On October 9th, NASA spacecraft will run into the moon, and on purpose. The Lunar Crater Observation and Sensing Satellite (LCROSS) and its rocket’s Centaur upper stage will impact the moon, with the goal of sending some of the (possibly present) ice above the lunar surface. Once out of the eternal shade of the moon’s south pole, sunlight will break the ice up into H+ and OH- molecules, which can be detected by the Lunar Reconnaissance Orbiter (LRO). The initial impact site was the crater Cabeus A, but the target was later changed to Cabeus (proper), selected for highest hydrogen concentrations with the greatest level of certainty, and for the high-contrast back drop to detect ejecta and vapor measurements. NASA has provided guides for amateur observations of the impact, a facebook group, and a Twitter feed so you don’t miss the moment.

Water is the only drink for a wise man.
—Henry David Thoreau