Eventually Aikins decided he’d have the best chance of survival if he landed in a giant net. He called some engineer friends to get their thoughts on the physics required to cushion his fall: If you wanted to stop 200 pounds of person traveling 120 mph in just 200 vertical feet—roughly how long it takes a parachute to open at terminal velocity—what are the G forces required to do that? (One G is equivalent to the force of gravity at the earth’s surface.
“They did the math for me and said, ‘It’s actually pretty easy. If you do it over 200 feet, you only have 2.4 G’s, which is nothing,’” Aikins says. (By comparison, a fighter jet imposes up to nine G’s on a pilot as it accelerates vertically.) “So I was like, 'Wow. Cool.'”
Uhh didn't he almost miss? At 120 mph I'd have to think there is little margin for error. I really don't get why people do stuff like this where death is a very non-trivial possibility.