This is a Petzval lens used from 1962-1972 in the KH-4 through KH-4B cameras that took photographs of the Earth's surface in the US photoreconnaissance satellite program, codenamed Corona. From an altitude of around 120 miles, the cameras photographed targets in the USSR and other nations. The film was reeled onto spools in a film return bucket that separated from the satellite, reentered the Earth's atmosphere, and then deployed a parachute that permitted an Air Force plane to retrieve it. By the end of the program in May 1972 the resolution of the cameras had improved dramatically to about two meters (six feet). The crack in the lens was made during the manufacturing process. Itek made this unflown lens and Hughes Danbury Optical Systems donated it to NASM in 1996.