Discoverer 8
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Discoverer 8, also known as Corona 9005, was an American optical
reconnaissance satellite A reconnaissance satellite or intelligence satellite (commonly, although unofficially, referred to as a spy satellite) is an Earth observation satellite or communications satellite deployed for military or intelligence applications. The ...
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.


Background

"Discoverer" was the civilian designation and cover for the
Corona Corona (from the Latin for 'crown') most commonly refers to: * Stellar corona, the outer atmosphere of the Sun or another star * Corona (beer), a Mexican beer * Corona, informal term for the coronavirus SARS-CoV-2, which causes the COVID-19 di ...
satellite photo-reconnaissance series of satellites managed by the
Advanced Research Projects Agency The Defense Advanced Research Projects Agency (DARPA) is a research and development agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. Originally known as the Adv ...
of the
Department of Defense Department of Defence or Department of Defense may refer to: Current departments of defence * Department of Defence (Australia) * Department of National Defence (Canada) * Department of Defence (Ireland) * Department of National Defense (Philipp ...
and the
U.S. Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Sign ...
. 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. 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. The camera, built by Fairchild Camera and Instrument with a f/5.0 aperture and focal length, had a ground resolution of . Film was returned from orbit by a single General Electric Satellite Return Vehicle (SRV) constructed by
General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...
. 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. Discoverer 8 was preceded by four operational missions, as well as three test flights whose satellites carried no cameras, all launched in 1959.


Spacecraft

The battery-powered Discoverer 8 was a cylindrical satellite in diameter, long and had a mass after second stage separation, including propellants, of roughly . After orbital insertion, the satellite and SRV together massed . The capsule section of the reentry vehicle was in diameter and long. 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.


Mission

Discoverer 8 was launched on 20 November 1959 at 19:25:24 GMT from Vandenberg LC 75-3-5 into a x
polar orbit A polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited (usually a planet such as the Earth, but possibly another body such as the Moon or Sun) on each revolution. It has an inclination of about ...
by a Thor-Agena A booster. 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. Due to Discoverer 8's eccentric orbit, the onboard ejection timer was unable to properly determine time of SRV separation, and after 15 orbits, a manual command was given from the ground to separate the SRV from the
satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus-d ...
for deorbit and recovery, which occurred on 21 November at 21:20 GMT. Telemetry from the capsule was received by the telemetry ship, ''USNS PVT. Joe E. Mann'' (positioned between the tracking stations at Kaena Point, Hawaii and Kodiak, Alaska) until ionization blackout. This data suggested the capsule was off course, and the recovery fleet was diverted southward to the expected landing place. The ships arrived in time to see Discoverer 8's capsule hit the water, its parachute undeployed. Later analysis determined that the ceramic reentry heat shield had failed to detach from the SRV, causing a faster than normal descent, in turn preventing the parachute from deploying. The satellite bus reentered on 8 March 1960.


Legacy

CORONA achieved its first fully successful flight with the mission of
Discoverer 14 Discoverer 14, also known as Corona 9009, was a spy satellite used in the Corona program managed by Advanced Research Projects Agency (ARPA) of the Department of Defense and the United States Air Force. On 19 August 1960, usable photographic film ...
, launched on August 18, 1960. The program ultimately comprised 145 flights in eight satellite series, the last mission launching on 25 May 1972. CORONA was declassified in 1995, and a formal acknowledgement of the existence of US reconnaissance programs, past and present, was issued in September 1996.


References

{{Orbital launches in 1959 Spacecraft launched in 1959 Spacecraft which reentered in 1960