NASA's LCROSS Lunar Mission Suffers Anomaly

NASA’s lunar impact mission, LCROSS, suffered an anomaly over the weekend that could threaten its mission, according to media sources.

The Lunar Crater Observation and Sensing Satellite (LCROSS) was launched together with the Lunar Reconnaissance Orbiter on June 18 (see our previous story). LCROSS remains attached to the Centaur upper stage. The mission plan calls for LCROSS to correctly position itself and the Centaur over a site on the Moon, then the two will separate and the Centaur will be commanded to impact the Moon. LCROSS will take readings of the material ejected from the impact and then itself crash into the Moon. The project is managed by NASA’s Ames Research Center.

According to Spaceflightnow.com and other media sources, while LCROSS was in a communications black-out period over the weekend, an anomaly caused the Centaur to burn a significant amount of fuel, leaving barely enough to accomplish the mission. Apparently a problem developed in LCROSS’s Inertial Reference Unit attitude sensor causing the spacecraft to switch to a backup star tracker, which required additional fuel to maintain orientation. Mission managers remain optimstic that LCROSS will achieve its basic objectives, but worry about how little propellant margin remains should any other problems arise.