MUST HAVE A GOOD HEAD FOR HEIGHTS
NOW ACCEPTING APPLICATIONS
Posted on 08/13/2002 7:55:13 PM PDT by Brett66
Going up? Space elevator wins support
U.S. company builds on Russian idea
Dan Rowe
National Post
Tuesday, August 13, 2002
The fantastic notion of a space elevator -- a concept that first appeared in a Russian technical journal in the early 1960s and then crept into the works of science fiction author Arthur C. Clarke in the 1970s -- could be a reality before long.
Seattle-based HighLift Systems is hosting a conference this week to meet with investors and other parties potentially interested in a device that could open the final frontier to the masses within 15 years because of the space elevator's relatively low costs and extremely high traffic volume.
NASA has given HighLift a US$570,000 grant to continue research into the elevator and the company has received an indication of support from the European Space Agency, which has representatives attending the Seattle conference.
"With a system as inexpensive as ours, every nation could have a space program. Most universities could have a space program. And a few corporations could have their own space program," said Michael Laine, the company's president.
"We're bringing it down to the level where maybe not everybody, but an awful lot of people can have access to space in a realistic way."
HighLift Systems' space elevator would not be quite the same as that of Mr. Clarke's imagination.
Unlike the science fiction version, this space elevator need not be anchored improbably both to Earth and an asteroid.
Instead, it would be tethered just to Earth from a floating platform in the equatorial Pacific Ocean.
From there, a 100,000-kilometre-long ribbon about one metre wide with the thickness of a sheet of paper would be propelled by rockets beyond the point in space where orbiting objects remain above a fixed point on the Earth's surface, the so-called geosynchronous orbit.
The elevator would be kept in place by the competing forces of gravity at the lower end of the shaft, and, at the far end, outward acceleration.
Mechanical climbers, powered by an electric motor, would scale the ribbon, hauling the cargo thousands of kilometres before catapulting the payload, which could include anything from satellites to human passengers, to its destination.
Travelling at average speeds of anywhere from 120 km/h to 160 km/h, the length of a voyage to low Earth orbit might be as brief as four hours.
A longer trip into the geosynchronous orbit would probably last a week.
Of the technology required to construct the US$10-billion elevator, the only piece that does not exist is the material that would constitute the ribbon -- carbon nanotube composite.
Mr. Laine said the material, expected to be highly conductive and 30 times stronger than steel, is not yet in production, but a Japanese car company is planning to begin producing it for use in the bodies of its vehicles.
Expected to be operational in 15 years, the space elevator's biggest advantage is the tonnage it can deliver.
"We expect to be able to lift five tonnes of cargo every day and ... we're going to do about 250 trips, or 1,200 tonnes of cargo a year. That compares to the space shuttle, which is able to launch 20 tonnes at a time, but only six times a year," Mr. Laine said.
The space elevator would offer more destinations to its customers at about one one-100th the cost of using the space shuttle.
"The shuttle has a very limited capability of lower orbit. Our system allows you to go lowest orbit, to geosynchronous orbit and you could use it as a slingshot to send you to to other destinations like Mars or Venus or asteroids."
That is why potential private-sector investors attending the Seattle conference include Fortune 100 companies whose interests lie in everything from energy to communications to manufacturing.
The public sector has already chipped in.
Perhaps the project's most impressive endorsement of all comes from the man whose writing inspired the development of the elevator.
In a letter to the editor in the April, 2001, issue of Scientific American, Mr. Clarke offered his support for the space project.
"When (not if!) the space elevator is built, the cost of reaching stationary orbit will be virtually zero," the veteran science fiction author said.
THE SPACE ELEVATOR:
A 100,000-kilometre-long ribbon, with one end attached to the Earth and the other end in space, relies on the competing forces of gravity and centripetal acceleration to remain taut over a single position. The estimated cost is less than U.S.$10-billion.
THE CLIMBER: A climber proceeds to the far end of the ribbon and releases, having sufficient energy to escape from Earth's gravity and travel to the Moon, Mars or Venus.
THE LASER: The climber is powered using a laser that beams at photo cells on the climber's underside. The power is converted to electricity, which is used by conventional electric motors and set of rollers to pull the climber up the ribbon at speeds up to 200 km/hr.
THE ANCHOR: The proposed anchor zone is in the Pacific Ocean near the equator, where high winds and fierce storms are not common.
Source: Highlift Systems
I wouldn't want to be living near the equator if it broke.
MUST HAVE A GOOD HEAD FOR HEIGHTS
NOW ACCEPTING APPLICATIONS
Check your physics textbook or at least a dictionary.
That wouldn't be the failure mode. The cable might snap in the middle, but it is balanced overall. A Boy Scout tentpeg could hold it down on the ground until the thing starts whipping around due to other factors.
That wouldn't be the failure mode. The cable might snap in the middle, but it is balanced overall. A Boy Scout tentpeg could hold it down on the ground until the thing starts whipping around due to other factors.
I don't have that old Analog Sci-Fi magazine around anymore, but in there they estimated the cable would have to be a kilometer thick at the main stresspoint. I think it was carbon fiber construction.
That's a lot of carbon.
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