Space

Canadian firm patents inflatable space elevator

The Thothx inflatable space tower would extend to 20 km above the Earth's surface
The Thothx inflatable space tower would extend to 20 km above the Earth's surface
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Patent drawing showing the main tower configuration
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Patent drawing showing the main tower configuration
Patent drawing showing the base of the tower and flywheels awaiting installation
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Patent drawing showing the base of the tower and flywheels awaiting installation
The Thothx inflatable space tower would extend to 20 km above the Earth's surface
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The Thothx inflatable space tower would extend to 20 km above the Earth's surface
The Thothx would act as a launching and landing area for spacecraft
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The Thothx would act as a launching and landing area for spacecraft
The Thothx could replace some satellites
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The Thothx could replace some satellites
The Thothx inflatable space tower
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The Thothx inflatable space tower
Patent drawing showing the inner core configuration
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Patent drawing showing the inner core configuration

In space travel, the first step is always the most expensive, but why blast-off in a rocket if you can catch a ride on a space elevator? Canadian space firm Thoth Technology has received a US patent for an elevator to take spacecraft and astronauts at least part way into space. If it's ever built, the 20 km (12.4 mi) high Thothx inflatable space tower holds the promise of reducing launch costs by 30 percent in terms of fuel, and may even replace some classes of satellites.

Space travel is a field that is rich in paradoxes. Even though the cosmos stretches out tens of billions of light years away from us, it's covering the first 100 km (62 mi) that mark the official boundary of space that presents the most difficult and expensive challenge for current technology.

Today, getting any higher than 50 km (31 mi) requires rocketry, but rockets are incredibly inefficient. Not only do they need to carry enough fuel to get a payload into orbit, but they also need fuel to carry the fuel to carry the fuel. Then, of course, there's the problem of atmospheric drag which means expending even more fuel.

Patent drawing showing the main tower configuration
Patent drawing showing the main tower configuration

Over the past century, scientists and engineers have come up with many ways of overcoming these limitations. They've moved launch sites to the equator to take advantage of the velocity of the Earth's rotation, they've tried launching rockets from balloons, and explored various catapult devices. However, one of the most efficient (at least, on paper) is also one that seems like pure fiction: a space elevator.

First proposed by Russian space pioneer Konstantin Tsiolkovsky in 1909 and popularized by Sir Arthur C Clarke in his novel The Fountains of Paradise, the space elevator is exactly what it sounds like. It's an elevator that can carry passengers and cargo from the Earth's surface and into geosynchronous orbit about 36,000 km (22,000 mi) up.

Such a cosmic lift would move payloads much more efficiently at an estimated cost of US$220 per kg ($100 per lb), which is a considerable saving on present costs of $25,000 per kg ($11,000 per lb). An elevator system would also have other advantages, such as being geographically fixed, and being able to carry out many of the functions of a satellite.

The Thothx inflatable space tower
The Thothx inflatable space tower

Unfortunately, current designs for space elevators are well beyond our ability to construct. They would need a tower or cable reaching up to geosynchronous orbit and another cable stretching thousands of miles beyond, with a counterbalance the size of an asteroid at the end to help hold up the structure. Worse, no material exists out of which the elevator could be made and still support its own weight, though carbon nanotubes, boron nitride nanotubes, and diamond nanothreads have all been suggested.

The more modest design of the Thothx tower aims to get around these limitations. According to the patent granted on July 21, the Thothx tower would be only 20 km (12.4 mi) high and about 230 m (755 ft) in diameter. Topped with a deck or decks, it could launch satellite payloads from the deck or pods attached to the tower. While 20 km may not seem like much compared to 36,000 km, it's still 20 times higher than any other manmade structure and high enough to shave a third off of launching costs.

The tower itself would be made of reinforced inflatable sections with an interior elevator tower made of multiple, extruded, pneumatically-reinforced segments. This forms an inner wall to the inflatable sections and a hollow middle for the elevator car. It also acts as a framework for raising decks, stabilizers, and other building components.

So wouldn't a giant inflatable tower flop in the wind unless it was tied down? The Thothx tower would be much too high for guy wires, so the company has proposed using a series of flywheels to provide dynamic stability, and to act as compressors to pressurize the tower. By adjusting pressure and spin, the flywheels can compensate for any bending of the tower and keep it fixed over its footprint.

As to the elevating component, the patent proposes that pressurized cars would run in the core or climb up the outside of the shaft like a mechanical spider, as a cable wouldn't be able to support its own weight without breaking.

The main function of Thothx would be for launching spacecraft, with the top of the tower acting as a launch pad for single stage to orbit rockets, landings, refueling, and relaunchings. In addition, the tower could be used for scientific research, communications, tourism, remote sensing, and mounting wind generators. Smaller, temporary towers (25 to 150 m) could also be used for providing large areas with communications and remote sensing.

"Landing on a barge at sea level is a great demonstration, but landing at 12 miles above sea level will make space flight more like taking a passenger jet," says Thoth President and CEO, Caroline Roberts, in a reference to the powered landing system being tested for the SpaceX Falcon 9.

Source: Thoth Technology

32 comments
martinkopplow
Interesting approach, though I don't take the flywheel thing for granted. The way they are described, they will not counteract lateral displacement, so the wind will still make the whole thing sway, probably enough to affect its integrity. Unless they come up with significant improvements, we're not going to see this in reality.
Bob Stuart
A rocket is inefficient mainly because the exhaust is usually moving far faster than it needs to, as well as "carrying everything." What you want at 12 miles high is enough speed to actually need a rocket, or you have only avoided a little bit of air drag. The atmosphere can, however, provide both fuel and lift to the first stage or two of a space shot. We'd be a lot farther ahead using Jumbo Jets harnessed together to make a giant glider tow to pick up a scramjet 2nd stage from a fast truck.
Bob
Nice if it would work. But getting up into the jet stream and it's potential tornado force winds would tear apart any man made building. The idea of landing on it would also be unlikely. The air would be so thin that any parachute would have to be huge and anything flying would have to be able to handle high velocity winds and the ability to fly slow enough to land in extremely thin air.
RobKeef
I had a similar idea but, my idea didn't have to support all that weight or land anything on it. My thought was to use regular weather balloons to support a tube and cable design. That a solar cable walker could climb inside of. Where stability and wind speeds become a problem the tube would end and a flying cable with wings would takeover. The wings would be computer controlled for zero weight and stability (similar to a kite). The number one problem with high altitude elevators is weight of structure. Which could be mitigated by Balloons and wings. That way you don't have to wait for carbon nano tube production (I have another idea on how to speed that up as well). Back to the cable, this could extend at least 40 miles and could reduce weight and cost of delivering costly space supplies like water and fuel. The walker would carry a small missile sized rockets. There's no reason you couldn't launch 50 a day. That would reduce the costs about 80% for small mundane supplies to space. Also reduce pollution by 9999%Once at the top the rocket would be thrown away from the structure prior to ignition. The savings of the structure to fuel weight would limit the size to only being able to carry liquids and nano devises. The average cost of taking one gallon of water or fuel to space is $10,000 from what I've heard. If you can't launch 10 gallons for 10 to 20 thousand per rocket then your scientist are worth a hoot. But, I'm only a fire fighter and dreamer. I see people doing things wrong all the time it just frustrates me. I would like to point out that your design is most likely for orbital skippers. However, the speed of those aircraft would incinerate your elevator design. P.S. if you can't put this to use then can you pass it on to Elon Musk I'd love to work for him.
Stickmaker
They've reinvented the Short Stack! (From one in a series of SF short stories about an inventor named Short.)
windykites
martinkopplow, The speed of rocket exhaust is called the specific impulse, and it helps to determine the thrust of a rocket. The faster the Exhaust, the greater the thrust. I agree with you about using the atmosphere on the first stage, as the oxidant for fuel (liquid hydrogen.) A horizontal takeoff, with some sort of catapulted or electromagnetic boost would also save fuel.
blueskydreamer
Unfortuately, make a start of the space rocket 20 km higher will not make any significant difference in fuel savings. http://space.stackexchange.com/questions/744/effect-of-atmospheric-drag-on-rocket-launches-and-benefits-of-high-altitude-laun
POOL PUMPREAPAIR guy longwood
My idea, is not to even try this foolish idea. and maybe spend, what no doubt is tax dollars, dreaming up half baked crap like this.
ezeflyer
Why not send everything up in a giant balloon and go from there?
Douglas Bennett Rogers
The novel idea here is a lighter than air building. The overpressure of the 100 mph jet stream is about the same as 50 mph at sea level. The jet stream coud also provide lift to support the building. Vehicles could be launched downward from the building. Or through a tube with the top open to near vacuum and the bottom at sea level. The doubling length ( at 1 g ) of S-glass is 20 mi.; carbon, 60 mi. The space elevator needs active stabilization, such as rockets.