What would be the highest altitude that sky diving can be attempted?
There is no limit. But one needs life support systems and one needs to come in at an angle that will avoid burning up like a meteorite. Let’s say, for the sake of argument, you jump out of a space shuttle orbiting at 20 km above the Earth. You do it in such a way that your initial velocity U = 0. What happens at this point? g ~ 9.81 m/sec^2 is what happens. You immediately start to accelerate. (g is actually a bit less, but not significantly less). And, at 20 km, the air density is very sparse… about .08 kg/m^3 under standard conditions. So, for all intents and purposes, you are jumping off in a vacuum. There is little drag despite your advancing velocity in the free fall. [This density and the extreme cold are two reasons you need support systems.] It can be shown you will reach a maximum velocity of well over 300 mph in the first 1,500 m of the fall, where there is little drag even though the velocity is high. But then the velocity starts to drop. This results because drag becomes
