Discoverer 18

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Discoverer 18
Mission type Optical reconnaissance
Operator US Air Force/NRO
Harvard designation 1960 Sigma 1
Spacecraft properties
Spacecraft type KH-2 Corona'
Bus Agena-B
Manufacturer Lockheed
Launch mass 1,240 kilograms (2,730 lb)
Start of mission
Launch date 7 December 1960, 20:20:58 (1960-12-07UTC20:20:58Z) UTC
Rocket Thor DM-21 Agena-B 296
Launch site Vandenberg LC-75-3-4
End of mission
Decay date 2 April 1961 (1961-04-03)
Orbital parameters
Reference system Geocentric
Regime Low Earth
Perigee 272 kilometers (169 mi)
Apogee 535 kilometers (332 mi)
Inclination 81.4 degrees
Period 92.6 minutes
The launch of Discoverer 18

Discoverer 18, also known as Corona 9013, was an American optical reconnaissance satellite which was launched in 1960. It was a KH-2 Corona satellite, based on an Agena-B.[1]

The launch of Discoverer 18 occurred at 20:20:58 UTC on 7 December 1960. A Thor DM-21 Agena-B rocket was used, flying from Launch Complex 75-3-4 at the Vandenberg Air Force Base.[2] Upon successfully reaching orbit, it was assigned the Harvard designation 1960 Sigma 1.

Discoverer 18 was operated in a low Earth orbit, with a perigee of 272 kilometres (169 mi), an apogee of 535 kilometres (332 mi), 81.4 degrees of inclination, and a period of 92.6 minutes.[3] The satellite had a mass of 1,240 kilograms (2,730 lb),[4] and was equipped with a panoramic camera with a focal length of 61 centimetres (24 in), which had a maximum resolution of 7.6 metres (25 ft).[5] Images were recorded onto 70-millimeter (2.8 in) film, and returned in a Satellite Recovery Vehicle, which was recovered three days after the launch. The Satellite Recovery Vehicle used by Discoverer 18 was SRV-508. Following the return of its images, Discoverer 18 remained in orbit until it decayed on 2 April 1961.[3] It was the first KH-2 satellite to complete its mission successfully.[6]


  1. ^ Krebs, Gunter. "KH-2 Corona". Gunter's Space Page. Retrieved 26 June 2010. 
  2. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 26 June 2010. 
  3. ^ a b McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 26 June 2010. 
  4. ^ Wade, Mark. "KH-2". Encyclopedia Astronautica. Retrieved 26 June 2010. 
  5. ^ "Corona". Mission and Spacecraft Library. NASA. Retrieved 26 June 2010. 
  6. ^ Pike, John (9 September 2000). "KH-2 Corona". Federation of American Scientists. Retrieved 26 June 2010.