The fourth of five test flights of the Corona KH-1 spy satellite series was lost when the second stage failed during launch.

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 assessing long-range bombers.

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.

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

[4]: 59 Launched on 29 Jun 1960 at 22:00:44 GMT from Vandenberg LC 75-3-4 by a Thor DM-21 Agena-A rocket,[7] the mission ended in failure when the Agena second stage malfunctioned.