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NASA Still Wants Space Elevator
Jerry Smith writes "The Guardian reports 'Each of the groups that will gather in New Mexico is competing to win a NASA prize set up to encourage entrepreneurs to start development work on the technology needed to create a space elevator.' It still might take a while though, progress is slow, so slow."
when a plane runs into the elevator? It only takes one crazy pilot.
The same technologies used to build a space elevator from earth would be usable for building other things: space elevators for other planets, for one, since every body in the system that could use a space elevator has a shallower gravity well than Earth; inter-orbital elevators; rotating tether slingshots; ...
Tornado's, earthquakes, hurricanes, flooding... Mother nature probably poses a very large threat to this thing. And it isn't like you can just let it float or move it around as the need arises, it has to be firmly attached to the planet. Granted a flood doesn't threaten it much, but high winds (hurricane, tornado) could damage the strand. An earthquake could damage the foundation that keeps it there in the first place.
And yes, an aircraft could just aim for it - though I'm sure there would be a lot of restricted airspace within miles of this strand, likely under the watch of the military, so you'd need a fast aircraft to make it there before getting blasted out of the sky. If they use this to launch satellites, you can bet access will be tightly controlled.
I'm still waiting for a giant slingshot. Something the size of an aircraft carrier. Muah!
Try reading 'Fountains of Paradise' to understand the scale at which the space elevator is envisioned. It's not an elevator in the sense you may be thinking of. The idea is to build an initial small elevator, and then use that elevator to lift extra mass onto the elevator itself, and to build up its size until it's a megastructure. The goal isn't to build an elevator with a single shaft that can handle 10 people at a time. The goal is more like having a vertical subway system that can handle a million passengers *per day*. Think of the New York City subway system... only vertical. *Thats* the long term dream/goal of people who are into the concept of the space elevator.
In terms of energy losses, the elevators are generally accepted to be more effecient (admittedly this is theoretical).
It takes enourmous amounts of energy to put anything in orbit. Period. Future technology, in whatever form it takes, will face the same physical limits.
Rocket fuels aren't cheap, and aren't going to get cheaper. Moreover, rockets have a very low weight limit - those commercial launches you mention put up tiny satellites, and even then they cost through the nose.
Show me the advanced launch tech that can put something heavy in orbit today. Oh, right, it's that model of effeciency the space shuttle. Trust me, if that's the cost per pound that a space elevator has to beat, we could make it out of pure gold and still come out ahead.
We don't have anything that can do what a space elevator can. Unless you can show me an example of a launch system (existing or theoretical) that can carry the same weight, then your arguement that "by the time we can build the space elevator, we'll have better tech", is invalid. Seriously, go take a look at stuff like the X-prize craft - these are the "spaceships of tommorow" and they still carry very little payload, to no higher than LEO, for a hefty price.
Erotic is when you use a feather. Exotic is when you use the whole chicken.
In the last discussion we had. You're getting very close to troll territory my friend.
REPOST:
With all the talk lately about a space elevator, I got to thinking after recent slashdot discussion, just what advantages would a space elevator offer over a tower launch? I contacted the man responsible for a similar idea, the skyramp, (warning: hideous javascript menu may break firefox), Carlton Meyer, and had a dialogue in which he pointed me to the tower launch archive.
The ideas I see bandied about there are similar to what I had in mind, which would be essentially an 11km tall tower (think pylons rather than skyscrapers, based at sea), with evacuated airless launch tubes, using nuclear reactors to power a maglev or pulley system to accelerate vessels to escape velocity. These would then emerge above the end of the troposphere [gatech.edu], with it's associated weather and air pressure, and have little to no fuel needed to escape the earth's gravity, meaning you could do a lot more while you were up there. At normal launch accelerations you can get to LEO with very little external propulsion.
Not only would this enable multiple launches daily, it is, unlike the space elevator, readily achievable with today's technology, and financially viable as well. Given NASA had an annual budget of $16.2 billion for 2005 [space.com], and a nuclear power plant costs a cool billion to build, give or take, we could have this up and running in a few years.
Space has got vast, essentially unlimited resources. One recent story pointed out the trillion dollar iron asteroid up there. The thing has about 5 tons of steel for every man, woman and child on earth. And thats just one of god knows how many... billions more?
Once we leap the cost to escape hurdle (as I think I have managed), we can proceed to use these resources. There are several obstacles in the way of this, first of which is zero gee mining, we have no idea how to do it. We can either mine the ore out there, or bring the asteroid back into orbit and slice it up there. Or slice it up and send it back to orbit. I would be opposed to moving it back into orbit for processing, purely for the debris issue. Perhaps a lunar base would have some merit there.
So we set up a mining and processing operation either on the moon or in deep orbit, and start cutting and processing one of those bad boys. Whats the first thing we build? A bigger processing and mining operation. Space exploration, much like the internet, has to be a largely incestuous affair at first, existing solely for its own benefit.
Once we have that mastered, we can move to algae pods in orbit for food production, oxygen refining, and fuel production (biodiesel or chemical engines), all of which can be powered by the immense energy of the sun, and use the raw materials abundantly available in space. Whether you ship that stuff back to earth or use it for further colonisation, its a vital step.
The production of automated scouts is also a high priority; a vast amount of surveyor and prospector drones to sweep and map every square inch of every rock and gas in the system, out to the Oort cloud, and figure out what they are made of. I'd err on the side of quantity rather than quality, still no reason not to have either. This could be combined with deep space observatories that would make hubble look like the end of a coke bottle.
So now we have a manufacturing bridgehead, a good idea of what's interesting out there, and a cheap means to launch to orbit. Actual manned system ships would come next, to either colonise or investigate the system. The rest, as they say, is (future) history.
A lot of this would require automation, robotics, right up to the point when we build a larger manufactory from the orginal small one. Robots would als
What he can't kill, he has sex on. Trent.
Um. All the first order research was done by the military. In particular the German military.
I'm going to assume you're including the efficiency of the electricity generation in that calculation. i.e. Start at around 35% efficient and get worse from there. It will almost certainly require a dedicated nuclear power station to run.
Rocket fuel is not the expensive part of the operation, the fuel cost is negligible compared to the cost of the administration and infrastructure. i.e. the NASA bureaucracy. The shuttle should of course have been scrapped decades ago and replaced by an unmanned heavy lifter, but that's NASA for you. Atlas V, Proton etc can both handle payloads about as big as the shuttle and for a tiny fraction of the price.
Um, I haven't made that argument. My argument is that by the time a space elevator comes around, rockets and rocket launches will be on a production line and their costs will be amortised over far more launches than currently. Commercialising the launch business will bring cheap space flight, NASA never will.
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The climbers going up the SE will be the size of a small bus, about 10 tons, and will go up one per day. It's unlikely any will come down the SE; standard reentry procedures are much cheaper for that. The very first thing we'll do with an SE is build another, and then another; after a decade or two, there'll probably be a dozen SEs sticking out from the Equator. The first one may cost $10 billion, but the second will be 20% of that.
I am feeling SO disappointed with my fellow slashdotters.
I've read through every comment on this thread that is scored 2 or above, and every one of you is seeing less than half of the space elevator's potential. You are all so one-way in your thinking.
Let me try to prime the pump of your imaginations...
Visualize a one pound iron ball, sitting in your hand. How much energy would that ball release on impact if you are on an airplane at 5,000 feet and you drop it out the window? Do you think it might break a car's windshield? Do you think it might put a heck of a dent in a car's roof?
Now drop it from 23,000 miles....
So long as we move enough mass down the space elevator, we can capture enough energy using existing regenerative braking technologies to power lifting side. If we move more mass down than that, the space elevator becomes a power generator. And the beauty of this is, it isn't important what we move downward, so long as we can put some kind regenerative braking on it.
As we begin to explore space elevator technologies, we should also begin to think about how to start nudging a near Earth asteroid into a position where we can get at it easily when we are ready to start dropping things down the elevator shaft. Ion engines might be the ticket. At first it won't matter much what we drop down the shaft, but eventually we'll get more picky.
At some point we'll want to build a solar powered distillery at the end of our string, so we can deliver bottled water mined from comets or icy asteroids to the thirsty. We'd do the bottling at the surface, after running the water through 23,000 miles of water wheels and turbines. And we'd probably build a solar furnace at Strings End to reduce nickel iron asteroids to ingots that would fit special drop tubes.
Well, that's it. I'm tired of playing Heinlein. Somebody else can imagine the distribution system for the surplus power.