eli5 why wouldn’t atronauts survive a fall from the ISS into the pacific?
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I was about to write that they would survive the fall, but not the impact. But re-entry would be too hot
The speed at which they would reach while they were falling would mean that when they hit the water it would be like hitting concrete. Ever tried belly flopping? Imagine how that hurts and feels. Now picture that from the height of the ISS going at a ridiculous speed.
Can’t survive a fall from the golden gate Bridge, so I doubt one from space will be any better.
Terminal velocity will smush you no matter how soft the surface you hit is.
When you rub your hands together hard and fast your hands get warm from friction.
Now imagine one hand is an astronaut and the other is the atmosphere/air.
Now imagine you can move your hand at over 17 thousand mph…… That’s a lot of heat.
because the ISS is high up. REALLY high. basically in space.
and when you fall from high up (but still kinda close to earth), then gravity accelerates you towards the ground. the higher up you start, the longer your fall and the longer you fall the more you accelerate. at some point air resistance (just stick your head out of a car window – when you’re not the one driving! – and you will feel it, now imagine that a hundred times stronger) will slow you down so much you reach what is called a “terminal velocity” – but while slowing you down this friction also heats you up, thats why space shuttles got heat shields, else they’d burn up. the more resistance you give, the worse the heat is, the less resistance you offer the higher your speed gets.
when you hit water at high enough speeds it doesnt have time to move away quickly enough and it’s actually quite hard. you can experience this by hitting a calm water surface with your flat hand fast enough. again imagine it 100 times stronger.
at the speeds the astronauts would impact the pacific it wouldnt matter if they hit rock, sand or water. they need some sort of braking mechanism beforehand.
and something protecting them from the heat.
and something that allows them to breathe during the fall.
The ISS is travelling at about 18,000 miles per hour with respect to the Earth’s surface. That’s about Mach 40, if I recall correctly. When an object enters the atmosphere going that fast, friction heats it to thousands of degrees, and it burns. It takes a very good heat shield to get a craft down from orbit; it was a small piece of damaged heat shield that caused the shuttle Columbia to burn up and disintegrate when they tried to get back to Earth.
An astronaut, without a craft that has a perfect heat shield, has no chance. They would burn up like a meteor.
Because you’d look up and make a wish upon them before you found out that the shooting star you were making a wish upon was an actual human being burning up on re-entry.
Quick, make a wish!
Heat from atmospheric re-entry would burn them up before they even make it to the ocean. This is why re-entry vehicles have massive [heat shields](https://www.youtube.com/watch?v=qRgRV1iMpEM).
Even if they did survive re-entry, hitting the ocean at that speed would be like hitting solid ground. The water just wouldn’t move out of the way fast enough to prevent damage to the body. This is why people who jump off high ledges or bridges can break bones.
Now, that’s not to say it isn’t possible. If a suit or device was created to solve the re-entry heat problem, you could feasibly parachute to the ground like the scene in the movie Lockout, where [Guy Pearce and Maggie Grace escape an exploding space station](https://www.youtube.com/watch?v=9eRqO9YIij0). In real life, [the record for the highest skydive is 135,889 feet,](https://www.skydivetecumseh.com/2020/06/30/highest-skydive-in-history/) though this isn’t technically space, which is said to begin around ~330,000 feet.
ok buddy, imagine if you go outside and you throw your whiffle ball. what happeds? i goes a little ways, then it hits the ground.
now throw it faster! you’ll find that it goes a little farther before it hits the ground.
now imagine there are no trees, or buildings or mountains, and you can throw your ball super super fast! what would happen? it would keep going and going and by the time it hit the ground, it would be so far that you couldn’t see it anymore.
now because the earth is round like your ball, the ground curves down as you get further away, that’s called the horizon. and if you throw your ball fast enough, the ground would curve away from it as it fell, and it would keep missing the ground and loop all the way around the earth and come up behind you…
this is called an orbit, and it’s what the ISS is doing all the time. you see champ, the whole space station is constantly falling, it’s just going so fast sideways that it keeps missing the ground.
so an astronaut couldn’t fall from the ISS. if he were outside it and let go, he would just keep falling right next to it. in order to hit the ground, he’d have to slow down somehow so that he stopped missing the ground.
one way to do this is to slow down just enough that he hits the atmosphere. you see, tiger, in outer space there is very little air.
you know how you can throw your whiffle ball so that it spins and curves? that’s because the air that surrounds it pushes on it as it flies along. that air also slows it down.
the space station doesn’t really have to worry about air all that much since there isn’t much up there. but if the astronaut were to slow himself down a bit, he would fly down into a place where there is more air. that air would push on him and slow him down even more.
but here’s the problem slugger, have you ever rubbed your hands together really fast? what happens? they get hot don’t they? that’s called friction. and when the air rubs against the falling astronaut, the friction creates heat. a lot of heat because he’s still going very fast.
have you ever roasted a marshmallow over a fire, buddy? what happens? the marshmallow heats up, chars black, and bursts into flames. you see, that’s what would happen to our falling astronaut as he heated up during reentry.
so he’d be a toasty little marshmallow long before he got to the pacific, if there was anything left to hit the pacific, and he would have stopped worrying about surviving the fall a long time ago.
now you run along and go play ball in the backyard, and if you plan on going up to the ISS, bring a fucking heat shield.
Technically they could. Slim chances, but still possible
1- They wouldn’t burn on the reentry. This only happens with massive objects because of the adiabatic compression in front of the object (and not because of friction, like some answers are claiming here… That’s a myth).
2- At some point, more height doesn’t mean more damage, because there’s a thing called terminal velocity, so, falling 500m, or 2000m it doesn’t really matter, and people have survived falls higher than that.
3- Falling on water isn’t a helpful factor. However, the “water feels like concrete” is an exxageration. It really depends on how the person lands: A “belly flop” from less than 1 meter feels like someone slapped you with a giant hand (and can even deal serious damage), an experienced diver can jump from 40~50 meters, but people can die (or at least break some bones) by jumping from barely 10 meters. The fact is that if instead of water the astronaut was aiming for some snow, or grassy field, his chances would be a lot better than a perfect fall on the water, but deppending on how the astronaut falled on the water, there’s still room to minimize some of the damage (We are talking about a body hitting water surface at terminal velocity, so we are still expecting a lot of damage).
4- There’s still the fact of how much the suit would help with the landing, if it would help reduce the terminal velocity, or cushion the fall on the ground, but I don’t even know if the suit would be relevant in this scenario.
5- There are other stuff to think about: After this fall, the person would be in no condition to swim, so even if he pulls this miracle, he would still fall to the bottom of the ocean like a piece of lead. So let’s say that somehow, there’s people nearby ready to catch him in the middle of the ocean, and bring him to a hospital.
So, yes… If all the stars align, and the Grim reaper is distracted when all this happens, the guy could survive, probably with fractures all over his body, but still alive.
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