The 31 km diameter and 7.5 km deep de Gerlache crater, located 30 km from the southern pole of the Moon was surveyed. At its bottom a 15 km diameter younger crater can be also found beside many smaller overprinting craters. At moderately sloping terrains a few m high, 100-200 m wide, curving quasi-parallel, km long set of ridges could be identified, which seem to be widespread on the surface, and might cover the half or even more of the crater. We named these girland like features in this work, which seem to be produced by mass movements on slopes (however differ from most of the already identified slope features, which show downslope elongated lineaments or fallen/redeposited debris on the Moon). At all locations they are superposed by recently formed 10-50 m diameter craters, thus might be older than the equilibrium crater population shown age of about 100 Ma old. This is the first identification of these features at the polar terrains, where they might contribute both in the shielding or exposing of subsurface ice. In de Gerlache crater ice occurrences have previously been located on moderately steep slopes, indicating they might be exposed by mass movement processes, where active movements might have happened in the last some 10 Ma using crater statistics based age of the shallow regolith layer. Only half of them were located at areas with modelled surface temperatures below 110 K, where temperature might be not enough to keep most of the deposited H2O there on Ga time scale. However the real values are probably more diverse because of the limited spatial resolution of available temperature data. Target areas are indicated for possible future missions, where periodic solar illumination, and subsurface ice at 0.5 m depth could be also present.

The LVS-PIE Phase A project successfully investigated the feasibility of using the Lunar Volatiles Scout instrument on the ispace Polar Ice Explorer rover to search for possible cold-trapped water ice deposits at the lunar poles. The suitability of the two systems for a joint mission was studied based on identified conflicts between both initial systems, such as the envelope for integration or the power budget. The interfaces were made compatible, mechanical structure and mechanisms were updated to enable system integration and thermal simulations were performed to refine the thermal design for safe operation within the thermal limits under lunar conditions. Thermal extraction simulations for the instrument constrained the power requirement during the instrument's heating phase. Real drilling down forces and reaction torques were determined with representative experiments for both rover and instrument revealing stable conditions during the envisioned drilling process. In the developed mission scenario, operational feasibility of the LVS-PIE mission concept was demonstrated using a notional traverse, remote sensing data and investigation of technical budgets. The mission can reach sites of high scientific interest at the lunar poles and perform relevant measurements with the instrument. A joined mission consisting of an instrument package for drilling and gas analysis on a rover below 20 kg total mass is found to be technically feasible and scientifically valuable.

Temperature regime at the LCROSS impact site is studied. All detected species in the Cabeus crater as well as CH4 and CO clathrate hydrates except H-2, CO, and CH4 are stable against evaporation at the LCROSS impact site. CO and CH4 can be chemisorbed at the surface of the regolith particles and exist in the form of clathrate hydrates in the lunar cold traps. Flux rates of delivery of volatile species by asteroids, micrometeoroids, O-rich, C-rich, and low-speed comets into the permanently shadowed regions are estimated. Significant amounts of H2O, CO, H-2, H2S, SO2, and CO2 can be impact-produced during collisions between asteroids and O-rich comets with the Moon while CH3OH, NH3 and complex organic species survive during low-speed comet impacts as products of disequilibrium processes. C-rich comets are main sources of CH4, and C2H4. (c) 2012 COSPAR. Published by Elsevier Ltd. All rights reserved.

The meteorite Serra de Mage, a eucrite inferred to be from the asteroid 4 Vesta, contains quartz veinlets. They are identical to antitaxial or 'crack-seal' quartz veinlets in terrestrial rocks, and are extraterrestrial and ancient because they pre-date a 4.40 Ga metamorphism. The quartz was likely deposited from liquid water solutions (as are terrestrial veins); other potential solvents or transport mechanisms are inadequate or unlikely. Because there is no indication of internal (magmatic) water in the eucrite meteorites and thus in Vesta, the water from which the veinlet was deposited probably came from outside Vesta. By analogy with water ice deposits on the Moon and Mercury, Vesta and similar asteroids may have had (or now have) polar ice deposits, possibly derived from comet impacts. (C) 2004 Elsevier B.V. All rights reserved.

[1] Both steady and episodic sources have been proposed as sources of hydrogen observed by Lunar Prospector in association with the regions of permanent shadow at the poles of the Moon. Either source could supply significant quantities of water to the poles. However, space weathering processes affect the retention of water in the cold traps. We investigate those effects by simulating the evolution of a column of regolith in the region of permanent shadow over time. We determine the hydrogen concentration as a function of depth using a Monte Carlo model of discrete impacts and of delivery from the solar wind. We treat the delivery, sublimation, sputtering, and very small scale impacts as continual processes. Comparing the amount of water delivered to the poles to the amount remaining after space weathering, we find a retention efficiency of 5.6%. The retention efficiency of the polar cold traps is adequate for preserving volatile deposits over long periods of time. The average hydrogen concentration in the regolith column is 4100 ppm in the top meter after 1 Gyr. This is a saturation level in the regolith. Increasing the amount of time deepens the enriched layer but does not lead to increased concentrations. In 1 Gyr, about 1.6 m of the regolith is gardened. Therefore the top meter, which is probed by the neutron spectroscopy technique, has reached steady state in the simulations. The 4100 ppm saturation level is about half of the amount of hydrogen inferred from the Lunar Prospector neutron data.

[1] The common wisdom that water ice may exist in lunar polar cold traps has become a significant factor in the selection of space research objectives. The purpose of this paper is to address two topics that are missing from the discourse on lunar water: the effect that the pristine cleanliness of the regolith has on water transport on the moon, and the limits on water exposure implied by the extremely high adsorption potentials of the surfaces of soil grains. Water transport is characterized by chemisorption on soil grains and the mixing of wet'' grains into the regolith by meteoritic gardening. Ballistic lateral flow, which is generally thought to be an efficient conduit for moving water to the poles, is actually a secondary phenomenon that is facilitated by solar wind and micrometeor erosion but not by thermal desorption, as is the case for the dominant lunar exospheric gases, He and Ar-40. Simulation results show that even under the most optimistic conditions, less than 7% of the water accumulated in the regolith resides in the polar cold traps, where water concentrations cannot be greater than 350 ppm. More important, when realistic transport parameters are used in the simulator, the polar water concentration is reduced by almost 2 orders of magnitude. In a word, the concept of water ice at the lunar poles is insupportable.