Posted on 02/15/2006 10:24:11 AM PST by Neville72
In January, LiftPort team members deployed a mile-long tether with the help of three large balloons in the Arizona desert (N Aung/LiftPort Group)Related Articles 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. Laines 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.
Centrifugal force keeps the counterweight extended. Actually, it should be counterMASS, since weight is only used relative to gravity, and this is more of an inertial effect.
No location actually ON THE EQUATOR has EVER been hit by a typhoon. Flat out, a simple fact.
Duh! They got tired out.
Next time hire robots with more endurance. Geesh!
You want the rotation. That's what keeps the ribbon and the counterweight taught
ok, and when we cycle from the solstice to equinox? I do not recall a ball on a string with one central point wobbling...and the earth's orbit isn't in a constant circle.
even a spinning propeller blade doesn't stay straight...
A good ten - fifteen Years ago, Scientific American (I think it was) published an article dealing with "materials science", which in passing mentioned the "Skyhook Method" of reaching orbit without recourse to gigantic, belching reaction-engines. It may even be that Arthur C. Clarke himself originiated this concept, as so many others... in any case, the critical factor in "elevator-ology" is the tensile strength of the "long wire", which in the materials-science community has long been dubbed "fictionite". Whatever its nature --woven, carbon nanotubes, etc.-- physics requires that as of about 1990, "fictionite" must test 100 times stronger than any known material. In aggregate, it may be that we are approaching this baseline; or perhaps the height of the strand(s) has decreased. But "fictionite" as 100X 1990's tensile strength would yet seem a readily comprehensible baseline. The fact that robotic "crawlers could ascend IF "fictionite" were available is beside the point. Gimme "fictionite", or spare the what-if scenarios, however attractive they may be. Awesome rendering, by the way!
Are they going to get Jack to make the first climb?
This space elevator I think has good solid science behind it. This pretty exciting. My only concern is earthquakes and fault lines. Protecting it against terrorist attcks would seem to be easy a huge no fly zone around it.
--here's the story--
http://science.nasa.gov/headlines/y2000/ast07sep_1.htm
I hope David Gregory was informed.
did nasa try this with the shuttle and determined that the cord as it waved through the radiation belt, generated an electrical charge ?
might be fuzzy on that so dont pounce
OK, maybe I don't fully understand... won't atmospheric friction cause this some trouble?
How much energy is needed to lift a ton 62,000 miles?
Does this imply a geostationary space station?
And once that 100 tonne cargo passes 22,240 miles, it also adds to the pull.
Still a LONG way to be dangling from a string, but not exactly JUST science fiction these days.
Scheduled a remedial reading course...
Ping.
Actually this thing should be more earthquake-resistant than a normal office building.
There are plenty of satellites sitting in geosynchronous orbit which always stay above the same point on the equator. The earth doesn't wobble to make the seasons - the axis is tilted with respect to the plane of our orbit around the sun.
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