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."
From reading previous threads in the past year, this could be the ultimate bug zapper.
"Rope Ladder to the Moon" -Jack Bruce/Pete Brown
It will be stable wherever the base is anchored. This is not a problem.
Good question. I guess we'll need a few more million dollars "to study the problem." :)
As the elevator whips out on the cable, the energy will come from the earth's rotational kinetic energy.
That did happen in Kim Stanley Robinson's "Red Mars". The station at the space end was destroyed. What you get is a superheated (by re-entry) cable 62,000 miles long wrapping itself around the planet until it's all back down leaving an amazing path of destruction.....pretty ugly, no?
It's pretty easy to tell that the guy's not telling the truth.
Over the past couple of years I've read a dozen articles about the potential for building a space elevator. Some very well educated research scientist wrote a few of them and none mentioned any one thing or problem or group of problems that would invalidate building a space elevator.
Heck, I'm just a humble satellite guy who understands orbits and can do a bit of math....
You admit as much. Perhaps their expertise is over your head.
It will be subject to gravitational and other perturbations up in space, where the opposite end is not anchored to anything. This is a problem.
What if it was right at the South Pole?
There must be some kind of mass balance. Whatever mass is sent up must be balanced by an equivalent mass coming down. The velocity changes would be positive for one and negative for the other, but balanced.
Attaching to the pole might require a giant dogchain swivel.
There must be a damping mechanism. This would apply whether the base is anchored at the equator or farther north or south.
You admit as much. Perhaps their expertise is over your head.
Irony alert.
I think that thing you just heard zinging overhead was the point.
Unless, as it seems, you're suggesting that a guy who does orbital mechanics for a living must obviously take a back seat in these matters to a guy who apparently excels in writing grant requests?
From the link... "Current plans call for a base tower approximately 50 km tall -- the cable would be tethered to the top. To keep the cable structure from tumbling to Earth, it would be attached to a large counterbalance mass beyond geostationary orbit, perhaps an asteroid moved into place for that purpose. "
See? All we have to do now is figure out how to capture an asteroid, move it TOWARD EARTH to within 25,000 miles, and stablize it into earth orbit. And tie a rope to it.
That could take weeks.
Actually, I haven't been to Fairmont since my first college track meet in 1969 (the "Fairmont Relays"). For that matter, I only became a West Virginian in 1997. But anyone can see that WV's senators are Byrd and Baby Brother. We clearly still have a few problems on the political front.
Given that the thing has to be dropped down to Earth from GEO, and that all of the necessary stuff (actually, twice the mass of the cable) has to be launched up there on rockets, how many heavy lift launches do you suppose it would take to do that? Answer: several, at $300 million a pop. Let's say it takes 10 launches (very unrealistic), so that's $3 billion out of your budget already.
Next, you've got to develop, design, build, and test EVERYTHING ELSE for $7 billion. Not gonna happen, even in the private sector.
You admit as much. Perhaps their expertise is over your head.
LOL! Put up or shut up about expertise, Zon.
96 - "They weren't able to measure the potential, but fortunately, they didn't lose the Shuttle when it blew up from the current it had generated."
"Actually the tether got stuck in the reel."
I think youall are both right. IIRC There were several experiements, and none completely successful.
The cable will be torqued in one direction by the rising object, and in the other by the descending one -- it will look like a 62,000 mile high letter "S".
Ya?
I know its moving, just like a rock on the end of a string spinning round (I've given up scarfing Oreos so I don't have enough mass to capture the rock in my orbit anymore, so we'll use a string for the gravity vector and the beanstalk).
So I spin and my rock whirls round and round; what is to stop a bug from traversing the string (other than a stiff breeze)? The rock has a lateral vector of 0 relative to me and the surface of my body. My body is spinning at the same rate (in radians per second) as the rock and the bug. A car coming down the beanstalk would not pick up any lateral velocity (in radians per second) relative to the surface of the earth.
And yes the cars move really fast. They need to, it is a long trip!
(Getting really dizzy now. Flumph! Ouch!)
I think I can see part of it. There is a lateral velocity change as it goes down the beanstalk, but I think there math that describes how that works, somewhere, probably having to do with orbital velocities, etc.
Or it goes into the side of the beanstalk requiring adjustments (or tearing it apart). Just like you said.
Some pretty amazing people seem to think it will work though.
Hmm. Bead, rock, string. spin rock on end of string. Raise and lower bead on string (using second string?) see how the "beanstalk" deforms. Science project anybody? Need really long string and something to spin to for you.
Thanks!
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