Hoyle is part of the Apache Point Observatory Lunar Laser-ranging Operation research project led by UC San Diego professor Tom Murphy. The team uses pulses of laser light reflected off the surface of the Moon to measure its orbit within the accuracy of a millimeter. Reflectors like Lunokhod 1 make their research possible.
Previously, the project had been using reflectors from the Apollo 11, 14 and 15 missions, as well as Lunokhod 2. But the team had been searching for Lunokhod 1 for years. “The moon kind of wobbles in its orbit,” Hoyle says, “so the more reflectors you have, the better idea you get of its actual path.”
Lunokhod 1 was last heard from in 1971. Then, in March, Mark Robins from Arizona State University and his team located a reflective speck on their Lunar Reconnaissance Orbiter Camera. The location of the speck was shared with Murphy’s team, which used its laser to identify Lunokhod 1 about 20 miles from where it was previously believed to be.
Currently, Murphy’s team is working to pinpoint the exact location of the recovered reflector. However, Lunokhod 1 has already proved to have much more reflective strength than Lunokhod 2, Hoyle says, which will prove useful to the team’s continued research.