Laser Ranging to the Lost Lunokhod~1 Reflector

Understand

In 1970, the Soviet Lunokhod 1 rover delivered a French-built laser reflector to the Moon.

• Although a few range measurements were made within three months of its landing, these measurements---and any that may have followed---are unpublished and unavailable.
• The Lunokhod 1 reflector was, therefore, effectively lost until March of 2010 when images from the Lunar Reconnaissance Orbiter (LRO) provided a positive identification of the rover and determined its coordinates with uncertainties of about 100 m.
• This allowed the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) to quickly acquire a laser signal.