@ C Stuart Hardwick 的回答
For the same reason it created what would become the Internet.
In the 1960s, the Cold War was at its height, and while US paranoia played no small part in that reality, Soviet policy did too. As the 1960s began, the US scrambled to prepare for what many assumed was an inevitable nuclear attack, and to ensure that US military command and control could survive and counter any Soviet incursion, in Europe or at home.
Communications was a particular vulnerability. Short-wave radio had global reach due to its ability to bounce off Earth’s ionosphere, but it’s easy to jam and limited in data density.
Project West Ford was an experiment to see if an artificial orbiting antenna could be used to enable more reliable high-speed communication.
The idea was simple: place into a medium-altitude polar orbit, a few hundred million tiny dipole antennas tuned to the 8 GHz band. Then use giant parabolic-dish antennas to bounce high-capacity communications signals around the world.
这个想法很简单：将几亿个微小的偶极天线放置到中等高度的极地轨道中，将其调谐到8 GHz频段。 然后，使用巨大的抛物面天线，来反射世界各地的高容量通信信号。
If that seems absurd, remember that for military purposes, technology that would otherwise be completely impracticable can often carry the day. One need only consider that the SR-71 Blackbird was a highly successful aircraft even though by design, it leaked fuel all over the tarmac.
In 1962, the first West Ford launch failed to deploy its payload. The second, a few months later, worked, and confirmed that the communications scheme did work—at least at first. As the dipoles dispersed, performance rapidly plummeted.
1962年， West Ford 公司的首次发射未能部署其有效载荷。 第二个月（几个月后）成功了，并确认了该通信方案确实起了作用-至少在一开始就如此。 随着偶极子的分散，性能迅速下降。
The experiment was declared a success, though that’s debatable, and raised objections from civilians and governments around the globe. Planners insisted that due to the low mass of the dipoles, they would all de-orbit within a few years and instead of burning up, simply drift down to the ground.
That’s almost certainly what happened to the vast majority of them; however, the first spacecraft is still up there, and due to a design flaw in the second, it’s believed that many clumps of metal fibers likely still remain in orbit.
几乎可以肯定，这就是绝大多数 偶极子 所要经历的事情； 但是，第一架太空飞船仍然在轨，而且由于第二架太空飞船的设计缺陷，人们认为许多金属纤维碎片可能仍留在轨道上。
These clumps, if present, constitute an ongoing threat, as they might be near the lower size limit for trackable objects, but would be large enough to cause serious damage in a collision. Individual dipoles—which are nothing but tiny metal hairs—would cause less damage in an impact than a paint chip.
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.
West Ford 项目（也称为 West Ford 针和针项目）是由麻省理工学院林肯实验室代表美国军方在1961年和1963年进行的一项测试，目的是在地球上方创建一个人造电离层。 这样做是为了解决美国军事通信中发现的一个主要弱点。
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.
To mitigate the potential threat, a ring of 480,000,000 copper dipole antennas (needles which were 1.78 centimetres (17.8 mm; 17,800 μm; 0.70 in; 700 thou) long and 25.4 micrometres (1.00 thou)  or 17.8 micrometres (0.70 thou)  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 Lab, Walter E. Morrow started Project Needles.
为了缓解潜在威胁，美军使用480,000,000 铜偶极天线（长1.78厘米（17.8毫米； 17,800μm； 0.70英寸； 700 thou）的针）和25.4微米（1.00 thou）或17.8微米（直径 直径 放置在轨道上，以促进全球无线电通信。选择这样的长度是因为它是研究中使用的8 GHz信号波长的一半。偶极子共同为Westford项目的抛物线天线（位于Westford镇）提供了支持，以便与遥远的地点进行通信。 1958年，沃尔特·E·莫罗（Walter E. Morrow）在麻省理工学院的林肯实验室创立了Project Needles。
（ Westford satellite exhibit at the Udvar-Hazy center ）
A failed first attempt launched on 21 October 1961; the needles failed to disperse. The project was eventually successful with the 9 May 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.
1961年10月21日进行了一次失败的首次尝试； 针头没有散开。但在1963年5月9日的发射让该项目最终完成，人造环将携带无线电广播系统进入太空。但是，这项技术最终被搁置了，部分原因是现代通信卫星的发展，另一部分原因是其他科学家的抗议。 
The needles were placed in medium Earth orbit at an altitude of between 3,500 and 3,800 kilometres (2,200–2,400 mi) at inclinations of 96 and 87 degrees. They have contributed to Earth’s orbital debris.
British radio astronomers, together with optical astronomers and the Royal Astronomical Society, protested the action. The Soviet newspaper Pravda also joined the protests under the headline “U.S.A. Dirties Space”.
英国射电天文学家，光学天文学家和皇家天文学会共同抗议这一行动。  苏联报纸《真理报》也以“美国的肮脏空间”为标题参加了抗议活动。
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.
史蒂文森研究了有关 Project West Ford 的已发表期刊文章。利用他所学到的知识，并援引他所读的文章，他成功地减轻了来自其他国家的绝大多数联合国大使所表现出的恐惧。他和他的文章解释说，太阳光的压力会导致偶极子仅在轨道上停留大约三年。国际抗议最终导致了一项协商条款，列入了1967年《外层空间条约》。 
Fifty years later, in 2013, some of the dipoles which had not deployed correctly still remained in clumps, contributing a small amount of the orbital debris tracked by NASA’s Orbital Debris Program Office. Their numbers have been diminishing over time as they occasionally re-enter. As of May 2019, 40 clumps of needles were still known to be in orbit.
五十年后的2013年，一些未正确部署的偶极子仍然以团块形式留在轨道上，这项轨道碎片能被NASA轨道碎片计划办公室追踪到。 随着时间的推移，它们的数量不断减少，因为它们偶尔会再入大气。截至2019年5月，仍已知有40束针在轨道上。  
【以及一篇很好的文章 https://www.wired.com/2013/08/project-west-ford/ ，即wiki里的参考文献1。】