A research team at JPL has concluded that the unidentified piece of space junk that had been in lunar space but crashed to Earth in November was likely the engine module used by the 1998 Lunar Prospector mission.
The junk’s identity is by no means certain, but the “leading candidate” is the translunar injection module of Lunar Prospector, says Paul Chodas, an asteroid tracker at NASA’s Jet Propulsion Laboratory in Pasadena, California. The module nudged the probe out of Earth orbit and then detached from the main spacecraft, which orbited the Moon for 19 months before it was deliberately slammed into the lunar south pole in July 1999.
Speculation about the source of the debris, known as WT1190F, ran rampant even before it plummeted through the atmosphere on 13 November. The only artificial object to make an uncontrolled re-entry at a precisely predicted place and moment, it presented a unique chance to witness such an event in real time. Researchers took advantage of the opportunity, monitoring the debris from a chartered jet as well as from ground-based observatories.