KH-3 Corona

KH-3 5 [USAF]

KH-3 6 [USAF]

The KH-3 (Keyhole-3) was third version in the Corona-program to build an optical reconnaissance satellite. These satellites were all launched under the name Discoverer.

The KH-3 payload consisted of the further improved C''' (Corona triple-prime) single panoramic camera and a single General Electric return vehicle (SRV, Satellite Return Vehicle). The C'''-camera was built by Itek Corporation and with a f/3.5 aperture and 61 cm focal length had a ground resolution of 7.5 m.

The satellite was based on the Agena-B upper stage, which provided attitude control in orbit. The film return capsule carried its own small solid-fuel retro motor to deorbit at the end of the mission with mid-air recovery of the returning capsule by a specially equipped aircraft.

The last mission of this series, KH-3 6, was modified and used a forward structure similar to the later KH-4 series with the KH-3 camera.

Six KH-3 satellites were launched, of which four resulted in a successful return of film. One mission failed to orbit. KH-3 5 deployed the small Oscar 1 ammateur satellite.

Discoverer 32 and 36 (KH-3 4 and 5) carried each an TR-17 type SECOR transponder.