NASA announced in April 2006 that a small, 'secondary payload' spacecraft, to be developed by a team at NASA Ames Research Center, Moffett Field, Calif., has been selected to travel to the moon to look for precious water ice at the lunar south pole in October 2008. The smaller secondary payload spacecraft will travel with the Lunar Reconnaissance Orbiter (LRO) satellite to the moon on the same rocket, the Evolved Expendable Launch Vehicle (EELV), to be launched from Kennedy Space Center, Florida. The NASA Ames team proposed the secondary payload mission, which will be carried out by the Lunar CRater Observation and Sensing Satellite (LCROSS).

The LCROSS mission gives an excellent opportunity to answer the question about water ice on the moon. The LCROSS represents a very creative, highly innovative mission, turning the upper stage of the rocket that brought LRO to the moon into a substantial impactor on the moon.

After launch, the secondary payload LCROSS spacecraft will arrive in the lunar vicinity independent of the LRO satellite. On the way to the moon, the LCROSS spacecraft's two main parts, the Shepherding Spacecraft (S-S/C) and the Earth Departure Upper Stage (EDUS), will remain coupled.