Water, Water Everywhere…on the Moon (or at least the Moon’s south pole)

According to findings reported in the New York Times there’s relatively abundant water at the bottom of a very deep, very dark crater near the moon’s south pole. There’s so much water, in fact, that this region of the moon appears to be wetter than the Sahara.

“Well, that’s not very wet,” you’re saying.

Okay, yes, it’s pretty dry. But, given that the assumption until recently by many planetary scientists was that the moon was utterly dry this is considerably damp.

The Sahara sands are 2 to 5 percent water, and the water is tightly bound to the minerals. In the lunar crater, which lies in perpetual darkness, the water is in the form of almost pure ice grains mixed in with the rest of the soil, and is easy to extract. The ice is about 5.6 percent of the mixture, and possibly as high as 8.5 percent of it.

That’s so much water, in fact, that if astronauts were to visit this crater they might be able to use eight wheelbarrows of soil to melt 10 to 13 gallons of water. The water, if purified, could be used for drinking, or broken apart into hydrogen and oxygen for rocket fuel — to get home or travel to Mars.

This discovery was made by NASA’s Lunar Crater Observation and Sensing Satellite — or Lcross, for short — which made the observations as it, by design, slammed into the Moon a year ago.

The $79 million Lcross mission piggybacked on the Lunar Reconnaissance Orbiter, which was launched in June last year and has been mapping out the lunar surface for a future return by astronauts. Lcross steered the empty second stage of the rocket, which otherwise would have just burned up in the Earth’s atmosphere, onto a collision course with the Moon.

Last October, as it neared impact, the Lcross spacecraft released the empty second stage and slowed down slightly so that it could watch the stage’s 5,600-mile-per-hour crash into a 60-mile-wide, 2-mile-deep crater named Cabeus. A few minutes later, Lcross, quickly transmitting its gathered data to Earth, met a similar demise.

You might recall that for people who watched the live Webcast video transmitted by Lcross, the event was a disappointment, with no visible plume from the impacts. But as they analyzed the data, scientists found everything they were looking for, and more. Last November, the team reported that the impact had kicked up at least 26 gallons of water, confirming suspicions of ice in the craters.

The new results increase the water estimate to about 40 gallons, and by estimating by amount of dirt excavated by the impact, calculated the concentration of water for the first time.

A series of articles reporting the Lcross results appeared in Friday’s issue of the journal Science.

– S.