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Discoverer 13



Discoverer 13 was an Earth-orbiting satellite designed to test spacecraft engineering techniques and to attempt deceleration, reentry through the atmosphere, and recovery from the sea of an instrument package. It represented the first successful recovery of an object from orbit. The cylindrical Agena A stage that was placed in orbit carried a telemetry system, a tape recorder, receivers for command signals from the ground, a horizon scanner, and a 120-lb recovery capsule that contained an American flag. The capsule was a bowl-shaped configuration 22 in. in diameter and 27 in. deep. A conical afterbody increased the total length to about 40 in. A Thiokol retrorocket, mounted at the end of the afterbody, decelerated the capsule out of orbit. A 40-lb monitoring system in the capsule reported on selected events, such as firing of the retrorocket, jettisoning of the heat shield, and others.

Discoverer 13 was launched on a Thor-Agena from Vandenberg (complex 75-3 on pad 50 on 10 August 1960. At 130 km altitude the first stage separated and the Agena placed the satellite into a 250 x 705 km, 82.9 degree inclination near-polar orbit On 11 August, after 17 orbits, a command was sent from a ground station on Kodiak Island to the spacecraft to start the recovery sequence. The Agena pitched down 60 degrees and the recovery vehicle was ejected by small springs at 23:11 UT. A cold gas system spun the vehicle up for stability, a retrorocket fired, reducing the velocity by about 400 m/s, and then the spin system despun the spacecraft. The orbit ejection subsystem dropped off just before it started to heat up on reentry, leaving the capsule and heat shield. At 15,000 meters a small parachute was deployed, a radio beacon and strobe lights were activated, and the heat shield was relelased. After stabilization a larger parachute was deployed. The capsule splashed down in the Pacific Ocean 610 km NNW of Honolulu on 11 August 1960 at about 23:30 UT (1:30 p.m. local time). The Haiti Victory, a Navy ship, sent out a helicopter which dropped frogmen into the water to attach a collar to the capsule for helicopter retrieval. It was retrieved at 3:30 - 4:15 p.m. and brought back to the ship, the first object ever recovered from orbit, and then taken to Pearl Harbor. The flag was presented to President Eisenhower on 15 August 1960. The Agena stage reentered the atmosphere and burned up on November 14, 1960.

The Discoverer program was a classified operation 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

  • 00048
  • 1960 Theta 1
  • Discoverer13

Facts in Brief

Launch Date: 1960-08-10
Launch Vehicle: Thor
Launch Site: Vandenberg AFB, United States
Mass: 850 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



NameRoleOriginal AffiliationE-mail

Selected References

  • Booda, L., First capsule recovered from satellite, Space Technol., 3, No. 4, 41-43, Oct. 1960.
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