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Continued Success for Space Elevator Tests

Posted by ryuzaki0 on from the world's-highest-kite dept.

Jacki O writes "According to their Web site the Space Elevator company Lifport recently managed to get their platform and climbing robot to the mile-high mark over the Arizona desert." From the announcement: "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 will 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."

8 of 572 comments (clear)

  1. Don't get me wrong here... by Skyshadow · · Score: 4, Interesting

    ...but it seems like the climber is the easy-ish part of a space elevator. If they were doing work with the carbon nanotubes, I'd be much more impressed.

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    1. Re:Don't get me wrong here... by Rei · · Score: 3, Interesting

      Yes, you refer to the exploits of Gerald Bull, who actually was working on what you mentioned. A fascinating bit of history, really.

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  2. Lightning Rod? by dorpus · · Score: 3, Interesting

    I'm just wondering, won't these things become a lightning magnet? You say it can be grounded, but what happens when these things stretch into higher parts of the atmosphere with more ions flying around?

    1. Re:Lightning Rod? by Anonymous Coward · · Score: 3, Interesting

      That is one of the outstanding questions WRT the space elevator: What happens when you ground the ionosphere?

      It's probably too diffuse to conduct well enough into the elevator tether easily, but I wouldn't be surprised if the tether is differentially charged to significant potentials, which could create interesting problems.

      On the other hand, it could be an interesting way to generate power for lifters, if you could find a way to have two strands with different potentials along them run the length of the elevator.

      I can see the signs now: "Beware the third braid."

    2. Re:Lightning Rod? by hador_nyc · · Score: 3, Interesting
      Well, they did have those two tethered satellite experiments that they ran on the Space Shuttle, and even in LEO with a relatively short tether the potentials between the satellite and the shuttle were pretty big.
      True, but the shuttle and the satellite were moving fast through the Earth's magnetic field. Granted the field fluctuates on it's own, but I think that is relatively insignificant compared to changes due to traveling at the speed needed for LEO. What's my point, I think the magnetic flux through the "elevator cable" would be significantly lower than that of through the wire between the two orbital objects. Still, the problem remains, and I don't know enough to guess on this one, is the flux generated by the natural fluctuations great enough when operating on a cable that long to cause a problem(induce a strong current). Also, there is a possibility of an interaction with the solar wind. Let's plug into the Arora Borealis(sp?).
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  3. Re:62k mile rope... what if it breaks? by Anonymous Coward · · Score: 3, Interesting

    Do the maths: taking the earth as 6,000,000m across and an average density of 2t/m^3:

    Volume ~ 4/3 * 3 * (3,000,000)^3 ~ 115,000,000,000,000,000,000 m^3
    Mass ~2xvolume tons: ~300,000,000,000,000,000,000 t

    To take a billionth part out would be 300 billion tons.

    Much of a problem?

  4. Re:So what? by Big_Breaker · · Score: 3, Interesting

    The point is that the cable is by far the hardest part. We aren't even close. When we are 75% of the way to producing an adequate cable we can start the other parts. I bet we would still finish those other components before the cable is ready.

    It's just a bit silly really... like building the lunar lander for Apollo but having boosters no larger than a bottle rocket.

    Get closer to the Saturn V THEN build the lander!

  5. Re:1500 feet not a mile by barawn · · Score: 3, Interesting

    You're telling this to a person who's followed every bit of news she can get her hands on about SWNTs (and to a lesser extent, MWNTs and non-carbon nanotubes, plus novel interlinked structures).

    Wait, so you do know how to build the cable? You should get in touch with these people!

    You took that comment the wrong way - it wasn't meant as "you don't know what you're talking about" it was meant as "since we don't know how to build it, we don't know how hard it is going to eventually be." Unfortunately the two have the same wording.

    I encourage you to check out spelsim or the gizmonics calculator. A 50GPa elevator weighs ten times as much as Edwards' calculation, and Edwards' calculation wasn't cheap.

    Edwards's calculation was feasible for a business. A 50 GPa elevator would be feasible for a government. And I have checked out spelsim. I know the deal. I just have different views on "feasible" than you do. What was the estimated total cost of Apollo in modern dollars? $200B or so? And the US GDP is 4 times larger than it was then (adjusted for inflation). Feasible for the US, today, is roughly $1 trillion dollars. (*)

    *: Now, whether or not it's sane to invest $1T in a space elevator - that's a different matter. Many people would argue that it wasn't sane to invest in Apollo either. I also know if you use percentage of GNP for Apollo - ~3%, and the years it took - ~10, you get about oh, half a trillion or so in current dollars. Close enough for me. And I know the reason we invested in Apollo was for military reasons. Don't shatter my deepfelt optimism that one day we'll invest as much money in exploration as we did in a giant pissing match.

    The climbers are.

    The climbers are not realistic present-day. Did you read the presentations from the Space Elevator conference on climber design? There were concerns that they might be impossible from power dissapation concerns. And the reliability requirements were way, way above what exists anywhere else.

    You can't go out and buy the climbers off the shelf. Therefore it makes sense to figure out exactly how much work they'll need to get working. Which... is what they're doing.

    Plus, as I said, the climbers block the development of the power system, since the power system needs to know how much power the climbers need.

    Frankly, I'm really baffled by the derision. If it takes 20 years to figure out the cable, then they have 20 years to develop the climber. Which means it costs less per year, so it can be funded via simpler methods - including volunteer time.