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]

Discoverer 23

Mission type	Photographic reconnaissance
Operator	US Air Force / NRO
Harvard designation	1961 Lambda 1
COSPAR ID	1961-011A
SATCAT no.	00100
Spacecraft properties
Spacecraft type	KH-5 ARGON
Bus	Agena-B
Manufacturer	Lockheed Corporation
Launch mass	1150 kg
Start of mission
Launch date	8 April 1961, 19:21:08 (1961-04-08UTC19:21:08Z) GMT
Rocket	Thor DM-21 Agena-B (Thor 307)
Launch site	Vandenberg, SLC-1E 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 altitude	294 km
Apogee altitude	624 km
Inclination	82.3°
Period	93.77 minutes
Discoverer ← Discoverer 22 Discoverer 24 → KH-5 Series ← Discoverer 20 (KH-5 1) Discoverer 24 (KH-5 3) →

The launch of Discoverer 23.

Launch

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.

Mission

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]