Lunar Prospector is the third mission selected by
NASA for full development and construction as part of the
Discovery Program. At a cost of $62.8 million, the 19-month mission was designed for a low
polar orbit investigation of the
Moon, including mapping of surface composition and possible
polar ice deposits, measurements of
magnetic and
gravity fields, and study of lunar outgassing events. The mission ended July 31, 1999, when the orbiter was deliberately crashed into a
crater near the lunar
south pole after the presence of water ice was successfully detected.