Topography of the Lunar Poles from Radar Interferometry: A Survey of Cold Trap Locations

Detailed topographic maps of the lunar poles have been obtained by Earth-based radar interferometry with the 3.5-centimeter wavelength Goldstone Solar System Radar. The interferometer provided maps 300 kilometers by 1000 kilometers of both polar regions at 150-meter spatial resolution and 50-meter height resolution. Using ray tracing, these digital elevation models were used to locate regions that are in permanent shadow from solar illumination and may harbor ice deposits. Estimates of the total extent of shadowed areas poleward of 87.5 degrees latitude are 1030 and 2550 square kilometers for the north and south poles, respectively. Topographic depressions near the lunar poles provide a low-temperature environment that is a potential reservoir of water ice deposits (1, 2). The case for lunar ice was recently strengthened by the detection of a hydrogen signature near the polar regions by the neu