NASA announced today it will send a rocket to crash into the moon, an early step to delivering the first astronauts there since the last Apollo missions more than 30 years ago.
The rocket, its designers hope, will crash near the moon's south pole in 2008. It should blast out a crater about a hundred feet wide and 15 feet deep. A 2,000-pound robotic probe, launched from Earth by the rocket, should fly behind, passing through the plume of debris kicked up by the impact, to take measurements of the crater and see what is in it.
The measuring probe -- called the Lunar Crater Observation and Sensing Satellite, or LCROSS -- will be cobbled together largely from leftover parts from other probes. The mission will cost about $80 million, which is very low budget by space standards.
Scientists and engineers are especially interested to find out if ice is mixed in with the lunar soil. The results from an earlier mission in the 1990s, called the Lunar Prospector, suggested a large amount was, especially in the floor of craters near the lunar pole, where sunlight never reaches to melt it.
"We can directly measure water ice, and then we can fly right through the plume," said project manager Daniel Andrews. Engineers believe much of the debris from the crash would be kicked as much as 35 miles above the moon's surface. It should be visible to amateur astronomers on Earth. Up to a dozen Earth-based telescopes will be used determine if there are telltale signs of water, and they will get a second chance when the LCROSS probe also crashes after transmitting its data.
If President Bush's "vision for space exploration," announced in 2004, is to succeed, NASA would very much need to take advantage of resources it can find on the moon. If there is ice to be found, it can be used for drinking water for astronauts and as coolant for equipment. It can be broken down into hydrogen and oxygen -- ingredients for rocket fuel that need not be brought from Earth.
The new mission came about, said NASA, as the result of a happy accident. It is meant to piggyback on a larger probe, called Lunar Reconnaissance Orbiter, or LRO, which is designed to map the moon in great detail, so that NASA can select landing sites for later probes.
Late last year a decision was made to launch LRO with a Delta 4 or Atlas 5 rocket, the largest nonshuttle boosters NASA has available, and planners realized they had given themselves a small gift. With LRO's weight already set, they now had the capacity to send an extra 2,000 pounds to the moon.
How to take advantage? On Jan.10, they asked engineers and scientists around NASA to come up with ideas for small ships that could piggyback on LRO's rocket.
They received 19 proposals. The list was narrowed to four, and the winner was announced today.
NASA currently hopes to have astronauts back on the moon around 2018, though many things have to go right between now and then. Recent reports indicate that NASA's early plans for a new crew exploration vehicle to replace the space shuttle are already in need of revision; the ship's lunar lander is currently too heavy to carry four astronauts as planned.
"We think we have assembled a very creative, highly innovative mission," said Andrews, "turning the upper stage of the rocket that brought us to the moon into a substantial impactor on the moon."