Goals: The Lunar Crater Observation and Sensing Satellite (LCROSS) was launched to determine if water-ice exists in a permanently shadowed crater at the Moon's South Pole. LCROSS will excavate the permanently dark floor of a crater with back-to-back impacts. The impacts will create a plume that specialized instruments will be able to analyze for the presence of water (ice and vapor), hydrocarbons and hydrated materials. The spacecraft was launched with the Lunar Reconnaissance Orbiter mission.
Accomplishments: LCROSS and its Centaur stage impacted the Moon on schedule on 9 Oct. 2009. The twin impacts of LCROSS and a companion rocket stage in the moon's Cabeus crater on Oct. 9, 2009, lifted a plume of material that might not have seen direct sunlight for billions of years. As the plume traveled nearly 10 miles above the rim of Cabeus, instruments aboard LCROSS and LRO made observations of the crater and debris and vapor clouds. After the impacts, grains of mostly pure water ice were lofted into the sunlight in the vacuum of space.
The missions found evidence that the lunar soil within shadowy craters is rich in useful materials, and the moon is chemically active and has a water cycle. Scientists also confirmed the water was in the form of mostly pure ice crystals in some places.