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Project West Ford (also known as Westford Needles and Project Needles) was a test carried out by Massachusetts Institute of Technology's Lincoln Laboratory on behalf of the United States Military in 1961 and 1963 to create an artificial ionosphere above the Earth. This was done to solve a major weakness that had been identified in US military communications.〔 ==History== At the height of the Cold War, all international communications were either sent through undersea cables or bounced off the natural ionosphere. The United States Military was concerned that the Soviets might cut those cables, forcing the unpredictable ionosphere to be the only means of communication with overseas forces.〔 So, a ring of 480,000,000〔 (Abstract)〕 copper dipole antennas (1.78 cm long needles, 25.4μm () / 17.8μm () in diameter)〔 〕 was placed in orbit to facilitate global radio communication. The length was chosen because it was half the wavelength of the 8 GHz signal used in the study.〔 The dipoles collectively provided passive support to Project Westford's parabolic dish (located in the town of Westford) to communicate with distant sites. In 1958, at MIT’s Lincoln Labs, Walter E. Morrow started Project Needles.〔 A failed first attempt launched on October 21, 1961;〔 the needles failed to disperse. The project was eventually successful with the May 9, 1963〔 launch, with radio transmissions carried by the man-made ring. However, the technology was ultimately shelved, partially due to the development of the modern communications satellite and partially due to protests from other scientists.〔 The needles were placed in medium Earth orbit between high at 96 and 87 degree inclinations and contributed to Earth's orbital debris. British radio astronomers, together with optical astronomers and the Royal Astronomical Society, protested this action. The Soviet newspaper ''Pravda'' also joined the protests under the headline "U.S.A. Dirties Space". The issue was raised in the United Nations where then US Ambassador to the UN Adlai Stevenson defended the project. Stevenson studied the published journal articles on Project West Ford. Using what he learned on the subject and citing the articles he had read, he successfully allayed the fears exhibited by the vast majority of UN ambassadors from other countries. He and the articles explained that sunlight pressure would cause the dipoles to only remain in orbit for a short period of approximately three years. The international protest ultimately resulted in a consultation provision included in the 1967 Outer Space Treaty.〔〔 Fifty years later in 2013, some of the dipoles that did not deploy correctly still remain in clumps which make up a small amount of the orbital debris tracked by NASA’s Orbital Debris Program Office. 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「Project West Ford」の詳細全文を読む スポンサード リンク
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