Discoverer 8

Discoverer 8, also known as Corona 9005,[1]^:236 was an American optical reconnaissance satellite launched on 20 November 1959 at 19:25:24 GMT, the fifth of ten operational flights of the Corona KH-1 spy satellite series. Overburn by the carrier rocket placed the satellite in a higher apogee, more eccentric orbit than planned, the camera failed to operate, and the film return capsule was lost on reentry after separation from the main satellite on 21 November.

Discoverer 8

Mission type	Optical reconnaissance
Operator	US Air Force / NRO
Harvard designation	1959 LAM
SATCAT no.	S00025
Mission duration	1 day
Spacecraft properties
Spacecraft type	CORONA KH-1
Bus	Agena-A
Manufacturer	Lockheed
Launch mass	835 kilograms (1,841 lb) after orbit insertion
Start of mission
Launch date	20 November 1959 19:25:24 GMT
Rocket	Thor DM-21 Agena-A (Thor 212)
Launch site	Vandenberg LC 75-3-5
End of mission
Decay date	8 March 1960
Landing date	21 November 1959 (SRV)
Landing site	Pacific Ocean (SRV)
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Eccentricity	0.10197
Perigee altitude	187 kilometers (116 mi)
Apogee altitude	1,679 kilometers (1,043 mi)
Inclination	80.650°
Period	103.70 minutes
Epoch	20 November 1959
Discoverer   Corona KH-1

Background

Thor Agena A with Discoverer 8, 20 November 1959

"Discoverer" was the civilian designation and cover for the Corona satellite photo-reconnaissance series of satellites managed by the Advanced Research Projects Agency of the Department of Defense and the U.S. Air Force. The primary goal of the satellites was to replace the U-2 spyplane in surveilling the Sino-Soviet Bloc, determining the disposition and speed of production of Soviet missiles and long-range bombers assess. The Corona program was also used to produce maps and charts for the Department of Defense and other US government mapping programs.[2]

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 panoramic 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.[3]

Discoverer 8 was preceded by four operational missions, as well as three test flights whose satellites carried no cameras, all launched in 1959.[1]^:51–56

Spacecraft

The battery-powered[3] Discoverer 8 was a cylindrical satellite 1.5 metres (4 ft 11 in) in diameter, 5.85 metres (19.2 ft) long and had a mass after second stage separation, including propellants, of roughly 3,850 kilograms (8,490 lb).[4] After orbital insertion, the satellite and SRV together massed 835 kilograms (1,841 lb).[1]^:236 The capsule section of the reentry vehicle was 84 centimetres (33 in) in diameter and 69 centimetres (27 in) long.[5] Like its operational predecessors, Discoverers 4-7, Discoverer 8 carried the C camera for its photosurveillance mission.

The capsule was designed to be recovered by a specially equipped aircraft during parachute descent, but was also designed to float to permit recovery from the ocean. The main spacecraft contained a telemetry transmitter and a tracking beacon.[4]

Mission

Discoverer 8 was launched on 20 November 1959 at 19:25:24 GMT GMT from Vandenberg LC 75-3-5[6] into a 187 kilometres (116 mi) x 1,679 kilometres (1,043 mi) polar orbit by a Thor-Agena A booster,[4] overburn of the Agena caused the satellite to end up in a much more eccentric, higher apogee orbit than its predecessors. As had happened with Discoverers 5 and 6, the camera film snapped on its way from its supply container.[1] After 15 orbits, on 21 November at 21:20 GMT, a command was given to separate the SRV from the satellite bus for deorbit and recovery.[4] However, telemetry from the capsule ceased upon separation,[1] and the capsule's descent parachute failed to deploy, the capsule impacting the Pacific Ocean outside the planned descent area. The capsule was not recovered.[4]

The satellite bus reentered on 8 March 1960.[7]

Legacy

CORONA achieved its first fully successful 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

1. Day, Dwayne A.; Logsdon, John M.; Latell, Brian (1998). Eye in the Sky: The Story of the Corona Spy Satellites. Washington and London: Smithsonian Institution Press. ISBN 1-56098-830-4. OCLC 36783934.
2. "Discoverer 1". NASA Space Science Data Coordinated Archive. Retrieved 24 October 2020.
3. Krebs, Gunter. "KH-1 Corona". Gunter's Space Page. Retrieved 24 October 2020.
4. "Discoverer 8". NASA Space Science Data Coordinated Archive. Retrieved 31 October 2020.
5. "Discoverer 7". NASA Space Science Data Coordinated Archive. Retrieved 31 October 2020.
6. McDowell, Jonathan. "Launch Log". Jonathon's Space Report. Retrieved 24 October 2020.
7. McDowell, Jonathan. "Satellite Catalog". Jonathon's Space Report. Retrieved 9 April 2020.