Discoverer 23


Discoverer 23
Mission typePhotographic reconnaissance
OperatorUS Air Force / NRO
Harvard designation1961 Lambda 1
COSPAR ID1961-011A
SATCAT no.00100Edit this on Wikidata
Spacecraft properties
Spacecraft typeKH-5 ARGON
ManufacturerLockheed Corporation
Launch mass1150 kg
Start of mission
Launch date8 April 1961, 19:21:08 (1961-04-08UTC19:21:08Z) GMT
RocketThor DM-21 Agena-B
(Thor 307)
Launch siteVandenberg, SLC-1E
Launch pad 75-3-5
End of mission
Decay date16 April 1962 (1962-04-17)
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Perigee altitude294 km
Apogee altitude624 km
Period93.77 minutes
The launch of Discoverer 23.

Discoverer 23, also known as KH-5 9016A, was a USAF photographic reconnaissance satellite under the supervision of the National Reconnaissance Office (NRO) 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.[2]


The launch of Discoverer 23 occurred at 19:21:08 GMT 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.[3] Upon successfully reaching orbit, it was assigned the Harvard designation 1961 Lambda 1.


Discoverer 23 was operated in an Earth orbit, with a perigee of 294 kilometres (183 mi), an apogee of 624 kilometres (388 mi), 82.3° of inclination, and a period of 93.77 minutes.[4] The satellite had a mass of 1,150 kilograms (2,540 lb),[5] 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).[6] Images were recorded onto 127 millimetres (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.[5] Discoverer 23 decayed from orbit on 16 April 1962, followed by the SRV on 23 May 1962.[4]·[5]


  1. ^ - 24 January 2020
  2. ^ - 24 January 2020
  3. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 22 June 2010.
  4. ^ a b McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 22 June 2010.
  5. ^ a b c Wade, Mark. "KH-5". Encyclopedia Astronautica. Archived from the original on 13 January 2010. Retrieved 22 June 2010.
  6. ^ "Corona". Mission and Spacecraft Library. NASA. Archived from the original on 3 October 2007. Retrieved 22 June 2010.