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If you had to jump off of the space station with with your friends, and all you could bring with you were your spacesuits, parachutes for each of you, and you had a magic device that had enough oxygen (midwest.social)

submitted 12 hours ago* (last edited 11 hours ago) by DancingBear@midwest.social to c/asklemmy@lemmy.ml

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for you to survive the journey. If you could somehow spray the oxygen to get you close enough to Earth to use the parachute and land safely, how would you do it?

Edit: and how much oxygen would it take to spray, would you need to use to oxygen to slow your decent? This is assuming the amount of oxygen you have would be the same amount required before you naturally deorbited like a junk satellite or something. So like, you don’t have any food so you wouldn’t make it that long, but that’s how much oxygen you magically have…. Could you make it out alive? And how?

Edit 2: one of you has a cool clipboard and space pen that astronauts have that you can do math with.

Edit 3: one of you is a stoner.

Edit 4: if the space station was in geosynchronous orbit, could an astronaut jump down off of it?

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[–] DancingBear@midwest.social 2 points 12 hours ago* (last edited 11 hours ago) (2 children)

What is it that makes you “burn up” on reentry? Is any of that avoided if you can decelerate yourself from going sideways… apologies I don’t know what to call it but you are like a baseball at that point going sideways across the yard relative to flat ground on earth I think.

Edit: that’s really cool though if you are saying we only need a few backpacks of oxygen to burn ourselves up though

[–] untorquer@lemmy.world 8 points 10 hours ago

It's friction with the air.

You've experienced a strong guest of wind, now multiply that by 700x. At some point the temperature of the air is meaningless. The impact of you on those air particles gives them soo much energy they get white hot and radiate heat as energy, thereby heating you up. Like standing next to a fire.

[–] mkwt@lemmy.world 5 points 11 hours ago (1 children)

The energy that makes you burn up is your own kinetic energy. The "small" deorbit burn slows you down just enough to touch the atmosphere, but you're still going nearly full speed: 7200 m/s. Around 30,000 km/hr.

If you slow down more in space, so that you enter the atmosphere at low speed, you don't burn up. But you need a whole lot more backpacks to handle the full speed. It's cheaper and burns less gas if you use the air to slow down.

[–] DancingBear@midwest.social 1 points 11 hours ago (2 children)

Do rockets aim straight up as they try to leave earth, why don’t they burn up on exit too

[–] JohnDClay@sh.itjust.works 1 points 5 hours ago

By the time they're going fast enough, they're high enough they don't have much air to worry about. (And they do have an angle over too, not just straight up)

Missiles do go more or less go straight though the atmosphere horizontally. Most are slower than what we're taking about, but hypersonic missiles get close to rocket speeds. And they do need big heat shields to keep from melting immediately.

[–] mkwt@lemmy.world 7 points 11 hours ago

Rockets do not aim straight up when they are leaving. They go straight up for a few seconds, and then they tilt over in the desired direction to pickup speed.

They don't burn up on the launch because they time the tilt over maneuver so that they get above nearly all of the atmosphere before they start picking up serious speed.