La Lune : un monde d’eau ! - Etat des connaissances et perspectives hydrotechniques

Since the first sample return missions of the 1960s, lunar scientists have operated under the presumption that the Moon is entirely dry. Four papers published in September 2009, challenge that notion: Infrared spectroscopic measurements of the lunar surface from spacecraft provide unambiguous evidence for the presence of hydroxyl (OH) and water. It is thought that the Moon formed by collision between Earth and a Mars-size body 4,524.10(9) years ago. In this paper, we first focus on the old results of the Apollo program. Secondly we are leading to an improved understanding in light of global remotely sensed data coming from multispectral imaging, geochemical mapping, and geophysical constraints. This new view offers a significant refinement to previous models for the compositional asymmetry of the Moon. The new reports of lunar surface water coincide with intense interest in water at the poles of the Moon. The results of the present studies lend credence to the lunar polar water hypothesis by providing a proven source of water on the surface of the Moon. What is the source of water ? Important continuous sources of water include reduction of lunar divalent iron in minerals to metallic iron by solar-wind hydrogen, producing water; and liberation of water from impacting interplanetary dust and small meteoroids. The most valuable result of these new observations is that they prompt a critical reexamination of the notion that the Moon is dry. It is not. Harvesting the lunar regotith for volatiles now becomes a serious option for long-term human activity. The Moon is the first waypoint for human exploration of the Solar System. This exploration is a must for the survival of humankind.