Discoverer 17, also known as Corona 9012, 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 12 November 1960 at 20:38:00 GMT. It was the second of ten Corona KH-2 satellites, based on the Agena-B.

Background

Discoverer 17 was the second of the KH-2 Corona spy satellites, which was distinguished from the predecessor KH-1 series in its incorporation of the improved C' camera, which replaced the C model carried on KH-1 missions. The improved camera had variable image motion compensation so that its carrying satellites could be flown in differing orbits. Like the C camera, the C' was manufactured by

Fairchild Camera and Instrument Fairchild Camera and Instrument Corporation was a company founded by Sherman Fairchild. It was based on the East Coast of the United States, and provided research and development for flash photography equipment. The technology was primarily use ...

under the supervision of Itek, a defense contractor that specialized in making cameras for spy satellites. The satellite also carried a Transit on Discoverer (TOD) payload Discoverer 16, the first of the KH-2 series, had failed to reach orbit after its launch on 26 October 1960.

Mission

The launch of Discoverer 17 occurred at 20:38:00 GMT on 12 November 1960. A Thor DM-21 Agena-B rocket was used, flying from LC 75-3-5 at the Vandenberg Air Force Base. Upon successfully reaching orbit, it was assigned the Harvard designation 1960 Omicron 1. It was the first KH-2 satellite to successfully reach orbit. Discoverer 17 was operated in a

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

, with a

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

of , an

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

of , 81.8° of

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

, and a period of 96.45 minutes. The satellite had a mass of , and was equipped with a panoramic camera with a

focal length The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative foca ...

of , which had a maximum resolution of . Images were recorded onto film, and returned in a Satellite Recovery Vehicle (SRV). The Satellite Recovery Vehicle used by Discoverer 17 was SRV-507. Shortly after Discoverer 17 began operations, its SRV separated prematurely. Two days after launch it was deorbited and recovered, however only of film was found to be aboard, and no images were taken. Following the separation of the SRV, Discoverer 17 remained in orbit until it decayed on 29 December 1960.

Science Results

In addition to its reconnaissance payload, Discoverer 17 carried a biological research payload, intended to investigate human tissues in space. Since at the time the United States did not publicly acknowledge its reconnaissance satellite programs, this was officially the satellite's primary mission. Unexpectedly high radiation levels during the flight led to the data from this experiment being considered particularly valuable by US Air Force scientists. Nevertheless, "samples of human gamma globulin and rabbit antiserum specific for human gamma globulin showed an increase in reactivity, and samples of synovial and conjunctival cells showed no changes in their cytological characteristics."

References

{{Orbital launches in 1960 Spacecraft launched in 1960 Satellites formerly orbiting Earth