This paper provides a report on a test that was carried out over 20 years ago to demonstrate that two 3He gas proportional neutron sensors could survive a high-impact penetrator test. This test was carried out as part of a risk reduction effort for a proposed mission that would send multiple penetrators to landing locations within lunar permanently shaded regions (PSRs). After landing, the neutron sensors would carry out in situ measurements within the PSRs to quantify the hydrogen abundances within these regions. Two penetrator shots were successfully carried out with the neutron sensors enclosed in the penetrators. The deceleration value for the shots exceeded 1,400 G's over less than 20 milliseconds. Pre- and post-penetration measurements of the 3He sensors show that the sensors themselves suffered no degradation in performance; one non-spaceflight quality high-voltage connector did indicate performance degradation. These results provide confidence that these types of 3He neutron sensors could be successfully used in a future penetrator mission to a planetary body.

Lunar Reconnaissance Orbiter (LRO) was launched in 2009 to study and map the Moon and is now completing its fifth extended science mission. The LRO (see Figure 1) hosts a payload of seven different scientific instruments. The Cosmic Ray Telescope for the Effects of Radiation instrument has characterized the lunar radiation environment and allowed scientists to determine potential impacts to astronauts and other life. The Diviner Lunar Radiometer Experiment (DLRE) has identified cold traps where ice could reside and mapped global thermophysical and mineralogical properties by measuring surface and subsurface temperatures. The Lyman Alpha Mapping Project has found evidence of exposed ice in south polar cold traps as well as global diurnal variations in hydration. The Lunar Exploration Neutron Detector has been used to create high-resolution maps of lunar hydrogen distribution and gather information about the neutron component of the lunar radiation environment. The Lunar Reconnaissance Orbiter Camera (LROC) is a system of three cameras [one wide-angle camera and two narrow-angle cameras (NACs)] mounted on the LRO that capture high-resolution black-and-white images and moderate resolution multispectral (seven-color band) images of the lunar surface. These images can be used, for example, to learn new details about the history of lunar volcanism or the present-day flux of impactors. The Miniature Radio Frequency (Mini-RF) instrument is an advanced synthetic aperture radar (SAR) that can probe surface and subsurface coherent rock contents to identify the polarization signature of ice in cold traps. The Lunar Orbiter Laser Altimeter (LOLA) has been used to generate a high-resolution, 3D map of the Moon that serves as the most accurate geodetic framework available for co-locating LRO (and other lunar) data. The data produced by the LRO continue to revolutionize our scientific understanding of the Moon, and are essential to planning NASA's future human and robotic lunar missions.

Lunar water ice is an important resource to support the construction of lunar base and other deep space activities, and it is crucial to detect lunar water ice. In this paper, we studied the detection of lunar water ice based on a small neutron generator through Monte-Carlo simulation. The schematic of the detection system and the principle are explained. The simulation results demonstrate that the change of thermal neutron flux with the increase of water content is most obvious and clear. There is a positive correlation between thermal neutron counting and water content in lunar soil. Using thermal neutron counting, the water content can be obtained by inversion.

Cubesats operating in deep space face challenges Earth-orbiting cubesats do not. 15 deep space cubesat 'prototypes'will be launched over the next two years including the two MarCO cubesats, the 2018 demonstration of dual communication system at Mars, and the 13 diverse cubesats being deployed from the SLS EM1 mission within the next two years. Three of the EM1 cubesat missions, including the first deep space cubesat 'cluster', will be lunar orbiters with remote sensing instruments for lunar surface/regolith measurements. These include: Lunar Ice Cube, with its 1-4 micron broadband IR spectrometer, BIRCHES, to determine volatile distribution as a function of time of day; Lunar Flashlight, to confirm the presence of surface ice at the lunar poles, utilizing an active source (laser), and looking for absorption features in the returning signal; and LunaH-Map to characterize ice at or below the surface at the poles with a compact neutron spectrometer. In addition, the BIRCHES instrument on Lunar Ice Cube will provide the first demonstration of a microcryocooler (AIM/IRIS) in deep space. Although not originally required to do so, all will be delivering science data to the Planetary Data System, the first formal archiving effort for cubesats. 4 of the 20 recently NASA-sponsored (PSDS3) study groups for deep space cubesat/smallsat mission concepts were lunar mission concepts, most involving 12U cubesats. NASA SIMPLEX 2/SALMON 3 AO will create ongoing opportunities for low-cost missions as 'rides'on government space program or private sector vehicles as these become available.

The design of the Lunar Exploration Neutron Detector (LEND) experiment is presented, which was optimized to address several of the primary measurement requirements of NASA's Lunar Reconnaissance Orbiter (LRO): high spatial resolution hydrogen mapping of the Moon's upper-most surface, identification of putative deposits of appreciable near-surface water ice in the Moon's polar cold traps, and characterization of the human-relevant space radiation environment in lunar orbit. A comprehensive program of LEND instrument physical calibrations is discussed and the baseline scenario of LEND observations from the primary LRO lunar orbit is presented. LEND data products will be useful for determining the next stages of the emerging global lunar exploration program, and they will facilitate the study of the physics of hydrogen implantation and diffusion in the regolith, test the presence of water ice deposits in lunar cold polar traps, and investigate the role of neutrons within the radiation environment of the shallow lunar surface.

The lunar poles feature a microenvironment that is almost entirely unknown to planetary science. Because of the very small tilt of the Moon's axis with respect to the sun, craters and other depressions near the poles are permanently shaded from direct sunlight. As a consequence, these surfaces should have maintained extremely low temperatures, well under 100 K, for billions of years. There is some evidence that these surfaces act as cold traps, capturing and sequestering volatiles from the Moon and elsewhere. Most popular attention had focused on the possible presence of water ice that might be used by astronauts in the future, but the poles may offer a unique scientific resource. Possible sources for volatiles at the lunar poles range from the Sun to interstellar clouds, and if present, such volatile deposits may provide unique information about many aspects of planetary science.

[1] Initial studies of neutron spectrometer data returned by Lunar Prospector concentrated on the discovery of enhanced hydrogen abundances near both lunar poles. However, the nonpolar data exhibit intriguing patterns that appear spatially correlated with surface features such as young impact craters (e. g., Tycho). Such immature crater materials may have low hydrogen contents because of their relative lack of exposure to solar wind-implanted volatiles. We tested this hypothesis by comparing epithermal* neutron counts (i.e., epithermal -0.057 x thermal neutrons) for Copernican-age craters classified as relatively young, intermediate, and old (as determined by previous studies of Clementine optical maturity variations). The epithermal* counts of the crater and continuous ejecta regions suggest that the youngest impact materials are relatively devoid of hydrogen in the upper 1 m of regolith. We also show that the mean hydrogen contents measured in Apollo and Luna landing site samples are only moderately well correlated to the epithermal* neutron counts at the landing sites, likely owing to the effects of rare earth elements. These results suggest that further work is required to define better how hydrogen distribution can be revealed by epithermal neutrons in order to understand more fully the nature and sources (e. g., solar wind, meteorite impacts) of volatiles in the lunar regolith.