Germany To Test Actively-Cooled Spacecraft 127
FleaPlus writes "The German Aerospace Center is planning to launch a novel reusable spacecraft in 2011, incorporating flat, damage-resistant tiles. Nitrogen will be pumped through the porous tiles, creating a protective gas layer that actively cools and shields the hottest parts of the spacecraft from the searing heat of reentry. The €12.5M unmanned 'SHEFEX II' project is a major technological step toward the team's eventual goal of a reusable space glider, which will be cheaper and easier to build than NASA's space shuttle."
Gary Hudson (Score:3, Interesting)
Re:why the obession with glider spacecraft? (Score:2, Interesting)
Because the USAF wanted the Shuttle to be able to use the atmosphere to break and turn back. This way, when launched in a polar orbit, it would be able to turn back and capture GLONASS or Russian Spy Satellites without appearing on the russian radar. Of course, the final design wasn't able to do such a manouver so the USAF has no use for it. But the design stick.
I've thought of that myself (Score:4, Interesting)
I've thought of active cooling myself. I always wondered, if you used an active cooling system, where would you radiate the heat? In other words, you can carry heat away from the underside of the ship by pumping a fluid through the tiles or whatever, but then you still have to re-radiate that heat someplace. OK, you might be able to transform some of the heat into useful work too; but we're talking about a lot of heat, and even if you got right to the Carnot efficiency the waste still has to go someplace.
I never got as far as doing the "back of the envelope" calculations on some substance with a heat capacity to absorb re-entry heat (and light enough to carry onboard) or the more tricky calculation of how you would conduct the heat from the underside and radiate it topside. I kind of assumed that actual aerospace engineers had done the calcs, and decided it just wouldn't work.
Weight kills in space, so I'd be curious to know how much the system weighs vs tiles or Russian-style ablative coatings. I'm assuming the Russians still use ablatives. I'm sure somebody will correct me if I'm wrong.
Re:why the obession with glider spacecraft? (Score:5, Interesting)
It is one thing I wish they would save a shuttle for.
NASA as a publicity fund raising stunt should save one shuttle's worth of parts and go retrieve the Hubbell Space telescope instead of crashing it into the ocean. Have the shuttle land and the load it directly for a flight to DC. Giving the whole pile (shuttle with Hubbell inside) to the Smithsonian.
Now that would be an awesome display. Heck I would donate money to help make that happen. To bad NASA doesn't think like awesome anymore.
Re:German technology (Score:3, Interesting)
Remember, German technology put the first man on the moon.
Ven the rockets are up, who cares vere they down?
"That's not my department", says Wernher von Braun
"In German oder English I know how to count down,
Und I'm learning Chinese," says Wernher von Braun
Re:Hot plasma? (Score:3, Interesting)
Isn't the hot air around the returning vehicle a plasma? If it is, can you repel it with proper use of electromagnetism?
Jon Goff, an aerospace engineer whose blog you should probably read in general because it's awesome and chock full of great aerospace analysis/ideas, had a rather intriguing discussion a few months ago about doing pretty much what you describe, applying magnetohydrodynamics to the problem of thermal protection during atmospheric reentry:
http://selenianboondocks.com/category/mhd-aerobraking-and-tps/ [selenianboondocks.com]
(Jon Goff's an engineer with Masten Space Systems, the company that won the most recent Lunar Lander Challenge)
Re:why the obession with glider spacecraft? (Score:1, Interesting)
Of course, there are much cheaper ways of controlling your landing, like parafoils. You don't need a big heavy wing all the way down.
Re:German technology (Score:1, Interesting)
The US propaganda machine makes going to the moon such a great thing. But it's pretty clear that getting into space is the major technology hurdle, the rest is just optimisation. The Russians won the space race, getting to the moon is an optimisation.
Just my two cents.
Re:why the obession with glider spacecraft? (Score:3, Interesting)
I suspect this has to do with the idea that anything except Single Stage To Orbit [wikipedia.org] And Back is not a "real" spacecraft. And that requires controlled landing, which requires either power to slow descend or wings to glid with.
Basically, the designers remember those old (and new) sci-fi shows that have spacecraft that can land, take off, land again, take off again... with just some refueling somewhere along the line. And they are right: being able to do that would dramatically lessen the cost of space travel. Unfortunately, the limits of chemical power very likely make this impossible for anything short of a Nuclear Lightbulb [wikipedia.org] design. And of course a Nuclear Lightbulb doesn't need wings, since it can do a powered landing with engines alone.
So, until we get rid of this childish fear of "nukular! wahh!", and actually build the NL SSTOAB rocket, expect to see lots more of such designs.
The Capsule is basically a reinforced airtight room with some heat protection at the bottom. It doesn't make sense to make that re-usable, especially since making it disposable allows you to use ablative heat protection, which is pretty much idiot-proof.
BTW. There sure has been a lot of space stories lately. I guess things are really starting to get moving again.
Unless you can land it on a runway who cares? (Score:3, Interesting)