Discoverer 23

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Discoverer 23
Mission type Optical reconnaissance
Operator US Air Force/NRO
Harvard designation 1961 Lambda 1
Spacecraft properties
Spacecraft type KH-5 Argon
Bus Agena-B
Manufacturer Lockheed
Launch mass 1,150 kilograms (2,540 lb)
Start of mission
Launch date 8 April 1961, 19:21 (1961-04-08UTC19:21Z) UTC
Rocket Thor DM-21 Agena-B 307
Launch site Vandenberg LC-1 launch pad 75-3-5
End of mission
Decay date 16 April 1962 (1962-04-17)
Orbital parameters
Reference system Geocentric
Regime Low Earth
Perigee 294 kilometers (183 mi)
Apogee 624 kilometers (388 mi)
Inclination 82.3 degrees
Period 93.8 minutes
The launch of Discoverer 23

Discoverer 23, also known as Corona 9016A, was an American area survey optical reconnaissance satellite which was launched in 1961. It was a KH-5 Argon satellite, based on an Agena-B.[1] It was the second KH-5 mission to be launched, and the second to end in failure.


The launch of Discoverer 23 occurred at 19:21 UTC on 8 April 1961. A Thor DM-21 Agena-B rocket was used, flying from launch pad 75-3-5 at the Vandenberg Air Force Base.[2] Upon successfully reaching orbit, it was assigned the Harvard designation 1961 Lambda 1.


Discoverer 23 was operated in a low Earth orbit, with a perigee of 294 kilometres (183 mi), an apogee of 624 kilometres (388 mi), 82.3 degrees of inclination, and a period of 93.77 minutes.[3] The satellite had a mass of 1,150 kilograms (2,540 lb),[4] and was equipped with a frame camera with a focal length of 76 millimetres (3.0 in), which had a maximum resolution of 140 metres (460 ft).[5] Images were recorded onto 127-millimeter (5.0 in) film, and ejected aboard a Satellite Return Vehicle, SRV-521. Due to a problem with Discoverer 23's attitude control system, the SRV ended up boosting itself into a higher orbit rather than deorbiting.[4] Discoverer 23 decayed from orbit on 16 April 1962, followed by the SRV on 23 May 1962.[3][4]


  1. ^ Krebs, Gunter. "KH-5 Argon (Agena-B based)". Gunter's Space Page. Retrieved 22 June 2010. 
  2. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 22 June 2010. 
  3. ^ a b McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 22 June 2010. 
  4. ^ a b c Wade, Mark. "KH-5". Encyclopedia Astronautica. Retrieved 22 June 2010. 
  5. ^ "Corona". Mission and Spacecraft Library. NASA. Retrieved 22 June 2010.