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. It was the second KH-5 mission to be launched, and the second to end in failure.

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. 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 km, an apogee of 624 km, 82.3° of inclination, and a period of 93.77 minutes. The satellite had a mass of 1150 kg, and was equipped with a frame camera with a focal length of 76 mm, which had a maximum resolution of 140 m. Images were recorded onto 127 mm 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. Discoverer 23 decayed from orbit on 16 April 1962, followed by the SRV on 23 May 1962. ·