Posted on 06/25/2004 2:21:35 PM PDT by Junior
WASHINGTON - President Bush (news - web sites) wants to return to the moon and put a man on Mars. But scientist Bradley C. Edwards has an idea that's really out of this world: an elevator that climbs 62,000 miles into space.
Edwards thinks an initial version could be operating in 15 years, a year earlier than Bush's 2020 timetable for a return to the moon. He pegs the cost at $10 billion, a pittance compared with other space endeavors.
"It's not new physics — nothing new has to be discovered, nothing new has to be invented from scratch," he says. "If there are delays in budget or delays in whatever, it could stretch, but 15 years is a realistic estimate for when we could have one up."
Edwards is not just some guy with an idea. He's head of the space elevator project at the Institute for Scientific Research in Fairmont, W.Va. NASA (news - web sites) already has given it more than $500,000 to study the idea, and Congress has earmarked $2.5 million more.
"A lot of people at NASA are excited about the idea," said Robert Casanova, director of the NASA Institute of Advanced Concepts in Atlanta.
Edwards believes a space elevator offers a cheaper, safer form of space travel that eventually could be used to carry explorers to the planets.
Edwards' elevator would climb on a cable made of nanotubes — tiny bundles of carbon atoms many times stronger than steel. The cable would be about three feet wide and thinner than a piece of paper, but capable of supporting a payload up to 13 tons.
The cable would be attached to a platform on the equator, off the Pacific coast of South America where winds are calm, weather is good and commercial airplane flights are few. The platform would be mobile so the cable could be moved to get out of the path of orbiting satellites.
David Brin, a science-fiction writer who formerly taught physics at San Diego State University, believes the concept is solid but doubts such an elevator could be operating by 2019.
"I have no doubt that our great-grandchildren will routinely use space elevators," he said. "But it will take another generation to gather the technologies needed."
Edwards' institute is holding a third annual conference on space elevators in Washington starting Monday. A keynote speaker at the three-day meeting will be John Mankins, NASA's manager of human and robotics technology. Organizers say it will discuss technical challenges and solutions and the economic feasibility of the elevator proposal.
The space elevator is not a new idea. A Russian scientist, Konstantin Tsiolkovsky, envisioned it a century ago. And Arthur C. Clarke's novel "The Foundations of Paradise," published in 1979, talks of a space elevator 24,000 miles high, and permanent colonies on the moon, Mercury and Mars.
The difference now, Edwards said, is "we have a material that we can use to actually build it."
He envisions launching sections of cable into space on rockets. A "climber" — his version of an elevator car — would then be attached to the cable and used to add more lengths of cable until eventually it stretches down to the Earth. A counterweight would be attached to the end in space.
Edwards likens the design to "spinning a ball on a string around your head." The string is the cable and the ball on the end is a counterweight. The Earth's rotation would keep the cable taut.
The elevator would be powered by photo cells that convert light into electricity. A laser attached to the platform could be aimed at the elevator to deliver the light, Edwards said.
Edwards said he probably needs about two more years of development on the carbon nanotubes to obtain the strength needed. After that, he believes work on the project can begin.
"The major obstacle is probably just politics or funding and those two are the same thing," he said. "The technical, I don't think that's really an issue anymore."
I don't know the guy, but I rather suspect that r9etb may very well have written more articles than you've "read" over that timespan.
Well, why don't you ask him how many articles he has written on the topic of space elevators and had them published. He is put one person in one specialize field. What I read was from several research scientists in several fields required to build a space elevator. ...Economics, nanotechnology, space flight, physics etc.
An article in Analog 30 years ago came up with a thickness of the cable of a mile at the maximum stress point. I think it was carbon fibers or spider silk, too soon for carbon nanotubes. Steel in any thickness would not support its own weight.
well, lets put some simple numbers to it.
the cable alone will weigh about 9 million lbs, minimum. The shuttle has a payload of about 40,000 lbs.
That means, just to carry the cable into orbit, will take about 230 shuttle flights.
Each shuttle flight, (before colombia) cost about $500 million.
somehow the numbers just don't add up.
Also, how do you connect together 230 pieces, and make each of them strong enough to hold 9 million pounds
Well, all that boring -- and practical -- and above all, UnPC -- stuff lives on, but only in the works of Niven and Pournelle, sadly.
If physics doesn't kill mankind's expansion into space, leftist environmentalists worried about things like disturbing the "environment" on a dead planet sure will.
I think that these neoluddite leftist nitwits' efforts notwithstanding, the future will be quite remarkable, if only because we've never seen such a mighty culture go face down onto the tarvey, shoelaces tied together, and blindsided into the gut. It's got to be a spectacular sight to behold. (If only there was some nice viewing stand safely outside the shock zone, though...)
Take a look here:
http://www.qadas.com/qadas/nasa/nasa-hm/0492.html
"Blew up" is a pretty strong word. They measured a potential greater than expected however.
Why don't you lay off the coffee for a few minutes?
162 - "An article in Analog 30 years ago came up with a thickness of the cable of a mile at the maximum stress point. I think it was carbon fibers or spider silk, too soon for carbon nanotubes. Steel in any thickness would not support its own weight."
I remember that. A cable a mile in diameter, that makes more sense. But, the article here specifies about 3 feet wide, and the thickness of a piece of paper, which works out to about 9 million pounds. As for cable a mile in diameter, I haven't got a clue, except, there is no way to build or launch it.
We have a long way to go studying Material Science before this happens.
NERVA was awsome. I would love to see it make a return.
Wow, that "Zon" is quite the jovial character, isn't he. That's an amazing death-grip he's got on your ankle. His teeth must be killing him by now! :)
Anyone can read the discussion and decide for themselves. It's obvious that you can't handle it. Your remarks give you away.
The Point is, I have more confidence in my other sources than r9etb. Apparently you have a problem with that.
If the cable is carbon a mile thick we might have trouble getting the materials together at all. OTOH, it would be a place to sequester all that nasty greenhouse carbon.
Would make a great attraction for some theme park.
Well, neither Niven nor Pournelle is known for being particularly politically correct. You have read the Larry Niven interview on Space.com where he explains why we don't have flying cars, haven't you?
I think that these neoluddite leftist nitwits' efforts notwithstanding, the future will be quite remarkable, if only because we've never seen such a mighty culture go face down onto the tarvey, shoelaces tied together, and blindsided into the gut. It's got to be a spectacular sight to behold. (If only there was some nice viewing stand safely outside the shock zone, though...)
People usually snap to their senses when the threat looms large enough. The key will be whether they snap to their senses before it's too late or if they will wait until nothing can be done about it before noticing the problem.
The universe just doesn't want us to get out of the gravity well cheaply or travel faster than the speed of light, it seems.
What about quantum entanglement with it's proven potential to instantaneously give information at a distance. And with nanotechnology in the future (keeping in mind the accelerating technology curve) creating an object at a distance could involve creating the necessary software programming at a distance to create an object at a distance. Say for example, a telescope on the moon.
They had a show about it the other night. It's amazing how close they were to making it mission ready. Perhaps, if we are lucky, it will make a return for the manned mission to Mars. It would greatly reduce their fuel needs.
How much of a distance and how do you turn it into "travel"? And how do you travel across long distances and multiple frames of reference without violating causality?
And with nanotechnology in the future (keeping in mind the accelerating technology curve) creating an object at a distance could involve creating the necessary software programming at a distance to create an object at a distance. Say for example, a telescope on the moon.
The current pace of technological growth is no guarantee of future technological advances. Given that the universe is finite, I don't believe that the potential of technology is infinite.
NASA also funded some crackpot anti-gravity research. They've clearly jumped the shark. They can save money on elevator research by reading the "Fountains of Paradise."
It's one thing for one satelite in one orbital position in space to avoid being hit very often. But a tether will have a continous string up to 62k miles.
By definition, ALL satelites MUST cross the equator twice each orbit, unless they're exactly on the equator. And that's where they have to anchor this thing, on the equator.
And the equator is exactly where the vast majority of satelites are. At 22k miles, in the Clarke belt transmiting Fox News to my house.
This thing wouldn't last a week before it was hit by something, and it's irrational to think they're going to clean the skys of all satelites below 62k miles altitude. It can't "dodge" traffic like the ISS and Shuttle occasionaly do, because it's physically anchored to the ground with huge stresses keeping it bow string tight.
Why is NASA giving money to this thing? It's got to be a huge hoax.
165 - perhaps, but I ran across something very interesting:
http://science.nasa.gov/newhome/headlines/ast08sep97_1.htm
"A propulsive tether would weigh about 90 kg (200 lbs.). In turn, it would eliminate the need to haul up to 4,000 kg (8,800 lbs.) of chemical propellants to the station. Atmospheric drag on the station will be about 0.3 to 1.1 newton (depending on the time of year), and the tether could produce 0.5 to 0.8 newton of thrust.
A reusable space tug - called an electrodynamic tether upper stage - could be built using the propulsive tether to haul satellites from a launch vehicle in low orbit to higher orbits. The sky is not quite the limit on propulsive tethers. The technique requires an ionosphere, a region of electrified gas which acts as part of the electrical circuit. Around the Earth, it tapers off around 1,500 km (900 miles).
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