There is a myth that a heavy (900Kg) steel cover was accidently blasted off the top of a 500ft test shaft at an unknown speed and had been launched into space during the American underground nuclear tests during the 1950's. Surprisingly enough, the manhole cover was never found and was seen leaving the shaft as it appeared as a blur in a single frame of a movie of the test. A calculation made before the event predicted a speed of six times that of Earth’s escape velocity which is rumoured to be enough not only to put it out of Earth’s gravitational pull but also out of our solar system! However this calculation is unlikely to be accurate and it was never expected to leave Earth. However contradictory claims argue this point by stating that due to the radiant energy caused by the explosion, the manhole cover would have come down as a fine rain of liquid steel. This claim has presumably been debunked by the fact that it would have been the shockwave energy which projected the manhole cover as the radiant energy was being absorbed by the 500ft chamber.
So was a manhole cover the first man made object in space? The single frame from the test movie and the calculation made before hand suggest that it should be right up there in the pecking order with Sputnik 1 (4th October 1957) but it is possible that the cover vaporised during flight and didn’t make it beyond Earth’s gravitational pull. One thing that can be answered though; is the fact that the cover was not accidently launched but presumably was deliberately launched.
