Astronomy

NASA scientists are preparing for a very unusual mission the likes that we haven’t seen in many years. They are hoping to discover hidden ice water in the lunar double of the moon – but the only way to do that is to ram two of their spacecrafts into the surface of the moon.  “I think that people are apprehensive about it because it seems violent or crude, but it’s very economical,” said Tony Colaprete, the principal investigator for the mission at NASA’s Ames Research Center in Moffett Field, Calif.

NASA’s previous Lunar Prospector mission detected large amounts of hydrogen at the moon’s poles before crashing itself into a crater at the lunar South Pole. Now the much larger Lunar Crater and Observation Sensing Satellite (LCROSS) mission, set for a February 2009 moon crash, will take aim and discover whether some of that hydrogen is locked away in the form of frozen water.

LCROSS will piggyback on the Lunar Reconnaissance Orbiter (LRO) mission for an Oct. 28 launch atop an Atlas 5 rocket equipped with a Centaur upper stage. While the launch will ferry LRO to the moon in about four days, LCROSS is in for a three-month journey to reach its proper moon smashing position. Once within range, the Centaur upper stage doubles as the main 4,400 pound (2,000 kg) impactor spacecraft for LCROSS.

The smaller Shepherding Spacecraft will guide Centaur towards its target crater, before dropping back to watch - and later fly through - the plume of moon dust and debris kicked up by Centaur’s impact. The shepherding vehicle is packed with a light photometer, a visible light camera and four infrared cameras to study the Centaur’s lunar plume before it turns itself into a second impactor and strikes a different crater about four minutes later.

“This payload delivery represents a new way of doing business for the center and the agency in general,” said Daniel Andrews, LCROSS project manager at Ames, in a statement. “LCROSS primarily is using commercial-off-the-shelf instruments on this mission to meet the mission’s accelerated development schedule and cost restraints.”

Figuring out the final destinations for the $79 million LCROSS mission is “like trying to drive to San Francisco and not knowing where it is on the map,” Colaprete said. He and other mission scientists hope to use observations from LRO and the Japanese Kaguya (Selene) lunar orbiter to map crater locations before LCROSS dives in.

“Nobody has ever been to the poles of the moon, and there are very unique craters - similar to Mercury - where sunlight doesn’t reach the bottom,” Colaprete said. Earth-based radar has also helped illuminate some permanently shadowed craters. By the time LCROSS arrives, it can zero in on its 19 mile (30 km) wide targets within 328 feet (100 meters).

“By understanding what’s in these craters, we’re examining a fossil record of the early solar system and would occurred at Earth 3 billion years ago,” Colaprete said. LCROSS is currently aiming at target craters Faustini and Shoemaker, which Colaprete likened to “fantastic time capsules” at 3 billion and 3.5 billion years old.