Fifty-one years ago this month, an United States Air Force C-119 Flying Boxcar aircraft successfully performed the first mid-air retrieval of a reentry body as it was returning from space. The recovered vehicle was named Discoverer XIV.
Corona was a covert reconnaissance program operated by the United States government from June of 1959 to May of 1972. The national security mission was to photographically surveil denied territory from orbit. The exposed film was then returned to Earth via a reentry capsule and recovered for subsequent development and photogrammetric analysis.
An evolutionary series of satellites, code named Key Hole (KH), were flown during the Corona Program. A total of 144 satellites were flown over the course of the surveillance effort; 71% of which provided useful results. Although not addressed here, the history of the development of the Key Hole camera system is a fascinating story in its own right.
A Corona satellite orbited the Earth at altitudes between 89 and 250 nautical miles. From its perch high in the heavens, the orbiting eye-in-the-sky exposed almost 6 statute miles of film during a typical mission. The camera systems used early in the Corona Program provided a target resolution of 25 feet. Later systems delivered a resolution of 6 feet.
The Discoverer Program served as a public front for Corona. Labled as a space technology development program, Discoverer was in fact used to fly the early Key Hole camera systems. The satellite also served as the means to develop and refine mid-air retrieval techniques for recovery of the Corona film canister. The last Discoverer mission (Discoverer XXXIX) was flown in April of 1962.
Successful recovery of the Corona film canister from orbit required precise targeting of the reentry vehicle. This would put the recovery aircraft in a position to make a mid-air retrieval. A special line suspension system deployed under the aircraft was used to snag the reentry vehicle as it slowly decended on its parachute. Once retrieved in this manner, the entire assemblage was reeled into the back of the recovery aircraft.
Success did not come easy for the Discoverer Program. The first dozen missions were failures for one reason or another. Either the satellite failed to achieve orbit or the recovery operation was unsuccessful. However, the importance of the mission was such that development flights continued.
Successful recovery of a Discoverer reentry capsule finally came on Thursday, 11 August 1960. Discoverer XIII had been boosted into a polar orbit by a Thor-Agena launch vehicle the previous day and had orbited the Earth 17 times before its return from space. Despite excellent placement into the target area, successful mid-air retrieval of the reentry vehicle did not occur. Navy frogmen had to fish Discoverer XIII out of the water.
Discoverer XIV was launched into space by a Thor-Agena launch vehicle on Thursday, 18 August 1960. After 17 polar orbits, the reentry vehicle returned to Earth on Friday, 19 August 1960. The mission was very successful including the mid-air retrieval operation. Interestingly, it wasn’t until the 3rd pass that the C-119 Flying Box Car from the 6593rd Test Squadron at Hickam AFB, Hawaii successfully made the grab. Nevertheless, Discoverer XIV became the first reentry vehicle in history to be recovered via mid-air retrieval.
The Corona Program went on to a highly successful operational life. The information gathered therein provided a tangible check on communist military activity and measurably improved the security of not only the United States, but that of the entire free world. Indeed, Corona was a key part of the national security apparatus at a time when the nuclear damocles hung in a particularly menacing manner over the heads of all those who hallow freedom.