NASA spacecraft finds new evidence for water ice on Mercury

A NASA spacecraft studying Mercury has provided compelling support for the long-held hypothesis the planet harbors abundant water ice and other frozen volatile materials within its permanently shadowed polar craters, the U.S. space agency announced Thursday in a statement. The new information comes from NASA's Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft. Its onboard instruments have been studying Mercury in unprecedented detail since its historic arrival there in March 2011. Scientists are seeing clearly for the first time a chapter in the story of how the inner planets, including Earth, acquired their water and some of the chemical building blocks for life. "The new data indicate the water ice in Mercury's polar regions, if spread over an area the size of Washington, D.C., would be more than two miles thick," said David Lawrence, a MESSENGER participating scientist at the Johns Hopkins University and lead author of one of three papers describing the findings. The papers were published online in Thursday's edition of Science Express. Launched on Aug. 3, 2004, MESSENGER is the first spacecraft to orbit Mercury. The spacecraft followed a path through the inner solar system, including one flyby of Earth, two flybys of Venus, and three flybys of Mercury.