value of about .00005/ohm meter, and then rising toward the interior. A transition at 250 km depth from a high conductivity to a low conductivity material is inferred, suggesting an olivine-like core at approximately 800 C, although other models are possible.

Colburn, D. S.↗
NASA NTRS1974

Results from the Apollo passive seismic experiment

Recent results from the Apollo seismic network suggest that primitive differentiation occurred in the outer shell of the moon to a depth of approximately 300 km; and the central region of the moon is presently molten to a radius of between 200 and 300 km. If early melting to a depth of 300 to 400 km was a consequence of accretional energy, very short accretion times are required. The best model for the zone of original differentiation appears to be a crust 40 to 80 km thick, ranging in composition from anorthositic gabbro to gabbro; overlying an ultramafic cumulate (olivine-pyroxene) about 250 km thick. The best candidate for the molten core appears to be iron or iron sulphide. A new class of seismic signals has recently been identified that may correspond to shallow moonquakes. These are rare, but much more energetic than the more numerous, deep moonquakes.

Lathum, G.↗
NASA NTRS1977

Results from the Apollo passive seismic experiment

Recent results from the Apollo Seismic Network suggest that primitive differentiation occurred in the outer shell of the moon to a depth of approximately 300 km and the central region of the moon is presently molten to a radius of between 200 and 300 km. If early melting to a depth of 300 to 400 km was a consequence of accretional energy, very short accretion times are required. It was shown that the best model for the zone of original differentiation is a crust 40 to 80 km thick, ranging in composition from anorthositic gabbro to gabbro, and overlying an ultramafic cumulate about 250 km thick. The best candidate for the molten core appears to be iron or iron sulphide. A new class of seismic signals recently were identified that may correspond to shallow moonquakes. These are rare, but much more energetic than the more numerous, deep moonquakes.

Latham, G.↗
NASA NTRS1974

Density within the moon and implications for lunar composition

A number of simple density models for the moon are discussed. The considered models are consistent with the lunar mass and moment of inertia, the latest information on the seismic velocity of the lunar crust and mantle, and assorted estimates of temperature in the lunar interior. New material presented includes the implications for density models of recent seismic evidence for a thin, high velocity layer beneath the lunar crust and for a zone of partial melting below 1000 km depth. The consequences of a dense, iron-rich central core are also explored.

Solomon, S. C.↗
NASA NTRS1981

Lunar seismology - The internal structure of the moon

It is pointed out that seismology has provided the most detailed information concerning the structure and state of the earth's interior. Beginning in 1969, seismometers were landed on the moon by the Apollo missions, providing the first opportunity to attempt similar studies on another planetary body. In September 1977 the operation of these instruments was terminated. A description is presented of the internal structure of the moon, as determined from the obtained lunar seismic data. The analysis of the lunar data is approached in a systematic fashion, using appropriate techniques to minimize the number of necessary assumptions, extract the maximum amount of structural information, and determine its reliability. The completed lunar seismic network consists of four stations located at the landing sites of Apollo missions 12, 14, 15, and 16. Attention is given to crustal structure, the structure of the lunar mantle, the attenuating region, and the core.

Goins, N. R.↗
NASA NTRS2004

Habitat Inspection Scanner, Bio-Structure Scanner, and In Situ Sub-Surface Composition Sensor

The extension of dielectric and inductive spectroscopy into in situ observations represents a significant exploration-enabling tool. This technology can be widely applied from microscopic to macroscopic. Dielectrometry and inductometry can measure sub-surface composition and its distribution. The primary environment that we cannot easily explored is the sub-surface of solid bodies. Weather as part of our equipment that we bring with us, or the locations we are exploring. These fundamental questions lie at the core of the exploration Initiative. To answer them we must use a whole host of complimentary tools including those that allow us to practically examine the sub-surface environment. A nondestructive approach offers significant advantages for both the initial identification of likely samples but also the monitoring of ecosystems and crew health. These include materials characterization, nondestructive inspection, and process quality control, damage monitoring, and hidden object detection and identification. The identification of natural resources such as water on the Moon or Mars is of great importance to the utilization of local resource in the support of human exploration crews. On the macroscopic scale, the understanding of what resources are available and how they are distributed is of primary importance to their productive utilization. Even if initial explorations do not require the use of local resources to succeed, eventual settlement and commercial development will. The routine examination of the structural integrity (micro cracks, leaks) of hi.inafi habitats in harsh envkmments ww!d also be enabled.

VanSteenberg, Michael↗
NASA NTRSDate not supplied

NASA Space Launch System Completes Green Run Testing, Begins Assembly

NASA’s Space Launch System (SLS) Program is poised in 2021 to shift its focus to the launch site with the completion of its last major integrated hardware and software test. SLS is NASA’s evolvable super heavy-lift launch vehicle for deep space exploration. Using proven propulsion technologies, SLS will be the most powerful launch vehicle in the world. That capability translates not only into more mass and volume to destinations but also simplified payload design and mission operations and greater opportunity for mission success. These capabilities will be important for the Artemis program, NASA’s plan to return humans to the Moon to stay in a sustainable way in order to develop and test technologies and operations needed for human missions to Mars and other destinations. SLS will anchor the transportation leg of an innovative, sustainable program of lunar exploration with commercial and international partners as the first step of human exploration of deep space. While all major hardware and software efforts made significant progress in 2020 and 2021, the most visible was the Green Run test series of the Artemis I core stage conducted at NASA’s Stennis Space Center (SSC) on the B-2 test stand. The series validated core stage design, performance, workmanship, and readiness for shipment to NASA Kennedy Space Center (KSC) for final processing, integration and launch. The core stage provides the backbone for SLS’ main propulsion system, consisting of two five-segment solid rocket boosters and four RS-25 liquid hydrogen (LH2)/liquid oxygen (LOX) engines. SLS also includes an Interim Cryogenic Propulsion Stage (ICPS) that will insert the Orion crew spacecraft into a lunar trajectory.

John Honeycutt↗