Spacecraft Will Be Sent to Seek Water on Moon

A previously planned lunar orbiter mission will be accompanied by a secondary spacecraft designed to crash into the moon in search of water that might be lurking in dark craters, NASA officials announced today.

The smaller payload will be launched on the same rocket with the Lunar Reconnaissance Orbiter in October 2008 and then take a separate path that leads it to slamming into the moon’s south pole, blasting up material that may include water ice, they said.

Scott Horowitz, the associate NASA administrator in charge of the agency’s new exploration initiative, said the opportunity for a second payload comes because of a recent decision to launch the robotic orbiter on a larger rocket. The extra payload capacity allowed NASA to consider supplementing the primary mission with something new, he added.

“This gave us a chance to consider additional high risk, high payoff science,” Mr. Horowitz said after a news conference announcing the new mission. “We got some terrific proposals for using the extra payload and selected one that buys us an early attempt to look at the resources that may exist on the moon.”

In January, NASA asked its centers to develop proposals that would increase understanding of the moon without interfering with the timing and primary mission of the orbiter, which is designed to conduct high-resolution lunar mapping to find potential landing sites. Officials narrowed an initial batch of 19 proposals down to four before selecting the polar impact mission, Mr. Horowitz said.

Earlier lunar missions identified abundances of hydrogen in dark craters near the south pole that are permanently shielded from sunlight, leading to speculation that the hydrogen detected was bound with oxygen as water. If areas on the moon contain water ice, NASA officials said, they would be prime landing sites for humans. Water can be broken apart to produce hydrogen for rocket fuel and oxygen for fuel and breathing, allowing astronauts to partly “live off the land” while exploring.

To discover the meaning of hydrogen in the dark craters, NASA selected a proposal from its Ames Research Center in Moffett Field, Calif., a combination spacecraft called the Lunar Crater Observation and Sensing Satellite, known as LCROSS.

Daniel Andrews, the project manager, said the plan involves using the expended upper stage of the rocket that sends the orbiter to the moon as an impact vehicle to hit a large polar crater and then using a small, sensor-laden spacecraft that had been attached to it to fly through the plume of debris.

When the 4,400-pound used rocket slams into a crater at about 5,600 miles per hour, Mr. Andrews said, it should send up a plume of vapor and debris, perhaps 1000 metric tons of it, that rises 30 to 40 miles above the surface, he said. About 15 minutes later, the trailing spacecraft, loaded with infrared cameras and spectroscopes to determine chemical composition, is to fly through the plume taking and relaying data before itself hitting the moon.

“We’re going to see the impact,” Mr. Andrews said, “And then fly through the plume while looking into the crater and also looking sideways 90 degrees out into space to see the plume material against the darkness.”

WARREN E. LEARY