The second half of the 20th century was marked by the Cold War, a struggle between the United States (and its allies) and the Soviet Union (and its). While the two major powers never fought a major battle, the hostilities were most definitely real. The United States, for example, had numerous military bases throughout Europe and for that matter, around the world. Keeping in contact with these bases required some sort of link between North America and overseas, and the Americans typically sent messages either via undersea cables or bounced them (as radio waves) off the ionosphere (explained here).
Unfortunately, neither was a great choice. The ionosphere is unreliable; being part of the upper atmosphere, its quality wavers. Undersea cables are consistently good — so long as they are intact. And the threat of the Soviets cutting those cables was real and significant. So the Americans came up with a new solution:
480 million copper needles.
The needles were each about two-thirds of an inch long and not much wider (if at all) than a human hair, as seen below (via MIT). They were launched into medium Earth orbit, about 2,300 miles above the planet. (Vostok 1, the first manned space flight, maxed out at 203 miles from the Earth.) Once there, the hope was that this ring of copper needles would act as a synthetic ionosphere — with Americans bouncing radio signals off them and toward bases abroad.
The experiment — called Project West Ford (after the town which contained one of the satellite dishes) — kind of worked. After a failed deployment in October of 1961, the coordinating team gave it a second go in May, 1963. This second attempt worked, as the team managed to succeed in getting the needles to spread, as intended, into orbit. A few test communications between Massachusetts and California were, per Damn Interesting, “intelligible,” but the ring of needles was not able to maintain its collective position in a manner which allowed for its long-term use. By July, Project Needles was ended.
The mediocre result and the protests from foreign scientists — including those from the UK, notable in no small part due to the fact that the UK was (and is) an ally of the U.S. — led to the project not being refined and repeated. But it was of no concern to the United States, which — along with the Soviet Union and others — was about to embark on an ever-expanding program of creatingtelecommunications satellites and sending them into orbit.
As for the needles? Because of their tiny, tiny size, they are able to fall to Earth without burning up in the atmosphere. The vast majority of them have done exactly this, although according to one account, some may still be out there, adrift in orbit.