The primary goal of the satellites was to replace the U-2 spyplane in surveilling the Sino-Soviet Bloc, determining the disposition and speed of production of Soviet missiles and long-range bombers assess.

The KH-1 payload included the C (for Corona) single, vertical-looking, panoramic camera that scanned back and forth, exposing its film at a right angle to the line of flight.

[4] Discoverer began with a series of three test flights whose satellites carried no cameras, all launched in the first half of 1959.

Either of these issues would have left Discoverer 9 with insufficient velocity to reach orbit, and the satellite crashed into the Pacific 400 miles (640 km) downrange.

[1]: 245  CORONA was declassified in 1995,[1]: 14  and a formal acknowledgement of the existence of US reconnaissance programs, past and present, was issued in September 1996.