Space-elevator tether climbs a mile high
15:29 15 February 2006
NewScientist.com news service
Kimm Groshong
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 A slim cable for a space elevator has been built stretching a mile into the sky, enabling robots to scrabble some way up and down the line.

LiftPort Group, a private US company on a quest to build a space elevator by April 2018, stretched the strong carbon ribbon 1 mile (1.6 km) into the sky from the Arizona desert outside Phoenix in January tests, it announced on Monday.

The company's lofty objective will sound familiar to followers of NASA's Centennial Challenges programme. The desired outcome is a 62,000-mile (99,779 km) tether that robotic lifters – powered by laser beams from Earth – can climb, ferrying cargo, satellites and eventually people into space.

The recent test followed a September 2005 demonstration in which LiftPort's robots climbed 300 metres of ribbon tethered to the Earth and pulled taut by a large balloon. This time around, the company tested an improved cable pulled aloft by three balloons.

Rock solid
To make the cable, researchers sandwiched three carbon-fibre composite strings between four sheets of fibreglass tape, creating a mile-long cable about 5 centimetres wide and no thicker than about six sheets of paper.

"For this one, the real critical test was making a string strong enough," says Michael Laine, president of LiftPort. "We made a cable that was stationed by the balloons at a mile high for 6 hours…it was rock solid."

A platform linking the balloons and the tether was successfully launched and held in place during the test. LiftPort calls the platform HALE, High Altitude Long Endurance, and plans to market it for aerial observation and communication purposes.

But the test was not completely without problems.

The company's battery-operated robotic lifters were designed to climb up and down the entire length of the ribbon but only made it about 460 m above ground. Laine told New Scientist that the robots had worked properly during preparatory tests and his team is still analysing the problem.

Carbon nanotubes
In March, LiftPort hopes to set up a HALE system in Utah's Mars Desert Research Station and maintain it for three weeks. Then, later in the spring, Laine says he wants to test a 2-mile (3.2-km) tether with robots scaling to at least half way up.

Laine aims to produce a functioning space elevator by 2018 – a date his company chose in 2003 based on a NASA Institute for Advanced Concepts study, which said an elevator could be built in 15 years. "This is a baby step, but it's part of the process," he says of LiftPort's recent test.

The idea is to build the actual elevator's ribbon from ultra-strong carbon nanotube composites and to have solar-powered lifters carry 100 tonnes of cargo into space once a week, 50 times a year.

Beams and climbers
Laine sits on the board of the California-based Spaceward Foundation, which partnered with NASA to put on two space-elevator-related competitions that were the first of the agency's Centennial Challenges programme – the Tether Challenge and the Beam Power Challenge.

The first is designed to test the strength of lightweight tethers while the beam challenge tests the climbing ability and weight-bearing capability of robots scaling a cable. Laine’s team is not competing in the NASA challenges so there is no conflict of interest.

In October 2005, none of the competition entrants performed well enough to claim the twin $50,000 purses. But the challenges are scheduled to take place again in August 2006 with $150,000 top prizes. Nineteen teams have signed up for the beam power challenge so far and three will compete in the tether challenge.

Ben Shelef, founder of the Spaceward Foundation, hopes the competitions will drum up interest and drive technological innovation. He told New Scientist he is pleased to hear of LiftPort's successful test. "A journey of a thousand miles starts with a single step," he says.

How about something more practical?

Walmart could use a tunnel to China...

Quoted: How about something more practical? Walmart could use a tunnel to China...

That's got to be one of the more stupid statements I've seen in a long time. I hope you're not serious.

I wonder if they can harness the induced current from the cable to power it.

I wonder how much a ride to 15 grand costs?

Quoted: I wonder if they can harness the induced current from the cable to power it.

I can't find a link to it, but way back when this tech was science fiction the modulation of the voltage produced(apparently the higher you go, and the weather/atmosphereic pressure change the voltage produced dramatically), and some type of storage was the big question. Also the space end of this thing has to be really, really geosynchronus to not go plop somewhere in everybody's backyard.
Interesting stuff though....

Quoted: Quoted: How about something more practical? Walmart could use a tunnel to China... That's got to be one of the more stupid statements I've seen in a long time. I hope you're not serious.

+1


A space elevator would be VASTLY useful

I bet Arthur C. Clarke is smiling.






FYI




http://en.wikipedia.org/wiki/Arthur_C._Clarke%27s_list_of_the_best_science_fiction_films

.

How does it handle wind? Winds aloft can get pretty serious at times, 200+ kts.

Quoted: Quoted: Quoted: How about something more practical? Walmart could use a tunnel to China... That's got to be one of the more stupid statements I've seen in a long time. I hope you're not serious. +1 A space elevator would be VASTLY useful

Ooops...pissed off the proffessor...

I'll go sit in the back of the classroom now...

Yes, of course it would be usefull....

Imagine if someone farted in it? Think how long the ride is!

How long is the ride?  62,000 miles is a long damn time. I guess if they could reach 500 mph it would be only 128 hours, but that is still 5 days.  Now you need a lot of life-support equip.  How far up could it still pull oxygen from the atmosphere, rather than have to store it?

How is it "powered by lasers"?  Wouldn't the tether bend in the wind?  Lasers go straight, as far as I know.  Would the rotation of the earth cause the end of it to pull away from the Earth so hard that it stays straight?

What if the cable breaks?  Would the trolleys be equipped to freefall back to earth with parachutes?  That would involve some form of science, because above a certain level, gravity might not get them going back toward Earth if there were some type of upward motion associated with the break.  And if they are spinning, there would have to be some sort of auto-stabilization system to reenter the atmosphere "shields-down" if they were up high.

This things almost as scary as the current space shuttle.

am i the only one that sees someone tring to base jump form it?

Quoted: am i the only one that sees someone tring to base jump from it?

"Yeeeehaaaaa!!"

Quoted: What if the cable breaks?  Would the trolleys be equipped to freefall back to earth with parachutes?  That would involve some form of science, because above a certain level, gravity might not get them going back toward Earth if there were some type of upward motion associated with the break.  And if they are spinning, there would have to be some sort of auto-stabilization system to reenter the atmosphere "shields-down" if they were up high.

That was postulated in the Red Mars/Blue Mars/Green Mars trilogy. The cable was so long that when it was broken, it wrapped itself around the planet something akin to three times. By the time the end of the cable hit, the difference in speed between the planet surface and the cable was such (A sort of whiplash effect) that the cable hitting was akin to a linear nuclear explosion. Basically, it wasn't pretty. And yes, the trip up or down took about 5 days, if I recall.

NTM

The idea is great, but logistically and from a safety stand point it sounds extravagant.

Quoted: The idea is great, but logistically and from a safety stand point it sounds extravagant.

Yup - but in terms of cost per pound, it is so much cheaper to get things into orbit, that it would likely be worth the investment at some point.

Quoted: Quoted: The idea is great, but logistically and from a safety stand point it sounds extravagant. Yup - but in terms of cost per pound, it is so much cheaper to get things into orbit, that it would likely be worth the investment at some point.

Agreed.  However, you can forget me being a beta tester on this one.

Quoted: Quoted: What if the cable breaks?  Would the trolleys be equipped to freefall back to earth with parachutes?  That would involve some form of science, because above a certain level, gravity might not get them going back toward Earth if there were some type of upward motion associated with the break.  And if they are spinning, there would have to be some sort of auto-stabilization system to reenter the atmosphere "shields-down" if they were up high. That was postulated in the Red Mars/Blue Mars/Green Mars trilogy. The cable was so long that when it was broken, it wrapped itself around the planet something akin to three times. By the time the end of the cable hit, the difference in speed between the planet surface and the cable was such (A sort of whiplash effect) that the cable hitting was akin to a linear nuclear explosion. Basically, it wasn't pretty. And yes, the trip up or down took about 5 days, if I recall. NTM

That actually sounds pretty cool!

Wouldn't the cable burn up as it whips into the atmosphere though?

Quoted: Quoted: How about something more practical? Walmart could use a tunnel to China... That's got to be one of the more stupid statements I've seen in a long time. I hope you're not serious.

are you an engineer, by chance?

What about a really really big rubber band for a really really big sligshot, and shoot what you want into space as a projectile?

Some one.  Please tell me an actual benefit from this thing.

Cause right now... it looks like ANOTHER big waste of money.

Quoted: How long is the ride?  62,000 miles is a long damn time. I guess if they could reach 500 mph it would be only 128 hours, but that is still 5 days.  Now you need a lot of life-support equip.  How far up could it still pull oxygen from the atmosphere, rather than have to store it?

Where are they going with that?  That's 1/4 of the distance to the moon!

An escalator, maybe.  But not an elevator.

Quoted: Quoted: Quoted: What if the cable breaks?  Would the trolleys be equipped to freefall back to earth with parachutes?  That would involve some form of science, because above a certain level, gravity might not get them going back toward Earth if there were some type of upward motion associated with the break.  And if they are spinning, there would have to be some sort of auto-stabilization system to reenter the atmosphere "shields-down" if they were up high. That was postulated in the Red Mars/Blue Mars/Green Mars trilogy. The cable was so long that when it was broken, it wrapped itself around the planet something akin to three times. By the time the end of the cable hit, the difference in speed between the planet surface and the cable was such (A sort of whiplash effect) that the cable hitting was akin to a linear nuclear explosion. Basically, it wasn't pretty. And yes, the trip up or down took about 5 days, if I recall. NTM That actually sounds pretty cool! Wouldn't the cable burn up as it whips into the atmosphere though?

On Earth the upper parts of the cable would burn up in the atmosphere, but Mars's atmosphere is less than 1% as thick as Earth's so the upper parts of a Martial elevator might not burn up.  Also a Martian elevator would be MUCH shorter than one being built on  the Earth.

Just to put the scale of this prototype to the real thing in proportion, the World Trade Center was 1,362 feet high.  A 1:62,000 scale model of it would be 0.26 inches high.  Think of the challenge of building the World Trade Center as compared to a 0.26" high model, just to put into perspective how much of a challenge remains.

Quoted: Some one.  Please tell me an actual benefit from this thing. Cause right now... it looks like ANOTHER big waste of money.

Some googling found the following numbers:
It currently costs about $23,000 to send 1 pound of payload to LEO (Low Earth Orbit) using the Space Shuttle.  ESA'a Arianne is a bit cheaper at ~$11,000/lb.  These costs are MUCH more to get a sattelite to geosynchronous orbit (where communications satelites are)

I couldn't find any concrete numbers for space elevator launch costs (not construction) but the estimates I've seen have been in the $500-$1000/lb to LEO or Geostationary orbit.  Even if the costs are 10x these estimates it is still cheaper to operate a space elevator than to lift payloads using rockets.  

ALSO, since the tether will go a bit past geostationary orbit, you can use the angular momentum as a kind of "sling" to throw a probe towards a planet without using any fuel.  You could have built and launched at least one and possibly 2 more Mars rovers for the same $820M is cost to build and launch the 2 we have now.

Basically a space elevator lets you build cool stuff and get it off the earth without having to pay out the nose to get it off the earth.

If you are interested in the idea of a space elevator, I recomend reading this essay by Arthur C. Clarke first, followed by this wikipedia article.

thanks for the links hooptie

Personally I'm more interested in a Space Ferris Wheel.  And only if there are corn dogs and funnel cakes at the end.

Chemical  rockets produce a lot of enviromental pollution too

If we build it, it would help our superpower status even more-think about a orbital rail gun shooting hypersonic, GPS guided projectiles for arty!

one,its never gonna happen.  I can't believe they are ever pushing forword with the idea.  Two, If it did work, it would not burn up,  things burn up in the atmosphere because of frriction against the atmosphere.  This thing would be stationary with the earths surface. wind would be a problem.  I'd say lightning would be a real problem.

Quoted: Quoted: Quoted: How about something more practical? Walmart could use a tunnel to China... That's got to be one of the more stupid statements I've seen in a long time. I hope you're not serious. are you an engineer, by chance?

No, just a space enthusiast who reads a hell of a lot.

I think there are many issues that would have to be overcome, and I can think of one very major one:

Heat expansion.

I don't know the thermal expansion characteristics of buckminsterfullerene tube, but I'm willing to bet that with 62,000 miles of the stuff, you're going to be gaining and losing at the very least a few miles of slack on a regular basis.

Quoted: I think there are many issues that would have to be overcome, and I can think of one very major one: Heat expansion. I don't know the thermal expansion characteristics of buckminsterfullerene tube, but I'm willing to bet that with 62,000 miles of the stuff, you're going to be gaining and losing at the very least a few miles of slack on a regular basis.

You gain and lose a few miles of slack just from the gravitational influence of the MOON.

Heat is not a problem with CN, expansion and contraction are similar to diamond.

The thing to remember is that the space elevator is not ATTACHED to the Earth, it is hanging DOWN from geosynchronous orbit.  It will have a tail, the most likely base station is a modified oil rig, the ribbon would slide up and down through it with the wind and tidal forces.  As long as it can be located laterally, it can slide up and down and packages can still be clipped onto it.

LiftCorps design uses a extra long ribbon that balances itself by streatching UP some 30,000 miles above geosynchronous orbit, instead of just dangling down from a artificial counterweight that would have to be lifted up through conventional means and would not be of much use once it was in place.  Extending the ribbon up would allow you to use it as a slingshot to launch packages to other planets.  On the other hand it is that much more technically demanding to make a ribbon that long.

Okay. So let's say the elevator goes all the way to the top.

THEN what? Is there a floor up there we can drop the stuff off at? Will it be at escape velocity so as to STAY up there? Are we going to have to pile everything up next to it?

I dunno. My brain is not capturing the practicality of this.




ETA: I'll read that eassay above. Thanks.

Quoted: Okay. So let's say the elevator goes all the way to the top. THEN what? Is there a floor up there we can drop the stuff off at? Will it be at escape velocity so as to STAY up there? Are we going to have to pile everything up next to it? I dunno. My brain is not capturing the practicality of this. ETA: I'll read that eassay above. Thanks.

Well yeah, packages released from the elevator would stay up, all you would need is a small thruster to give it seperation from the teather.

Quoted: Some one.  Please tell me an actual benefit from this thing. Cause right now... it looks like ANOTHER big waste of money.

Domination of space.



We can either control the high ground, or we can let the Chinese do it.