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Space Elevator
Scientist Sees Space Elevator in 15 Years
By CARL HARTMAN, Associated Press Writer 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." ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Posted by Big John |
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Big John wrote:
Scientist Sees Space Elevator in 15 Years By CARL HARTMAN, Associated Press Writer 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. The space elevator concept is "discovered" by all the non-SF-reading journalists about once per decade. Hey, isn't the sunspot cycle 11 years long? Hmm..... My favorite variation was describe in (IIRC) Scientific American a while back. Rather than being attached to the ground, this elevator would rotate in orbit like a huge two-armed windmill. As one end descended into the upper atmosphere, about 50,000 ft AGL, an aircraft would dock with the free end (hey, if they can catch falling satellites...) and be hauled up into space. This variant has the advantages needing no ground facilities, avoiding terrestrial storms, and the capability of serving many different points on the globe. |
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"Big John" wrote in message
... 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 Fountains of Paradise". Not Foundations. |
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Space Elevators are obvious, but how does a Space Trim Tab work? :-)
Ron Wanttaja |
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"Ron Wanttaja" wrote in message ... Space Elevators are obvious, but how does a Space Trim Tab work? :-) Ron Wanttaja I dunno, but this seems as good a time as any to bring up a stupid, complicated idea of mine for access to space. First, you should be familiar with the Kelly Aerospace idea of towing the spaceship to altitude. If not, Google for "Eclipse project", NASA, and perhaps F106. They towed an idling F106 behind a C141 as a proof of concept project. Second, you should be aware of the "payout winches" used to ground launch hang gliders. These just pay the line out at a constant tension, rather than reeling them in at a high rate of speed, as in sailplane launches. So here's the scheme: You build a tow plane about the size of a 747. The payout winch is mounted such that it "pays out" from the CG of the airplane, on top. You have somewhere around 100,000 lbs of Vectran tow rope (several tens of kilometers) on the payout device. This is within the cargo capability of a 747, though you may want to throw on a couple of extra engines because of the additional drag. The spacecraft has a CG hook on the bottom. You take off, and climb as high as you can, while paying out the tow line. The spacecraft pilot basically controls the pay out. Pitch up, and a little more line pays out. Pitch down, and it stops. If the spacecraft can maintain a 45 degree angle behind the towplane, it will be 70% of the towrope's length higher than the towplane. At some point, the true airspeed of the tow plane will not provide enough airspeed for the spacecraft to continue to climb. So the towplane starts to turn, and the spacecraft maneuvers to the outside of the turn. Now it's just like playing "crack the whip". The air-breathing booster is down in the (relatively speaking) thick atmosphere at 50,000 feet, while the spacecraft is above most of the atmosphere at say, 100,000 feet. That's when the spacecraft releases and fires its rockets. Because the atmosphere is so much thinner, and the spacecraft is going faster than it would be at lower altitudes, the increase in peak altitude achievable should be much higher than just the 50,000 ft altitude difference between the tow plane and the spacecraft. After the spacecraft releases, the towplane also releases the towline, and it descends under a parachute, separately. There, I feel better. Tim Ward |
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You should post this on sci.space.tech
It is a moderated news group and the signal to nise ration is high. im Ward" wrote: "Ron Wanttaja" wrote in message .. . Space Elevators are obvious, but how does a Space Trim Tab work? :-) Ron Wanttaja I dunno, but this seems as good a time as any to bring up a stupid, complicated idea of mine for access to space. First, you should be familiar with the Kelly Aerospace idea of towing the spaceship to altitude. If not, Google for "Eclipse project", NASA, and perhaps F106. They towed an idling F106 behind a C141 as a proof of concept project. Second, you should be aware of the "payout winches" used to ground launch hang gliders. These just pay the line out at a constant tension, rather than reeling them in at a high rate of speed, as in sailplane launches. So here's the scheme: You build a tow plane about the size of a 747. The payout winch is mounted such that it "pays out" from the CG of the airplane, on top. You have somewhere around 100,000 lbs of Vectran tow rope (several tens of kilometers) on the payout device. This is within the cargo capability of a 747, though you may want to throw on a couple of extra engines because of the additional drag. The spacecraft has a CG hook on the bottom. You take off, and climb as high as you can, while paying out the tow line. The spacecraft pilot basically controls the pay out. Pitch up, and a little more line pays out. Pitch down, and it stops. If the spacecraft can maintain a 45 degree angle behind the towplane, it will be 70% of the towrope's length higher than the towplane. At some point, the true airspeed of the tow plane will not provide enough airspeed for the spacecraft to continue to climb. So the towplane starts to turn, and the spacecraft maneuvers to the outside of the turn. Now it's just like playing "crack the whip". The air-breathing booster is down in the (relatively speaking) thick atmosphere at 50,000 feet, while the spacecraft is above most of the atmosphere at say, 100,000 feet. That's when the spacecraft releases and fires its rockets. Because the atmosphere is so much thinner, and the spacecraft is going faster than it would be at lower altitudes, the increase in peak altitude achievable should be much higher than just the 50,000 ft altitude difference between the tow plane and the spacecraft. After the spacecraft releases, the towplane also releases the towline, and it descends under a parachute, separately. There, I feel better. Tim Ward |
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On Fri, 25 Jun 2004 22:42:15 -0700, Richard Riley
wrote: On Fri, 25 Jun 2004 20:47:03 -0500, Big John wrote: :Scientist Sees Space Elevator in 15 Years : :By CARL HARTMAN, Associated Press Writer : :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. OK, so you use a whole lotta solar power beamed at your cart to climb 62,000 miles straight up (without becoming a crispy critter, but that's another topic). Where are you going to get the mass and energy to accelerate yourself laterally to reach orbital velocity? Aren't you just going to decelerate the beanstalk and send it whipping to the west as the earth rotates beneath you, winding the beanstalk along the equator like an earth sized yo-yo? At 24,000 mile you're at geosynchronis orbit, ready to float free. If you want an orbit lower down you just burn a little rocket fuel (that you brought up with you) to slow down & drop lower. The other 38000 miles of line wants to pull away from the Earth so acts as a counter weight keeping the whole thing pulling straight up. If you keep going past the 24,000 mark before cutting loose you start picking up the velocity you need to get to the Moon, as well as many other fun spots around the system . Any deflection caused by sending payloads up gets cancelled out by stuff coming back down, i.e "My Parents Went to Jupiter & All They Got Me Was This Cheap T-Shirt" x 10-6. H. |
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"Tim Ward" wrote in message ... "Ron Wanttaja" wrote in message ... Space Elevators are obvious, but how does a Space Trim Tab work? :-) Ron Wanttaja I dunno, but this seems as good a time as any to bring up a stupid, complicated idea of mine for access to space. First, you should be familiar with the Kelly Aerospace idea of towing the spaceship to altitude. If not, Google for "Eclipse project", NASA, and perhaps F106. Snip Why not resurrect project Orion and ride the wake of nuclear blasts into space. Tony |
#9
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"Anthony" wrote in message ... "Tim Ward" wrote in message ... "Ron Wanttaja" wrote in message ... Space Elevators are obvious, but how does a Space Trim Tab work? :-) Ron Wanttaja I dunno, but this seems as good a time as any to bring up a stupid, complicated idea of mine for access to space. First, you should be familiar with the Kelly Aerospace idea of towing the spaceship to altitude. If not, Google for "Eclipse project", NASA, and perhaps F106. Snip Why not resurrect project Orion and ride the wake of nuclear blasts into space. Tony Cost? Even if the hardware was free, the infrastructure to support a surface launch would be awfully expensive. I know Niven & Pournelle had something like that in Lucifer's Hammer, but that was an effort to throw off alien conquerors. I thought Orion was space-to-space transportation. The system I've proposed wouldn't be cheap, but it could conceivably take off and land from a regular airport. Tim Ward |
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"Howard Eisenhauer" wrote in message news On Fri, 25 Jun 2004 22:42:15 -0700, Richard Riley wrote: On Fri, 25 Jun 2004 20:47:03 -0500, Big John wrote: :Scientist Sees Space Elevator in 15 Years : :By CARL HARTMAN, Associated Press Writer : :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. OK, so you use a whole lotta solar power beamed at your cart to climb 62,000 miles straight up (without becoming a crispy critter, but that's another topic). Where are you going to get the mass and energy to accelerate yourself laterally to reach orbital velocity? Aren't you just going to decelerate the beanstalk and send it whipping to the west as the earth rotates beneath you, winding the beanstalk along the equator like an earth sized yo-yo? At 24,000 mile you're at geosynchronis orbit, ready to float free. If you want an orbit lower down you just burn a little rocket fuel (that you brought up with you) to slow down & drop lower. The other 38000 miles of line wants to pull away from the Earth so acts as a counter weight keeping the whole thing pulling straight up. If you keep going past the 24,000 mark before cutting loose you start picking up the velocity you need to get to the Moon, as well as many other fun spots around the system . Any deflection caused by sending payloads up gets cancelled out by stuff coming back down, i.e "My Parents Went to Jupiter & All They Got Me Was This Cheap T-Shirt" x 10-6. H. This space elevator thing is elegant in a Newtonian sort of way but I suspect that there is a lot more to it that hasn't been completely thought out. They say put it on the equator where the winds are low. Well, they are low most of the time but there is always the occasional typhoon. Then there are the electrical effects. A carbon nanotube cable will conduct electricity pretty well. Some claim it's a room temperature superconductor candidate. A tropical lightning strike can be several million amps and this cable will be a pretty good lightning rod. There's the induced voltages too. The normal atmospheric potential gradient is several million volts per meter. What about tidal effects? Twice each day the Moons gravity will pull on the structure. Bill Daniels |
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