Flown COAS Spare Light Bulb Assembly carried to the lunar surface on board the Apollo 15 Lunar Module Falcon. Assembly measures 2 x 1.75. Assembly consists of a small light bulb inside a housing which would be inserted into the COAS to illuminate the optical reticle used for docking alignment. In fine condition. Accompanied by a letter of authenticity from Dave Scott, complete with images and diagrams of the assembly, which reads, in part: “I hereby certify that the Lunar Module COAS Spare Light Bulb Assembly included with this letter was carried aboard the Lunar Module ‘Falcon’ during Apollo 15…The Crewman Optical Alignment Sight (COAS) is an alignment aid that provides fixed line-of-sight attitude reference between the Lunar Module and the Command Module as well as the horizon (Earth and Moon) and stars…To ensure this capability during a mission, a spare bulb assembly was carried aboard the spacecraft…This LM COAS Spare Bulb Assembly has been in my personal collection since returning to Earth.” RR Auction COA.