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NASA NTRS2012

Feasibility and Definition of a Lunar Polar Volatiles Prospecting Mission

The recent Lunar Crater Observing and Sensing Satellite (LCROSS) mission has provided evidence for significant amounts of cold trapped volatiles in Cabeus crater near the Moon's south pole. Moreover, LRO/Diviner measurements of extremely cold lunar polar surface temperatures imply that volatiles can be stable outside or areas of strict permanent shadows. These discoveries suggest that orbital neutron spectrometer data point to extensive deposits at both lunar poles. The physical state, composition and distribution of these volatiles are key scientific issues that relate to source and emplacement mechanisms. These issues are also important for enabling lunar in situ resource utilization (ISRU). An assessment of the feasibility of cold-trapped volatile ISRU requires a priori information regarding the location, form, quantity, and potential for extraction of available resources. A robotic mission to a mostly shadowed but briefly .unlit location with suitable environmental conditions (e.g. short periods of oblique sunlight and subsurface cryogenic temperatures which permit volatile trapping) can help answer these scientific and exploration questions. Key parameters must be defined in order to identify suitable landing sites, plan surface operations, and achieve mission success. To address this need, we have conducted an initial study for a lunar polar volatile prospecting mission, assuming the use of a solar-powered robotic lander and rover. Here we present the mission concept, goals and objectives, and landing site selection analysis for a short-duration, landed, solar-powered mission to a potential hydrogen volatile-rich site.

Heldmann, Jennifer↗

NASA NTRS2021

Lunar Auger Dryer ISRU (LADI) Breadboard Testing and Model Validation

In 2009, the Lunar Reconnaissance Orbiter (LRO)and Lunar Crater Observation and Sensing Satellite(LCROSS) provided definitive proof of water in the Lunar’s southern permanently shadowed region (PSR)[1]. Both the 2020 NASA Technology Taxonomy[2] and the Lunar Surface Innovation Initiative (LSII) team identified capability gaps in icy regolith transfer and reactor processing in Permanently Shadowed Region(PSR) environmental conditions. A screw conveyor dryer system operating from inside the PSR can continuously process water (and volatiles) for both breathable air and propellant. NASA’s Johnson Space Center (JSC) began development of a similar sub-system for Mars operation in 2017 and fabricated a unique breadboard test stand for validating the feasibility of this concept. This testing was postponed with the redirection of NASA’s mission from Mars to Moon. A JSC led trade study[3] in FY20 formulated a plan to leverage existing hardware to test concept feasibility, developed a lunar auger dryer sizing tool, and identified that both a physical flow and thermal model is required to develop an Engineering Development Unit (EDU) for environmental testing. Beginning in FY21, the Game Changing Development Program (GCDP) funded a three-year technology development project to increase the Technology Readiness Level (TRL) of the Lunar Auger Dryer ISRU (LADI) subsystem to TRL 5.

Lunar↗

NASA NTRS2021

Lunar Auger Dryer ISRU (LADI) Breadboard Testing and Model Validation

Lunar↗

NASA NTRS2022

Lunar Auger Dryer ISRU (LADI) Mechanical Testing and Supporting Models

In 2009, the Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS) provided definitive proof of water in the Lunar’s southern permanently shadowed region (PSR). Both the 2020 NASA Technology Taxonomy and the Lunar Surface Innovation Initiative (LSII) team identified capability gaps in icy regolith transfer and reactor processing in Permanently Shad-owed Region (PSR) environmental conditions. A water processing plant operating from inside the PSR can continuously process water (and volatiles) for both breathable air and propellant. NASA’s Johnson Space Center (JSC) began development of the primary sub-system for a Mars plant in 2017 and fabricated a unique breadboard test stand for validating the feasibility of this concept. This testing was postponed with the redirection of NASA’s mission from Mars to Moon. A JSC led trade study in FY20 formulated a plan to leverage existing hardware to test concept feasibility, developed a lunar auger dryer sizing tool, and identified that both physical flow and thermal models are required to develop an Engineering Development Unit (EDU) for environmental testing. Beginning in FY21, the Game Changing Development Program (GCDP) funded a three-year technology development project to increase the Technology Readiness Level (TRL) of the Lunar Auger Dryer ISRU (LADI) subsystem to TRL 5.

Lunar↗

NASA NTRSDate not supplied

Lunar Water Extraction Via Lunar Auger Dryer ISRU (LADI)

In 2009, the Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS) provided definitive proof of water in the Lunar’s southern permanently shadowed region (PSR)1. Both the 2020 NASA Technology Taxonomy2 and the Lunar Surface Innovation Initiative (LSII) team identified capability gaps in icy regolith transfer and reactor processing in Permanently Shadowed Region (PSR) environmental conditions. A water processing plant operating inside the PSR can continuously process water (and volatiles) for both breathable air and propellant. NASA’s Johnson Space Center (JSC) fabricated a unique breadboard test stand for validating the feasibility of this concept,developed a lunar auger dryer sizing tool, and identified the physical flow and thermal models required to design an Engineering Development Unit (EDU) for environmental testing. Over the two years this project was active, models were developed including: a) a sizing tool that scales the auger parameters based on production targets, b) accurate thermal models in both lab and lunar conditions, c) a Discreet Element Model (DEM) for observing particle effects in low-g, and d) incorporated these subsystem models into a MATLAB parametric Modular Open System Approach (MOSA) system model. These models were validated by testing the auger in both a mechanical and thermal system configuration. The results of this testing increased the Technology Readiness Level (TRL) of the Lunar Auger Dryer ISRU (LADI) system to TRL 4.

Lunar↗

NASA NTRS2007

Is There Water on the Moon? NASA's LCROSS Mission

NASA is preparing for its return to the moon with the Lunar CRater Observation and Sensing Satellite (LCROSS) mission. This secondary payload spacecraft will travel with the Lunar Reconnaissance Orbiter (LRO) satellite to the Moon on the same Atlas-V 401 Centaur rocket launched from Cape Canaveral Air Force Station, Florida. The LCROSS mission will robotically seek to determine the presence of water ice at the Moon's South Pole. The 1000kg Secondary Payload budget is efficiently used to provide a highly modular and reconfigurable LCROSS Spacecraft with extensive heritage to accurately guide the expended Centaur into the crater. Upon separation, LCROSS flies through the impact plume, telemetering real-time images and characterizing water ice in the plume with infrared cameras and spectrometers. LCROSS then becomes a 700kg impactor itself, to provide a second opportunity to study the nature of the Lunar Regolith. LCROSS provides a critical ground-truth for Lunar Prospector and LRO neutron and radar maps, making it possible to assess the total lunar water inventory. This presentation contains a reference to video animation of the LCROSS mission that will be covered separately.

Noneman, Steven↗

NASA NTRS2012

Lunar Floor-Fractured Craters: Classification, Distribution and Implications for Magmatism and Shallow Crustal Structure

Floor-fractured craters (FFCs) are a class of lunar craters defined by their distinctly shallow, often plate-like floors, and combinations of radial, con-centric, and polygonal floor-fractures; a variety of other interior features are often observed, such as moats, ridges, small dark-haloed pits, and patches of mare material. They were first classified by Schultz [1] , who recognized eight overall types of floor-fractured crater. These eight subtypes have widely differing appearances, a factor that could provide insight into formation mechanisms (different manifestations of the same mechanism, or indicators of varying formation mechanisms). Two formation mechanisms for FFCs were initially proposed: 1) magmatic intrusion [1], in which magma rising toward the surface in dikes encountered low-density breccia lenses beneath crater floors and spread laterally to form sills, raising and fracturing the crater floor. 2) viscous relaxation [2], in which the properties of the crust permitted viscous flow in the vicinity of the crater, causing long-wavelength relaxation of the topography and uplift and fracturing of the crater floor. Critical to distinguishing between these two end-member hypotheses and identifying others is a quantitative assessment of the topography of FFCs and knowledge of their regional and local settings. The purpose of this study is to use newly available Lunar Reconnaissance Orbiter (LRO) Lunar Orbiter Laser Altimeter (LOLA) altimeter and Lunar Reconnaissance Orbiter Camera (LROC) image data to provide an updated global catalog of the locations, classes, morphometric and morphologic characteristics of all lunar floor-fractured craters. We use the excellent 8-class system initially described in Schultz [1] as a starting point for classification and the enhanced LOLA/LROC data sets to examine and categorize all FFCs; we found evidence for a new FFC class, discernably different from the previously existing types. Our approach, and the global categorization of all FFCs, permits the spatial distribution of each FFC-subtype to be plotted and assessed allowing for further investigation into FFC formation mechanisms. Upon completion, the data set will be made available on our web site at http://www.planetary.brown.edu/html_pages/data.htm.

Jozwiak, L. M.↗

NASA NTRSDate not supplied

Impacts into a Strength‐Layered Target: The Time Evolution of the Excavation‐Stage Flow

Impact cratering has dominated the evolution and modification of planetary surfaces throughout the history of the solar system. Impact craters can serve as probes to understanding the details of a planetary subsurface; for example, Oberbeck and Quaide suggested that crater morphology can be used to estimate the thickness of a regolith layer on top of a more competent unit. Lunar craters show a morphological progression from a simple bowl shape to flat‐floored and concentric craters as diameter increases for a given regolith thickness. The final shape of the impact crater is a result of the subsurface flow‐field initiated as the projectile transfers its energy and momentum to the target surface at the moment of impact. Therefore, when a regolith layer is present over a stronger substrate, such as is the case on the lunar mare, the substrate modifies the flow‐field resulting in the distinctive final crater morphology. Here we report on a series of experimental impacts into targets composed of a thin (2 cm) layer of loose sand on top of a stronger substrate. We use the Ejection‐Velocity Measurement System (EVMS, Fig.1) developed by [3] to examine the ejecta kinematics at specific times during the formation of these craters in strength‐layered targets.

J. L. B. Anderson↗

NASA NTRS1966

Interpretation of the Ranger records

Structures of lunar craters, mares, lineaments, and collapse depressions from Ranger Block III photographs

LUNAR TOPOGRAPHY↗

NASA NTRSDate not supplied

Experimental Impacts into Strength-Layered Targets: Ejecta Kinematics and Crater Morphometry

Impact craters can serve as probes of the subsurface structure of a planetary body and provide hints about a target's properties. Crater morphology, for example, can be used to estimate the thickness of a regolith layer above a more competent unit. Small lunar craters in the maria show a morphological progression from a simple bowl shape to flat-floored and concentric as crater diameter increases for a given regolith thickness. The final shape is a result of the subsurface flow-field initiated as the projectile transfers its energy and momentum to the target surface. In strength-layered targets, such as the lunar maria, the substrate modifies the flow field and thereby the excavation of the crater. Here we report on a series of experimental impacts into targets composed of a layer of loose sand above a stronger substrate. As we varied the sand's thickness, we imaged individual ejecta trajectories as the craters grew, from which we derived ejection-speed scaling relationships. In addition, we used a 3D scanner to construct topographic maps of the substrate, pre-impact target, and post-impact surface. This permitted us to examine the final craters' morphologies and morphometries with respect to the original stratigraphy of the target. As expected, craters became shallower and smaller as the sand's thickness decreased, transitioning from bowl-shaped to concentric as observed on the Moon. Subtle and important details show that the stronger substrate affected the subsurface flow-field by redirecting material upward and outward even when the interface was still well below the final crater's floor. Compared to the control target (loose sand only), the stronger substrate below the sand layer resulted in a much more complex pattern of ejecta. While most of the ejected material was still contained within a typical outward-moving curtain, a number of ejected particles moved along low-speed, high-angle (near 90°) trajectories. The number of these high-angle trajectories increased as the sand layer thinned, perhaps implying that self-secondary cratering would require the presence of a strong subsurface layer below the impact site. Such results refine our understanding of crater excavation in layered targets with implications for ejecta deposits and final crater shapes observed on the Moon.

Jennifer L B Anderson↗

NASA NTRS1972

On the definition of crater saturation diameter

A theoretical model is developed for determining the diameter D sub p such that the density of lunar craters exceeding D sub p constitutes a specified proportion p of the maximum number that could be observed on a crater-saturated surface. It is shown that this diameter is sensitive to the value of the exponent in the fresh crater size distribution, and is much more informative than usual log-log plot intercept definition of satureation diameter.

Marcus, A. H.↗

NASA NTRS1976

Comparison of the crater morphology-size relationship for Mars, moon, and Mercury

Morphology-size data are examined for Martian, Mercurian, and lunar craters. It is shown that both Martian and Mercurian craters exhibit central peaks at lower diameters than those on the moon and that gravity has affected the diameter at which central peaks form on Mars. A quantitative analysis of Martian crater statistics demonstrates that a complete range of crater shapes from small bowl craters to larger and more complex terraced craters occurs on Mars. The complexity of the shapes is found to increase as the sizes of craters increase. It is concluded that aeolian erosion on Mars does not completely mask differences in crater interior structure caused by differences in the gravitational forces on Mars and the moon.

Smith, E. I.↗

NASA NTRS2017

Evolution of Circular Polarization Ratio (CPR) Profiles of Kilometer-scale Craters on the Lunar Maria

When sufficiently large impact craters form on the Moon, rocks and unweathered materials are excavated from beneath the regolith and deposited into their blocky ejecta. This enhances the rockiness and roughness of the proximal ejecta surrounding fresh impact craters. The interior of fresh craters are typically also rough, due to blocks, breccia, and impact melt. Thus, both the interior and proximal ejecta of fresh craters are usually radar bright and have high circular polarization ratios (CPR). Beyond the proximal ejecta, radar-dark halos are observed around some fresh craters, suggesting that distal ejecta is finer-grained than background regolith. The radar signatures of craters fade with time as the regolith grows.

moon↗

NASA NTRS2017

Lunar Exploration Missions Since 2006

The announcement of the Vision for Space Exploration in 2004 sparked a resurgence in lunar missions worldwide. Since the publication of the first "New Views of the Moon" volume, as of 2017 there have been 11 science-focused missions to the Moon. Each of these missions explored different aspects of the Moon's geology, environment, and resource potential. The results from this flotilla of missions have revolutionized lunar science, and resulted in a profoundly new emerging understanding of the Moon. The New Views of the Moon II initiative itself, which is designed to engage the large and vibrant lunar science community to integrate the results of these missions into new consensus viewpoints, is a direct outcome of this impressive array of missions. The "Lunar Exploration Missions Since 2006" chapter will "set the stage" for the rest of the volume, introducing the planetary community at large to the diverse array of missions that have explored the Moon in the last decade. Content: This chapter will encompass the following missions: Kaguya; ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun); Chang’e-1; Chandrayaan-1; Moon Impact Probe; Lunar Reconnaissance Orbiter (LRO); Lunar Crater Observation Sensing Satellite (LCROSS); Chang’e-2; Gravity Recovery and Interior Laboratory (GRAIL); Lunar Atmosphere and Dust Environment Explorer (LADEE); Chang’e-3.

LUNAR EXPLORATION MISSIONS 200↗

NASA NTRS2018

Accommodations for Secondary Payloads in NASA's Space Launch System

NASA's new heavy-lift launch vehicle, the Space Launch System (SLS), is moving closer to its planned 2019 launch, with the in-space stage and spacecraft adapters complete and all other major elements of the rocket manufactured and currently being outfitted for flight. Exploration Mission-1 (EM-1), the first flight of SLS and the new Orion crew vehicle, will verify and validate new systems and provide an unparalleled opportunity for 13 6U CubeSat-class payloads to be released into deep space. Payloads are being developed by NASA, industry, international and academic partners and were selected for the EM-1 flight to address strategic knowledge gaps in the agency's plans for human deep space exploration. Destinations range from the lunar surface to an asteroid to an orbit around the Earth-moon L2 libration point. Missions include studying the effects of space radiation on a living organism (yeast), landing the smallest lander to date on the moon, and searching for water in permanently shaded lunar craters. Propulsion technology demonstrations include solar sails, use of inert water to carry out lunar gravity assist maneuvers, and use of new "green" chemical propellants. SLS employs an evolutionary design approach, with an initial capability of at least 26 metric tons (t) to trans-lunar injection (TLI). The later Block 1B configuration, which will become the Agency's workhorse launch vehicle into the 2020s, will lift at least 34 t to TLI in its crew configuration and at least 37 t in the cargo configuration. In addition to greater lift capability, Block 1B will also offer larger payload volume than Block 1 for both co-manifested and secondary payloads. In Block 1B, various combinations of 6U, 12U and 27U payloads may be accommodated in the vehicle's stage adapter. Opportunities for deep space research once out of reach for small science payloads will be within reach, opening many possibilities for exciting new technology demonstrations and scientific missions. This paper will provide an overview of the capabilities and the status of the Block 1 vehicle, with particular emphasis on the secondary payload accommodations and the deployment system. Brief descriptions of the 13 6U EM-1 payloads will be included. In addition, a discussion of the payload developers' responsibilities and the Space Launch System Program's roles and responsibilities in accommodating these and future payloads will be included. Finally, the author will look ahead to SLS Block 1B and missions beyond EM-1 and the opportunities for 6U, 12U and 27U CubeSats.

Robinson, Kimberly F.↗

NASA NTRS2020

Experimental Impacts into Strength-Layered Targets: Ejecta Kinematics

AImpact cratering has dominated the evolution and modification of planetary surfaces through-out the history of the solar system. Impact craters can serve as probes to understanding the details of a planetary subsurface; for example, Oberbeck and Quaide, suggested that crater morphology can be used to estimate the thickness of a regolith layer on top of a more competent unit. Lunar craters show a morphological progression from a simple bowl shape to flat-floored and concentric craters as crater diameter in-creases for a given regolith thickness. The final shape of the impact crater is a result of the subsurface flow-field initiated as the projectile transfers its energy and momentum to the target surface at the moment of impact. Therefore, when a regolith layer is present over a stronger substrate, such as is the case on the lunar surface, the substrate modifies the flow-field and thereby the excavation flow of the crater, which is reflected in the morphology of the final crater. Here we report on a series of experimental impacts into targets composed of a thin layer of loose sand on top of a stronger substrate. We use the Ejection-Velocity Measurement System developed to examine the ejecta kinematics during the formation of these craters.

Anderson, J. L. B.↗

NASA NTRS1986

Size-velocity distribution of large ejecta fragments

The characteristics of three primary extraterrestrial craters and the associated craters were examined to generate a size-velocity distribution for large ejecta fragments. The lunar craters Copernicus and Aristillus and the Martian crater Dv on Olympus Mons were used. Attention was focused on the radial distances between the primary and secondary crater centers and the diameters of the secondaries. The primary craters selected are all relatively young, which avoided contamination of the data from secondaries from other primaries. Attempts were made to account for the speed of the hypervelocity impacts and the elemental compositions of the impactors. An apparent velocity cutoff of about 1 km/sec was observed for the secondaries, which implies that no meteoroid impacts can accelerate ejecta to escape velocities from the moon or Mars.

Vickery, A. M.↗

NASA NTRS2011

Using Microwaves to Heat Lunar Soil

This slide presentation reviews the use of microwaves to heat lunar soil in order to obtain water. There appears to be large amounts of water in the lunar poles, in Martian areas in lower latitudes and some of the Moons of Jupiter. The presence of water in the south lunar polar region was demonstrated by the Lunar CRater Observation and Sensing Satellite (LCROSS) mission. Microwaves can be used to extract water from lunar soil without excavation. Using microwaves on a lunar soil simulant at least 95% of the water from the regolith permafrost simulant was extracted (2 minutes). The process is modeled using COMSOL Multiphysics Finite Element analysis microwave physics module and demonstrated usingan experiment of an microwave apparatus on a rover.

Ethridge, Edwin C.↗