Past Missions

LADEE

The Lunar and Atmosphere and Dust Environment Explorer will launch in the summer of 2013 and fly at low altitudes to study the thin lunar exosphere before it is perturbed by future humans, and to characterize the lunar dust environment to assess its possible impact on future engineering on the lunar surface.

LCROSS

is a co-manifested spacecraft with the Lunar Reconnaissance Orbiter and will intentionally impact a lunar polar crater. The resulting plume will be observed by orbiting and ground-based telescopes to ascertain whether water exists in a permanently shadowed region of the Moon.
http://www.nasa.gov/mission_pages/LCROSS/main/