Discoverer 3 [USAF]
These Discoverer satellites were development models of the KH-1 Corona reconnaissance satellite without camera to test the return vehicle for the film.
Discoverer 2 was launched into a 239 km × 346 km polar orbit by a Thor-DM18 Agena-A booster. The spacecraft was three-axis stabilized and was commanded from Earth. After 17 orbits, on 14 April 1959, a reentry vehicle was ejected. The reentry vehicle separated into two sections, one consisting of the protection equipment, retrorocket and main structure and the other the reentry capsule. It was planned that the capsule would reenter over the vicinity of Hawaii for recovery, but a timer malfunction caused premature capsule ejection and reentry over the north polar region. The capsule was never recovered. The main instrumentation payload remained in orbit and carried out vehicular performance and communications tests.
Discoverer 3 failed to reach orbit due to a failure of the Agena-A upper stage.
When the first eight missions failed to return the capsule successfully, two more Discoverers with the imaging system replaced by a diagnostics payload were launched:
Discoverer 12 again failed to reach orbit, when the Agena-A attitude control failed.
Discoverer 13 was launched on a Thor-DM18 Agena-A from Vandenberg on 10 August 1960. At 130 km altitude the first stage separated and the Agena placed the satellite into a 250 &tinmes; 705 km, 82.9° inclination near-polar orbit On 11 August, after 17 orbits, a command was sent from a ground station on Kodiak Island to the spacecraft to start the recovery sequence. The Agena pitched down 60° and the recovery vehicle was ejected by small springs. A cold gas system spun the vehicle up for stability, a retrorocket fired, reducing the velocity by about 400 m/s, and then the spin system despun the spacecraft. The orbit ejection subsystem dropped off just before it started to heat up on reentry, leaving the capsule and heat shield. At 15,000 meters a small parachute was deployed, a radio beacon and strobe lights were activated, and the heat shield was released. After stabilization a larger parachute was deployed. The capsule splashed down in the Pacific Ocean 610 km NNW of Honolulu. The Haiti Victory, a Navy ship, sent out a helicopter which dropped frogmen into the water to attach a collar to the capsule for helicopter retrieval. It was brought back to the ship and taken to Pearl harbor. The flag was presented to President Eisenhower on 15 August 1960. The Agena stage reentered the atmosphere and burned up on November 14, 1960.
Some satellites carried secondary payloads mounted on the satellite:
|Type / Application:||Technology|
|Configuration:||Agena-A, 1 SRVs|
|Propulsion:||Bell 8048, Star 12 retro motor|
|Orbit:||239 km × 346 km, 89.90° (#2); 245 km × 614 km, 82.85° (#13)|
|Discoverer 2 (Corona 2)||1959 γ||13.04.1959||Va 75-3-4||Thor-DM18 Agena-A|
|Discoverer 3 (Corona 3)||1959-F02||03.06.1959||Va 75-3-4||F||Thor-DM18 Agena-A|
|Discoverer 12 (Corona 12)||1960-F08||29.06.1960||Va 75-3-4||F||Thor-DM18 Agena-A|
|Discoverer 13 (Corona 13, Soctop 1)||1960 θ||10.08.1960||Va 75-3-5||Thor-DM18 Agena-A|
Further Discoverer missions:
Further Corona missions:
Further Aftrack SIGINT missions: