Posted on 02/15/2006 7:54:40 PM PST by FARS
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.
I have completed 90% of the time machine I am building... It's all there, mostly, just a pesky 10% left that involves presently nonexistent materials, unachievable energies, and other unstudied physical principles that have never been described in any way.
Thank you. What was the posting picture bit? I'm new.
--I'm not sure either--
Why use "ultra-strong carbon" when you can use MEGA-ultra strong carbon instead? Fools.
"... and to have solar-powered lifters carry 100 tonnes of cargo into space once a week, 50 times a year."
I guess they have taken into account some dramatic acceleration in the earth's solar orbit due to the effects of this space elevator (THE space elevator- the one that will be built real soon... that one), which will force us to change our calander system to only 50 weeks a year, instead of the absurd 52-week pattern that we currently follow.
It's good to plan ahead like that.
Your humor is instructive.
This is not like that at all. This is based on well known physics, and at on theoretically possible materials. Currently nonexistent it's true. But if you don't try to make them existent, they never will be.
Which works out to about 740 miles per hour for the weekly round trip.
Doesn't that missing 10% make it hard to decide what color to make it?
Only 370. You don't need to wait for the return basket to send the next one up. In fact, it helps reduce weight if it works like a dumb waiter.
90%? I figure, "1 down, 61,999 to go."
You hit the LIGHTNING nail on the head. The electrical capacitance between the earth and ionosphere is 400,000 volts with an average discharge rate, via lightning, of 1800 Amps. You puncture that capacitor with ANYTHING solid and you've shorted out that giant capacitor, the ENTIRE WORLD'S WEATHER changes when you remove that 50V/meter electro-gradient from the atmosphere. I've been in contact with liftport for a few months now, telling them to forget pie-in-the-sky space elevators and make useful LOWER atmospheric applications, all the governments of the world will STOMP on them asap if they screw up the entire world's weather just to get mass to LEO cheaper...by shorting out the GIANT CAPACITOR of the earth-ionosphere.
My thoughts exactly.
you may not need a laser to push the robot to the top. All the megajoules coming down may provide a cute source of energy.
7.2 x 10^9 watts coming out of that filament, right?
It would make more sense to tap that power for a rail gun and launch a few tons of cargo into space every few minutes.
Noisy proposition that would be...
But if you put a HUGE Leyden jar at the bottom, and route that to...and then cross connect to...FREE ENERGY, right to the meter!
As an ADDED bonus, no more Global Warming...unless it heats up even quicker.
Has anyone seen how they deal with coriolis acceleration?
They act as if it doesn't exist.
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