http://www.thestar.com/news/sciencet...nar-oasis?bn=1


NASA spacecraft finds lunar oasis
Published On Wed Oct 20 2010



It was a cold and dismal place to find an oasis.

But a spacecraft that NASA deliberately crashed into a lunar crater last year has discovered a large reservoir of water on the desert-like moon — water that could be transformed into fuel for future space missions.

Found in the vast Cabeus crater near the moon’s south pole, the water represents about 5.6 per cent by weight of the lunar soil there.

“For comparison, that’s about twice as wet as the Sahara desert,” says Anthony Colaprete, a key scientist for the Lunar Crater Observation and Sensing Satellite (LCROSS) mission.

While that may sound dreadfully dry to earthlings, by lunar standards it is absolutely sopping, he says.

“For the moon, that is an oasis,” says Colaprete, a principle investigator at NASA’s Ames Research Center in California. Moffett Field, Calif.

The mission findings were published Thursday in the journal Science.

The mission hurtled the spent upper stage of an Atlas V rocket, which had propelled the probe from Earth, into the crater. It then sent the LCROSS probe down through the resulting plume to analyze the ejected debris.

Using an array of light and thermal imagers, the “shepherding” spacecraft detected a slew of minerals, frozen gases, and a large quantity of ice particles and water vapour.

At the concentrations detected you could squeeze about 13 gallons of water out of every ton of Cabeus dirt, Colaprete says.

And that’s more than enough, he says, to conceive of building a moon station there that could split water into its hydrogen and oxygen components to fuel missions to Mars and beyond.

“It’s in the top half metre or so of dirt (and) it is accessible,” Colaprete says.

“If you needed to extract it and use it to live off the land to create, for example, rocket fuel, to help yourself reach other destinations . . . we can get to it.”

Using the Moon as a launching pad for such monumentally long missions would be considerably cheaper than sending them up directly from Earth, which has six times the gravitational pull.

Water-based fuels created on the moon could be transported up to an orbiting fuelling station at far less cost than lifting it off the earth, Colaprete says.

The LCROSS mission also found methane in the crater’s soil, which could be used for fuel as well, he says.

The Cabeus crater itself is in perpetual shadows and at 40 Kelvin (minus 233C) is one of the coldest places on the moon. Indeed, it is so cold that water that would otherwise evaporate into the vacuum of space is frozen fast onto the lunar surface.

NASA scientists had thought of the crater as a likely place to find water because previous missions had detected large amounts of hydrogen there.

“It was the most obvious place where there was hydrogen at the south pole and that was the principle reason we went to that crater,” Colaprete says.

A study published earlier this year had reported that the moon’s soil contained minuscule amounts of water. But these molecular-sized water deposits are actually trapped in other lunar materials.

That bound water has likely been there since the moon was formed 4.5 billion years ago after a massive asteroid collision with the Earth.

The Cabeus water, on the other hand, is free of other lunar materials and was likely deposited by a comet impact into the crater between one and two billion years ago.