Lunar Prospector. Computer artwork of the Lunar Prospector (LP) spacecraft near the Moon. Data from the LP will provide details of the Moon's composition, evolution and internal processes. The spacecraft will orbit the Moon at an altitude of just 99 kilometres for a year. The instruments on its booms will determine the composition of the Moon's surface rocks (including the presence of valuable minerals), the level of volcanic or tectonic activity, and whether water ice exists at the lunar poles. They will also make measurements of the Moon's magnetic and gravity fields that will reveal details of the lunar core. The LP is due to be launched in September 1997.