Is it possible to re-enter the earths atmosphere without heating up?

[YOyoYOhowsDAjello]

No, the speed at which you would descend would be the problem and since you cannot control that without massive amounts of fuel for propulsion it's kind of a moot point.

Obviously I'm not an expert on all this, but wouldn't you be able to use a series of parachutes at strategic altitudes to take care of this?

 

[Rubycon]

Obviously I'm not an expert on all this, but wouldn't you be able to use a series of parachutes at strategic altitudes to take care of this?

The speed is too great for parachutes to be practical. The size and complexity of the firing pyros for multiple staged chutes, etc. A ball inside a ball design - sure but again it's getting complex by the second.

 

[Hacp]

Yes it is possible. Just commission a couple of air conditioners.

 

[silverpig]

Yes it is possible, but it is not at all practical.

 

[YOyoYOhowsDAjello]

The speed is too great for parachutes to be practical. The size and complexity of the firing pyros for multiple staged chutes, etc. A ball inside a ball design - sure but again it's getting complex by the second.

(Too great even assuming the 0 speed relative to the ground when starting?)

I believe that that speed is the primary problem here, and after that is taken care of, then mass and surface area shouldn't be a big deal. My comments about the parachutes are regarding JulesMaximus's statement that seems to say that mass, surface area, and speed are all equally important problems.

For example, if we took the vehicle (since it doesn't have to be the space shuttle as per the OP) up in your space elevator and dropped it from some height that would count as "space", then would we be able to slow it down enough to have a "cool" re-entry?

I think that it does sound possible.

After the massive horizontal velocity relative to the ground is taken care of somehow, then I think it would be reasonable to assume we could build something that would allow for cool re-entry.

Am I way off?

 

[The Boston Dangler]

i'm in agreement with yoyo

 

[PaperclipGod]

Yes it is possible, but it is not at all practical.

I'm gonna go ahead and take this as the final answer. Everyone who has disagreed thus far has done so on the basis of practicality (or failure to read), which is sort of moot considering the impracticality of the question itself.

I was just wondering if a "cool" re-entry was theoretically possible... seeing a shuttle get red-hot on reentry is one of those things I've always just expected, and I wasn't sure if there were some other factors contributing to the heat that I didn't know about.

 

[Red Squirrel]

Here's another idea, some mechanism to absorb the heat, run a stirling engine, which runs a nitrogen compressor, which has coils to cool the surface. The heat from the compressor and condenser would be thrown behind the shuttle, keeping the front portion cool. Basically you're using the heat to combat the heat. In the end it creates more heat, but at least you can put it where you want (behind the shuttle). Sounds too simple though, probably would not work.

 

[Kanalua]

I think in theory you could do it, but the amount of fuel needed to gently bring a spacecraft from orbit, then a slow decent through the upper layers of the atmosphere (where there is little air) then maintaining steady decent to the troposphere before you could employ some type of parachute system to take advantage of the increasing atmospheric resistance.

It would probably be more expensive and much more dangerous than the current drop like a rock and use a high tech frying pan to keep the craft from burning up technique...

 

[PaperclipGod]

Here's another idea, some mechanism to absorb the heat, run a stirling engine, which runs a nitrogen compressor, which has coils to cool the surface. The heat from the compressor and condenser would be thrown behind the shuttle, keeping the front portion cool. Basically you're using the heat to combat the heat. In the end it creates more heat, but at least you can put it where you want (behind the shuttle). Sounds too simple though, probably would not work.

Would a heatpipe be more efficient?

 

[coloumb]

With current known technology - too damn expensive.

However - it would be possible in the near future - maybe 100-300 years and only if the human race still isn't moving at a snails pace with regards to space exploration/development.

 

[Mr. Pedantic]

For example, if we took the vehicle (since it doesn't have to be the space shuttle as per the OP) up in your space elevator and dropped it from some height that would count as "space", then would we be able to slow it down enough to have a "cool" re-entry?

I think that it does sound possible.

Maybe. Depending on the height there might not be enough atmosphere for parachutes to be effective.

(Too great even assuming the 0 speed relative to the ground when starting?)

0 velocity relative to the ground does not mean 0 velocity relative to the surrounding atmosphere. In GEO you're still moving through the atmosphere at over 3km/s.

I think that it does sound possible.

After the massive horizontal velocity relative to the ground is taken care of somehow, then I think it would be reasonable to assume we could build something that would allow for cool re-entry.

Am I way off?

You couldn't. As soon as you start reducing the "massive" horizontal velocity relative to the ground you start falling. You could theoretically modulate your height by modulating your horizontal velocity, but you get to a point where to make your re-entry smooth you're travelling too fast to make the concept very useful.

Here's another idea, some mechanism to absorb the heat, run a stirling engine, which runs a nitrogen compressor, which has coils to cool the surface. The heat from the compressor and condenser would be thrown behind the shuttle, keeping the front portion cool. Basically you're using the heat to combat the heat. In the end it creates more heat, but at least you can put it where you want (behind the shuttle). Sounds too simple though, probably would not work.

Why bother? All you need for the front to handle the heat of reentry is a layer of ceramic tiles. It requires little maintenance, no active energy consumption, and there's less that can go wrong.

Would a heatpipe be more efficient?

If you use energy to speed up energy transfer, then you can get massive thermal gradients that can't be achieved with passive heat transfer, and you can also modulate the rate of thermal transfer depending on need. But again, heatpipes would be more simple, cheaper, and wouldn't go wrong as often.

 

[So]

Of course it is! Come on guys... all you have to do is do it under power. If you have a retrorocket with enough fuel to come down and decelerate at the same rate that you went up, you could easily do it. The problem is getting that much fuel into space.

Oh, also, I suspect you could substantially reduce your heating loads with a long glide slope.

 

[tatteredpotato]

Think of it this way:

You need energy to slow down the craft. In the case of the space shuttle, the energy is dissipated over the surface of the space shuttle via friction. If you would add rockets, their discharge causing friction with the atmosphere would provide the same effect.

 

[guyver01]

You're all missing the obvious answer.

If the space shuttle lowered its landing gear, and all if it's tires were inflated to maximum sidewall pressure... the explosive force of the tires exploding would cause enough "woosh" to counteract all heating and friction on the shuttle.

 

[nerp]

You'd need a lot of fuel and energy to counter gravity. It would require something so large that it would probably not be able to get into orbit in the first place. Physics says it is possible, technology says "tough shit, humans. For now."

 

[darkxshade]

It can be done, all you have to do is decompress the earth by introducing near infinite amount of pressure into the vacuum of space until there is no more vacuum. :awe:

 

[dighn]

of course. just need to move slower, which is impossible with current technology. but lets say a space elevator is built, you'd be able to move things slow enough.

 

[JTsyo]

Well for a design like that mentioned in the OP, the answer would be to beam power from the earth to the vehicle. With that power you can have a controlled descend at low speeds, reducing the amount of heat generated.

 

[sandorski]

This reminds me of a SG Episode when a Bad Guy(don't recall who it was..probably a Replicator) was Beamed into Upper Orbit and they burnt up on re-entry. I always thought it was a little odd, as the person started from a completely stationary position and almost began to burn up immediately as it began to fall.

 

[Fritzo]

What causes the heat is your re-entry speed vs. the atmosphere. If you were able to use retro rockets to keep you at a slow reentry speed, you would not heat up. You would need an incredible amount of fuel to do this however.

 

[DesiPower]

The speed is too great for parachutes to be practical. The size and complexity of the firing pyros for multiple staged chutes, etc. A ball inside a ball design - sure but again it's getting complex by the second.

I always had this question... obviously I have no knowledge about rocket science...
Why the EFF so we have to enter the atmosphere at that high speed? cant we slow down just before reentry? cant we control the speed? or will it take a lot of thrust to slow down, something equivalent to liftoff? If so, how about we don't accelerate to that speed and instead of one day make it a 5 day trip? will that cause O2 issues?

 

[Hacp]

Ok I have figured out a way. Create a vaccum field around your space ship. Then you won't heat up.

 

[nerp]

I always had this question... obviously I have no knowledge about rocket science...
Why the EFF so we have to enter the atmosphere at that high speed? cant we slow down just before reentry? cant we control the speed? or will it take a lot of thrust to slow down, something equivalent to liftoff? If so, how about we don't accelerate to that speed and instead of one day make it a 5 day trip? will that cause O2 issues?

The reason why is due to fuel constraints. To control the speed, you'd need so much fuel that the size of the craft would be too big to launch in the first place.

 

[JulesMaximus]

(Too great even assuming the 0 speed relative to the ground when starting?)

I believe that that speed is the primary problem here, and after that is taken care of, then mass and surface area shouldn't be a big deal. My comments about the parachutes are regarding JulesMaximus's statement that seems to say that mass, surface area, and speed are all equally important problems.

For example, if we took the vehicle (since it doesn't have to be the space shuttle as per the OP) up in your space elevator and dropped it from some height that would count as "space", then would we be able to slow it down enough to have a "cool" re-entry?

I think that it does sound possible.

After the massive horizontal velocity relative to the ground is taken care of somehow, then I think it would be reasonable to assume we could build something that would allow for cool re-entry.

Am I way off?

How is it possible though? The Space Shuttle weighs approximately 165,000 lbs empty. How big a parachute would you need to slow it enough to have a cool re-entry? We had parachutes on the capsules we sent up in the 60s but those capsules were tiny compared to the space shuttle and they needed 3 huge chutes to slow those enough to splash down in the ocean and they also needed heat shields to re-enter the Earth's atmosphere from orbit. I think heat resistant tiles is probably the best solution for now.