Search NASA⌕ Search

SEARCH · Search NASA

Results for “lunar poles”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

High Spatial Resolution Studies of Epithermal Neutron Emission from the Lunar Poles: Constraints on Hydrogen Mobility

The data from the collimated sensors of the LEND instrument are shown to be of exceptionally high quality. Counting uncertainties are about 0.3% relative and are shown to be the only significant source of random error, thus conclusions based on small differences in count rates are valid. By comparison with the topography of Shoemaker crater, the spatial resolution of the instrument is shown to be consistent with the design value of 5 km for the radius of the circle over which half the counts from the lunar surface would be determined. The observed epithermal-neutron suppression factor due to the hydrogen deposit in Shoemaker crater of 0.25 plus or minus 0.04 cps is consistent with the collimated field-of-view rate of 1.7 cps estimated by Mitrofanov et al. (2010a). The statistical significance of the neutron suppressed regions (NSRs) relative to the larger surrounding polar region is demonstrated, and it is shown that they are not closely related to the permanently shadowed regions. There is a significant increase in H content in the polar regions independent of the H content of the NSRs. The non-NSR H content increases directly with latitude, and the rate of increase is virtually identical at both poles. There is little or no increase with latitude outside the polar region. Various mechanisms to explain this steep increase in the non-NSR polar H with latitude are investigated, and it is suggested that thermal volatilization is responsible for the increase because it is minimized at the low surface temperatures close to the poles.

neutron↗
NASA NTRS2004

Accessing the Lunar Poles for Human Exploration Missions

The National Vision for Space Exploration calls for an American return to the Moon in preparation for the human exploration of Mars and other destinations. The surface environment of the Moon is a challenge for human operations, but recent findings from robotic and Earth-based studies have indicated that the polar regions of the Moon may offer advantages in terms of thermal conditions, availability of solar energy, and access to local resources. While accessing these regions represents a challenge due to orbital dynamics and propulsive performance, methods for accessing the regions with humans are being actively pursued, and environmental data gathering is planned through future robotic missions.

Joosten, B. Kent↗
NASA NTRSDate not supplied

New Topographic Products for the Lunar South Pole from the Lunar Orbiter Laser Altimeter (LOLA)

Due to the Moon’s low obliquity and highly cratered topography, its polar environments host regions of extreme illumination conditions. Multiple lines of evidence indicate the presence of geologically stable ice and other volatiles on or below the surface within polar permanently shadowed regions (PSRs). These regions are valuable targets for science and exploration as they hold clues to the history of water in the inner solar system and may hold sufficient reserves for in-situ resource utilization. Standing high above the PSRs, peaks of long-duration sunlight are oases where landed assets can easily generate power and communicate. For these reasons, the lunar south pole is the target of many upcoming missions including NASA’s Artemis program. The Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO) provides the global geodetic framework with which past, present, and future missions can accurately geolocate their data. Laser altimeters like LOLA are unaffected by shadows and, therefore, provide the most direct measurements of topography within PSRs. Here we present the latest work to improve LOLA’s polar topographic maps and resulting derived products, such as PSR maps, which are crucial tools for science and exploration of the polar regions

Michael K Barker↗
NASA NTRS2023

A New View of the Lunar South Pole from the Lunar Orbiter Laser Altimeter (LOLA)

Upcoming missions to the lunar south pole require detailed maps over large areas to fully characterize landing sites locally and regionally and to place their data into proper geologic context. To that end, we enhanced the Lunar Orbiter Laser Altimeter (LOLA) altimetry dataset for the south polar region, from which we produced new maps of topography, topographic roughness, and permanently shadowed regions (PSRs). The roughness maps reveal a diversity of terrains characterized by hectometer-scale roughness which is controlled in this region primarily by cratering and downslope mass transport. The south polar region is littered with linear roughness features of order ~1 – 10 km wide and ~10s – 100s of km long hypothesized to be secondary impacts within extended ejecta rays. Non uniformities in these features could reflect variations in secondary impactor properties and/or target terrain properties. Poleward of 80° S, the PSR cumulative size-frequency distribution (CSFD) shows an approximately power-law behavior whose exponent has a spatial variation of ~10%. PSRs with areas < 1 km2 contain 15 ± 5% of the total PSR area. Finally, we studied the effect of false positives and false negatives on the accuracy of the measured PSR cumulative size-frequency distribution (CSFD) and on the area for any individual PSR. The new maps presented here have many applications in the science and exploration of the lunar south polar region, such as geologic mapping and traverse planning.

Michael K. Barker↗
NASA NTRSDate not supplied

Using Virtual Reality for Science Missions At The Lunar South Pole

The Lunar VR toolkit, built on Mixed Reality Exploration Toolkit (MRET), combines LOLA 5m topographic data, CAD models (e.g., lander, rover), procedural textures, and geologic features (e.g., rocks, craters) for sub-5m simulation of the lunar surface. Future capabilities include the incorporation of real-time mission telemetry to provide a full mission lifecycle tool, test instrument design and operation concepts, pre-operations planning and walk-throughs of traverses, and situational awareness support during actual mission operations. We will discuss the critical features we think are needed for lunar south pole mission planning and the development of our Lunar VR toolkit.

Thomas G Grubb↗
NASA NTRS1998

Evidence for Phyllosilicates near the Lunar South Pole

While theoretically water ice could be stable in permanently shadowed areas near the lunar poles, there is conflicting observational evidence for the existence of water ice at either pole. Clementine's bistatic radar resumed a weak signal commensurate with water ice in the South Pole Aitken Basin; however, groundbased radar searches have not detected such a signal at either pole. Lunar Prospector measured large amounts of H (attributed to water) at both poles; however, Galileo near-infrared spectral measurements of the north polar region did not detect the prominent 3.0 micron absorption feature due to interlayer and adsorbed water in phyllosilicates. Evidence for the existence of water at the lunar poles is still ambiguous and controversial. We present evidence, based on the analysis of Galileo SSI images, for the presence of phyllosilicates near the lunar south pole. Using the color image sequence (560 nm, 670 nm, 756 nm, and 889 nm) of Lunmap 14 taken during the Galileo Earth-Moon pass I, we have identified areas that show evidence for a 0.7 microns absorption feature present in Fe-bearing phyllosilicates.

Vilas, Faith↗
NASA NTRSDate not supplied

Structural Sizing of a 50-m-Tall Thermoplastic Composite Solar Array Truss Tower Structure for the Lunar South Pole

At the lunar south pole, solar arrays elevated by truss towers are exposed to near continuous sunlight since the sun remains near the horizon. Recent studies suggest that tower heights on the order of 50 m are needed to meet the power requirements to support a sustained lunar presence. While eventually towers may be constructed using materials sourced in-situ, initially structural elements will likely be brought from the Earth, deployed, and assembled. Thermoplastic composites offer the benefit of high specific stiffness and strength properties along with welding for assembly joints, and therefore represent a promising material system for this application. The focus of this paper is on the structural sizing of such towers. A set of expressions based on beam theory are presented for preliminary sizing of the truss tower structure for strength and buckling. The loading condition that drives sizing is base excitation resulting from moonquakes. A point design, developed through finite element analysis, verifies the analytical sizing routine and shows the importance of joints. The results show a viable point design and highlight the factors most significant in the structural sizing.

Thermoplastic composites↗
NASA NTRSDate not supplied

Structural Sizing of a 50-m-Tall Thermoplastic Composite Solar Array Truss Tower Structure for the Lunar South Pole

At the lunar south pole, solar arrays elevated by truss towers are exposed to near continuous sunlight since the sun remains near the horizon. Recent studies suggest that tower heights on the order of 50 m are needed to meet the power requirements to support a sustained lunar presence. While eventually towers may be constructed using materials sourced in-situ, initially structural elements will likely be brought from the Earth, deployed, and assembled. Thermoplastic composites offer the benefit of high specific stiffness and strength properties along with welding for assembly joints, and therefore represent a promising material system for this application. The focus of this paper is on the structural sizing of such towers. A set of expressions based on beam theory are presented for preliminary sizing of the truss tower structure for strength and buckling. The loading condition that drives sizing is base excitation resulting from moonquakes. A point design, developed through finite element analysis, verifies the analytical sizing routine and shows the importance of joints. The results show a viable point design and highlight the factors most significant in the structural sizing.

Thermoplastic composites↗
NASA NTRS2025

Structural Sizing of a 50-m-Tall Thermoplastic Composite Truss Tower Structure for the Lunar South Pole

At the lunar south pole, solar arrays elevated by truss towers are exposed to near continuous sunlight since the sun remains near the horizon. Recent studies suggest that tower heights on the order of 50 m are needed to meet the power requirements to support a sustained lunar presence. While eventually towers may be constructed using materials sourced in-situ, initially structural elements will likely be brought from the Earth, deployed, and assembled. Thermoplastic composites offer the benefit of high specific stiffness and strength properties along with welding for assembly joints, and therefore represent a promising material system for this application. The focus of this paper is on the structural sizing of such towers. A set of expressions based on beam theory are presented for preliminary sizing of the truss tower structure for strength and buckling. The loading condition that drives sizing is base excitation resulting from moonquakes. A point design, developed through finite element analysis, verifies the analytical sizing routine and shows the importance of joints. The results show a viable point design and highlight the factors most significant in the structural sizing.

Thermoplastic composites↗
NASA NTRS2001

Integration of Lunar Polar Remote-Sensing Data Sets: Evidence for Ice at the Lunar South Pole

In order to investigate the feasibility of ice deposits at the lunar south pole, we have integrated all relevant lunar polar data sets. These include illumination data, Arecibo ground-based monostatic radar data, newly processed Clementine bistatic radar data, and Lunar Prospector neutron spectrometer measurements. The possibility that the lunar poles harbor ice deposits has important implications not only as a natural resource for future human lunar activity but also as a record of inner solar system volatiles (e.g., comets and asteroids) over the past billion years or more. We find that the epithermal neutron flux anomalies, measured by Lunar Prospector, are coincident with permanently shadowed regions at the lunar south pole, particularly those associated with Shackleton crater. Furthermore, these areas also correlate with the beta=0 circular polarization ratio (CPR) enhancements revealed by new processing of Clementine bistatic radar echoes, which in turn are colocated with areas of anomalous high CPR observed by Arecibo Observatory on the lower, Sun-shadowed wall of Shackleton crater. Estimates of the extent of high CPR from Arecibo Observatory and Clementine bistatic radar data independently suggest that approximately 10 square kilometers of ice may be present on the inner Earth-facing wall of Shackleton crater. None of the experiments that obtained the data presented here were ideally suited for definitively identifying ice in lunar polar regions. By assessing the relative merits of all available data, we find that it is plausible that ice does occur in cold traps at the lunar south pole and that future missions with instruments specifically designed to investigate these anomalies are worthy.

Nozette, Stewart↗
NASA NTRS2024

NIAC Phase I Final Report Lunar South Pole Oxygen Pipeline (LSPOP)

The Lunar South Pole Oxygen Pipeline (LSPOP) Phase I NIAC, is to analyze the feasibility of constructing a pipeline at the Moon’s South Pole for transporting gaseous oxygen from point of generation to point of use. A lunar pipeline has never been pursued and will revolutionize lunar surface operations for the Artemis program and reduce cost and risk. Our starting concept is for a 5 km pipeline to transport oxygen gas from an oxygen production source, for example from our molten regolith electrolysis (MRE, currently at TRL 5, see references[1],[2],[3],[4],[5],[6] for technical discussions of the MRE process) extraction site, or any other source, to an oxygen storage/liquification plant near a lunar base. The pipeline is designed to: 1) be constructed robotically from regolith-derived metals with minimal material transferred from Earth, 2) be repairable robotically, 3) have an oxygen flow rate of ~2 kg/hour, which is commensurate with the NASA initial projected need of 10,000 kg/year, 4) operate with minimal power over the lifetime of the pipeline, with a goal of high operational reliability and the ability to survive in the lunar environment for > 10 years. We compare this concept to a pipeline concept with pipe produced on Earth and then transported to and assembled on the Moon. Both approaches will use earth-based compressors, valves, and fittings which are integrated into the pipeline on the Moon.

NIAC Phase I↗
NASA NTRS2007

Lunar South Pole Illumination: Review, Reassessment, and Power System Implications

This paper reviews past analyses and research related to lunar south pole illumination and presents results of independent illumination analyses using an analytical tool and a radar digital elevation model. The analysis tool enables assessment at most locations near the lunar poles for any time and any year. Average illumination fraction, energy storage duration, solar/horizon terrain elevation profiles and illumination fraction profiles are presented for various highly illuminated sites which have been identified for manned or unmanned operations. The format of the data can be used by power system designers to develop mass optimized solar and energy storage systems. Data are presented for the worse case lunar day (a critical power planning bottleneck) as well as three lunar days during lunar south pole winter. The main site under consideration by present lunar mission planners (on the Crater Shackleton rim) is shown to have, for the worse case lunar day, a 0.71 average illumination fraction and 73 to 117 hours required for energy storage (depending on power system type). Linking other sites and including towers at either site are shown to not completely eliminate the need for energy storage.

Fincannon, James↗
NASA NTRS2017

Searching for Water Ice at the Lunar North Pole Using High-Resolution Images and Radar

Permanently shadowed regions (PSRs) at the lunar poles are potential reservoirs of frozen volatiles, and are therefore high-priority exploration targets. PSRs trap water and other volatiles because their annual maximum temperatures (40-100K) are lower than the sublimation temperatures of these species (i.e. H2O approx.104K). Previous studies using various remote sensing techniques have not been able to definitively characterize the distribution or abundance of ice in lunar PSRs. The purpose of this study is to search for signs of ice in PSRs using two complimentary remote sensing techniques: radar and visible images.

Mitchell, J. L.↗
NASA NTRS2020

Effective Crewed Surface Science near the Lunar South Pole: Some Illumination Considerations

Exploration near the lunar South Pole has substantial scientific promise for expanding our understanding of the Moon beyond what has been accomplished by Apollo and other lunar missions. An obvious difference from the Apollo experience is that the polar location for Artemis will guarantee the Sun is going to be low above the horizon. A great deal of excellent work has been, and is being, done on the availability of light (“yes/no”) for exploration purposes [e.g., 1-4]. However, we raise the additional consideration of the qualitative effects of low solar elevation on crew traverses, crew observations, and other science measurements [see also 5, though ground rules of that study presumed higher Sun]. We emphasize that our view is that these issues are unlikely to be mission objective-threatening, particularly if adequately considered in advance.

C. I. Fassett↗
NASA NTRSDate not supplied

Model Correlation and Thermal Analysis of xEMU Boot at Lunar South Pole Temperatures

The National Aeronautics and Space Administration (NASA) Artemis program plans to send astronauts to the lunar south pole, a region of the moon that is colder than previous lunar missions and low earth orbit operations. The spacesuit boots that will be used on these missions will be directly impacted by these extremely cold temperatures (down to ~50 K). To assess the performance of the Exploration Extravehicular Mobility Unit (xEMU) lunar boot in these extreme temperatures, the boot was tested at the Jet Propulsion Lab (JPL) in the Cryogenic Ice Transfer, Acquisition Development, and Excavation Laboratory (CITADEL) thermal vacuum (TVAC) chamber. This data was used to correlate thermal models to predict operational performance of the boots on the lunar south pole. This paper documents the data analysis, thermal boot model correlation, and operational predictions conducted using data from the xEMU TVAC test. Data from the test series was used to determine expected thermal conductances within the boot and between the boot and environment. These conductances were used to correlate a Thermal Desktop model of the xEMU boot across 10 different test points which varied external temperature, internal boot ventilation flowrate, and contact pressure. The correlated model was then used to predict operational performance in the lunar south pole. While the predictions indicate promising evidence for performance of the boots at the 100K test point, there is still substantial uncertainty in performance, particularly at the 48K test point. The results of this test series and model correlation stress the importance of improved testing for characterizing the expected thermal resistance between the outside of the boot and the lunar surface.

thermal analysis↗