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Space NASA Science

LaserMotive Finds Success In Space Elevator Competition 258

Posted by Soulskill
from the i'll-still-take-the-stairs-for-now dept.
Bucc5062 writes "LaserMotive has achieved the first step towards the creation of a working space elevator by qualifying for the $900,000 prize in a contest sponsored by NASA. To achieve this first level, LaserMotive needed to propel a platform up a cable dangling from a helicopter at over 2 m/s. They hit a top speed of 4.13 m/s. The next level of qualification will be to achieve a climb speed greater then 5 m/s. LaserMotive beamed roughly 400 watts of laser power to a moving target at a distance of 1 kilometer, as part of the vertical laser alignment procedure. The target was a retro-reflective board a little larger than 1 meter on a side. The contest will continue for another two days with at least two other teams challenging for the prize. To win the Power Beaming competition, the LaserMotive system uses a high-power laser array to shine ultra-intense infrared light onto high-efficiency solar cells, converting the light into electric power which then drives a motor. 'Our system will track the vehicle as it climbs, compensating for motion due to wind and other changes. Building on our experience from last year’s competition, we are designing an improved system able to capture the full $2,000,000 prize.'"
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LaserMotive Finds Success In Space Elevator Competition

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  • by Gothmolly (148874) on Thursday November 05, 2009 @11:07AM (#29994958)

    Leik Myrabo at RPI has been working on this stuff for years. In his words, if we can hit an enemy ICBM travelling at many times the speed of sound with a laser, surely we can keep one focused on a friendly target with a known/desired trajectory. These projects will NOT become accidental Death Stars. Given the absurdly high percentage that fuel makes up of a vehicles launch weight, anything you can do to power the craft externally gives you huge savings.

    • Re: (Score:3, Insightful)

      by v1 (525388)

      I was thinking about the test and the first thing that came to mind is: ok they're beaming up radiation of some sort, probably more-or-less straight up, (since basing the power at the same spot the platform is tethered makes sense) and they're suspending it from a helicopter.... which would place the platform approximately directly between the beam generator and the heli...

      so isn't this going to be a little bad for the heli / its crew?

      The only way I see to avoid this would be to beam up the energy from som

      • by natehoy (1608657) on Thursday November 05, 2009 @11:33AM (#29995282) Journal

        Well, they're basing the tests on a helicopter, so the beam is relatively small. So for the test, they could easily beam the power from somewhere other than the anchor point. Having the beam come from a different direction wouldn't invalidate the important concept of "can beam power from ground to power the platform".

        Not to mention, this test is based on a laser capable of delivering 400 watts of power to the target using infrared. Your average aluminum helicopter skin isn't going to vaporize under those conditions. Heck, I doubt you'd even scorch the paint.

        In the "real world" use of this, the suspension unit is going to be much further away and specifically designed with protective shielding. In fact, the endpoint might have solar panels pointed back to Earth so any "stray" IR could be caught and used at the station - though it's far more likely they'd have a solar panel up there, too, and beam IR down to the elevator once it reaches a certain point and the beam from Earth starts dissipating too much.

      • Re: (Score:3, Interesting)

        by AGMW (594303)

        ... I suppose for actual "space elevator" applications the same thing will apply, only you'll be irradiating the floating counterweight or whatnot, and the destination.

        Why not cover that side of the counterweight in the solar panels as well, and scoop up as much power as you can for use on the station ... Perhaps even send some back down by having a power laser pointed down to fire energy at the top of the climber for when it gets nearer the top ...

        Is there also an issue of having more than one climber on the cable at any one time - surely that means you'd want to be firing the power laser at a suitable angle anyway, to power a specific cable car.

        • Assuming we want to avoid any kind of problems with changing weather patterns (since we dont really know the implications of beaming massive amounts of power down), as long as we have an 18000 mile long cable, couldnt we just run the power back down the inside of the insulated elevator cable?
    • Are we serious? (Score:5, Interesting)

      by Kupfernigk (1190345) on Thursday November 05, 2009 @11:26AM (#29995188)
      The key word that's part of ICBM is "ballistic", from the Greek ballein, I throw. It's travelling through extremely thin gas, and its trajectory is therefore practically simple Newtonian dynamics. Its position from moment to moment should be extremely predictable. Now consider an object attached to a rope in the atmosphere. It's subject to constantly changing wind forces in three dimensions. Even when it's out of the atmosphere, the beam is subject to deviation caused by atmospheric effects, which is why stars twinkle and big telescopes need clever adaptive control systems. Its path is many times less predictable. In a nutshell, it's the difference between catching a lofted cricket ball or baseball, and catching a fly. It is not an object with a "known/desired" trajectory.

      The problem is, I'm sure, soluble, but the technical difficulty should not be underestimated.

      • by blueg3 (192743)

        The problem is, I'm sure, soluble

        Soluble, sure, but only in aqua fortis.

        Or did you mean solvable?

        • by IndustrialComplex (975015) on Thursday November 05, 2009 @12:04PM (#29995624)

          Soluble, sure, but only in aqua fortis.

          Or did you mean solvable?

          Well Archimedes did say, "Give me a powerful enough solvent, and a large enough bathtub, and I'll dissolve the Earth."

        • If you care to investigate you will find that (according to Merriam-Webster among others) soluble has both meanings. If you knew any Latin - and you obviously don't, despite referring to nitric acid as aqua fortis - you would know that u and v in Latin are interchangeable, and that soluble and solvable are from exactly the same root. While I'm exposing your linguistic inadequacies, I should perhaps explain further that the Latin root means to "loosen", and so is applicable both to loosening the bonds of a s
          • Did someone pee in your Corn Flakes this morning?

            I really think it was meant as a tongue-in-cheek remark. Maybe it will help to know, even if there wasn't an alternate, if somewhat archaic, definition, no one with half a brain would really question your intelligence, unless in jest.

      • by circletimessquare (444983) <<circletimessquare> <at> <gmail.com>> on Thursday November 05, 2009 @11:46AM (#29995432) Homepage Journal

        it's the difference between catching a lofted cricket ball or baseball, and catching a fly."

        to complete your allegory in terms of childhood classic movies, the solution to the problem is less bad news bears and more karate kid

      • > In a nutshell, it's the difference between catching a lofted cricket ball or
        > baseball, and catching a fly.

        Some of these people have already built laser systems that can shoot a fly out of the air.

      • Re: (Score:3, Insightful)

        by Chris Burke (6130)

        The key word that's part of ICBM is "ballistic", from the Greek ballein, I throw. It's travelling through extremely thin gas, and its trajectory is therefore practically simple Newtonian dynamics. Its position from moment to moment should be extremely predictable.

        In theory, yes. In practice, it's going to depend on how accurately you can measure its position and velocity at any given moment. The missile is moving very rapidly relative to the target size it presents, so small errors in measuring its positi

        • by amplt1337 (707922)

          Not to mention that if you're beaming power, you can always make the target a good bit wider than the beam.

          Just sayin.

      • by khallow (566160)

        The key word that's part of ICBM is "ballistic", from the Greek ballein, I throw. It's travelling through extremely thin gas, and its trajectory is therefore practically simple Newtonian dynamics. Its position from moment to moment should be extremely predictable. Now consider an object attached to a rope in the atmosphere. It's subject to constantly changing wind forces in three dimensions. Even when it's out of the atmosphere, the beam is subject to deviation caused by atmospheric effects, which is why stars twinkle and big telescopes need clever adaptive control systems. Its path is many times less predictable. In a nutshell, it's the difference between catching a lofted cricket ball or baseball, and catching a fly. It is not an object with a "known/desired" trajectory.

        You have it exactly backwards. The professor was right. The object attached to the rope is predictable because you'll know exactly where it is all the time (say via GPS stuck right on the vehicle, some tracking signal, or other means) plus it's not moving very fast. The ICBM will be fired by someone who doesn't want you to hit it and they'll have plenty of tricks to keep you from doing so. They won't tell you where they are. The missile will be traveling at hypersonic speeds. They'll bring decoys. They'll f

      • The key word that's part of ICBM is "ballistic", from the Greek ballein, I throw. It's travelling through extremely thin gas, and its trajectory is therefore practically simple Newtonian dynamics. Its position from moment to moment should be extremely predictable.

        That's why penetration aids [wikipedia.org] were invented. Sure, it's easy to hit something, but picking out which of the 20-30 ballistic targets is the actual warhead that's trying to blow you away is hard.

    • by Joce640k (829181)

      Can't they attach a parabolic mirror the the elevator and use the sun for power.

      They could get more than 400W from a mirror, easy...

      • by Kupfernigk (1190345) on Thursday November 05, 2009 @11:35AM (#29995316)
        The sun is effectively at infinity, so the reflection from the parabolic mirror will come to a focus at some distance from the mirror and thereafter diverge. This won't work. You would need, in fact, a large array of flat mirrors which were steerable so they all converged on the target, and continued to do so as it rose. This could be technically very difficult indeed. It makes a lot more sense to use electricity to power one laser which then only requires steering. You can generate the electricity with solar panels if you like.

        (A C Clarke had a story in which large numbers of flat mirrors were used to vaporise a football referee. Obviously, everybody holding a mirror had to steer it. In reality, the target would have been so bright they would probably not have been able to aim effectively.)

        • Re: (Score:3, Interesting)

          by natehoy (1608657)

          Possibly. MythBusters did a test where they took relatively large but not ungainly array of flat mirrors and rigged them into a parabolic array, and set some dry wood on fire with it. I think it involved a few dozen small mirrors, but they were all pre-calibrated to aim at the same point.

          Assuming bright sunlight approximately straight up in the sky (so everyone in the audience has access to some sunlight they can aim), Clarke's story might be considered "plausible" on the MythBusters scale. If you have 5

          • by swillden (191260)

            Hmm, I ought to send that one in. Seeing them try to scale this one up could be fun.

            Poor Buster...

      • by natehoy (1608657)

        400W is only the test unit, and probably had almost no payload. A mirror capable of generating 400W of focused light is probably going to be too heavy for the small test platform they were testing with.

        The purpose of this was a scale test of a proposed much larger (and therefore useful) elevator box that could carry some payload, and that would need to be powered by a necessarily much larger ground-based laser.

        If and when this ever reaches the point where they are talking about putting people or useful carg

      • > They could get more than 400W from a mirror, easy...

        Even if it wasn't too heavy to lift itself such a system would require that the cable be much, much larger and therefor much, much, much more expensive. It makes much more sense to minimize the weight of the car and put as much of the big, heavy stuff on the ground as possible.

    • by vivian (156520)

      I too would love to see this work - though they are going to have to be moving a hell of a lot faster than 5 M/s (18 kM/h) for it to be anything like a practical solution.

      Since there is no tangential velocity, unless the thing gets up to geo, there's going to have to be a big rocket to supply the additional deltav to reach orbit.
      To reach geosynchronous orbit (about 36000 kM above sea level, I think) is going to take about 2000 hours, or 83 days.
      I imagine you wouldn't want to take more than a week or so to

      • by timeOday (582209)
        What's wrong with taking 83 days? How often do launches occur now? And couldn't many payloads climb in parallel?
      • Since there is no tangential velocity, unless the thing gets up to geo, there's going to have to be a big rocket to supply the additional deltav to reach orbit.

        That's correct. The space elevator design calls for the elevator to stretch from the surface, to a large space station in GEO, to a point the same distance the other side of GEO. That way you can get a big bunch of the velocity needed for an interplanetary trajectory simply by going to the outer end of the space elevator and letting go!

        And you're also quite right in saying that 5 m/s is too slow for human transit to GEO, but it's probably good enough for cargo payloads. One of the biggest problems, though,

      • by Dan Ost (415913)

        As the elevator gets further from Earth, the pull of gravity decreases. Therefore, the energy required to move 5m/s close to Earth might allow the elevator to go much faster than 5m/s as the elevator's altitude increases.

        But even if it doesn't, 83 days might not be unreasonable if we're talking about cargo rather than astronauts.

      • by jcochran (309950)

        I suspect that it's speed is dependent upon the amount of work the climber needs to perform.
        Interestingly enough, the required work decreases as the climber gains altitude. After all, the gravitational pull gets reduced with the greater distance from earth due to the inverse square law. And, yes, I'm aware that the efficiently of the power transmission also goes down with the inverse square law, but I'll assume they step up the power as required to keep the amount of power the climber gets as close to the m

        • by spitzak (4019)

          Gravity actually goes down faster than the inverse square law. It is zero at geo-synchronous orbit level, which is smaller than the non-zero 1/n^2 of inverse square.

          The reason is the centrifugal force of the cable spinning around with the earth.

    • "In his words, if we can hit an enemy ICBM travelling at many times the speed of sound with a laser, surely we can keep one focused on a friendly target with a known/desired trajectory"

      But we haven't demonstrated that we can hit an enemy ICBM with a laser, so what's the point?

    • by timeOday (582209)
      I'm sure there must be a good answer to this, but why does a space elevator require laser power at all, instead of just running electricity up the "rope"?
      • by stevelinton (4044)

        The rope is too long. You'd lose too much power to electrical resistance along the way.

         

    • Maybe I'm just dense today, but why does the space elevator need to be beam powered? You've got a nono-tube ribbon the elevator is climbing, why can't there be power wires/rails on the sides? It just seems if the ribbon can't take the weight of power transmission lines that cargo is going to be extremely limited amount of cargo this thing can move.

  • Finally (Score:2, Funny)

    by Shane112358 (1532293)
    Ad Astra! Ad Luna! Ad Lagrange Point 2!
  • I hope to see a functional space elevator in my lifetime. This would help space travel immensely by taking making the issue of getting out of our atmosphere a relatively dull process it allows us to put more focus on ships that can be bigger and designed for long term space travel. Say to mars

  • Uh-oh (Score:5, Funny)

    by Pete Venkman (1659965) on Thursday November 05, 2009 @11:15AM (#29995044) Journal

    What if someone farts in the space elevator? You'll be stuck for way more than a few floors.

  • by wisebabo (638845) on Thursday November 05, 2009 @11:24AM (#29995150) Journal

    Congratulations to LaserMotive and I hope that they (or one of the other participants) quickly claim the remaining prizes.

    Still, it occurred to me that the real system (capable of climbing to Geo-sync and beyond) won't be designed in a vacuum (ha ha). I mean, the cable on which these climbers ascend will be exquisitely engineered as well, probably down to the nano-level if it's going to work at all. So shouldn't the contest be that of a cable/climber combination? I mean like what if the cable or climber or both was using some nano patterned material like the underside of a gecko's foot (which lets them cling upside down to ceilings). Or maybe if there was some sort of nano (or not, I saw one made out of large metal bits) "velcro" like material in which case there would have to be hooks on one surface and clasps on another.

    As long as the surface of the cable didn't add appreciably to the weight of the (supposed) carbon nanotube structure, it could add tremendously to the gripping power of the climber while still allowing for a practical cable.

    • by CopaceticOpus (965603) on Thursday November 05, 2009 @11:45AM (#29995422)

      Nobody is able to design the cable. We simply don't have the technology, which is why they're focusing on the climber instead.

      This is a bit like having a contest to design a cool hat to be worn while using an anti-gravity belt. If someone wins the contest, then we are one step closer to being able to float while wearing a cool hat - all that's left is the bit with the belt.

      • Re: (Score:3, Informative)

        by mengel (13619)

        I thought these guys [aip.org] had it pegged?

        Carbon nanotubes, with a tensile strength of up to 100 GPa, are the strongest material ever discovered [10]. To exploit this superior property for practical applications, individual carbon nanotubes have been assembled into macroscopic fibers [11,12]. However, these macrofibers show a very low tensile strength of less than 3.3 GPa [12 15]. This is mainly due to the clustering of nanotube ends, internanotube slippage and intrananotube defects. In contrast, the CCTs hav

      • Mod parent up. (Score:4, Insightful)

        by thatseattleguy (897282) on Thursday November 05, 2009 @12:04PM (#29995620) Homepage
        Mod parent up- right on. The cable needs to be made of "baloneyium" (as someone famously opined about the composition of Niven's Ringworld). Its composition and engineering are way beyond our current capabilities - not so far that it's not worth pursuing, mind you, but this contest does seem to put the proverbial laser-powered cart before the carbon-nanotube horse.
        • Re:Mod parent up. (Score:5, Insightful)

          by IndustrialComplex (975015) on Thursday November 05, 2009 @12:19PM (#29995840)

          Let's say that at our current progress it would take us 30 years to develop a way to manufacture the cable. Then let's assume that it will take 15 years to develop a machine capable of climbing that cable.

          Since the two technologies are completely distinct from each other (i.e. the solution will come from different industries) Doesn't it make sense to develop them in parallel rather than wait for the cable to be developed and then have to wait an additional 15 years for the climber technology to mature?

          I've certainly polished my shoes while waiting for the limo to arrive. If the limo didn't arrive, it would have made the shoe polishing pointless, but I wouldn't want to pay for a limo to wait while I got ready.

          • Re: (Score:3, Insightful)

            I am going to go out a limb here and state that creating the cable is several orders of magnitudes harder than creating a machine to climb it. Maybe even an order of magnitude more orders of magnitude.

            All these little contests do is try to generate support and interest in the space elevator concept. I don't think anything revolutionary will come out of them.

            Its all about the cable.

            • Re: (Score:2, Insightful)

              by FlyingBishop (1293238)

              Meh. Laser propulsion likely has other uses if we develop it to the point where it's useful for space elevators.

              • Re: (Score:3, Informative)

                by natehoy (1608657)

                Actually, this company isn't developing propulsion. Propulsion is an electric motor. This company is demonstrating energy transmission. LaserMotive is even skeptical about the concept of a space elevator, but participated because they wanted prize money to fund further development of energy transmission for more, shall we say, earthly profitable pursuits.

                Long before this could be used for an elevator (due to the lack of "baloneyum" as someone else put it), this technology will probably be perfected and i

              • Re: (Score:2, Informative)

                by gv250 (897841)
                RTFA:

                LaserMotive's two principals, Jordin Kare and Thomas Nugent, said they were relieved after two years of work. They said their real goal is to develop a business based on the idea of beaming power, not the futuristic idea of accessing space via an elevator climbing a cable.

            • by khallow (566160)

              All these little contests do is try to generate support and interest in the space elevator concept. I don't think anything revolutionary will come out of them.

              Wake me when you come across a problem. All I'm hearing are advantages so far.

          • Let's say that at our current progress it would take us 30 years to develop a way to manufacture the cable.

            No. Let's say that it will take us three days to develop the cable.

            I mean - as long as we're saying random stuff that has no connection with reality, we might as well say nice, positive, cool, fun things.

            Once you've made it clear that you have no interest whatsoever in reality and are merely writing scifi, you might as well make it scifi that is worth listening to.

          • Since the two technologies are completely distinct from each other (i.e. the solution will come from different industries)

            And therein lies the limiting assumption of your argument. Something as complicated and grandiose as a space elevator is going to be an extremely complex system of interdependency. Developing the system as a set of discrete parts that can be duct taped together in the end, while it probably will produce a solution, will more than likely produce an expensive, hacky, less robust and less elegant design than if the entire system is approached cohesively as one unit from the start. This is the fundamental appr

      • by khallow (566160)

        Nobody is able to design the cable. We simply don't have the technology, which is why they're focusing on the climber instead.

        This is a bit like having a contest to design a cool hat to be worn while using an anti-gravity belt. If someone wins the contest, then we are one step closer to being able to float while wearing a cool hat - all that's left is the bit with the belt.

        This is an inappropriate metaphor for two reasons. First, the crawler is an integral part of the system. It's not a "cool hat", but part of the belt. Second, it is something we can attain. We don't have the technology yet for an Earth to orbit system (though current technology is good enough for a lunar system), but we know enough that we can design the system even if we can't yet make the materials that we'd build the elevator out of.

        • by Beezlebub33 (1220368) on Thursday November 05, 2009 @03:21PM (#29998200)
          Mod parent up: One of the arguments of the Augustine group against a return-to-Moon-first strategy is that we would have to first climb out of the Earth's gravity well, only to go into the Moon gravity well, and then have to climb out of that. If the space elevator would work on the moon (without unobtainium cabling), then it solves a large part of the moon gravity well problem.

          In addition, a moon space elevator will not have a number of the serious problems that an earth space elevator would have, in particular flying space junk (though there is some around the moon at this point), hurricane force winds, and terrorists. Don't think for a minute that a space elevator is not a juicy target for some pissed off group that knows how to fly planes.
      • by bobbuck (675253)
        Even if they could make the cable how are they going to dampen swings and bounces? In space there's no air to dampen the motion and there's no nowhere for the accumulating energy to go except to make the anchor bounce and sway more and more. The bad part is that the more it swings the higher the gravity will be. Does anyone remember riding the rotating sail-swing ride at the amusement park? It'd be like that but instead of your 150 lb best friend pulling on the cables it'll be ton of potential satellite try
    • by MrTester (860336)

      If the contest is to develop combination cable/climber technology, the only entrants will be those who have the means (financial AND intellectual) to do both. They are two very different scientific skill sets. You would weed out a lot of teams who can bring great value to only one, or the other.

      Keep them as seperate contests, running in parallel.

  • by digitalPhant0m (1424687) on Thursday November 05, 2009 @11:57AM (#29995562)
    Now we've just got to get the helicopter to drop the rope from space, and we're set.
  • I wonder how fast this is at realigning the laser to aim at the elevator. You wouldn't want a gust of wind to push it a few feet to the side and have the laser give the helicopter cancer.
    • by ubercam (1025540)

      That would be terrible! Imagine having to get tumors removed from the rotors or putting the chemotherapy additives into the poor thing's fuel tank... Sure it would probably be able to fly for a bit, but it would probably crash and start puking up oil everywhere. Awful stuff.

      • by nschubach (922175)

        Poor Helicopter. If only the cost of treatment wasn't so high. I wonder if it has insurance.

  • by nightfire-unique (253895) on Thursday November 05, 2009 @12:20PM (#29995850)
    ..we had some great engineers to rush this projects. :)
    • by FauxPasIII (75900)

      Eh, just convert all the hammer-producing cities to Wealth and then switch civics to Universal Suffrage. We'll be there in no time!

  • At the rate of this progress, the space elevator will be in place well before OBL is located. Well done.

  • Is there an obvious plan for the crawler failing half way up the cable? In this test you just set it down with the chopper, but what do you do half way to geosync orbit?

    I guess a second crawler has to go up underneath the failed one, trigger some kind of mechanical release and carry its dead weight down.

    • > Is there an obvious plan for the crawler failing half way up the cable?

      Yes. The passengers rappel down.

    • by natehoy (1608657)

      You'd employ exactly the same technology you'd use to lower the empty elevator car normally. Probably turn the electric motor into a regenerative brake and beam the power back to Earth for storage to use on the next mission, or something.

  • dumb questions (Score:2, Interesting)

    by zogger (617870)

    These are probably really dumb, but what the heck..

    This theoretical tether eventually...they can't run the power up from the ground inside the tether, or maybe down from the geosynch anchor point that has some huge solar power array? Why does the power have to be beamed to the traveling module? Ya, I realize it is a huge distance, but seeing as how they are considering some carbon nanotube structure for the tether, and carbon nanotubes (some) can transmit electricity very efficiently as well (1,000 times be

    • People have proposed building merely tall (a few miles) towers to generate electricity. Given an elevator-sized structure, you'd think the static charge ought to be great enough to power the vehicle.

      • Even if there was enough "static" to supply power less than .04% of the elevator will be in the atmosphere.

    • Re: (Score:3, Informative)

      by natehoy (1608657)

      Well, I'm not a scientist but several obvious ones come to mind.

      For starters, you are going to have resistance greater than air through all but superconductive materials. Second, you're going to have trouble grounding it unless you have two cables, then you're going to need to keep the cables separated or shield them which means two discrete materials. Third, you'll have the issue of voltage surges through (as you've stated in your post) lightning strikes, static electricity, etc - very bad for electric m

      • Weather is hardly an issue when less that .04% of it will be in the atmosphere.

        • by natehoy (1608657)

          That 0.04% still represents a good chunk of distance to be covered. A fall is still fatal even if only the lower 0.0001% of the cable fails due to weather.

          Now, maybe they'll have a different material near the bottom, one that is more weather-proof where the stuff further up is more radiation-proof. But you've still got to solve for the WHOLE cable. 99.96% of a complete cable is precisely as useful as 0%

  • So when this thing gets scaled up for carrying passengers, just how powerful a laser will it need.

    Personally I'd be very wary of traveling in what's basically a lift (american: elevator) with a honkin' great laser firing at the capsule.

    • by natehoy (1608657)

      Compared to riding into space on a rocket? I'll take "giant laser" for 10,000,000,000, Alex.

    • by malakai (136531)

      The idea isn't to use laser power solely. The laser climber is for the early work when there's a very thin cable connecting the two points. Slowly, after year(s) of trips, the cable would be reinforced with more cables. Each new cable increases the tether capacity and allows a larger climber. Eventually lasers are ditched and the bigger climbers rely on other on board energy sources.

  • To give you some idea of the scales involved, even traveling at the targetted 5m/sec speed continuously, it would take the climber nearly 3 MONTHS to get to geosynchronous height of approx 35,000 km.

  • Check out the web site for the space elevator competition [spaceelevatorgames.org]. It includes videos of climb attempts, and lots of data about what they're trying to accomplish and why.

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