So we want to calculate how much durability one would need to survive a fall from Low Earth orbit.

Low Earth orbit starts at 160km.

We will assume that a human like creature falls and that it starts at rest.

For the weight of the creature I will assume 60 kg.

High End

The whole energy of the fall comes from the gravitational potential energy. So we know that in total the kinetic energy on impact can not be higher than the initial gravitational potential energy.

The potential energy is given by the formula GMm/r_1 - GMm/r_2, where M is the mass of earth, m is the mass of the object falling, r_1 is the initial distance from the center of the earth and r_2 is the final distance from the center of the earth. G is the gravitational constant.

Radius of earth is 6371000 m = r_2

r_2 + 160000m = r_1

G = 6.67408*10^-11

M = 5.972*10^24 kg

m = 60 kg

So setting in we get:

(6.67408*(10^-11) * 5.972*(10^24) * 60)/6371000 - (6.67408*(10^-11) * 5.972*(10^24) * 60) / (6371000 + 160000) = 9.1959e7 J

Room level

Low End

The terminal velocity for a human is 53 m/s, near the ground.

So while someone falling from great heights might initially have a higher speed when going towards the ground the speed will drop towards that value.

0.5*60*53^2 = 8.427e4 J

So at terminal velocity this would only be low end wall level.

What is realistic?

The actual value would likely lie somewhere inbetween those two.

One could try to do a more accurate method using the drag equation and the barometric formula, even though I am not quite sure whether that would work (at some point of the fall we would likely talk about supersonic stuff which it usually is hard to get the needed values for).

For now I would stay with wall level for such a feat.

Also let me mention that this is only for low earth orbit falling. For higher alitudes the potential energy value would go closer to the kinetic energy when falling with escape velocity, while for lower it would mostly just stay the same (the realistic value would go towards to terminal velocity value) except for short falls where not even that much speed if attained.

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