Guy Gugliotta. “U.S. Planning Base on Moon To Prepare for Trip to Mars.” Washington Post. March 26, 2006: “In some ways, the moon will be harder than Mars. Moon dust is much more abrasive than Mars dust; Mars has atmosphere; Mars has more gravity (one-third of Earth’s); Mars has plenty of ice for a potential water supply, while the moon may have some, but probably not very much.”