Is the Final Frontier Just One Ride Away On a Space Elevator?
By Lee Gomes
Wall Street Journal
August 22, 2007; Page B1
http://online.wsj.com/article/SB118773478835004552.html?mod=technology_featured_stories_hs
Tie a rock to the end of a piece of ribbon, then spin it over your head. It
will be pulled taut as the rock circles about. Now, imagine a ribbon 62,000
miles long, anchored near the equator with a weight on the other end. The
centrifugal force of the earth's rotation will make it behave the same way.
You'll end up with not only the world's biggest nunchuck, but also a kind
of elevator to outer space.
A space elevator is one of those ideas from 1950s-style futurism that are
so whacky they might just work. A thriving community of elevator buffs
certainly thinks so; they meet online at sites like spaceelevator.com.
NASA is sufficiently intrigued that it has kicked in millions of dollars
for a space-elevator design competition. The third annual running of the
contest takes place in October outside of Salt Lake City; 22 teams, mostly
from universities, have signed up to compete.
[NASA]
An artist's concept of a space elevator, looking down along its length
toward Earth.
To the extent that a space elevator is feasible at all is due to advances
in the science of nanotechnology, especially carbon nanotubes. These are
atomic-scale threads with a tensile strength greater than steel but with
vastly less weight; when bound together, they become unimaginably strong.
The long spine of the proposed elevator would be 30 inches wide but only as
thick as a sheet of paper. Wade Adams, a nanotech researcher at Rice
University, said nano engineers have created threads 15% as strong as those
needed for an elevator, and continue to make steady progress. Existing
nanotube threads are already triple the strength of the Kevlar strands used
in bulletproof vests.
The main theorist of the space elevator is Brad Edwards, a former Los
Alamos National Lab physicist who spent three years under a NASA contract
figuring out if a working elevator could be built. Yes, he concluded, and
here's how:
A rocket would take two spools, each the size of a living room with 31,000
miles of ribbon wrapped around it, to an orbit of 22,000 miles. Both would
be unrolled, one being allowed to waft back to earth, the other pulled up
and away from earth by a spacecraft and then anchored with a weight at the
end. Then they'd be joined in the middle.
The bottom portion would be secured onto an oil rig-like platform located
along the equator, 1,500 miles west of Mexico, a location chosen for its
uneventful weather.
The ribbon would weigh 800 tons, or about 26 pounds a mile. Were it to
break, the top segment would float away into space while the bottom would
fall to earth. Nothing you'd want to be on hand to see, of course, "but
nothing that would threaten the planet," says Dr. Edwards.
The actual cab of the elevator -- the "climber" -- would attach to the
ribbon via rollers. It would zip up at 120 miles an hour, requiring a week
to reach the very top. While there's nothing but deadly space radiation to
keep people from making the trip, the elevator is mostly conceived as an
all-cargo affair, especially for satellites.
Remarkably, it could also be used for trips to the moon, Mars or beyond.
Recall, says Dr. Edwards, that the earth rotates once every 24 hours,
meaning that something tethered to it 62,000 miles up travels at more than
20,000 miles an hour. If you're at the top of the elevator and time it
right when you let go, you can be whipped to just about anywhere you want
to go, with a nudge or two from booster rockets.
The teams at the October event will be entering a miniature version of a
climber that will need to go up and down a 400-foot tether. To win the $1
million prize, a climber has to make the trip within a specified time. Last
year, a team from the University of Saskatchewan (this year, five of the 22
entries are from Canada) came within 0.04 second of winning.
Climbers, in general, get their power from the ground. Last year, the
Saskatchewan team members aimed powerful light beams at their climber,
which then used solar panels to convert the light into electricity. This
year, says captain Clayton Ruszkowski, they're switching from light beams
to lasers that are a million times as strong as the one in your DVD drive.
Back east in Cambridge, Mass., the MIT team is working on a climber that
will work on beamed-up microwave energy.
Dr. Edwards estimates a real elevator would cost $12 billion and could pay
for its operations by capturing 25% of the commercial satellite-launching.
As for NASA, says Dr. Edwards, it's committed to the contest not
necessarily because it's sold on the idea, but because it's interested in
the sort of spinoff technologies that elevator research might make
possible, such as for advanced composite materials that might be used in
other spacecraft.
Another use of the space elevator contest is to get schoolchildren
interested in something besides their iPods. Diana Jennings, associate
director of the Institute for Advanced Concepts, a NASA-funded outfit
sponsoring the contest, says young eyes light up when she talks about the
elevator.
Not even the space shuttle elicits that reaction. "Everything else is just
TV for them now," she says.
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George Antunes, Political Science Dept
University of Houston; Houston, TX 77204
Voice: 713-743-3923 Fax: 713-743-3927
antunes at uh dot edu
