[math-fun] Did speeding American manhole cover beat Sputnik into space?

FYI -- http://www.theregister.co.uk/2015/07/16/america_soviets_space_race/ "in a test codenamed Pascal B" "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."