tkdguy Posted December 11, 2008 Report Share Posted December 11, 2008 This article suggests the space elevator may not be that great a deal after all. Quote Link to comment Share on other sites More sharing options...
Vondy Posted December 11, 2008 Report Share Posted December 11, 2008 Re: Slow Space Elevator I find the notion of laser propelled launch interesting. It would take a substantial power-source, such as a dedicated rectenna from a large SPS array (etc) or nuclear reactor, and the choreography of the lasers to push the load up would require a great deal of sophistication, but the theory is sound and the technical hoops we need to jump through to make it a reality are somewhat more realistic (that's my impression at least). It does have the drawback of being beholden to the weather (you need really clear days), but it doesn't have the limited placement issues a "space-elevator" has. You could build laser-motive launch stations in more places. http://www.space.com/businesstechnology/technology/laser_propulsion_000705.html Quote Link to comment Share on other sites More sharing options...
austenandrews Posted December 12, 2008 Report Share Posted December 12, 2008 Re: Slow Space Elevator Yeah, in terms of speed, they're more kin to mule-driven canal boats than elevators. Quote Link to comment Share on other sites More sharing options...
McCoy Posted December 12, 2008 Report Share Posted December 12, 2008 Re: Slow Space Elevator This article suggests the space elevator may not be that great a deal after all. Old news. In Fountains of Paridise Carke wrote of useing resonance and climber speed to "tune" a beanstalk. Ideally they would be like San Francisco cable cars, paired climbers so that the descending one transfers energy and momentum to the ascending one. Quote Link to comment Share on other sites More sharing options...
Zeropoint Posted December 13, 2008 Report Share Posted December 13, 2008 Re: Slow Space Elevator Speed, schmeed. Even if it takes weeks to get something to orbit, the savings in MONEY (and the amount of rocket exhaust spilled into the environment) will be far more than enough to justify such an endeavor. Quote Link to comment Share on other sites More sharing options...
ghost-angel Posted December 13, 2008 Report Share Posted December 13, 2008 Re: Slow Space Elevator I thought they figured out the whole idea was bonkers decades ago. It always struck me as a "looks good on paper, would never actually hold up to reality" kind of concepts. Quote Link to comment Share on other sites More sharing options...
Kristopher Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator It always struck me as a "looks good on paper' date=' would never actually hold up to reality" kind of concepts.[/quote'] I've always had the same impression. Quote Link to comment Share on other sites More sharing options...
AmadanNaBriona Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator I thought they figured out the whole idea was bonkers decades ago. It always struck me as a "looks good on paper, would never actually hold up to reality" kind of concepts. Recent material and power advances un-bonkered the idea. For the longest time the big hangup was the tether.... It needs to be strong enough to handle the workload while still being low mass enough not to act like a giant oribital velocity bullwhip if the tether was broken. Quote Link to comment Share on other sites More sharing options...
tkdguy Posted December 14, 2008 Author Report Share Posted December 14, 2008 Re: Slow Space Elevator Good point. I can see equipment and even satellites being launched into orbit that way. I doubt people will want to spend weeks just getting into orbit and living in the elevator all that time. Quote Link to comment Share on other sites More sharing options...
McCoy Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator I thought they figured out the whole idea was bonkers decades ago. It always struck me as a "looks good on paper, would never actually hold up to reality" kind of concepts. I've always had the same impression. Physics is sound. Just a matter of finding a strong enough material to make the tether, and it looks like carbon nanotubes will do. Big problems are political, getting it past the NIMBY's. Quote Link to comment Share on other sites More sharing options...
McCoy Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator Good point. I can see equipment and even satellites being launched into orbit that way. I doubt people will want to spend weeks just getting into orbit and living in the elevator all that time. *shrug* There was a time people spent months in cramped conditions to get from Europe to North America. Quote Link to comment Share on other sites More sharing options...
AmadanNaBriona Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator *shrug* There was a time people spent months in cramped conditions to get from Europe to North America. I was thinking about coffin ships, but more of the William Gibson nature rather than the Irish Migration. But yeah. Sleep in shifts, everyone has their own internet connection, and good interior design and folk would endure without much fuss. Quote Link to comment Share on other sites More sharing options...
McCoy Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator I was thinking about coffin ships, but more of the William Gibson nature rather than the Irish Migration. But yeah. Sleep in shifts, everyone has their own internet connection, and good interior design and folk would endure without much fuss. Better than the crewed mission to Mars. Six people sharing what amounts to an efficency apartment they can't leave for two and a half years. Quote Link to comment Share on other sites More sharing options...
AmadanNaBriona Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator Better than the crewed mission to Mars. Six people sharing what amounts to an efficency apartment they can't leave for two and a half years. Why do I smell a reality TV show... Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator Better than the crewed mission to Mars. Six people sharing what amounts to an efficency apartment they can't leave for two and a half years. Why do I smell a reality TV show.... . . Oh please, God, no . . . Quote Link to comment Share on other sites More sharing options...
Vondy Posted December 14, 2008 Report Share Posted December 14, 2008 Re: Slow Space Elevator Why do I smell a reality TV show... Selling the broadcast rights could help underwrite the cost. Ferengi Space Exploration! Quote Link to comment Share on other sites More sharing options...
Basil Posted December 15, 2008 Report Share Posted December 15, 2008 Re: Slow Space Elevator Significant goof in the article. First, it's the Coriolis effect; it is NOT a force. Second and more important, it refers to the effect of moving north or south; in or out is simple inertia. As others have said, this "bug" has been known about for a long time. People go on weeks-long cruises just to land up where they started. Why is a week long "cruise" to outer space somehow inconceivable? Quote Link to comment Share on other sites More sharing options...
tkdguy Posted December 15, 2008 Author Report Share Posted December 15, 2008 Re: Slow Space Elevator I suppose it could be considered a cruise. But keep in mind it's more dangerous than a cruise. And how would it affect the cost? It's supposed to be a cheap way of getting to space, but so was the space shuttle, which didn't live up to that promise. Edit: Don't get me worng. I'm all for the space elevator. But if it takes weeks or even months to get to space, it won't entirely replace conventional rockets. There may be an incident where we'll need to get to space quickly. Quote Link to comment Share on other sites More sharing options...
Vondy Posted December 15, 2008 Report Share Posted December 15, 2008 Re: Slow Space Elevator There may be an incident where we'll need to get to space quickly. And we can get you there by shooting you in the backside with a laser. Quote Link to comment Share on other sites More sharing options...
lemming Posted December 15, 2008 Report Share Posted December 15, 2008 Re: Slow Space Elevator And we can get you there by shooting you in the backside with a laser. Hmm, Now I'm thinking about Paranioa. Quote Link to comment Share on other sites More sharing options...
Barton Posted December 15, 2008 Report Share Posted December 15, 2008 Re: Slow Space Elevator The carbon nanotubes that everyone talks about for this project do not yet exist. They MAY soon, they may not. Until super-super strong and super-super light nanotubes exist the space elevator is sci-fi. Quote Link to comment Share on other sites More sharing options...
Nyrath Posted December 15, 2008 Report Share Posted December 15, 2008 Re: Slow Space Elevator And how would it affect the cost? It's supposed to be a cheap way of getting to space, but so was the space shuttle, which didn't live up to that promise. Edit: Don't get me worng. I'm all for the space elevator. But if it takes weeks or even months to get to space, it won't entirely replace conventional rockets. There may be an incident where we'll need to get to space quickly. The space elevator is NOT a Navy SEAL rapid reaction force transport vehicle. It is the equivalent of 18-wheel truckers. The idea is to provide cheap shipping for bulk cargo from the Earth's surface into orbit. One of the main reasons that the space shuttle has bloated costs is NASA's ulterior motives. As Jerry Pournelle put it, the Shuttle program was designed as a full employment program for ex-Apollo technicians. They made jobs for all the Apollo techs, even though the shuttle didn't need them all. There is an article about Space Elevator economics here: http://en.wikipedia.org/wiki/Space_elevator_economics Quote Link to comment Share on other sites More sharing options...
Cancer Posted December 15, 2008 Report Share Posted December 15, 2008 Re: Slow Space Elevator Big problems are political' date=' getting it past the NIMBY's.[/quote'] Actually, NIMBY isn't an issue. The elevator site has to be on the equator, and the best sites in terms of weather are in the open ocean. So there's some substantial new space and admiralty legal issues. The bottom of the tether has to be modestly mobile ... something like a deep-ocean oil-drilling rig will do, which can move a few km in a day. But you have this quasipermanent structure based in international waters, extending upward through international airspace, and out beyond the atmosphere into international space. Legally, there's nothing like a relevant precedent for its status. What national entity (if any) is responsible for it? Who provides police (and naval) protection (pirates, anyone)? Who pays when damage or loss of life occurs on or around it? Who collects the fees for hoisting stuff up (and pays the penalties for loss of a payload)? Who insures the thing, and its cargo? The slower speed ... 20 to 30 days in a tens-of-tons bulk carrier isn't a huge deal. You won't have commuters, and that transit time limits its usefulness for putting humans up there, but for freight service (which might be unmanned, or have a single crew) it still wins big. It also depends on how many elevator cars you can have running on the tether at once. AFAIK those are still development questions. There are design competitions ongoing now for elevator car technology, things that can climb a ribbon cable at speed using a remote power source. And making the fibers long enough to be spun into a useful ribbon is also ongoing work. It's not dead yet, and at no time did I think it'd be smooth sailing in the development process. Heck, I'm still wondering if there's a way to harness the electromagnetic effects the thing will create. There's a few million volts of potential difference between Earth's surface and the top of the atmosphere, and then you'll have 30,000+ km of this ribbon cable rotating through Earth's magnetic field every 24 hours, which varies if for no other reason than it's compressed on the sunward side and extended in a tail out the night side. So the time-derivative terms of Maxwell's equations mean there'll be some current generated .... Quote Link to comment Share on other sites More sharing options...
ghost-angel Posted December 15, 2008 Report Share Posted December 15, 2008 Re: Slow Space Elevator THAT gives a whole new meaning to "Do Not Touch Third Rail" Quote Link to comment Share on other sites More sharing options...
McCoy Posted December 16, 2008 Report Share Posted December 16, 2008 Re: Slow Space Elevator But if it takes weeks or even months to get to space' date=' it won't entirely replace conventional rockets. There may be an incident where we'll need to get to space quickly.[/quote'] How do we get there quickly now? How long does it take to assemble, fuel, and preflight the shuttle? Quote Link to comment Share on other sites More sharing options...
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