spacetoday.net: Water ice seen in Mars impact craters

Water ice seen in Mars impact craters

Posted: Fri, Sep 25, 2009, 7:56 AM ET (1156 GMT)
Mars crater ice (NASA/JPL)

Fresh impact craters on Mars have revealed deposits of nearly pure water ice hidden just below the surface, scientists announced Thursday. Mars Reconnaissance Orbiter (MRO) images revealed the bright ice deposits in five small craters ranging in depth from 0.5-2.5 meters; the ice sublimated in a matter of weeks after the craters were first spotted. Scientists believe the ice comes from a layer of subsurface ice exposed by the craters; the ice may come from a more humid episode in the planet's climate perhaps as recent as 10,000 years ago. One of the craters is just a few hundred kilometers from the Viking 2 landing site, and scientists said that the lander might have been able to expose the ice itself had it dug about 10 centimeters deeper.