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Inflatable Tower Could Climb To the Edge of Space
MonkeyClicker writes with mention of a proposal that could see an inflatable tower helping to carry people to the edge of space without the need for rocket propulsion. This would function in place of previous space elevator designs which featured a large cable and could be completed much faster, if proponents of the project are to be believed. "To stay upright and withstand winds, full-scale structures would require gyroscopes and active stabilization systems in each module. The team modeled a 15-kilometer tower made up of 100 modules, each one 150 meters tall and 230 meters in diameter, built from inflatable tubes 2 meters across. Quine estimates it would weigh about 800,000 tonnes when pressurized — around twice the weight of the world's largest supertanker."
What problem is the inflatable tower going to solve?
Actually, "out of Earth's gravity well" would truly be the "edge of space", i.e., infinitely far away. As I understand, the biggest problem in getting to space is to spend as little time as possible in the deepest part of the well, because, going straight up, maintaining that altitude costs a lot of power. But if the structure is self-supporting, then you can hoist up your fuel and payload using more efficient means, since you don't have to actively maintain your altitude. It's called "gravity drag". I'm not really up on the numbers, but the first 10% costs you a helluva lot more fuel than the "last" 10%, for most values of $destination.
This could have some use for escaping earth's gravity. Among all the theorized technologies one of the most promising has always been just launching stuff into space via rail gun style. If you have a long tube with nothing but vacuum inside it you can drastically increase the efficiency of such a device. The problem is the end of the device has to exit into something near vacuum or it would be like slamming into a solid wall made of atmosphere.
If a tower like this could be built such that it contained a vacuum corridor inside it then we could perhaps finally pursue this idea with already existing technologies.
Jupiter would probably be easier. 8-12% Helium by volume in the upper atmosphere, and the rest is Hydrogen.
Buckminster Fuller (my hero ;-) already came up with this, altho' he intended to use concrete. Basically, if the structure is large enough, making the inside of the structure a few degrees warmer than the outside air will cause it to float. Bucky described a sphere about 1 mile in diameter to be airborne, and somewhat smaller cones to be sea cities.
Later . . . Jim
I don't think the idea is to make it lighter than air, but just use air to provide some physical structure to it.
Don't harsh my sci-fi utopia buzz, man.
I'm all about the inflatable towers to outer space. But not until we've got bullet trains from Chicago to Memphis so I can go listen to some R&B and eat BBQ and be home by morning. First the bullet trains, then the inflatable towers to outer space.
You are welcome on my lawn.
No. LEO orbital velocity is about 5 miles per SECOND, and even then it has to be lateral. The nice part of a space elevator is that it goes all the way up to geosync orbit heights, the point at which you can let go and you're already in orbit. This is 25,000 miles above us. The highest this kind of thing could reach is probably no more than 50 miles, 1/500th the useful height.
Jherico
What can the average user can do to ensure his security? "Nothing, you're screwed"
From The Article: "He calculates the tower could be extended up to low Earth orbit at 200 kilometres."
Actually, it would be kinda fun if you could just take the elevator to get up to the space station.
I just had a flash back from my Newtonian Mechanics class: A Spider lands on the center of a record player rotating at 45rpm's. The Spider attaches a web to the center of the record and begins to walk to the edge of the record looking for a way off. Given the weight of the spider, speed of the record; How far will the spider travel before being thrown off?
I RTFA; but some of the details seemed a little fuzzy, like the density of the outside with respect to the inside of the tube, load bearing. Maybe a 3D Real Time Model could be fashioned in something like Blender3D. If the math proves out, cool. But if not, then maybe the model could be applied to some other similar engineering solution. That in itself would be a worthy engineering accomplishment.
A 20km-tall inflatable structure is indeed admirable, and a realistic step in the right direction towards building real super-structures like a space elevator, a floating Buckyball, etc.
An novel approach for non-rocket launch, which may be more possible with the current state of technology than a space elevator (in that it requires less quantity of unobtanium), is a launch loop. It uses reactive centrifugal force to hold itself aloft.
http://en.wikipedia.org/wiki/Launch_loop
The air has to expand, the container does not. You must of course allow the excess air to escape as you heat it or pressure will build up. The density of the air inside is greatly reduced at the higher temperature, so the container weighs less. If it manages to weigh less than the same volume of cold air, then it will float. Somehow I have difficulty seeing this with a concrete container, but the principle is fine. The gas bags in the old Zeppelins were flexible, but were not particularly elastic. That meant they had to vent gas as they rose, to avoid excess pressure on the bags. There is a limit to this kind of thing, as you will no doubt be able to imagine....The available lift is dropping as you go higher, since the air outside is geting less dense.
And the magic word I have to type is phoenix...somehow I can't see the old Zeppelins arising from their ashes, although it was a great thrill to see one of the new ones in flight in Germany back in 2000.
This didn't go well the last time. Newspaper headline:
NIGHTMARE ON DREAMSPACE: MUMS, DADS, KIDS PLUNGE TO EARTH
HORRIFIED witnesses told last night how they watched helplessly as parents and children plummeted to the ground after a huge bouncy castle was sent rocketing 120ft into the air.
http://www.mirror.co.uk/news/top-stories/2006/07/24/killed-by-the-bouncy-castle-115875-17435718/
http://www.google.com.au/search?q=dreamspace+inflatable
"I came up with lots of ideas like this in college...I also smoked a lot of weed in college."
Wow. And they say smoking weed is bad for you.