ironing board cover for tabletop_business table cover

A manhole cover was accidentally launched from its shaft during an underground nuclear test in 1957. During the Operation Plumbbob nuclear tests, a 900-kilogram (1,984 lb) steel plate cap was blasted off the test shaft at an unknown speed and appeared as a blur on a single frame of film of the test. It was never recovered, but it likely burned up in the atmosphere due to friction. If the manhole cover had made it into space, it would have been the first known man-made object in space, as it pre-dated the launch of Sputnik 1 by 38 days. A calculation before the event gave a predicted speed of six times Earth escape velocity. After the event, Dr. Robert R. Brownlee described the best estimate of the cover's speed from the photographic evidence as going like a bat out of hell!^[27][28][29]