The Lunar Crater Observation and Sensing Satellite (LCROSS) was a robotic spacecraft operated by NASA. The mission was conceived as a low-cost means of determining the nature of hydrogen detected at the polar regions of the Moon. Launched immediately after discovery of lunar water by Chandrayaan-1, the main LCROSS mission objective was to further explore the presence of water in the form of ice in a permanently shadowed crater near a lunar polar region. It was successful in confirming water in the southern lunar crater Cabeus.
LCROSS spacecraft, artist's rendering
The flash from the LCROSS Centaur impact.
An illustration of the LCROSS Centaur rocket stage and Shepherding Spacecraft as they approach impact with the lunar south pole on October 9, 2009.
LRO (top, silver) and LCROSS (bottom, gold) prepared for fairing
Lunar water is water that is present on the Moon. Diffuse water molecules in low concentrations can persist at the Moon's sunlit surface, as discovered by the SOFIA observatory in 2020. Gradually, water vapor is decomposed by sunlight, leaving hydrogen and oxygen lost to outer space. Scientists have found water ice in the cold, permanently shadowed craters at the Moon's poles. Water molecules are also present in the extremely thin lunar atmosphere.
Composite image of the Moon's south polar region, captured by NASA's Clementine probe over two lunar days. Permanently shadowed areas could harbour water ice.
Direct evidence of lunar water in the Moon atmosphere obtained by the Chandrayaan-1's Altitudinal Composition (CHACE) output profile
