Space elevator ? How can it work?

  1. I have been reading about the so called "SPACE ELEVATOR" in various articles in the news
    papers and magazines and reading that in a contest recently a company won a $900,000.
    prize as their creation climbed a mile long cable suspended from a helicopter in under 4 min.
    I understand that this "Space Elevator" if it works is supposed to transport materials into
    space (The Space Station ?) The full size unit would be a cheaper way to send food,water and
    equipment into space ........but will someone explain how it would work ? IF the space Station
    were attached to the end of the cable and it is going at 17,000 miles an hour in Earth orbit, how can the Space Elevator be hooked up and have any chance of working ?

    Please forgive me if this subject has been talked about before this. I searched for SPACE
    ELEVATOR and only got " ? lifter".
     
  2. jcsd
  3. minger

    minger 1,498
    Science Advisor

  4. Mech_Engineer

    Mech_Engineer 2,299
    Science Advisor
    Gold Member

    The point is that the winning design climbed the cable using power transmitted to it by a laser on the ground. Climbing the cable of a space elevator is fairly straightforward, but getting power to it can be difficult, and one possibility is a ground-based laser station which beams power to the elevator as it climbs the cable. This proof-of-concept showed it might be in the realm of possibility.

    As it is we don't have a way of creating a cable strong enough to act as a space elevator, and overall the elevator power system is a small one of many problems that need to be addressed before it becomes a possibilty.
     
  5. I would think maintenance/replenishment of the strand would be key.
     
  6. It wouldn't be hooked up to the station. It would be a geostationary platform from which the cargo were to be distributed.
     
  7. OK. Thanks for all the answers. I was thinking they were trying to get the thing from
    a parking lot up into something already in space.
     
  8. DaveC426913

    DaveC426913 16,371
    Gold Member

    No, they drop the cable from the orbiting satellite to the ground. It's stationary because the satellite is in geostationary orbit.

    Now that you've got the cable in place, you have to start getting payloads up it. That's where there's a lot of research. A payload that needs to climb 35,000km is going to be mostly motor. So they're looking at ways of keeping the motor on the ground. thus, lasers.
     
  9. It couldn't, as once the paylods arrived at the proper altitude, they'd be woefully shy of the ISS' orbital velocity.

    While that's fine for a 1 mile cable, the question is how well will this method work at 180 nmi distant?

    The motor? Or the power supply?

    With solar power and a worm drive, you could easily take your time, perhaps a couple of days, working your way up the cable.

    My concern involves the wear and tear on the cable!
     
  10. FredGarvin

    FredGarvin 5,087
    Science Advisor

    How about the fact that the cable is still only available in La La Land? That seems like a pretty big concern to me.
     
  11. DaveC426913

    DaveC426913 16,371
    Gold Member

    As Arthur C. Clarke said: the space elevator will be built ten years after everyone stops laughing.

    A lot of people aren't laughing.
     
  12. Academic scientists and engineers don't care about such practical matters. They need to hype up their pet projects so they can get tenure and government funding.
     
    Last edited: Dec 20, 2009
  13. Do you have a source for this statement?
     
  14. FredGarvin

    FredGarvin 5,087
    Science Advisor

    I have seen some pretty ridiculous things funded in my short time, so I can appreciate that aspect.

    Trust me Dave, the people who aren't laughing are the bean counters and the wackos that will have NOTHING to do with being responsible for trying to build this monstrosity. I have yet to see one credible source talk about its feasibility. It's a nice idea though.
     
  15. Arthur C Clark's The Fountains of Paradise gives a good description of how a space elevator might work.
     
  16. DaveC426913

    DaveC426913 16,371
    Gold Member

    No, what I'm trying to tell you is that there are whole communities of scientists and engineers that have banded together to solve these problems. I suppose if I directed you to these that would be pretty much the last word on the subject...
     
  17. FredGarvin

    FredGarvin 5,087
    Science Advisor

    Yeah. Please do. When I see a credible engineering source, I'll believe it.
     
  18. I remember watching a seminar by a Ph.D physicist who claimed that we should put solar panels on the Moon and beam the energy back to Earth using microwaves. He didn't spend one second talking about practical economic or engineering realities. Projects like the space elevator and fusion power are being promoted by these kinds of people. They could care less if their pet projects ever materialize, as long as they can publish lots of papers and scam some money out of DARPA.
     
  19. That's certainly a major issue, Fred!

    I would offer that no systems are developed once all the technology is in place. From the SR-71 to Apollo to the Space Shuttle, Pegasus... Much of the technology was developed along with the system. Most of the time that involved refinement of existing technology until it worked as designed and met specs.

    Not always, however, particularly with R&D efforts. Often, there's no specific project in mind, but someone gets an idea, and runs with it so long as funding holds out. They often shelve whatever they have at that point, but occasionally a need will surface, either inside or outside the firm, and the technology is used/rented/sold.

    Carbon nanotubes are real. They do exist. However, we have not yet developed any appreciable means of making them into high-tension cabling. We're not even certain that nanotubes are the best solution. Time will tell.
     
  20. DaveC426913

    DaveC426913 16,371
    Gold Member

    That does not detract from respectable organizations working on it.

    There are crackpots working on space flight too. Does it then follow that "space flight" is crackpottery?
     
  21. DaveC426913

    DaveC426913 16,371
    Gold Member

    On the other hand, looking around, I'm not finding as much as I thought I would.

    ISEC seems to be the biggest organization, and it's just a half-dozen guys. Maybe interest has died away in the intervening years.

    This makes me sad.
     
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