Clementine was a spacecraft designed to make charged particle measurements, do imaging on a variety of frequencies, and perform laser altimetry on the Moon and near Earth asteroid 620 Graphos. It was also to test the spaceworthyness of its sensors and hardware. Clementine was a joint project of NASA and the Strategic Defense Initiative Organization.

Mission History

Clementine was launched from Vandenberg Air Force base on January 25 1994 at 16:34 UTC aboard a Titan II-G rocket. The craft attained lunar orbit on February 19 1994 after two Earth flybys, the first on February 5 and the second on February 15. It then began its mission with a elliptical polar orbit with a perilune of about 400 km at 28 degrees S latitude that took five hours to complete. It remained in this orbit for a month, when on March 26 is was rotated to a new orbit of 29 degrees N latitude.

The spacecraft exited lunar orbit on May 5. On May 7, after the first of two Earth transfer orbits, a computer malfunction caused one of Clementine's attitude control thrusters to fire continuously for 11 minutes, until all of its fuel had been exhausted. The errant thruster put Clementine into an 80 RPM spin, which made certain that the second part of its mission, the 620 Graphos flyby, would yield no useful results. Clementine was instead put into a geocentric orbit in the Van Allen radiation belts to study the effect of radiation exposure on the spacecraft instruments.

Clementine died a slow death in the Van Allen belts, and in June 1994, power levels on the craft dropped to a point where transmitted telemetry became unintelligible.


The spacecraft was octagonal in shape, 1.88 meters high and 1.14 meters across. It carried two gimbal mounted GaAs/Ge solar panels, which recharged a 15 amp-hour, 47 w hr/Hg Ni-H common pressure vessel battery. Sensors were all mounted together on one of the eight sides, perpendicular to the solar panels, and were protected in flight by a single sensor cover. A high-gain fixed antenna was mounted on one end of the craft, and the 489 N thruster was located on the opposite end.

Propulsion was provided by a bipropellent system for maneuvers and a hydrazine system for attitude control. The bipropellent system used nitrogen trioxide and monomethyl hydrazine, and had a total capacity of approximately 1900 m/s. 550 m/s of that capacity was required for lunar insertion and 540 m/s was required for lunar departure.

Attitude control was provided by two inertial measurement units, two star tracker cameras, and 12 attitude control thrusters. While in lunar orbit, the craft was three axis stabilized by reaction wheels.

Clementine carried seven instruments, a UV/Visible camera, a near infrared camera, a long wavelength infrared camera, a high resolution camera, two star tracker cameras, a laser altimeter, and a charged particle telescope. Clementine also carried an S-band transmitter, which was used for communications, tracking, and a gravimetry experiment.

Onboard data processing was performed by two computers. The first, a MIL-STD-1750A computer operating at 1.7 million instructions per seconds provided savemode, attitude control, and housekeeping operations. The second, a RISC 32-bit processor operating at 18 million instructions per second, was used for image processing, image compression (courtesy of the French Space Agency CNES), and autonomous operations. Data was save on a 2 Gbit dynamic solid state recorder.

The Clementine spacecraft used a lunar transfer booster called the Clementine Interstage Adapter Satellite to get it from the Earth to the Moon.

Clementine carries NSSDC (National Space Science Data Center) Master Catalog ID 1994-004A. The information here was obtained in part from