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Program 437 was the second anti-satellite weapons program of the U.S. military.〔Peebles, Curtis. "High Frontier: The United States Air Force and the Military Space Program", 1997〕 The US anti-satellite weapons program began development in the early 1960s and was officially discontinued on 1 April 1975. Program 437 was approved for development by U.S. Secretary of Defense Robert McNamara on November 20, 1962, after a series of tests involving high altitude nuclear explosions. The program's facilities were located on Johnston Island, an isolated island in the north central Pacific Ocean. ==History== Program 505, a similar program based out of the Kwajalein Missile Range in the North Pacific, was already up and running by 1962 and was the world's first operational anti-satellite program. The project did complete successful tests, but because it used a slightly shorter ranged (modified) Nike Zeus anti-ballistic missile it was discontinued in 1966 in favor of Program 437's PGM-17 Thor ballistic missile. Program 437's used Thor DSV-2E missiles armed with a W49 or W50 nuclear weapon, which would destroy or disable targets through nuclear explosion or the resulting electromagnetic pulse. Eight Thor DSV-2E missiles were launched between May 2, 1962 and November 1, 1962. Though the program would routinely run successful tests with unarmed Thor missiles, the only high altitude nuclear explosions were conducted through Operations Argus, Hardtack I, and Dominic/Fishbowl between 1958-1962. Operation Argus operated out of the South Atlantic, while Hardtack and Dominic conducted their high altitude tests from the Johnston Island facilities. "Tightrope" was part of "Fishbowl" but was a lower altitude detonation.〔http://afspacemuseum.org/johnston/〕 Some results of these tests, Dominic's 1962 Starfish Prime test in particular, presented concerns throughout the program's existence. In addition to the widespread effects of the nuclear explosion's electromagnetic pulse, which inadvertently damaged many satellites as well as land based electronics as far as 1500 km away, a large amount of charged particle radiation was released by the nuclear explosion. This radiation became trapped by the Earth's magnetic field, creating artificial belts of radiation 100 to 1,000 times stronger than background levels. The heightened levels of radiation eventually crippled one-third of all satellites in low orbit, while rendering seven others completely useless, including the first commercial communication satellite ever, Telstar. It was eventually concluded that the due to the wide radius of damage, wartime deployment of Program 437 would result in indiscriminate destruction of friendly and enemy satellites, potentially destabilizing or escalating otherwise non-nuclear conflicts. In addition to these problems, the Soviets deployed numerous military satellites, making specific targeting impractical or ineffective. Furthermore, the United States Air Force had a limited supply of Thor missiles, and all military resources (especially financial) had become increasingly strained with the US involvement in the Vietnam War. In October 1970, the Department of Defense transferred Program 437 to standby status as an economic measure. Test launches were no longer run, and the weapons system would take fourteen to thirty days to intercept targets, requiring components stored at Vandenberg Air Force Base to be airlifted by a C-124 Globemaster II to Johnston Island for deployment. These obstacles further degraded the weapon's suitability and effectiveness for war. Part of Program 437 was 437 Alternate Payload (AP) which was used for satellite inspection. Thor DSV-2J missiles were used for the 437 Alternate Payload program. Eighteen DSV-2J Thors were launched from the Atoll between February 14, 1964 and November 6, 1975.〔http://afspacemuseum.org/johnston/〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Program 437」の詳細全文を読む スポンサード リンク
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