Agena top stages

by Jean-Jacques Serra
The Agena stage was developped by Lockheed for the USAF. The first version used for Discoverer in 1959 was equipped with a Bell 8096 motor derived from the Hustler designed for the PDBP (Powered Disposable Bomb Pod) for the B-58 bombardier. This motor used the nitric acid/UDMH couple as propellant; it was capable of 67 kN during 2 minutes (ISp = 250 seconds). It couldn't be re-ignited on the contrary of the 1960 Agena-B. The Agena-D version featured a more powerful engine with 71 kN and a doubled burning time. All those rockets had the same diameter (1.52 m) and a variable length depending on the payload to which there wore most often attached.

The Agena was used from 1959 to 1987. It's the American most used top stage with 362 launches including a majority of military payloads.

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Thor Agena

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Atlas Agena

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Titan 3 Agena

The titan 3B was a military launcher using an Agena top stage. It was used to launch reconnaissance satellites from the KH-8 series between 1966 and 1984. The same launcher was used for the classified SDS and Jumpseat launches to Molniya type orbits. In 1975 a version with a a longer first stage and wider cap was introduced: Titan 34B (or Titan 3B Ascent Agena). It was specifically devoted to those military launches.

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