 | |
| Mission type | Optical reconnaissance |
|---|---|
| Operator | US Air Force/NRO |
| Harvard designation | 1961 Xi 1 |
| COSPAR ID | 1961-014A |
| SATCAT no. | 00108 |
| Mission duration | 2 days |
| Spacecraft properties | |
| Spacecraft type | Corona KH-2 |
| Bus | Agena-B |
| Manufacturer | Lockheed |
| Launch mass | 1,150 kilograms (2,540 lb) |
| Start of mission | |
| Launch date | 16 June 1961, 23:02:52 UTC |
| Rocket | Thor DM-21 Agena-B 303 |
| Launch site | Vandenberg LC-75-1-1 |
| End of mission | |
| Decay date | 12 July 1961 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Perigee altitude | 223 kilometers (139 mi) |
| Apogee altitude | 361 kilometers (224 mi) |
| Inclination | 82.1 degrees |
| Period | 90.4 minutes |
Discoverer 25, also known as Corona 9017, was an American optical reconnaissance satellite which was launched in 1961. It was the fifth of ten Corona KH-2 satellites, based on the Agena-B.[1]
The launch of Discoverer 25 occurred at 23:02 UTC on 16 June 1961. A Thor DM-21 Agena-B rocket was used, flying from Launch Complex 75-1-1 at the Vandenberg Air Force Base.[2] Upon successfully reaching orbit, it was assigned the Harvard designation 1961 Xi 1.
Discoverer 25 was operated in a low Earth orbit, with a perigee of 223 kilometres (139 mi), an apogee of 361 kilometres (224 mi), 82.1 degrees of inclination, and a period of 90.4 minutes.[3] The satellite had a mass of 1,150 kilograms (2,540 lb),[4] and was equipped with a panoramic camera with a focal length of 61 centimetres (24 in), which had a maximum resolution of 7.6 metres (25 ft).[5] Images were recorded onto 70-millimeter (2.8 in) film, and returned in a Satellite Recovery Vehicle two days after launch. The Satellite Recovery Vehicle used by Discoverer 25 was SRV-510. Once its images had been returned, Discoverer 25's mission was complete, and it remained in orbit until it decayed on 12 July 1961.[3]
The Satellite Recovery Vehicle was designed to be recovered in mid-air by a Fairchild C-119J Flying Boxcar aircraft. As SRV-510 descended, the C-119J was unable to capture it, and the capsule had to be recovered at sea after it landed. The film it returned was affected by streaks across images.[4]
