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Details On Inflatable Space Modules
Decibel writes "Although it's been mentioned on Slashdot twice now, this article contains more details about Robert T. Bigelow's plan to orbit massive inflatable space habitats, with the first test modules to be launched next year. It also details the $50 million "America's Space Prize", with the objective to "spur development of a low-cost commercial manned orbital vehicle capable of launching 5-7 astronauts at a time to Bigelow inflatable modules by the end of the decade.""
There's this, too. The guy does pretty much what you describe but adds some kind of metal infrastructure as well. The structure of this type that was up in the panhandle of Florida through a hurricane fared remarkably well.
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I'm sure it's being addressed but the first thing I think of is the effects of micrometeoroid impacts on whatever skin they're using. Then I wonder about the effects of extreme temperature gradients on the skin. I'm sure rapid decompression of the "air bladder" should the skin be pierced has been considered as well.
Pardon me if I seem a bit old-fashioned but I'll wait for the answers/results of these questions before I would invest any more time or money into this.
If it can be done, super! It sounds like it could be an interesting marvel.. if they can pull it off.
fms,chi
I can't quite envision how an inflatable object would behave in zero-G (perhaps just like any other object?), but in a vacuum, presumably explosion would be quite a difficult problem.
Zero-G doesn't matter in this case. Think about when you blow up a ballon, this air pressure inside is greater than outside, it's same in space just the pressure can be much lower to maintian the shape. They probably keep it around normal atmospheric pressure the comfort of the astronauts.
Make you wonder though, when you pop a ballon with a pin it goes bang...
If (big if) you inflate to sea level air pressure you need to contain 15 psi. Not a big deal. A bike tire can take up to 100 psi, a plastic 2l coke bottle can take over 150 psi. Make the habitat B I G and it will hold a lot of air. If something pops a hole in it, it will take a long time (many minutes) to deflate. Somebody will have to put down their beer, float over to the hole and slap on a peel-n-stick patch.
None of them can see the clouds; The polished wings don't care.
With all the needle jokes and condom comparisons one could get the impression that these inflatable modules are less rugged than the aluminium modules now used for the ISS.
This is not the case. They are made out of multiple layers of kevlar (the same stuff that bulletproof vests are made of). In tests with the NASA-designed transhab inflatable module they have proven to be much more resistant to space debris than aluminium hulls.
Also even if a particulary large piece of space debris should punch a hole in one of these modules, they are so big that there would be plenty of time to evacuate them before the pressure drops too much. A long-time station will probably also have a repair kit on board.
Third, the problem of space debris is particulary severe in low earth orbit. But in a higher earth orbit there is much less space debris, and the stuff that is there moves with much lower relative velocities. So from a space debris point of view low earth orbit is the absolute worst case. A station at an Earth/Moon lagrange point or in deep space would need little or no space debris protection.
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All inhabited spacecraft are inflated structures and all are prone to punctures. In space, you can't easily prevent the puncture (even aluminum capsules have some risk), but what happens next determines the survival of the crew. If the puncture just leaves a pinhole, then all that's needed is a patch. If the hole leads to a larger tear, then death soon ensues. This problem is not unique to space as a jet airliner is just a big balloon that will pop if poorly designed or maintained.
Materials such as rip-stop nylon use strong threads at crossing angles to prevent propagation of a hole or tear. The same principle could be used in inflatable spacecraft to limit the scope of an puncture damage. The interlacing threads would limit the damage to one or a few cells of the structural material.
Two wrongs don't make a right, but three lefts do.
The only reason why a balloon goes bang when you pop it with a pin is because the rubber rips and the air is violently released. If you put a piece of scotch tape over an inflated balloon and insert a pin you'll see that the balloon didn't pop but there's a hole. The tape reinforced the balloon and kept the rubber from tearing apart.
These inflatable habitats would simply leak air. There wouldn't be any Hollywood gratifying explosions.
...the exact opposite of an inflatable space station, is a skin tight space-suit! If we could develop that technology, space walks could become as easy as diving! (If not a smidge easier.)
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You can start to get respect for these inflatable structures when you realise that normal atmospheric pressure is just about 10 *tonnes* per square meter.
These structures seem to be made from a woven kevlar material.
They also have to be able to survive impact from debris in LEO and micrometeors without simply popping.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"http://www.monolithic.com/ has already constructed many inhabitable earthly structures using this technology.
They inflate a large plastic dome, and then they start building - from the inside. They first spray 3 feet of polyurethane, which provides excellent insulation. They use the polyurethane as a support for an inner shell of steel reinforcement bars. Once the bars are in place, they spray 3 feet of concrete.
So, by building from the outside in, they can keep building no matter what the outside temperature is. The plastic dome that gives shape to the structure remains as the outer skin. The building has the strength and thermal capacity of concrete, the incredible insulation of polyurethane, and has the strongest shape known to man.
This is better than geodesic domes. A bit more expensive, though.
Incidentally, those wacky Russians did a test of this thing's ability to survive reentry and it seemed to to pretty ok. Check it out.
No, you can't.
10 tonnes per square meter =
22,046 pounds per square meter =
22,046 pounds per 1550 square inches =
About 14.2 psi.
You can exert more pressure with your little finger.
FTA: The ISS is pressurized to 14.7 psi. Skylab was 12. These inflatable things are going to be about 10.
The enemy's door is down! Duh!
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Check out this fascinating detailed design for a completely reusable Saturn-V size rocket, powered by a Gas Core Nuclear Reactor engine. The engine emits non-radioactive hydrogen propellant. The rocket described would be able to lift 1000 tons of cargo into orbit and return to a powered landing, for only 5% of today's cost per pound.
I know "nuclear" is still a dirty word, but the gas core reactor design is a completely different approach than a big pile of plutonium. Very promising in terms of power, safety and cost.
It's a long article, 14 parts, but well worth reading. Skip the first 5 or 6 sections if you just want to know how the thing works.