Discoverer 4
Mission type | Optical reconnaissance |
---|---|
Operator | US Air Force / NRO |
Harvard designation | 1959-U01 |
SATCAT no. | F00068 |
Spacecraft properties | |
Spacecraft type | CORONA KH-1 |
Bus | Agena-A |
Manufacturer | Lockheed |
Launch mass | 870 kilograms (1,920 lb) after orbit insertion |
Start of mission | |
Launch date | 25 Jun 1959 22:47:45 | GMT
Rocket | Thor DM-21 Agena-A (Thor 179) |
Launch site | Vandenberg LC 75-3-5 |
Corona KH-1 → |
Discoverer 4, also known as Corona 9001,
Background
"Discoverer" was the civilian designation and cover for the
The first series of Corona satellites were the Keyhole 1 (KH-1) satellites based on the Agena-A upper stage, which not only offered housing but whose engine provided attitude control in orbit. The KH-1 payload included the C (for Corona) single, vertical-looking, panoramic camera that scanned back and forth, exposing its film at a right angle to the line of flight.[3]: 26 The camera, built by Fairchild Camera and Instrument with a f/5.0 aperture and 61 centimetres (24 in) focal length, had a ground resolution of 12.9 metres (42 ft). Film was returned from orbit by a single General Electric Satellite Return Vehicle (SRV) constructed by General Electric. The SRV was equipped with an onboard small solid-fuel retro motor to deorbit at the end of the mission. Recovery of the capsule was done in mid-air by a specially equipped aircraft.[4]
Discoverer 4 was preceded by three Discoverer test flights whose satellites carried no cameras.[1]: 51–54
Spacecraft
The battery-powered[4] Discoverer 4 was composed of two sections: the satellite proper and the SRV. Together, they massed (870 kilograms (1,920 lb)) after orbit insertion.[1]: 236 It was the first Discoverer equipped with the C camera and the first satellite built for photo surveillance.[1]: 54
Mission
Launched 25 Jun 1959 22:47:45 GMT from Vandenberg LC 75-3-5 by a Thor-Agena rocket, the satellite was lost when its carrying Agena failed to reach orbit.[1]: 54
Legacy
As a result of the loss of Discoverers 3 and 4 during launch, the Air Force Ballistic Missile Division (BMD) halted flights until the Agena failures could be evaluated. In consultation with
CORONA achieved its first fully successful operational flight with the mission of Discoverer 14, launched on August 18, 1960.[1]: 59 The program ultimately comprised 145 flights in eight satellite series, the last mission launching on 25 May 1972.[1]: 245 CORONA was declassified in 1995,[1]: 14 and a formal acknowledgement of the existence of US reconnaissance programs, past and present, was issued in September 1996.[1]: 4
References
- ^ OCLC 36783934.
- ^ "Discoverer 1". NASA Space Science Data Coordinated Archive. Retrieved 24 October 2020.
- ^ "Corona: America's First Satellite Program" (PDF). Central Intelligence Agency. 1995. Archived from the original (PDF) on June 12, 2007. Retrieved 25 January 2020.
- ^ a b Krebs, Gunter. "KH-1 Corona". Gunter's Space Page. Retrieved 7 November 2020.
- OCLC 794229594.