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.""

Comments

Physical Concerns?

[waldoj]

Can anybody explain what, if any, physical concerns exist with the use of an inflatable bladder in space? 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. Obviously, they've thought this through, but if somebody could explain the challenge of the proposition, I'd love to hear it.

I only know enough about this to know that I don't know enough about it.

-Waldo Jaquith

Re:The biggest challenge

[Jormundgandr]

This is not such a big problem. People have been doing it successfully for 50 years. The early orbiters didn't even use fancy-schmancy ceramic tiles to keep them safe, they just used tough heat-resistant ablatives to protect the soft, delicious astronauts inside.

As for the deceleration, all that atmosphere tends to help, especially when you deploy parachutes ;)

Seriously, you make it sound as if inventing a wheel would be impossible today, because small-time inventors don't have the massive government funding those 10,000 b.c. technicians did.

Re:The biggest challenge

[AKAImBatman]

Did you read my response? A Big Gemini capsule could easily meet the requirements. Especially on the reentry part. All that's needed is a classic epoxy/silicon heat shield, then the parawing for landing. On the ground the heat shield would be peeled off and replaced, the parawing repacked, and the capsule would be ready for relaunch.

Re:Safe Space?

[cmowire]

It's not plastic.

It's Kevlar fiber, generally, along with a variety of other materials, all of which have been tested in space or are currently on the space station. Just because a cheap injection-molded plastic toy breaks easily doesn't mean that all non-metallic materials are easily broken.

They've already worked the water supply angle out there. It depends on the project. The Transhab had the water supply going down the center, so you could stay in the shadow of it during radiation events.

Leakproofing is one of the problems they solve to make it all work. Just because a cheap rubber balloon can't hold pressure for years on end doesn't mean that all non-metallic materials have leaks.

Re:Amazingly

[ackthpt]

Getting back onto topic, I wonder what sort of materials something like this would be made out of, it seems like something without rigidity would be more susceptible to micrometeorite punctures?

At the velocity anything is moving foam rubber or carbon fibre would be the same thing. After what a paint chip did to sone of the shuttle windows (what, 8" of layered safety glass?) I'd be more worried about larger bits and how to disperse their kinetic energy rather than try to put something rigid in the path (keep in mind, if it's facing away from the Sun it could have a very low surface temperature, thus more brittle.)

Maybe like one beachball inside another beachball with a layer of sand between...

Re:The biggest challenge

[sbeitzel]

Now, why can't you use thrusters to decelerate to 0mph and then just get 'pulled in' by gravity?

Well, what are you going to be pushing out of those thrusters? The really basic problem with space travel is that we like to think of it like terrestrial travel: we want to be able to make big changes in velocity over short periods of time. The problem is that in space, there's not a lot of stuff to grab onto and throw around. About the only thing you've got lots of is light, but photons aren't very massive, so solar sails take a long time to effect a large delta-vee.

So, there's not a lot of stuff lying around. So, bring some with you! Except, for each ton of stuff you bring up the gravity well, you have to throw away several tons in the process (check out the relative size of the space shuttle and the liquid fuel tank and solid rocket boosters it uses to get up into orbit). Those extra tons of propellant translate directly into dollars, and that's what makes it expensive to get up there and then come back.

This is why people are constantly looking for a way to get stuff up into LEO without burning up lots and lots of propellant. Space elevators, balloons, high-altitude airplane launches...