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In early 1992, after a 4-month effort by the National Aeronautics and Space Administration (NASA), the U.S. Department of Defense, and industry, it was concluded that a mission to a near-Earth asteroid using new lightweight technology was desirable and feasible. The mission was subsequently expanded by 2 months to include mapping of the moon to demonstrate spacecraft and sensor performance before the demanding asteroid flyby. The interstage adapter of the spacecraft, which houses the solid rocket motor, was designed to remain in a highly eccentric Earth orbit as a radiation experiment platform and additional sensor target. The name Clementine was selected for the spacecraft because the old ballad "My Darlin' Clementine" is about the daughter of a miner and this mission would assist in determining the mineral content of the moon and the asteroid. And, as in the song, after the asteroid flyby, Clementine was to be "lost and gone forever." The Clementine spacecraft was built at the Naval Research Laboratory in Washington, D.C., and carried sensors designed and built by the Lawrence Livermore National Laboratory.
The spacecraft was launched with a refurbished Titan IIG ICBM into a 226-km by 259-km parking orbit at a 67deg inclination on 25 January 1994. On 3 February, the spacecraft was spun to 60 revolutions per minute, and the kick motor was fired, injecting the spacecraft into a phasing orbit transfer trajectory to the moon. The spacecraft was placed into a 400-km by 2940-km, 5-hour orbit around the moon on 19 February, where it remained until 3 May. The asteroid flyby was aborted on 7 May 1994 because a software error had depleted the spacecraft attitude-control propellant.
The spacecraft is an octagonal prism about 2 m high (Fig. 1).(Fig. 1 omitted) A 110-pound thruster for maneuvers in space is on one end of the prism, and a high-gain fixed dish antenna is on the other end. The power system consists of a gimbaled, single-axis, GaAs-Ge solar array, which provides a total spacecraft power of 360 W at 30 V dc, with a specific power of 240 W/kg, based on the lightweight construction. The spacecraft dry mass is about 227 kg, with a roughly equal mass for liquid fuel.
The main instrumentation on Clementine consists of four cameras, one of...