Obayashi To Build Space Elevator By 2050 488
mattr writes "Japan's Obayashi Corp. has announced plans to build a space elevator by 2050. They are famous for wrecking skylines with the over-sized bullet train station in Kyoto, the world's tallest self-supporting tower Tokyo Sky Tree and just recently, the beginnings of the Taipei Dome. It will take a week at 200 kph for your party of 30 to reach the 36,000-km-high terminal station, while the counterweight [swings along at] 96 km high, a quarter of the way to the Moon."
Does anyone feel that this is a good concept? (Score:5, Interesting)
Look, ultimately you can't know if a technology is a good idea without actually building the tech, full scale, and spending the time and money to create revised versions to fix the major problems.
After you do that, some technologies are still a dog, no matter how you try to hide it. Nuclear power is an instance of that : sure it works, but the risk of catastrophe overshadows everything, and means that if you try to build and run a reactor everything costs too much because of the dangers. In the long run, nuclear is not feasible because other technologies will keep getting cheaper.
I feel a space elevator is a dog for a similar fundamental reason : there's one 36,000 km high structure.
Any serious failure to a manufacturing defect along 36,000 km of cable, and you lose every last dime invested in the project. (not to mention the falling cable might cause some nasty problems). If someone ever wants to attack a space elevator, it's a perfect terrorism target. One homemade cruise missile (in 2050, I suspect making a cruise missile won't be much harder than RC airplanes are today. Heck, some garage tinkerers already have done similar projects) and the ENTIRE elevator falls.
Not to mention laser fire, railgun fire, bad weather, etc etc. There's a lot of things and it only has to fail at one point.
Furthermore, you have to complete the elevator project before it is worth anything. Invest all that money to FINISH the cable, you can't get incremental results. And this multi-billion dollar structure (realistically probably hundreds of billions) has a rather limited cargo capacity : one load of passengers a week is NOT a rapid movement to space.
So, no. It's an idea that has somehow gained traction, but it is most likely a non-starter.
I propose a much simpler idea : rather than use lasers on the ground to transmit power to the elevator climber car, scale up those laser arrays a few orders of magnitude to the point that they can vaporize propellant off the bottom of the spacecraft. Pulse the beams right, and planar shockwaves will be created, giving net thrust without any kind of nozzle.
Advantages :
1. Ablative Laser propulsion doesn't require anything in the spacecraft in the way of aerospace hardware but a small instrument package to report attitude and accelerations back to the ground. Gyroscopes for stabilization would be nice, but not essential.
2. If a laser module on the ground fails or wears out, the launch continues..10 or 50% redundancy is entirely feasible.
3. You can do one launch every few minutes, assuming you use LED diode pumped fiber optic lasers, and have sufficient cooling capacity to remove the waste heat and sufficient power generation. That could be a metric ton or so to orbit every 15 minutes, 24/7, 7 days a week.
4. You do 1000 or 10,000 unmanned cargo launches before you send the first man up in a spacecraft identical to the one used for cargo (well, with life support inside, but identical flight hardware). This kind of sampling size allows you to honestly evaluate the safety of the system. In the event of a problem, you turn the beam off instantly and deploy parachutes. (such as beam heating of the side walls or something). No rocket to explode.
5. Each spacecraft will be extremely cheap, just a block of an inert solid bolted to the bottom, and a small instrument package (an iphone has all the circuitry needed, although of course you would use more sensitive accelerometers) and a radio. Obviously, some kind of orbital maneuvering system is also needed, but you can get to orbit without it.
Disadvantages :
1. Reflected beams from the lasers might cause problems for observers on the ground. Might have to create a large exclusion zone around the launch site, with air travel forbidden in a large radius. Not a big deal, tons of places in the Arizona desert. Still, with so many people involved, it seems likely a few people would be blinded if the lasers used were visible light.
2. It would r
Re:Great concept except for .... (Score:2, Interesting)
The fact that we don't have the necessary structural materials yet to actually make a space elevator.
We have the materials, just not the means to produce them in the necessary quantities. I'm pretty sure the ancient Egyptians didn't have the necessary materials to build giant stone tombs either, but they built them so large that it took the rest of the world to build something bigger.
Neither Japan nor any Japanese company has the financial solvency to undertake such an effort
Well, if nobody wants to finance something so obviously profitable a few decades in the future then we really need to rethink our economic system, because at this rate, humanity isn't going anywhere in every sense of the word.
No no wants to spend a week in an elevator even if it means you get to go into orbit. Christ I can barely make it to the 15th floor without some jackass farting. A whole week. Don't think so.
Think of it as another form of transport then. Nobody wants to travel for a week, but people have been riding cruise ships on month long trips just fine.
And such companies usually have spent the bulk of the cash on P.R. - hence the slashdot article.
Make no mistake. The primary use of a space elevator is not for amusement. Setting up orbital infrastructure and mining resources in space would skyrocket Earth economy to unimaginable levels. Once we have that set up, we can think of building more of the things, and use knowledge gained in the first one, to improve future designs. As a bonus, building one means we already have the necessary infrastructure to produce the required materials. Somebody is going to make a killing.
Bring it on (Score:5, Interesting)
Where will they build it? (Score:4, Interesting)
Re:Does anyone feel that this is a good concept? (Score:3, Interesting)
A few corrections.
1. The cable is permanently stretched by a counterweight at the 96000 km altitude. If you sever the cable 1 km from the surface, the bottom 1 km falls to the ground, the top 95999 km fly away and settle in an orbit around the Earth.
2. If you can manage to build a 96000 km cable, it should be trivial in comparison to build a protective sheath in the form of a 10-foot-thick concrete chimney surrounding the base of the cable up to the elevation of 5 km or so. That takes care of R/C helicopters, cruise missiles and 20mm rifle rounds.
3. With the first space elevator in place, it is relatively straightforward to use it to build the second elevator next to it. You hang a horizontal platform at 36000 km, you start hauling up sections of the cable, and you grow the second elevator in place in both directions at once, until one end reaches the surface. Assuming that you can produce the cable cheaply enough and that you know how to weld sections of the cable without jeopardizing tensile strength, soon you will have two cables, then five, then twenty ... The hard part is to get the first one up there.
Re:Counterpoint (Score:2, Interesting)
Well, in Europe, most long-distance train tickets are much more expensive than the comparable flight. I would take that as a strong indication that planes are in fact cheaper overall than trains. I don't really know why, though.
It is simple, really. Railroads have enormous infrastructure to maintain and costs of doing that are mostly fixed. Trains demand high utilization to be cost effective. That could be achieved only through massive subsidizing and that is not very popular. Mind you, automobile road networks are even costlier than railroads, but due to their apparent more "democratic" asynchronous nature, they get much more utilization. If railroads were devised as some kind of endless high speed conveyor belts on which you can gradually embark with your personal or cargo vehicle at certain points along the route, they would be quite a success.
"Running costs are negligible" (Score:5, Interesting)
Vandalism, terrorist or not, and theft are probably the biggest issues. Carbon fibre hasn't taken over for the cables of suspension footbridges for just that reason.