The Clementine Mission
Clementine was launched on January 25, 1994, from Vandenburg Air Force Base onboard a Titan IIG rocket. After two Earth flybys, lunar orbit was achieved on February 19, 1994. Lunar mapping took place over approximately two months in two systematic mapping passes over the Moon.
Over the course of 71 days in orbit, Clementine systematically mapped the 38 million square kilometers of the Moon at eleven different wavelengths, from the ultraviolet (415 nm) to the near-infrared (2800 nm) parts of the spectrum (nearly 1,000,000 images). In addition, the spacecraft took 620,000 high-resolution CCD images and about 320,000 near-infrared thermal images, mapped the topography of the Moon with laser ranging equipment, improved knowledge of the surface gravity of the Moon through radio tracking, and carried a charged-particle telescope to characterize the solar and magnetospheric energetic-particle environment.
After successfully completing the lunar mapping phase of the mission, Clementine suffered an onboard malfunction that resulted in the activation of its altitude thrusters. This exhausted all the fuel for altitude control and left the spacecraft spinning at 80 revolutions per minute. This prevented Clementine from performing the planned close flyby on the near-Earth asteroid Geographos. Observations of the Moon were organized into four periods as follows.
- First Observational Period
Orbits 1-31 were the shakedown and testing period, during which the spacecraft observation sequences were tested and refined. Observations of special targets, such as Apollo landing sites, were acquired during this period.
- Second Observational Period
Orbit 32-168 were the first month's systematic mapping passes. This period started on February 26 and ended on March 26, 1994.
- Third Observational Period
Orbits 169-297 were the second month's systematic mapping passes. This period started on March 26 and ended on April 21, 1994.
- Fourth Observational Period
Orbits 298-348 were used to make observations to fill in gaps in the coverage, acquire observations of special targets, acquire stereo observations over Orientale Basin, and obtain calibration data.