| Discoverer 23 | |
| Mission Type: | Photographic reconnaissance |
| Operator: | US Air Force / NRO |
| Harvard Designation: | 1961 Lambda 1 |
| Spacecraft Type: | KH-5 ARGON |
| Spacecraft Bus: | Agena-B |
| Manufacturer: | Lockheed Corporation |
| Launch Mass: | 1150 kg |
| Launch Date: | GMT |
| Launch Rocket: | Thor DM-21 Agena-B (Thor 307) |
| Launch Site: | Vandenberg, SLC-1E Launch pad 75-3-5 |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Low Earth |
| Orbit Periapsis: | 294 km |
| Orbit Apoapsis: | 624 km |
| Orbit Inclination: | 82.3° |
| Orbit Period: | 93.77 minutes |
| Apsis: | gee |
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, an apogee of, 82.3° of inclination, and a period of 93.77 minutes.[4] The satellite had a mass of,[5] and was equipped with a frame camera with a focal length of, which had a maximum resolution of .[6] Images were recorded onto 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]