There’s water on the moon — a lot of it
NASA today unveiled the latest data collected by its LCROSS (Lunar CRater Observation and Sensing Satellite) and LRO (Lunar Reconnaissance Orbiter) missions, which launched 16 months ago from Cape Canaveral, and it’s full of interesting news.Remember that LCROSS (pictured at right) crashed last October into a crater near the moon’s South Pole, throwing up a 10-mile-high plume of material that may have been in shadow for billions of years.
LRO, meanwhile, is still orbiting and mapping the moon. It carries seven different instruments that measure temperature, radiation, ultra-violet light and other characteristics of the moon.
If you know enough science, you can read about today’s findings in the journal Science, where six separate papers will be published this week. If not, you can go to NASA’s Web site, where there’s a series of videos and images that explain these discoveries in simpler terms.
The gist, however, is that the plume of debris that LCROSS threw up not only had water ice, but also volatile chemicals — methane, ammonia, hydrogen gas, carbon dioxide and carbon monoxide — and some light metals, including sodium, mercury and maybe silver.
This mixture could be the remnants of a comet crash, NASA says, but it also shows that the moon is chemically active and has a water cycle, in which water reacts with particles of lunar soil.
The material was like “fluffy, snow-covered dirt,” said NASA’s chief lunar scientist, Michael Wargo, in a press briefing today, and the LRO’s instruments show that areas outside of the moon’s shadowed regions may be cold enough to have snowy dirt too.
This is good news for future moon missions. “Rather than having to brave cold and dark conditions, we could land in an area adjacent (to the shadowed parts) where the sun is shining and dig a small distance below the surface to get the ice,” said Dave Paige of UCLA, the principal investigator for LRO’s Diviner instrument.
Added Wargo, “Once you make a discovery of a potential resource, the next thing you do is go prospecting and try to understand whether the resource is an ore — a valuable commodity.”
The moon also has some of the coldest places in the solar system, LRO has discovered — as cold as the objects in the Kuiper Belt at the outer edge of the solar system. One spot measured 29 degrees above absolute zero, Paige said, and three percent of the moon’s surface is cold enough to keep water ice frozen indefinitely.
One next step is to figure out more precisely where the water ice is located on the moon and “How far do I have to walk before I find it,” said Tony Colaprete, the LCROSS project scientist at NASA Ames. If a 10-kilometer area around the LCROSS crash site had 5 percent water, that would be the equivalent of a billion gallons, he said.
Another next step is to analyze the area below the snowy dirt for clues to “ancient processes that may have affected the evolution of the earth and the moon,” Colaprete said. “It’s like quarrying ice on the poles of the earth, but we can learn so much more.”To what extent NASA will be in charge of new moon missions remains to be seen, though, since the agency has been directed by Congress to work more closely with the private sector.
Wargo said LRO is making “the highest resolution and most capable maps of the moon ever made,” and they could help identify appropriate landing sites for future missions.
(FROM NASA: The picture above is a surface temperature map of the south polar region of the moon made by Diviner. The data were acquired during September and October 2009 when south polar temperatures were close to their annual maximum values. The map shows the locations of several intensely cold impact craters that are potential cold traps for water ice as well as a range of other icy compounds commonly observed in comets. The approximate maximum temperatures at which these compounds would be frozen in place for more than a billion years is shown next to the scale on the right. The LCROSS spacecraft was targeted to impact one of the coldest of these craters, and many of these compounds were observed in the ejecta plume.
ian, Nov 8-2010
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