Imagine the title transport device of Roald Dahl's Charlie and the Great Glass Elevator (the follow-up to the more popular children's book), becoming a reality. That is the lofty goal of NASA and a number of private companies.

Last October saw the first NASA-sponsored Space Elevator Games, which offered a $200,000 prize to the first team that could make a machine climb up a 164-foot tether, powered only by a mirror and a beam of light from a 10,000-watt bulb. Actually, none of the home-brewed contraptions on display could reach higher than 40 feet.

But dammit, government and private-sector spending is soaring. And indeed, the hottest idea in space enterprise is a tether to take us all the way from Earth to orbit.

Worldwide government spending on space is reaching $50 billion a year, a one-quarter-percent jump over 2000. NASA represents only $16 billion of that total, but during the next 20 years, the U.S. space agency is likely to sign contracts totaling as much as $400 billion to launch a human mission to Mars. Further, in 1998, private-sector spending on space applications began to exceed government spending, and that gap is widening. A critical mass of entrepreneurs have been backing space-related companies for years.

So why such importance on an elevator, something so seemingly banal we may actually ride one when shopping for clothes at the department store?

A working space elevator would reduce the cost of launching anything into space by roughly 98 percent. The $500 million it takes to launch the average satellite (insurance not included) would be history. In addition to cutting costs, the space elevator would increase the amount of cargo capacity for orbital trips; more than 90 percent of a space shuttle's weight is fuel, with cargo making up less than 5 percent. But no fuel is necessary on the elevator, because the car would be electric, with power cells energized by a ground-based laser beam. (Of course, like all things, there is a downside.)

The theory behind the elevator is quite manageable, as a recent Business 2.0 article points out. First proposed 111 years ago by a Russian scientist, the idea was popularized by Arthur C. Clarke in his 1978 novel, The Fountains of Paradise. It goes like this:

Earth is constantly spinning. So if you attach a counterweight to it with a cable, and put it far enough away — 62,000 miles — the cable will be held taut by the force of the planet's rotation, just as if you spun around while holding a ball on a string. And if you've got a taut cable, you've got the makings of an elevator.

The cable, known to elevator scientists as a ribbon, would be dropped in stages from space and hooked up to a floating platform similar to an offshore oil rig. An elevator car roughly the size of a Boeing 747, able to carry hundreds of people or 200 tons of cargo, could climb and descend the ribbon at a speed of 120 mph. That means the first trip to geosynchronous orbit (22,000 miles) would take seven days, but scientists say that could be reduced to four days by the time the first passengers make the journey.

However, until 1991 no substance came close to being strong, lightweight and durable enough to do the job of the required material for the ribbon. Then came carbon nanotubes, an arrangement of carbon atoms that became the strongest material ever tested. Nanotubes are as much as 100 times stronger than steel, yet they weigh only a fifth as much.

Indeed, a carbon nanotube string the width of sewing thread could easily lift a large car. A nanotube elevator ribbon would need to be no thicker than plastic food wrap. Nanotubes would also make the elevator car simultaneously large yet light. The longest nanotubes thus produced measure only a few inches, though that doesn't prevent them from being ribbon-ready.

(via Wikipedia)

The problem is that, at $500 per gram, nanotubes are currently too expensive, and worldwide production is estimated to be less than 100 pounds per day. Perhaps, then, commercializing nanotubes is the key to building the elevator.

LiftPort Group, a private U.S. company on a quest to build a space elevator by April 2018, is focused on the short-term earning power of nanotubes, planning to produce the "longest, strongest" nanotubes possible. The company's founder, Michael Laine, is chasing the success of carbon fiber, a similar material that has blossomed into a $2 billion market, according to Business 2.0. "Long before you see an elevator climbing into the sky, you're going to see bridges, buildings, cars, and boats designed in a fundamentally different way," Laine says. "Every industrial process we've got, we're going to throw out the window."

In January tests, LiftPort stretched the strong carbon ribbon 1 mile (1.6 km) into the sky from the Arizona desert outside Phoenix, New Scientist announced mid-February. LiftPort's desired outcome: a 62,000-mile tether that robotic lifters — powered by laser beams from Earth — can climb, ferrying cargo, satellites and eventually people into space.

The theory is solid, the materials exist, and garage-dwelling inventors and entrepreneurs continue tinkering.

Sources

The 62,000-Mile Elevator Ride
by Georgia Flight
Business 2.0, Feb. 24, 2006

Space-elevator tether climbs a mile high
by Kimm Groshong
New Scientist, Feb. 15, 2006

Additional

Second Round of Space Elevator Technology Completed
by Michael Hoffman
DailyTech, Feb. 16, 2006