西福特计划

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西福特计划(Project West Ford),别名西福特针(Westford Needles)或针计划(Project Needles),是一个通过在以近地轨道上散布金属针形成云状环来反射无线电信号,从而解决当时美军通信方面存在的重大弱点的计划。

计划概况[编辑]

背景[编辑]

冷战时期,远距离的国际通信主要由海底电缆和自然存在的电离层反射无线电进行。美军对万一被当时的苏联切断其海底电缆后要依靠性质不稳定的电离层来联络其海外部队感到担忧,因而寻求能在全球范围内都可以稳定地进行无线电通讯的办法。

内容[编辑]

本计划打算将4亿3000万根[1] 偶极天线(全长1.78厘米,直径25.4微米(1961年)/17.8微米(1963年)的针状物)[2][3]散布在轨道上形成云状环,然后通过设置在西福特镇卫星天线来进行远程通信的辅助。

该计划由麻省理工学院受美国军方委托在其林肯实验室进行。

实施与结果[编辑]

第一次散布于1961年10月21日进行,但并没有成功。[3]第二次散布则于1963年5月9日成功进行,在轨道上形成人工的环状针云并利用其成功进行了通信。[3]然而由于现代通信卫星的发展和遭到各界的抗议,本技术最终未能获得广泛运用。[4]

太空垃圾[编辑]

本计划散布的针状物分布于高度在3500公里到3800公里之间,轨道倾角在96度到87度之间的轨道范围,最终成为了太空垃圾[5] 。根据当时美国联合国大使阿德莱·史蒂文森的说法,在太阳辐射压力的作用下,这些针将会在短短3年内离开轨道。但事实上直到现在仍有相当数目的针残留在轨道上,[6] 偶然才会返回大气层[7]

国际影响[编辑]

相关的国际条约[编辑]

外部链接[编辑]

参考资料[编辑]

  1. ^ I. I. Shapiro; H. M. Jones; Perkins, C.W.: Orbital properties of the West Ford dipole belt; Proceedings of the IEEE; Volume 52, Issue 5, May 1964 Page(s): 469 - 518 (Abstract, english)
  2. ^ Lovell, A. C. B.; Blackwell, M. Ryle; D. E.; Wilson, R., West Ford Project, Interference to Astronomy from Belts of Orbiting Dipoles (Needles), Quarterly Journal of the Royal Astronomical Society. June 1962, 3: 100 
  3. ^ 3.0 3.1 3.2 Wiedemann, C.; Bendisch, J.; Krag, H.; Wegener, P.; Rex, D., 寫於Darmstadt, GermanySawaya-Lacoste, Huguette, ., Modeling of copper needle clusters from the West Ford Dipole experiments, Proceedings of the Third European Conference on Space Debris. Noordwijk, Netherlands: ESA Publications Division. March 19-21, 2001, 1, October 2001: 315–320, ISBN 92-9092-733-X 
  4. ^ Kendall, Anthony. Earth's Artificial Ring: Project West Ford. DamnInteresting.com. May 2, 2006 [2006-10-16]. 
  5. ^ Position Paper on Space Debris Mitigation - Implementing Zero Debris Creation Zones (PDF), International Academy of Astronautics. Paris, France: International Academy of Astronautics. October 12, 2005, October 15, 2005 
  6. ^ Hall, Christopher D., West Ford dipoles, Blacksburg, Virginia: Virginia Tech Department of Aerospace and Ocean Engineering. September 18, 2003, "many clumps of the needles are indeed still in orbit" 
  7. ^ Barhorst, L.J.C.., 寫於Medemblik, The Netherlands, RAE Table of Earth Satellites, Farnborough, England: Royal Aerospace Establishment / Defence Research Agency. January 20, 2008:  34, "148 pieces, 94 have decayed" 
  8. ^ 8.0 8.1 Terrill Jr., Delbert R., Project West Ford, The Air Force Role in Developing International Outer Space Law (PDF), Air Force History and Museums Program. Maxwell Air Force Base, Alabama: Air University Press. May 1999: 63 
  9. ^ Butrica, Andrew J.., Introduction, Beyond the Ionosphere: The Development of Satellite Communications, history.nasa.gov, The NASA History Series. NASA 
  10. ^ Bondi, H., West Ford Project, Introductory Note by the Secretary, Quarterly Journal of the Royal Astronomical Society. June 1962, 3: 99 
  11. ^ Protests Continue Abroad, The New York Times. London: Reuters. October 22, 1961, October 23, 1961: 12 [2008-04-17], ISSN 1674510 
  12. ^ Teltsch, Kathleen, 6 Soviet Space Failures Believed To Have Been Probes of Planets, The New York Times. United Nations, NY. June 15, 1963, June 16, 1963: 2 [2008-04-17], ISSN 1521970