Launching humans into space is difficult, dangerous and expensive - and we do it anyway, for good reason.rnDifficultrnThere is enough energy (kinetic plus potential) in 1 pound of anything in orbit to melt and vaporize every molecule in 1 pound of iron four times over. Energy in an orbiting shuttle - about the same weight and size as a Boeing 737 - is comparable to that required for a 737 to travel around the world (energy input in about 10 minutes for shuttle vs. 50 flight hours for 737).
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