Thor-Agena

Missions

The clandestine CORONA program used Thor-Agena from June 1959 until January 1968 to launch United States military reconnaissance satellites operated by the Central Intelligence Agency. During this program, 145 launch attempts were made. OSCAR 1, the first non-governmental satellite, was launched on a Thor-Agena B aboard Discoverer 36 in December 1961. Alouette 1, Canada's first satellite, was also launched on a Thor-Agena B.

Versions

The Thor-Agena A (Thor-DM18 Agena-A) was used for 16 launches between 21 January 1959 and 13 September 1960. On 19 August 1960, a Thor-Agena A launched Discoverer 14, from which usable photographic film was recovered by a Fairchild C-119 Flying Boxcar aircraft, marking the first successful recovery of film from an orbiting satellite and the first mid-air recovery of an object returning from Earth orbit. The Thor-Agena B (Thor-DM21 Agena-B or Thor-SLV2 Agena-B) was used for 44 launches between 26 October 1960 and 15 May 1966; its first successful launch was on 12 November 1960 with Discoverer 17, and its last launch was on 15 May 1966 with Nimbus 2.

A variant with Solid Rocket Boosters (TAT Agena-B or Thor-SLV2A Agena-B) existed. The Thor-Agena D (Thor-DM21 Agena-D or Thor-SLV2 Agena-D) was used for 83 launches between 28 June 1962 and 17 January 1968; its first launch was on 28 June 1962 with KH-4 19, and its last launch was on 17 January 1968 with Multigroup 3 and Setter 1B-2. A variant with Solid Rocket Boosters (TAT Agena-D or Thor-SLV2A Agena-D) existed. On 28 February 1963, the maiden flight of a Thrust-Augmented Thor Agena (TAT Agena-D) carrying a spy satellite launched from Vandenberg Air Force Base went off course; mission control detonated the launch vehicle at an altitude of 44 km.

The detonation produced a large circular cloud visible for hundreds of miles over the southwestern United States, attracting widespread media attention and appearing on the cover of Science Magazine in April 1963 and Weatherwise Magazine in May 1963, with a full page in Life Magazine. After launch records were declassified, the United States Air Force released a memo explaining the cloud resulted from a military operation.