LiftPort Successfully Tests Its Space Elevator Technology

[C1ay]

LiftPort Group, the space elevator companies, has announced that it has successfully completed preliminary tests of its high altitude robotic lifters under its waiver to use airspace granted by the Federal Aviation Administration (FAA). The lifters are early prototypes of the technology that the company is developing for use in the LiftPort Space Elevator, its commercial space elevator to ferry cargo back and forth into space.

 

lefthttp://hypography.com/gallery/files/9/9/8/balloontest_thumb.jpg[/img]In tests conducted in Washington state last week, the robotic lifters successfully climbed 1,000 feet up a simulated, working space elevator -- a model elevator "ribbon" attached to a moored high altitude balloon. According to the company, these tests represent the first-ever use of this technology on a free-hanging ribbon in the development of the LiftPort space elevator concept.

 

"These tests mark an historic milestone, in regards to the general space elevator concept as well in the development of the LiftPort Space Elevator, and we appreciate the FAA's willingness to work with us on these tests," said Michael Laine, president of LiftPort Group. "The ability to test our hardware in a simulated working environment is a critical step in the ultimate development of the LiftPort Space Elevator. Additionally, these tests are dual use -- not only will they help us learn more about the things we need to do to ultimately build the LiftPort Space Elevator, but they have great value for real world applications today. Our system called HALE (High Altitude Long Endurance) will have uses in a variety of fields. For example, after a natural disaster, we can provide radio, cellular or Internet access using our platform as a relay station. Or it could provide real time surveillance over the damaged region. Once our hardware is tested, we believe it can be deployed to save lives."

 

The company plans additional tests later this fall. Dates for the tests will be forthcoming.

 

A revolutionary way to send cargo into space, the LiftPort Space Elevator will consist of a carbon nanotube composite ribbon eventually stretching some 62,000 miles from earth to space. The LiftPort Space Elevator plans to be anchored to an offshore sea platform near the equator in the Pacific Ocean, and to a small man-made counterweight in space. Mechanical lifters are expected to move up and down the ribbon, carrying such items as people, satellites and solar power systems into space.

 

Headquartered in Bremerton, Wash., LiftPort Inc. is a privately held company dedicated to the development of the first commercial elevator to space. For more information, or to sign up for a free subscription to the company's newsletter on the LiftPort Space Elevator, visit at the company's web site at http://www.liftport.com

 

Source: LiftPort

[UncleAl]

the LiftPort Space Elevator will consist of a carbon nanotube composite ribbon eventually stretching some 62,000 miles from earth to space.

That is crap at face value. We won't even talk about the usual pie-in-the-sky stuff re Arthur C. Clark's Fountains of Paradise

 

1) Geosynchronous orbit is about 22,300 miles overhead. Nothing comes out to 62,000 miles/kilometers/furlongs.

 

2) A conductive ribbon shorting out the lower atmosphere, the ionosphere, and the van Allen radiation belts is a brief fireworks dispay.

 

3) No material imaginable will maintain its strength given continuous irradiation in the van Allen radiation belts.

 

4) What wll power the elevator's ascent? 22,300 miles at 100 mph is 9.3 days. There is no air after the first 25 miles of altitude. Whatever you use, it cannot mass anything or you reproduce the Space Scuttle wherein most of the payload is useless vehicle mass.

[Turtle]

___I have to think that 62,000 is a typo. Probably they meant 62 miles, the accepted space boundary (wasn't that the mark for that civilian rocket contest?) :doh:

[CraigD]

That is crap at face value.

My experience with the various press releases from LiftPort, Inc, leads me to take little they print seriously. Perhaps they’re making a positive contribution by promoting enthusiasm for space science by doing things like announcing open-to-all “climber” contests at SciFi Cons. My cynical side says they’re mostly interested in getting the donation $$s of good-hearted but poorly educated space fans.

3) No material imaginable will maintain its strength given continuous irradiation in the van Allen radiation belts.

Space elevator proponents’ answer to this objection, is that one can constantly replace degrading cable material with new with continuous swarm of “construction spiders”.

 

I’d take a step back, and ask weather anything in the current research yet supports the idea that super-long C60 tubules are structurally capable of the application being proposed. To my knowledge, given the current state of the art, this simply isn’t known yet.

4) What wll power the elevator's ascent? 22,300 miles at 100 mph is 9.3 days. There is no air after the first 25 miles of altitude. Whatever you use, it cannot mass anything or you reproduce the Space Scuttle wherein most of the payload is useless vehicle mass.

This objection, at least, I think can be well answered. Many of the materials proposed for skyhook cable construction are conductive, and even were they not, compared to a self-bearing 36,000 km cable, running conductors along one is no major feat. Aluminum EHVDC power lines over 2,000 km long already exist. Also, since a long, vertical cable orbiting the earth is effectively an electrical generator, providing electricity to a space elevator car should be among the lease daunting challenges posed.

 

A couple of interesting, and often unmentioned possibility in the design of a space elevator:

• Not reaching the ground. Skip the troublesome last 10 km or few, and have the cable base free-float at a high altitude. Deliver payloads using airplanes, balloons, sub-orbital rockets, super-cannons, etc, all of which could be very low-energy compared to an orbital launch
  
• Don’t remain vertical. A long orbiting cable rotating end-over-end. High-speed rendezvous with an end as it reaches is perigee, attach yourself, and swing up to an orbit or escape trajectory. Multiple rotating cables could be used in a stepping-stone fashion, reducing length and hence structural requirements.

I admit these are wild, pie-in-the-sky speculations, but the advantages of a mechanical path to space over the currently available means seem to warrant liberal applications of imagination.

[nkt]

CraigD,

 

"Don't remain vertical"? You mean have a cable whip through the air at hypersonic velocites? I think the frictional heating would kill it in minutes, even without the electrical generation or tensile stresses.

 

Not reaching the ground by stopping 10 Km (not 10,000!) from the surface might be a good idea, assuming you can somehow stop it getting pulled down by gravity.

 

The NASA space tether idea failed as it was deployed due to electrical heating due to induced eddies as it cut the lines of magnetic flux at ultra-high speed. Anything that can run power up to the craft will suffer the same fate. Indeed, anything magnetic or metallic would likely have some issues the minute it stopped being Faraday cage based and small.

[CraigD]

Many good issues, nkt. I’ll take a stab at them.

 

Incidentally, I’m not the originator of these ideas. They’re all pretty old and pre-www, though discussion of the space elevator, then termed the “skyhook”, was read into the US Congressional Record in the late 1970s, and actually had the support of a few congresspeople as an alternative to the Space Shuttle. They seem hard to find electronically - the best I’ve been able to find with a reasonable amount of searching is this Wikipedia article about “rotovators”. (searches seem to get clogged with reference to big farm machines, which apperantly go by the same name)

… You mean have a cable whip through the air at hypersonic velocites? I think the frictional heating would kill it in minutes, even without the electrical generation or tensile stresses.

Many rotovator designs only call for their use in airless environs, such as the moon. None that I’ve seen dare try reaching lower than about 10 km above ground, thus avoiding the really high-density atmosphere. One possible solution is to have a very thermally conductive cable, possibly with an active heat exchange system, allowing it’s high-friction low end to radiate from its low-friction high end. As usual, super materials seem to be required.

 

By carefully choosing the direction and rate of the cables rotation so that it “rolls” like a wheel (low end opposite its direction of rotation), its airspeed can be minimized.

Not reaching the ground by stopping 10 Km (not 10,000!) from the surface might be a good idea, assuming you can somehow stop it getting pulled down by gravity.

Not a problem. A space tether is essentially in orbit at its center of gravity. If more than half its mass is above this orbit, it will actually fall up. Managing the orbit of a giant, thin orbiting cable that’s touching the atmosphere is not a trivial problem, but if one can stabilize one that’s attached to the ground, one should be able to stabilize one at any height above it.

 

(oops – thanks for catching my sloppy extra zeros)

The NASA space tether idea failed as it was deployed due to electrical heating due to induced eddies as it cut the lines of magnetic flux at ultra-high speed. Anything that can run power up to the craft will suffer the same fate. Indeed, anything magnetic or metallic would likely have some issues the minute it stopped being Faraday cage based and small.

This would be a colossal problem for a cable that is conductive along its whole length (another problem with one made of C60 tubules, which are highly conductive). However, if the cable had many short, non-connected conductors, the induced voltage could be kept manageable.