| Mission type | Optical reconnaissance |
|---|---|
| Operator | US Air Force/NRO |
| Mission duration | Failed to orbit |
| Spacecraft properties | |
| Spacecraft type | KH-5 Argon |
| Bus | Agena-B |
| Manufacturer | Lockheed |
| Launch mass | 1,150 kilograms (2,540 lb) |
| Start of mission | |
| Launch date | 8 June 1961, 21:16 UTC |
| Rocket | Thor DM-21 Agena-B 302 |
| Launch site | Vandenberg LC-1 launch pad 75-3-4 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Epoch | Planned |
Discoverer 24, also known as Corona 9018A, was an American area survey optical reconnaissance satellite which was launched in 1961 but failed to achieve orbit. It was a KH-5 Argon satellite, based on an Agena-B. [1] It was the third KH-5 to be launched.
The United States of America (USA), commonly known as the United States or America, is a country comprising 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the most populous city is New York City. Most of the country is located contiguously in North America between Canada and Mexico.
A reconnaissance satellite or intelligence satellite is an Earth observation satellite or communications satellite deployed for military or intelligence applications.
KH-5 ARGON was a series of reconnaissance satellites produced by the United States from February 1961 to August 1964. The KH-5 operated similarly to the Corona series of satellites, as it ejected a canister of photographic film. At least 12 missions were attempted, but at least 7 resulted in failure. The satellite was manufactured by Lockheed. Launches used Thor-Agena rockets flying from Vandenberg Air Force Base, with the payload being integrated into the Agena.
The launch of Discoverer 24 occurred at 21:16 UTC on 8 June 1961. A Thor DM-21 Agena-B rocket was used, flying from launch pad 75-3-4 at the Vandenberg Air Force Base. [2] Thor performance was normal and cutoff and staging occurred on time, but the Agena suffered a massive power supply failure during ascent. Since the power failure had caused loss of Agena telemetry data, it was unclear exactly what happened following staging or if engine start ever occurred. Radar tracking indicated that the stage was on a ballistic trajectory and tumbling. It impacted the Pacific Ocean some 400 miles downrange. [3]
Thor-Agena was a series of orbital launch vehicles. The rockets used Thor first stages and Agena second stages. They are thus cousins of the more-famous Thor-Deltas, which founded the Delta rocket family. The first attempted launch of a Thor-Agena was in January 1959. The first successful launch was on February 28, 1959, launching Discoverer 1.
Space Launch Complex 1 (SLC-1) was a launch pad at Vandenberg Air Force Base in California, United States. SLC-1 consisted of two pads, SLC-1E and SLC-1W. Both sites were built in 1958 for the never activated 75th Strategic Missile Squadron for Thor Agena A launches. SLC-1E launch pad 75-3-5, SLC-1W launch pad 75-3-4. Both were upgraded to a Space Launch Complex (SLC) in 1966. Deactivated with phaseout of Thor-Agena. SLC-1E deactivated 1968, 45 Launches; SLC-1W deactivated in 1971, 56 launches.
Vandenberg Air Force Base is a United States Air Force Base 9.2 miles (14.8 km) northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command (AFSPC).
Discoverer 24 was to have operated in a low Earth orbit. It had a mass of 1,150 kilograms (2,540 lb), [4] and was equipped with a frame camera with a focal length of 76 millimetres (3.0 in), which had a maximum resolution of 140 metres (460 ft). [5] Images would have been recorded onto 127-millimeter (5.0 in) film, and returned in a Satellite Recovery Vehicle, before the satellite ceased operations. The Satellite Recovery Vehicle carried aboard Discoverer 24 was SRV-541. [4]
A low Earth orbit (LEO) is an Earth-centered orbit with an altitude of 2,000 km (1,200 mi) or less, or with at least 11.25 periods per day and an eccentricity less than 0.25. Most of the manmade objects in outer space are in LEO.
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 focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power.
