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I've been reading a lot about various "bootstrap" efforts, such as mining asteroids to get materials for larger space structures. Related to this, I was thinking about converting all the "slag" or waste of the asteroid into modular panels that could be snapped together to form space stations.
Is anyone aware of a modular panel design, similar in concept to the panels that make up geodesic domes, which could be used to create other shapes (in particular building doughnut-shaped space stations)?
If you could create a modular panel that could be snapped together to create more doughnut-shaped spinning space stations, manufacturing the panels would be quite easy (IMHO), and could be done in-situ on an asteroid.
See http://www.permanent.com/ for interesting reading on a bootstrap effort.
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With my modest understanding of building materials I would say it would be dificult to use the slag of mined asteroids to construct a space station. The reason is 'tensil strength'. After all the good stuff is mined away the slag would be like dirt. Dirt just doesn't have a lot of tensil strength. Once you pressurize the structure the material would be blown apart. Steel and plastic have high tensil strength and are best for holding in pressure.
The slag would be useful as radiation protection, though. You could manufacture it into whatever shape you like to surround the living quarters.
I would suggest using inflatible habitats for the station. You could make your 'donut station' on Earth with a thin kevlar hull. Launch it up to the asteroid. Inflate it. Then start packing the 'sandbags' around it.
This would save a lot on launch costs, of course. Zubrin's fifty-meter diameter sphere would only weigh 8 tonnes. A donut shape wouldn't be much different.
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Well, I made a thread called "Carriers" that talked about belt-based fusion/fission powered outposts, that would basically be based around a single huge vessel at first (which would have processing facilities, docks, quarters, and so on), and then evolve around that (with factories, trade vessels, hangars, etc.). This could be a center of interplanetary commerce, and could serve as a base for outer solar system missions.
Another important factor is the potential of space elevators. If they work out, these plans will be much more feasible.
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Inflatable stations are great - I think that's how you would start off, by launching a doughnut-shaped kevlar/demron space station with artificial gravity, then send it on its way to an asteroid. Do a search on TransHab if you haven't already.
However, you probably could not manufacture kevlar as easily as you could melt down slag, so infinite expansion of a station would not be easy with kevlar until you have significant industrial capacity at the asteroid in question.
As far as tensile strength, according to PERMANENT, lunar simulants were melted and achieved 50,000 psi, which is not bad. I guess the difference is there is no hydrogen to pollute the glass, therefore it's stronger.
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Another important factor is the potential of space elevators. If they work out, these plans will be much more feasible.
I've got the book on the space elevator, and it's interesting reading. They seem to have answered every question I can think of.
The drawback to the space elevator is you are putting all your eggs in one basket. If you have one major foulup, you are out of business for years until you can rebuild it.
Personally, I can't figure out why they cancelled the damned X-33. I suppose NASA didn't like it because it didn't have a cockpit on it.
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Well, they say subsequent elevators could be built for under $5 billion, which means you could have dozens of elevators (the equator is rather huge, and more advanced designs may not need equatorial positioning). So if one goes down, no problem, just send up a new ribbon/strand, and get back to work.
The X-33 was designed to test the feasiblity of a concept-it wasn't cancelled, it was successful. I don't believe it was ever intended as an actual vehicle.
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soph, the X-33 site is long gone, probably due to the fact that NASA doesn't want people seeing what a waste it was. As far as I know, though, the X-33 program was to build a STO space shuttle. Yes, the X-33 itself was a small version, and Lockheed (or Boeing, I can't recall), was to build a larger scale version. Make no mistake about it, though, the X-33 program was intended to be a shuttle replacement. I'm almost certain of this... too bad all the sites are non-existant now.
Some useful links while MER are active. [url=http://marsrovers.jpl.nasa.gov/home/index.html]Offical site[/url] [url=http://www.nasa.gov/multimedia/nasatv/MM_NTV_Web.html]NASA TV[/url] [url=http://www.jpl.nasa.gov/mer2004/]JPL MER2004[/url] [url=http://www.spaceflightnow.com/mars/mera/statustextonly.html]Text feed[/url]
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The amount of solar radiation reaching the surface of the earth totals some 3.9 million exajoules a year.
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I can't figure out why they cancelled the damned X-33.
Lockheed-Martin refused to honour the clause in the contract that stated the contractor must share the cost of any set-back during development. When Lockmart made a last-minute change of the propellant tank from solid wall composite to hollow wall, honey comb structure, it failed. Lockmart did not want to pay for that failure; they wanted NASA to pay for it all. After 2 years of the lawyers arguing over it, NASA agreed to proceed with an aluminum tank. Then George W. Bush cancelled the X-33/VentureStar project.
The X-33 was supposed to be a scale model of the VentureStar. It was supposed to fly, but wouldn't carry anything. The idea was any technology set-back (such as a tank design failure) would be made on the smaller vehicle which was cheaper to repair/redesign. The full-size vehicle would be built after everything was proven. In light of the tank failure, that was a good decision.
I wouldn't call the X-33 successful. It was cancelled before it was completed, and never flew. I don't blame NASA; I blame Lockmart.
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The X-33 was designed to test the feasiblity of a concept-it wasn't cancelled, it was successful. I don't believe it was ever intended as an actual vehicle.
Yes, it was cancelled after a hydrogen tank failure.
X-33 was a SSTO 1/2-scale space plane. Very impressive stats. Used metallic heat shielding which would have been low or zero maintenance. Nothing expendable like External Tanks or SRBs. Used the linear aerospike engine.
Very impressive piece of hardware. I've read a lot about it. It was partially funded by NASA and mostly by Lockheed Martin. I guess it was cancelled because there was little prospect for a commercial market after iridium and globalstar imploded.
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Lockheed-Martin refused to honour the clause in the contract that stated the contractor must share the cost of any set-back during development. When Lockmart made a last-minute change of the propellant tank from solid wall composite to hollow wall, honey comb structure, it failed. Lockmart did not want to pay for that failure; they wanted NASA to pay for it all. After 2 years of the lawyers arguing over it, NASA agreed to proceed with an aluminum tank. Then George W. Bush cancelled the X-33/VentureStar project.
Thanks, this is useful info.
Do you know if the X-33 was technically feasible? What I mean, was it going to be successful? Perhaps it became clean that it could not succeed, so that played a part in cancelling it. I know it was high-risk, but also high-reward.
I haven't been able to find any info on its payload capacity either.
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This page has three links to futuristic space colonies (artwork) that could be built from asteroid material.
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The X-33 was technically feasible. In fact, it didn't really have any new technology. The aerospike engines were developed in the 1970's as one option for the first space shuttle. The lifting body was developed during the late 1960's and early 1970's: see X-24B, HL-10, etc. The metallic heat shield had been under development and NASA already flew the space shuttle with a one or two tiles replaced with metallic tiles. I used to say that the only new technology was the composite cryogenic propellant tank, but the DC-X had used a solid wall composite hydrogen tank. That tank on DC-X was specifically touted as development for the X-33/VentureStar. The X-33 was really just a new application of existing technologies; it made use of the latest of everything, but really nothing was new.
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another old topic has been fixed for forum software coversions of the past...
Void has talked about making use of all stepping stones on the way outwards from earth and these places are on his list to go see by human eyes.
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