/sci/ - Science & Math

[Anonymous No.4602383]

>>>/m/7684186
>Kidding aside, you can reenter atmosphere in a space suit and be fine (until the landing). You're not massive enough for gravity to speed you up to the point where your velocity would start fires and shit.

[Anonymous No.4602395]

>>4602383
>>Kidding aside, you can reenter atmosphere in a space suit and be fine (until the landing). You're not massive enough for gravity to speed you up to the point where your velocity would start fires and shit.

[Anonymous No.4602411]

>Kidding aside, you can reenter atmosphere in a space suit and be fine (until the landing). You're not massive enough for gravity to speed you up to the point where your velocity would start fires and shit.

[Anonymous No.4602419]

>Kidding aside, you can reenter atmosphere in a space suit and be fine (until the landing). You're not massive enough for gravity to speed you up to the point where your velocity would start fires and shit.

Until you realize the lack of friction in the upper atmosphere thus speeding you up to godly speeds. Then you hit a massive wall of air molecules turning you into a cinder.

[Anonymous No.4602577]

How fast you're going by the time you hit the atmosphere and begin heating up from drag and the compression of molecules before you depends on how fast you were going beforehand or how far your fictional spaceman is from Earth when he begins accelerating towards it.

[Anonymous No.4602584]

>>4602577
This. In principle, the statement holds for a low-velocity suborbital reentry.

Coming back from orbit? Not so much.

[Anonymous No.4602587]

This is pretty much what MOOSE was designed for, right? Spacesuits with parachutes and some insulating foam.

[Anonymous No.4602592]

>>4602587
MOOSE is fucking awesome.

And yeah.

[Anonymous No.4602595]

>>4602587
http://en.wikipedia.org/wiki/MOOSE
So you need foam insulation, and ablative shield, and a parachute.

[Anonymous No.4602626]

>>4602595
That's for orbit.

If you were to just drop from 100 km up, you could probably survive with nothing but a suit and a chute.

[Anonymous No.4602642]

Unless I were coming in from orbital heights or orbital speeds, I'd be more worried about G forces. The highest straight-down dive is 32km. How are we defining "atmosphere"? The mesophere? Further than that and the distances involved are going to accelerate you to speeds you'd need active braking and a hell of a parachute.

[Anonymous No.4602652]

Let's not forget your body turning into jelly after breaking the sound barrier.

[Anonymous No.4602663]

>>4602652
The speed of sound is variable based on atmospheric density. If your parachute is good enough and you're not going absurdly fast by the time you get to a point where the parachute actually has enough air to brake on to mean something, it could slow you sufficiently. We would need to know the exact atmospheric density in bars or pascal at various heights.

[Anonymous No.4602670]

Lsts just all agree yer fucked and stop pretending

[Anonymous No.4602672]

>>4602670
That guy is hosed.

[Anonymous No.4603898]

>>4602587
Yes but that's more than just a space suit. The guy in that thread implied that a normal space suit wont be a problem because falling speed depends on mass (it does not) and that objects in orbit start out stationary and gain velocity from gravity when the start to fall. (things in orbit are already in a state of constant falling)

[Anonymous No.4604009]

In the interest of going somewhere in this thread, how feasible would it be to create a wearable suit that could withstand re-entry?

I ask because I just saw Lockout last weekend, and the finale consists of the protagonist + love interest jumping out of an exploding space station in these halo-looking heavy suits, that dis-engage after reentry so they can parachute down. So, what're the odds of actually developing such a technology?

[Anonymous No.4604017]

>>4604009
For the record, I don't mean something like MOOSE, just a tough-as-nails suit by itself.

[Anonymous No.4604026]

>>4604017
You could make a humanoid shaped heat shield, but that's not an optimal shape. And would probably be really bulky.

[Anonymous No.4604503]

>>4604009
It's very NOT feasible if they happen to be jumping out of a ship already moving at orbital velocities. Their acceleration towards earth would be about 10m/s^2, so every 1m40s, they're traveling another km/s. Consider that low-earth orbit at 300km already has you traveling at 7-8km/s and geostationary has you at 35,786km going ~3km/s. That's a lot of speed by the time you get to a point where heat from compressing air is a problem, and a lot of braking to do. An object falling into atmosphere from an orbital velocity is almost assuredly screwed.

Aerobraking would begin somewhere around the 50km mark, albeit very slowly. 15-20km is the point where a parachuting human moving at orbital velocities would realize his mistake.

There are some more complications from radiative heat loss, oxygen supply, radiation shielding, etc. that are all very not good and get worse the further out you are.

Falling from LEO height if you are somehow not moving at orbital speeds with a parachute and a really good suit, you could probably pull that off. Falling from LEO already moving at orbital velocity, or falling from much higher whether or not you're moving fast to start with, and you're almost assuredly toast unless this is a really spectacular "future" suit.

[Anonymous No.4604848]

> You're not massive enough for gravity to speed you up ...
Forgetting that gravity doesn't care how massive you are. The acceleration is the same regardless of mass.

[Anonymous No.4604891]

Somewhat related, project excelsior was the world's highest skydive from 31.3km above the earth's surface.
http://en.wikipedia.org/wiki/Project_Excelsior