As any space enthusiast knows, beachball-sized Sputnik was the first manmade object to orbit the Earth after it was launched by the Soviets in October 1957. But it's possible the US managed to put an object into space a few months before that.
In 1956, astrophysicist Dr Robert Brownlee was asked by his boss at the Los Alamos National Laboratory in New Mexico to figure out a way to test nuclear weapons underground. The scientists working on Operation Plumbbob were concerned about the amount of radiation spewed out by the nukes during tests above the surface, so Dr Brownlee started experimenting with the idea of blowing up small a-bombs below the surface.
"Most of the radiation generated in a blast has a half life of about four hours," Dr Brownlee, 91, of Loveland, Colorado, told The Register. "We figured you could keep everything in but for a few per cent by going underground. But Mother Nature can outwit you in a great variety of ways."
In July 1957, for an experiment codenamed Pascal A, the team drilled a borehole 500ft deep for what was to become the world's first underground nuclear test. Unfortunately, the bomb yield was much greater than anticipated – 50,000 times greater, apparently. Fire shot hundreds of feet into the air from the mouth of the uncapped shaft, in what Dr Brownlee described as "the world's finest Roman candle."
https://www.theregister.co.uk/2015/07/16/america_soviets_space_race/
