Source: nasa.gov
10-20-2007 14:52
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Clementine was a joint project between the Strategic Defense Initiative Organization and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon and the near-Earth asteroid 1620 Geographos. The observations included imaging at various wavelengths including ultraviolet and infrared, laser ranging altimetry, and charged particle measurements. These observations were originally for the purposes of assessing the surface mineralogy of the Moon and Geographos, obtaining lunar altimetry from 60N to 60S latitude, and determining the size, shape, rotational characteristics, surface properties, and cratering statistics of Geographos.
Clementine was launched on 25 January 1994 at 16:34 UTC (12:34 PM EDT) from Vandenberg AFB aboard a Titan IIG rocket. After two Earth flybys, lunar insertion was achieved on February 21. Lunar mapping took place over approximately two months, in two parts. The first part consisted of a 5 hour elliptical polar orbit with a perilune of about 400 km at 28 degrees S latitude. After one month of mapping the orbit was rotated to a perilune of 29 degrees N latitude, where it remained for one more month. This allowed global imaging as well as altimetry coverage from 60 degrees S to 60 degrees N.
After leaving lunar orbit, a malfunction in one of the on-board computers on May 7 at 14:39 UTC (9:39 AM EST) caused a thruster to fire until it had used up all of its fuel, leaving the spacecraft spinning at about 80 RPM with no spin control. This made the planned continuation of the mission, a flyby of the near-Earth asteroid Geographos, impossible. The spacecraft remained in geocentric orbit and continued testing the spacecraft components until the end of mission.
More information on the Clementine mission, instruments, and early results can also be found in the Clementine special issue of Science magazine, Vol. 266, No. 5192, December 1994.
Clementine Flight Plan (1994)
January 25 Launch (16:34 UTC)
February 3 Leave Earth Orbit
February 5 First Earth Flyby
February 15 Second Earth Flyby
February 19 Enter Lunar Orbit
February 26 Start of Systematic Mapping - Cycle 1 (South)
March 26 End of Cycle 1, Start of Cycle 2 (North)
April 21 Completion of Cycle 2
May 5 Exit Lunar Orbit
(May 7 Computer Malfunction (14:39 UTC))
*May Earth and Lunar Flybys
*June-August Cruise to Geographos
*August 31 Geographos Flyby
* not accomplished due to malfunction
Editor:Liu Fang
