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LaserMotive Finds Success In Space Elevator Competition
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.'"
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.
I want to delete my account but Slashdot doesn't allow it.
Ad Astra! Ad Luna! Ad Lagrange Point 2!
What if someone farts in the space elevator? You'll be stuck for way more than a few floors.
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.
The problem is, I'm sure, soluble, but the technical difficulty should not be underestimated.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
(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.)
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
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.
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
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
A longevity vaccine would prevent longevity, there's no need to develop that one, you could use a gun against your head for that purpose, you mean an Aging vaccine.
Now we've just got to get the helicopter to drop the rope from space, and we're set.
I thought these guys had it pegged?
Of course, producing enough of the stuff and making the belt out of it is still non-trivial...
- "History shows again and again how nature points out the folly of men" -- Blue Oyster Cult, 'Godzilla'
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.
..we had some great engineers to rush this projects. :)
A government is a body of people notably ungoverned - AC
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 better than copper according to some wiki thing I just read)...
And with that said, to counteract that, how the heck are they going to avoid lightning and static electricity and so on on *any* tether? Won't this aspect imperil any construction and use of this for a space elevator, has this been theoretically solved yet, or is it even a problem? (yes, this is all googleable, I would rather get a clear short synopsis from folks who know about this better)
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 solid in a liquid, and loosening a "knotty" problem.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
Surgeon General's Warning:
Don't look down with remaining eye.
"Kill 'em all and let Root sort 'em out"
Outside of the fact that we can't effectively design the cable, how high would the cable be placed out in to space?
The counterweight has to be beyond geostationary orbit. So at least 25k miles. Plus the whole assembly will be dragged along by the part connected to Earth so it's not going straight out to geostationary. I've heard something like 60k miles.
making the issue of getting out of our atmosphere a relatively dull process
...until someone creates space elevator music. Then it will become a dull, agonizing process.
Your brain is not a computer.
You are thinking of a vehicle which completely wraps itself around the cable, why not a space elevator which has several dozen cars moving on it at all times by having multiple "rails" and sending vehicles behind each other like our current train system. When a vehicle gets to the top or the bottom it is disconnected and moved out of the way for loading/unloading. Even two "rails" would allow for a circuit transfer while having 6+ would mean a constant flow of travel.
Orwell was an optimist.
You seem to be rather ignorant of the idea, and all of your concerns are addressed directly in Edwards' book, The Space Elevator.
A single climber on a single cable is the first step, as it is most cost effective to launch. Once it is up, the first priority is widening the ribbon, and producing more ribbons. Once they are in place, loss of any single ribbon would be not be very significant, as the ribbon itself is cheap, and deploying it is now cheap.
Next, the goal was always to run multiple climbers up the ribbon, in a single direction, as that makes best use of the ribbons capacity. For climbers spaced along the ribbon, the force of gravity is greatly reduced the further up you go, so you can fit considerably more on the ribbon as compared to a single heavy climber. Still, you have the option of clearing the ribbon and sending up very heavy items, it would just cost more.
Anything else you can think of has also likely been addressed in that book, from technology to economics.
No conrflakes required. I'm afraid that's an example of the English sense of humour, which doesn't travel well and is why we need to spend so much on our Armed Forces.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
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.
The more people I meet, the better I like my dog.
I have a degree in physics, maybe you should go check your book. The force of gravity varies as 1/r^2, so the vast majority of the ribbon is not at all deep in the potential well.
If that is difficult to understand, here is an example, straight from the book on page 167: you can have 24 50 ton climbers spaced along a 200 ton capacity ribbon. They even developed a formula for it: "Within an upper limit of 1/3 of the ribbons capacity, the maximum number of climbers is 6C/M, where C is the ribbon capacity, and M is the mass of the proposed climber."
As for your three points:
1. The ribbons are not expected to fail often. It will happen eventually, but it just won't be a big deal.
2. That is not an insurmountable engineering problem, and depending on where they break, you may not even lose the whole thing.
3. It is not enormous, nor expensive; the first 200 ton ribbon discussed masses 8,900 tons, and is expected to cost $5B. (For perspective, the Sears Tower weighs in at 222,500 tons, and the Golden Gate Bridge at 419,800 tons.)
It is "friggin obvious" that it will happen at some point, it is only a matter of when. The necessary materials may be difficult or impossible to produce with current methods, but once molecular nanotechnology arrives, they will be both manufacturable, and extremely cheap, without question.
For comparison, the first ribbon (20 ton capacity) is estimated at ~$6B. While I won't discourage you from advocating laser propulsion in the near term, the capacity and economics will never allow for large scale manned space operations. It is not and will never be a replacement for the space elevator,
Yes, but this is more like losing all of Cape Canaveral and Houston whenever a bolt breaks in a Space Shuttle during liftoff.
Well, my degree is engineering, and I am going to simplify my argument for you to understand it.
See, the reason the Space Shuttle and aerospace operations in general is so darn expensive is because rockets are very large, complex assemblies of hardware whereby if a small number of failures occur, you lose the entire mission. You have to design and build a rocket to handle the enormous amounts of vibration and G-forces of launch, yet every ounce you add reduces payload because chemical rockets have such low ISP. This permeates to every aspect of design. Then, during manufacturing, you have to have ridiculous levels of quality control, with every assembly step taking place in a clean room. You have to use the most expensive available materials, such as titaniums and carbon fiber and stainless steel, because the cheaper materials are too weak and weigh too much. The whole endeavor becomes ridiculously complex, with enough paperwork to make Communist Russia proud.
A space elevator still fundamentally has the same constraint. Every bit of elevator cable has to be made in a similar clean room, paperwork happy environment. Every mission has to be done as carefully as a space shuttle mission, with many missions dedicated just to conducting yet another inspection of the cable. Every bit of weight you add to the cable as you are building it (whether that weight be for safety systems or whatnot) reduces the cargo capacity, yet making the cable lighter makes it more expensive and unsafe.
You've basically solved nothing by going with a space elevator, and cost estimates in that book you read are probably off by at least an order of magnitude.
Remember, it only costs a bit over a million dollars (I'll find the exact number if you like) to fuel the space shuttle. All the rest goes to costs like I mentioned above.
With laser launch, all the important hardware (the lasers and mirrors) stays on the ground. It can weigh any arbitrary amount, and be built to whatever shoddy standard you want. It only has to work well enough such that enough lasing modules are online during an entire launch. You can mass produce the modules in China, and you don't need to have paperwork tracking the fate of every last bolt going into a laser module : because if the module fails, it's not going to compromise the mission. (unless a LOT of modules all were to all fail at once)
Rather than a thousands of miles long cable, you have a big campus of buildings spread across many square miles. Nothing short of a megaton range nuke is going to take out your ability to launch spacecraft.
The spacecraft itself will not fail if you don't make it in a clean room. It's just a bolt of inert metal strapped to a radio beacon. You don't actually even need the beacon to work. The payload can be anything you want, and once laser launches are in full swing, spacecraft and satellites will be made to much lower, mass production standards since if the spacecraft fails while in orbit, you don't lose as much money as you would today. Even manned missions will rely on redundancy much more than high quality hardware, since it's cheaper to launch everything and the kitchen sink than it is to make your manned space habitat to the exacting standards of today.
A comparable anology is to compare the cost of computing when google does it versus the mainframes of the 1960s.
I look forward to your rational as to why laser launch "It is not and will never be a replacement for the space elevator"
Seems like you could get a lot more cargo up into space if you are launching 200 tons every 10 minutes (a full scale laser launcher with as much light output as the space shuttle main engines) than 200 tons every few days.