Did speeding American manhole cover beat Sputnik into space? Top boffin speaks to El Reg

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."

Let's try again

The next month, in a test codenamed Pascal B, the team wanted to experiment with reducing the air pressure in the explosives chamber to see how that affected the explosion and radiation spread. A four-inch-thick concrete and metal cap weighing at least half a ton was placed over a 400ft-deep borehole after the bomb was installed below. The lid was then welded shut to seal in the equipment.

Before the experiment, Dr Brownlee had calculated the force that would be exerted on the cap, and knew that it would pop off from the pressure of the detonation. As a result, the team installed a high-speed camera to see exactly what happened to the plug.

The camera was set up to record one frame every millisecond. When the nuke blew, the lid was caught in the first frame and then disappeared from view. Judging from the yield and the pressure, Dr Brownlee estimated that it left the ground at more than 60 kilometres per second, or more than five times the escape velocity of our planet.

It may not have made it that far, though – in fact the boffin, who retired in 1992, believes it never made it into space, but the legend of Pascal B lives on. It was likely destroyed before it could escape Earth's gravity.

"I have no idea what happened to the cap, but I always assumed that it was probably vaporized before it went into space. It is conceivable that it made it," he told us.

"Many years later, when I was in Baikonur, the subject of Russia being the first to launch something into space came up. I did not raise my hand to add to the discussion, though I thought about doing so."

Did a twisted chunk of American hardware make it into space before the Soviets? We'll never know, but this was just one of the weird and wonderful experiences Dr Brownlee has had in a lifetime's nuclear research, about which we'll be telling you more later today. ®