A 10 metric ton safe needs a minimum of 9.8 kilonewtons of thrust to fly (this being downward-directed thrust). The first stage of a Saturn V rocket provided 3

A 10 metric ton safe needs a minimum of 9.8 kilonewtons of thrust to fly (this being downward-directed thrust). The first stage of a Saturn V rocket provided 35100 kilonewtons of thrust. This is where I came up with the 3500:1 ratio.