/sci/ - Science & Math

[Anonymous No.11272823]

Why don't astronauts just free fall from space with a parachute to reenter earth? It would eliminate the need for a heat shield since the human body won't reach speeds requiring it due to terminal velocity being low.

[Anonymous No.11272839]

The density of the atmosphere is so low at such heights that a parachute wouldn't function. Think about how a parachute actually works; basically the fabric smacks into air molecules and slows down. If there are very few air molecules to smack into it wont slow very much. The result is that the astronaut is going very, very fast already by the time the parachute starts working, and they're going so fast that they start burning up.

The Red Bull Stratos is probably about as high as you could possibly fall from and still have a parachute work.

[Anonymous No.11272843]

>>11272839
>and they're going so fast that they start burning up.
The terminal velocity of a human body though is much lower than the speed at which you would start burning like a shuttle does when it comes dashing in at 5k+ km/hr

[Anonymous No.11272880]

>>11272843
terminal velocity doesn't apply in a true vacuum because there is no air resistance. An important aspect of terminal velocity calculations is the resistance of the medium. The only limit to your speed in a vacuum freefall is the amount of time you're falling and in an extreme scenario the speed of light. A person can go much, much faster than "terminal velocity" if they freefell from outside the atmosphere.

[Anonymous No.11272904]

>>11272823
Parachute isn't going to work but plenty of effort has been put into escape pods and spacediving.

[Anonymous No.11272916]

Spacediving example.

[Anonymous No.11272917]

>>11272916
that's rad as fuck

[Anonymous No.11272928]

Technical Sergeant's first trip down the well the hard way.

[Anonymous No.11272930]

The earth and associated atmosphere, moves through space at 30 kilometers per second.

...so friction I suppose.

Although it's a bit hit or miss to be honest.

[Anonymous No.11272933]

>>11272917
Orbital spacediving could become a serious sport someday soon.

[Anonymous No.11273054]

>>11272917
https://youtu.be/luaRtGn2tsI?t=431

[Anonymous No.11273068]

>>11272823
When you are in orbit you are basically falling sidesways around the Earth; the ISS is moving at 27,600 km/hr. Your skydiving astronaut would need some way to shed that horizontal (relative to the Earth's surface) velocity.

[Anonymous No.11273293]

>>11272843
Terminal velocity and parachutes both only apply when you have atmosphere.

[Anonymous No.11273308]

>>11273068
This is the only answer showing any level of reading comprehension in this thread.

[Anonymous No.11273310]

>>11272880
Wouldn't they be gradually slowed as the atmosphere became denser? Especially if they had a means of increasing their surface area.

Joseph Kittinger, 1960's space jump. Best footage compilation happens to be a music video,
https://www.youtube.com/watch?v=A2zKARkpDW4

[Anonymous No.11273502]

>>11272843
That doesn't matter when you have a shitton of orbital velocity. And if you have a means of shedding your orbital velocity safely, you might as well just use that to deorbit normally.

[Anonymous No.11273647]

>>11272823

you'd have to use a tether until enough atmosphere

[Anonymous No.11273681]

>>11272916
reddit af

[Anonymous No.11273960]

>>11272823
top kek op

[Anonymous No.11273970]

>>11273310
They would slow, but it wouldn't be gradual and they'd burn the fuck up. Remember they have to slow down from 18,000 m/s and they have a very short distance to do it over

[Anonymous No.11274765]

>>11272823
The parachute required for such a feat would need to be extremely massive. It'd need to be rigid too. However, yes, that could work.

[Anonymous No.11275124]

>>11273681
Still looks cool. The fact is, a spacediver would have to be on their back going -Z and probably with their head pointing towards Earth like when Soyuz reenters.