English: An engineering backup of the Clementine lunar and asteroid orbiter on display in the Smithsonian Air and Space Museum in Washington, D.C.

Its official name is the the Deep Space Program Science Experiment (DSPSE), but it was nicknamed Clementine because after its mission was over it was intended to be "lost and gone forever". It was jointly funded by the "Star Wars" missile defense initiative and NASA and launched in January 1994. Clementine carried a variety of instruments designed to measure the lunar surface in visible, ultraviolet, and infrared light. It also had laser ranging altimetry radar, gravimetry instruments (changing gravity over the Moon means heavier elements are below), and charged particle measurements. Lunar mapping too two months, during which time Clementine slowly made 300 orbits of the Moon.

Clementine was then supposed to fly to the near-Earth asteroid 1620 Geographos. During this time, it would fly around the Earth twice, testing how well its radiation-hardened instruments held up. These flybys would also build up speed, allowing it to come within 60 miles of Geographis. Unfortunately, on May 7, 1994, one of Clementine's attitude thrusters did not turn off. It burned up the spacecraft's entire fuel supply and caused Clementine to enter a fast spin. Clementine was put into a geosynchronous orbit and passed through the Van Allen radiation belts to test its radiation shielding. Clementine finally failed in June 1994.