... Tonight's Sky . ... Walls of lunar crater may hold patchy ice . NASA's Lunar Reconnaissance Orbiter discovers that small patches of ice could make up at most 5 to 10 percent of material in walls of Shackleton Crater. ... Radar data indicate that the walls of the Moon's Shackleton Crater may hold ice. ... Radar measurements of Shackleton Crater place an upper bound on the ice content of the uppermost meter of loose material of the crater's walls at between 5 and 10 percent ice by weight. ...