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Discoverer 8



The Discoverer 8 spacecraft consisted of a main satellite body and a separable reentry vehicle containing a recovery capsule. It was designed to test launching techniques, propulsion, communications, orbital performance, engineering, and recovery techniques. The spacecraft was put into a near-polar orbit by the Thor-Agena A booster, but at a higher altitude than initially planned. After 15 orbits the reentry vehicle was separated from the main body on 21 November at 21:20 UT by ground command and the capsule released over the Pacific Ocean for descent to Earth. The descent parachute failed to deploy and the capsule impacted the ocean outside the planned descent area and was not recovered.

The spacecraft was a cylindrical Agena A upper stage 1.5 m in diameter, 5.85 m long with a mass including propellants of roughly 3850 kg. The mass excluding propellants was 795 kg, which included 140 kg for the reentry vehicle. The capsule section (a.k.a. bucket) of the reentry vehicle was 84 cm in diameter and 69 cm long and held a parachute, a black and white film canister, and a tracking beacon. The capsule was designed to be recovered by a specially equipped aircraft during parachute descent, but was also designed to float to permit recovery from the ocean.

The Discoverer program was managed by the Advanced Research Projects Agency of the Department of Defense and the U.S. Air Force. The primary goal of the program was to develop a film-return photographic surveillance satellite to assess how rapidly the Soviet Union was producing long-range bombers and ballistic missiles and where they were being deployed, and to take photos over the Sino-Soviet bloc to replace the the U2 spyplanes. It was part of the secret Corona program which was also used to produce maps and charts for the Department of Defense and other US government mapping programs. The goal of the program was not revealed to the public at the time, it was presented as a program to orbit large satellites to test satellite subsystems and investigate the communication and environmental aspects of placing humans in space, including carrying biological packages for return to Earth from orbit. In all, 38 Discoverer satellites were launched by February 1962, although the satellite reconnaissance program continued until 1972 as the Corona project. The program documents were declassified in 1995.

Alternate Names

  • 00025
  • 1959 Lambda 1
  • Discoverer8
  • KH-1 9005

Facts in Brief

Launch Date: 1959-11-20
Launch Vehicle: Thor
Launch Site: Vandenberg AFB, United States
Mass: 795 kg

Funding Agency

  • Department of Defense-Department of the Air Force (United States)


  • Surveillance and Other Military
  • Astronomy

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



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