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NASA NTRS2008

Analysis of Lunar Highland Regolith Samples from Apollo 16 Drive Core 64001/2 and Lunar Regolith Simulants - An Expanding Comparative Database

We present modal data from QEMSCAN(registered TradeMark) beam analysis of Apollo 16 samples from drive core 64001/2. The analyzed lunar samples are thin sections 64002,6019 (5.0-8.0 cm depth) and 64001,6031 (50.0-53.1 cm depth) and sieved grain mounts 64002,262 and 64001,374 from depths corresponding to the thin sections, respectively. We also analyzed lunar highland regolith simulants NU-LHT-1M, -2M, and OB-1, low-Ti mare simulants JSC-1, -lA, -1AF, and FJS-1, and high-Ti mare simulant MLS-1. The preliminary results comprise the beginning of an internally consistent database of lunar regolith and regolith simulant mineral and glass information. This database, combined with previous and concurrent studies on phase chemistry, bulk chemistry, and with data on particle shape and size distribution, will serve to guide lunar scientists and engineers in choosing simulants for their applications. These results are modal% by phase rather than by particle type, so they are not directly comparable to most previously published lunar data that report lithic fragments, monomineralic particles, agglutinates, etc. Of the highland simulants, 08-1 has an integrated modal composition closer than NU-LHT-1M to that of the 64001/2 samples, However, this and other studies show that NU-LHT-1M and -2M have minor and trace mineral (e.g., Fe-Ti oxides and phosphates) populations and mineral and glass chemistry closer to these lunar samples. The finest fractions (0-20 microns) in the sieved lunar samples are enriched in glass relative to the integrated compositions by approx.30% for 64002,262 and approx.15% for 64001,374. Plagioclase, pyroxene, and olivine are depleted in these finest fractions. This could be important to lunar dust mitigation efforts and astronaut health - none of the analyzed simulants show this trend. Contrary to previously reported modal analyses of monomineralic grains in lunar regolith, these area% modal analyses do not show a systematic increase in plagiociase/pyroxene as size fraction decreases.

Schrader, Christian M.↗

NASA NTRS2019

Building an Economical and Sustainable Lunar Infrastructure to Enable Human Lunar Missions

To enable return of human missions to the surface of the Moon sustainably, a new study was initiated to assess the feasibility of developing an evolvable, economical and sustainable lunar surface infrastructure using a public-private partnerships approach. This approach would establish partnerships between NASA and private industry to mutually develop lunar surface infrastructure capabilities to support robotic missions initially and later evolve to full-scale commercial infrastructure services in support of human missions. These infrastructure services may range from power systems, communication and navigation systems, thermal management systems, mobility systems, water and propellant production to life support systems for human habitats. The public-private partnerships approach for this study leverages best practices from NASA's Commercial Orbital Transportation Services (COTS) program which introduced a new innovative and economical approach for partnering with industry to develop commercial cargo transportation services to the International Space Station (ISS). In this approach, NASA and industry partners shared cost and risk throughout the development phase which led to dramatically reducing development and operations costs of these transportation services. Following this approach, a Lunar COTS concept was conceived to follow this model and gradually develop cost-effective surface infrastructure capabilities in partnership with industry to provide economical, operational services for small-scale robotic missions. To support human missions, this work has now been extended to analyze full-scale lunar infrastructure systems. This infrastructure system will have capabilities to support human missions from a few days to several months and will also maximize the use of existing lunar resources, such as, water from ice deposits at the lunar poles. The plan includes a gradual buildup of these capabilities using a phased-development approach that will eventually lead to operational infrastructure services. By partnering with industry to develop and operate the infrastructure services using the COTS model, this plan will also result in significant cost savings, reduced risk and increased reliability. This paper will describe the Lunar COTS concept goals, objectives and approach for developing an evolvable, economical and sustainable human lunar infrastructure as well as the challenges and opportunities for development.

Lunar Surface Systems↗

NASA NTRS2024

New Cryogenic Method for Combining Lunar Regolith Simulant and Frozen Volatiles to Generate Icy Lunar Simulated Regolith

There is a requirement within the lunar science and exploration communities to develop lunar simulants containing volatiles that are solids at the cryogenic temperatures found in the permanently shadowed regions (PSRs), such as those found near the Lunar South Pole. Icy regolith simulants would be used for curation training, as well as for various research activities. One of the most critical aspects of developing a regolith simulant that is more physically and chemically like icy lunar regolith is minimizing any form of modification driven by elevated temperatures. Here we document our ongoing efforts to combine materials at ultralow temperatures, designed to minimize any chemical reactions or other physical changes during the production of the icy regolith. Our goal is to document how one can create an essentially “unreacted” icy regolith that can serve as an effective “time zero” start point from which advanced curation research will proceed. This is done using commercial off-the-shelf equipment as much as possible, along with creating a custom spray plate that can be adapted to a wide variety of methods, all for the planetary simulant community. This method creates crystals of various volatiles such as water, methanol, along with CO 2 ice and these components are combined with lunar regolith that is at -196°C temperature to avoid chemical reactions, and/or phase changes thus creating a more chemically relevant icy lunar regolith. The rules of chemistry stay the same regardless of location whether it’s in the lab, or directly on the lunar surface, and therefore we aim for creating a more authentic icy lunar simulant in the laboratory by operating at ultralow temperatures. It is also envisioned that this method will lead to advanced materials testing in the future. In addition, this method is directly applicable to prior missions such as LCROSS.

Cryogenic Lunar Simulant and Icy Volatile Producti↗

NASA NTRS2024

New Cryogenic Method for Combining Lunar Regolith Simulant and Frozen Volatiles to Generate Icy Lunar Simulated Regolith

Cryogenic Lunar Simulant and Icy Volatile Producti↗

NASA NTRS2025

South Pole Lunar Lighting Studies for Driving Exploration on the Lunar Surface

NASA’s Artemis lunar missions will face new exploration challenges due to inherently low sun angles in the lunar south pole region. Whereas the Apollo missions were afforded sunlight for approximately 8 to 50-degrees above the horizon, sunlight for the next lunar missions will only be 1 to 2-degrees about the horizon. With this low angle, long shadows and high contrasts of light and dark areas will be faced by the crew and remote teleop operators while exploring the lunar surface. With this in mind, NASA developed an integrated virtual Lighting and Navigation Simulation to understand these challenges. Two studies have been conducted in this Lunar South Pole environment to evaluate the effects of natural and artificial lighting on driving and navigating a lunar rover across the surface. Early NASA studies, such as this, are used to aid in developing techniques and explore concepts of operations to promote mission success and crew safety. In the Phase One development evaluation, six astronauts were teleported to ten different lighting conditions. For each location, drivers were to drive to an imaginary target approximately 200-meters straight ahead and provide subjective feedback on their ability to drive under the given lighting conditions. Phase Two, a more operational study, four astronauts and a remote operator tested five different Artemis lunar mission scenarios. Results indicated sun direction at such low angles, especially when driving a high speed, can severely impact the crew’s ability to safely drive the rover. In the up-sun situation, with the sun directly in the driver’s eyes and compounded long shadows, the consistent preference among drivers was to initiate a tacking strategy of approximately +/- 20 to 30-degrees to improve visibility. This maneuver does require more time and rover energetics. Conversely, driving down-sun required the crew to tack as well to avoid the shadow of rover blocking the terrain. Less appreciated is how the surrounding landscape is lit. Traveling into shadowed areas, especially while facing a lit terrain beyond the shadowed area, drivers enter at their own risk due to pupil contraction making artificial lights useless. Additionally, the constant transitioning between dark and light areas are mentally taxing to the crew and natural navigational references such as the stars are invisible and therefore unusable. Slope and depth magnitude are very difficult hazards to judge when approaching a shadowed crater. This naturally leads to slower driving speeds than originally anticipated. As for observing scientifically interesting features, assessing them accurately varies greatly by the lighting condition. In most cases, the task can be completed, but the strategy is to use the sun to one’s advantage. Crew workload distribution in the cockpit for driving operations was split amongst crew. The driver primarily focused attention on visual terrain (80%) but referenced displays approximately 20% of the time, while the co-pilot/navigator generally provided directional cues to the driver. These natural lighting conditions present significant challenges for safe rover operations; however, early studies having given investigators a “first-look” into understanding of how operating on the South Lunar Pole can be accomplished.

LTv↗

NASA NTRS1978

Lunar interaction with the solar wind - Effects on lunar electrical conductivity estimates

The lunar electromagnetic response, measured at very low frequencies with the moon in the solar wind, is used to evaluate interior electrical conductivity at great depth and to determine limits on the size of possible lunar core. A theory is developed wherein compression of the magnetic field in the lunar tail cavity caused by inflowing plasma at the lunar limbs and in the lunar wake, bends the magnetic field in the lunar interior and thereby alters the tangential component of magnetic field observed on the dayside surface. This theory strongly indicates that cavity fringing cannot explain the enhanced East-West fluctuations. It is proposed that the East-West fluctuations might be due to diamagnetic currents caused by lunar surface photoelectrons in the lunar terminator region.

Goldstein, B. E.↗

NASA NTRS1989

CIS-lunar space infrastructure lunar technologies: Executive summary

Technologies necessary for the creation of a cis-Lunar infrastructure, namely: (1) automation and robotics; (2) life support systems; (3) fluid management; (4) propulsion; and (5) rotating technologies, are explored. The technological focal point is on the development of automated and robotic systems for the implementation of a Lunar Oasis produced by Automation and Robotics (LOAR). Under direction from the NASA Office of Exploration, automation and robotics were extensively utilized as an initiating stage in the return to the Moon. A pair of autonomous rovers, modular in design and built from interchangeable and specialized components, is proposed. Utilizing a buddy system, these rovers will be able to support each other and to enhance their individual capabilities. One rover primarily explores and maps while the second rover tests the feasibility of various materials-processing techniques. The automated missions emphasize availability and potential uses of Lunar resources, and the deployment and operations of the LOAR program. An experimental bio-volume is put into place as the precursor to a Lunar environmentally controlled life support system. The bio-volume will determine the reproduction, growth and production characteristics of various life forms housed on the Lunar surface. Physicochemical regenerative technologies and stored resources will be used to buffer biological disturbances of the bio-volume environment. The in situ Lunar resources will be both tested and used within this bio-volume. Second phase development on the Lunar surface calls for manned operations. Repairs and re-configuration of the initial framework will ensue. An autonomously-initiated manned Lunar oasis can become an essential component of the United States space program.

Faller, W.↗

NASA NTRS2004

Lunar and Planetary Science XXXV: Lunar Remote Sensing: Fire, Ice, and Regolith

The session "Lunar Remote Sensing: Fire, Ice, and Regolith" included the following:Compositional and Structural Study of the Aristarchus Plateau from Integrated UV-VIS-NIR Spectral Data; Clementine 2.7-?m Data: Mapping the Mare and Searching for Water; On the Search for Water at the Lunar Poles: Results of Forward Modeling of Permanently Shaded Areas and Lunar Prospector Measurements; Searching the Moon for Aluminous Mare Basalts Using Compositional Remote-Sensing Constraints I: Finding the Regions of Interest; Semi-automated Extraction of Contours from Lunar Topographic Maps; Basalts in Mare Humorum and S.E. Procellarum; The Hansteen and Helmet Volcanic Dome Regions on the Moon: Stratigraphy and Ages; Derivation of Elemental Abundance Maps at 15-km Spatial Resolution from the Merging of Clementine Optical and Lunar Prospector Geochemical Data; Remote Sensing and Geologic Studies of the Balmer Region of the Moon; Lava Flows in Mare Nubium and Mare Cognitum: A Geological History Based on Analysis of Multispectral Data; Development of Ground-based Lunar VIS/NEAR IR Spectral Imager; A BRDF Measurement Apparatus for Lab-based Samples; A New Source of High Resolution Lunar Images: Amateur Astronomers! ; Leakage of Gamma Rays and Neutrons from Thick Targets Bombarded by Energetic Protons; Progress on Reviving Lunar Orbiter: Scanning, Archiving, and Cartographic Processing at USGS; Modeling Lateral and Vertical Mixing by Impact Cratering with Applications for the Moon; Optical Maturity Study of Stuart#s Crater Candidate Impact; Evidence for Three Basins Beneath Oceanus Procellarum; and Ellipses of the South Pole-Aitken Basin: Implications for Basin Formation.

Source record↗

NASA NTRS2004

Lunar and Planetary Science XXXV: Lunar Crust as Sampled by Basins and Craters

The session "Lunar Crust as Samples by Basins and Craters" included:Radar Properties of Lunar Basin Deposits; Numerical Modeling of the South Pole-Aitkin Impact; Lunar South Pole-Aitken Impact Basin: Topography and Mineralogy; Comparison of the Geologic Setting of the South Pole-Aitken Basin Interior with Apollo 16: Implications for Regolith Components; Identifying Impact Events Within the Lunar Cataclysm from 40Ar-39Ar Ages of Apollo 16 Impact Melt Rocks; Apollo 16 Mafic Glass: Geochemistry, Provenance, and Implications; Lunar Meteorite PCA 02 007: A Feldspathic Regolith Breccia with Mixed Mare/Highland Components; Compositional Constraints on the Launch Pairing of LAP 02205 and PCA 02007 with Other Lunar Meteorites; An In-Situ Study of REE Abundances in Three Anorthositic Impact Melt Lunar Highland Meteorites; A Crustal Rock Clast in Magnesian Anorthositic Breccia, Dhofar 489 and Its Excavation from a Large Basin; The Origin and Impact History of Lunar Meteorite Yamato 86032; Evolved Lithologies and Their Inferred Sources in the Northwestern Procellarum Region of the Moon; and Revisiting the Interpretation of Thorium Abundances at Hansteen Alpha.

Source record↗

NASA NTRS2007

Lunar e-Library: A Research Tool Focused on the Lunar Environment

As NASA plans and implements the Vision for Space Exploration, managers, engineers, and scientists need lunar environment information that is readily available and easily accessed. For this effort, lunar environment data was compiled from a variety of missions from Apollo to more recent remote sensing missions, such as Clementine. This valuable information comes not only in the form of measurements and images but also from the observations of astronauts who have visited the Moon and people who have designed spacecraft for lunar missions. To provide a research tool that makes the voluminous lunar data more accessible, the Space Environments and Effects (SEE) Program, managed at NASA's Marshall Space Flight Center (MSFC) in Huntsville, AL, organized the data into a DVD knowledgebase: the Lunar e-Library. This searchable collection of 1100 electronic (.PDF) documents and abstracts makes it easy to find critical technical data and lessons learned from past lunar missions and exploration studies. The SEE Program began distributing the Lunar e-Library DVD in 2006. This paper describes the Lunar e-Library development process (including a description of the databases and resources used to acquire the documents) and the contents of the DVD product, demonstrates its usefulness with focused searches, and provides information on how to obtain this free resource.

McMahan, Tracy A.↗

NASA NTRS2008

Constellation Architecture Team-Lunar: Lunar Habitat Concepts

This paper will describe lunar habitat concepts that were defined as part of the Constellation Architecture Team-Lunar (CxAT-Lunar) in support of the Vision for Space Exploration. There are many challenges to designing lunar habitats such as mission objectives, launch packaging, lander capability, and risks. Surface habitats are required in support of sustaining human life to meet the mission objectives of lunar exploration, operations, and sustainability. Lunar surface operations consist of crew operations, mission operations, EVA operations, science operations, and logistics operations. Habitats are crewed pressurized vessels that include surface mission operations, science laboratories, living support capabilities, EVA support, logistics, and maintenance facilities. The challenge is to deliver, unload, and deploy self-contained habitats and laboratories to the lunar surface. The CxAT-Lunar surface campaign analysis focused on three primary trade sets of analysis. Trade set one (TS1) investigated sustaining a crew of four for six months with full outpost capability and the ability to perform long surface mission excursions using large mobility systems. Two basic habitat concepts of a hard metallic horizontal cylinder and a larger inflatable torus concept were investigated as options in response to the surface exploration architecture campaign analysis. Figure 1 and 2 depicts the notional outpost configurations for this trade set. Trade set two (TS2) investigated a mobile architecture approach with the campaign focused on early exploration using two small pressurized rovers and a mobile logistics support capability. This exploration concept will not be described in this paper. Trade set three (TS3) investigated delivery of a "core' habitation capability in support of an early outpost that would mature into the TS1 full outpost capability. Three core habitat concepts were defined for this campaign analysis. One with a four port core habitat, another with a 2 port core habitat, and the third investigated leveraging commonality of the lander ascent module and airlock pressure vessel hard shell. The paper will describe an overview of the various habitat concepts and their functionality. The Crew Operations area includes basic crew accommodations such as sleeping, eating, hygiene and stowage. The EVA Operations area includes additional EVA capability beyond the suit-port airlock function such as redundant airlock(s), suit maintenance, spares stowage, and suit stowage. The Logistics Operations area includes the enhanced accommodations for 180 days such as closed loop life support systems hardware, consumable stowage, spares stowage, interconnection to the other Hab units, and a common interface mechanism for future growth and mating to a pressurized rover. The Mission & Science Operations area includes enhanced outpost autonomy such as an IVA glove box, life support, and medical operations.

Toups, Larry↗

NASA NTRS2008

Lunar Dust Charging by Secondary Electron Emission and its Complex Role in the Lunar Environment

The lunar surface is covered with a thick layer of micron/sub-micron size dust grains formed by billions of years of meteoritic impact. With virtually no atmosphere and exposed to the solar wind plasma and solar electromagnetic radiation, the lunar surface and the dust grains are electrostatically charged. The dominant charging processes include: photoelectric emissions (UV, X-rays), impact of solar wind electrons and ions, and secondary electron emissions (SEE) induced by energetic solar wind electrons. During the Apollo missions, the astronauts found the lunar dust to be extraordinarily high in its adhesive characteristics, sticking to the suits and the mechanical equipment. Electrostatically charged lunar dust is believed to be transported over long distances by the induced electric fields, as indicated by the observed dust streamers and the horizon glow [e.g., 1-3]. The hazardous effects of dust in the lunar environment are recognized to be one of the major issues that must be addressed in planning the forthcoming missions for robotic and human exploration of the Moon. Theoretical studies are being performed along with the development of analytical models and a variety of experimental investigations, to better understand the lunar dust phenomena. [e.g., 4-6]. The lunar dust is believed to be charged negatively on the lunar night-side by interaction With solar wind electrons. However, rigorous theoretical expressions for calculation of SEE yields and the sticking efficiencies of individual micron size dust grains are not yet available, and the information has to be obtained by experiment. On theoretical considerations, however, it is well recognized that SEE yields, similar to the photoelectric yields for small-size grains, would be totally different from the corresponding bulk values [e.g., 7-9]. Some theoretical models for charging of individual small spherical particles have been developed [e.g., 10], and some limited measurements on individual metallic dust grains at keV electron energies have been made [e.g., i 1]. In this paper, we present the first measurements of the secondary electron emission yields of individual micron/sub-micron size dust grains selected from sample returns of Apollo 11 and Apollo 17 missions.

Abbas, M. M.↗

NASA NTRS2011

A Fractal Model for the Capacitance of Lunar Dust and Lunar Dust Aggregates

Lunar dust grains and dust aggregates exhibit clumping, with an uneven mass distribution, as well as features that span many spatial scales. It has been observed that these aggregates display an almost fractal repetition of geometry with scale. Furthermore, lunar dust grains typically have sharp protrusions and jagged features that result from the lack of aeolian weathering (as opposed to space weathering) on the Moon. A perfectly spherical geometry, frequently used as a model for lunar dust grains, has none of these characteristics (although a sphere may be a reasonable proxy for the very smallest grains and some glasses). We present a fractal model for a lunar dust grain or aggregate of grains that reproduces (1) the irregular clumpy nature of lunar dust, (2) the presence of sharp points, and (3) dust features that span multiple scale lengths. We calculate the capacitance of the fractal lunar dust analytically assuming fixed dust mass (i.e. volume) for an arbitrary number of fractal levels and compare the capacitance to that of a non-fractal object with the same volume, surface area, and characteristic width. The fractal capacitance is larger than that of the equivalent non-fractal object suggesting that for a given potential, electrostatic forces on lunar dust grains and aggregates are greater than one might infer from assuming dust grains are sphericaL Consequently, electrostatic transport of lunar dust grains, for example lofting, appears more plausible than might be inferred by calculations based on less realistic assumptions about dust shape and associated capacitance.

Collier, Michael R.↗

NASA NTRS2016

Summary of the Results from the Lunar Orbiter Laser Altimeter after Seven Years in Lunar Orbit

In June 2009 the Lunar Reconnaissance Orbiter (LRO) spacecraft was launched to the Moon. The payload consists of 7 science instruments selected to characterize sites for future robotic and human missions. Among them, the Lunar Orbiter Laser Altimeter (LOLA) was designed to obtain altimetry, surface roughness, and reflectance measurements. The primary phase of lunar exploration lasted one year, following a 3-month commissioning phase. On completion of its exploration objectives, the LRO mission transitioned to a science mission. After 7 years in lunar orbit, the LOLA instrument continues to map the lunar surface. The LOLA dataset is one of the foundational datasets acquired by the various LRO instruments. LOLA provided a high-accuracy global geodetic reference frame to which past, present and future lunar observations can be referenced. It also obtained high-resolution and accurate global topography that were used to determine regions in permanent shadow at the lunar poles. LOLA further contributed to the study of polar volatiles through its unique measurement of surface brightness at zero phase, which revealed anomalies in several polar craters that may indicate the presence of water ice. In this paper, we describe the many LOLA accomplishments to date and its contribution to lunar and planetary science.

LRO↗

NASA NTRS1963

Lunar Flight Study Series: Volume 8. Earth-Moon Transit Studies Based on Ephemeris Data and Using Best Available Computer Program. Part 3: Analysis of Some Lunar Landing Site Problems Utilizing Two Fundamental Principles

This report presents two fundamental properties of lunar trajectories and makes use of these properties to solve various lunar landing site problems. Not only are various problems treated and solved but the properties and methods are established for use in the solution of other problems. This report presents an analysis of lunar landing site problems utilizing the direct mission mode as well as the orbital mission mode. A particular landing site is then specified and different flight profiles are analyzed for getting an exploration vehicle to that landing site. Rendezvous compatible lunar orbits for various stay-times at the landing site are treated. Launch opportunities are discussed for establishing rendezvous compatible lunar orbits without powered plane changes. Then, the minimum required plane changes for rendezvous in the lunar orbit are discussed for launching from earth on any day. On days that afford rendezvous compatible opportunities, there are no powered plane change requirements in the operations from launch at AMR through the rendezvous in lunar orbit, after the stay at the lunar site.

Tucker, W. B.↗

NASA NTRS2019

An Astronaut's Risk of Experiencing a Critical Impact from Lunar Ejecta During Lunar EVA

The Moon is under constant bombardment by meteoroids. When the meteoroid is large, the impact craters the surface, launching crater ejecta far from the impact potentially threatening astronauts on the lunar surface. In the early 1960’s, the ejecta impact flux was thought no more than the sporadic meteoroid flux but with speeds one to two orders of magnitude smaller. However, the Lunar Module designers realized by 1965 that meteoroid bumpers do not perform well at the smaller ejecta impact speeds. Their estimates of the Lunar Module risk of penetration by ejecta were 25 to 50% of the total risk. This was in spite of the exposure time to ejecta being only a third of that to sporadic meteoroids. The standard committee based the 1969 NASA SP-8013 lunar ejecta environment on Zook’s 1967 flux analysis and Gault, Shoemaker and Moore’s 1963 test data for impacts into solid basalt targets. However, Zook noted in his 1967 analysis, that if the lunar surface was composed of soil, that the ejected soil particles would be smaller than ejected basalt fragments and that the ejection speeds would be smaller. Both effects contribute to reducing the risk of a critical failure due to lunar ejecta. The authors revised Zook’s analysis to incorporate soil particle size distributions developed from analysis of Apollo lunar soil samples and ejected mass as a function of ejecta speed developed from coupling parameter analyses of soil impact-test data. The authors estimated EVA risk by assuming failure occurs at a critical impact energy. At these impact speeds, this might be true for suit hard and soft goods. However, these speeds are small enough that there may be significant strength effects that require new test data to modify the hypervelocity critical energy failure criterion. With these caveats, Christiansen, Cour-Palais and Freisen list the critical energy of the ISS EMU hard upper torso as 44 J and the helmet and visor as 71 J at hypervelocity. The authors then assumed that the lunar EVA suit fails at 50 J critical energy. This results in a 1,700,000 years mean time to failure using the results of this analysis and a 3,800 years mean time to failure using NASA SP-8013.

Bjorkman, Michael D.↗

NASA NTRS2019

A Joinable Undercarriage to Maximize Payload (JUMP) Lunar Lander for Cargo Delivery to the Lunar Surface

Currently, NASA has engaged industry to develop a series of small to medium capacity landers with payload capacities of up to 5-9 tons by the mid to late 2020s. This contrasts with the former Constellation program, where the Altair lunar lander was targeting a payload capability of roughly 14-20 tons. Investment in smaller landers may present future challenges in delivering habitat modules larger than lunar lander cabins or small logistics modules to the lunar surface. Additionally, given a projected SLS flight rate of 1-2 launches per year, a lunar surface buildup from small elements seems problematic at best. While commercial launchers provide a supplement to SLS, many of the current and projected launch vehicles deliver less than 20 tons to a Trans-Lunar Injection – even fewer to the lunar surface. However, a possible solution could emerge if the lander itself could be launched in pieces with a buildup in Cislunar space. Thus, launchers with these capacities could contribute to a lunar lander capable of delivering 30 tons or more to the lunar surface. This paper introduces the notional concept of a Joinable Undercarriage to Maximized Payload (JUMP) lander. Key elements of a proposed JUMP lander concept will be discussed, followed by recommendations and forward work.

Human spaceflight↗

NASA NTRS2021

A theoretical assessment of the feasibility of potential Lunar Reconnaissance Orbiter radio occultation observations of the lunar ionosphere

The existence of a “dense” lunar ionosphere has been controversial for decades. Positive ions produced from the lunar surface and exosphere are inferred to have densities that are.106– 107m−3near the surface and smaller at higher altitudes, yet electron densities derived from radio occultation measurements occasionally exceed these values by orders of magnitude. For example, about 4% of the single-spacecraft radio occultation measurements from Kaguya/SELENE were consistent with peak electron densities of∼3×108m−3. Space plasmas should be neutral on macroscopic scales, so this represents a substantial discrepancy. Additional observations of electron densities in the lunar ionosphere are critical to resolving this long standing paradox. Here we theoretically assess whether radio occultation observations using two-way coherent S-band radio signals from the Lunar Reconnaissance Orbiter (LRO) spacecraft could provide useful measurements of electron densities in the lunar ionosphere. We predict the uncertainty in a single LRO radio occultation measurement of electron density to be∼3×108m−3, comparable to occasional observations by Kaguya/SELENE of a dense lunar ionosphere. Thus an individual profile from LRO is unlikely to reliably detect the lunar ionosphere; however, averages of multiple (∼10) LRO profiles acquired under similar geophysical and viewing conditions should be able to make reliable detections. An observing rate of six ingress occultations per day (∼2000 per year) could be achieved with mini-mal impact on current LRO operations. This rate compares favorably with the 378observations reported from the single-spacecraft experiment on Kaguya/SELENE between November 2007 and June 2009. The large number of observations possible for LRO would be sufficient to permit wide-ranging investigations of spatial and temporal variations in the poorly understood lunar ionosphere. These findings strengthen efforts to conduct such observations with LRO.

Paul Withers↗