The private space industry is expected to grow by $7.7 billion in 2004. But many of the fledgling ventures seem extremely risky. Like, say, the company that wants to build an elevator to the stars.

It's not cheap to get stuff into orbit. Just to shoot something into space costs at least $15 million. To reach geosynchronous orbit 22,241 miles up -- where about half of all satellites go so they can stay above the same spot on Earth -- your costs rise above $100 million. Tack on another 10% to 20% for insurance. And make sure you build that satellite right the first time because, once it's up there, you can't fix it. Wouldn't it be nice if you could take an elevator to space?

In the future, you may be able to. That's the hope of the hundreds of space elevator enthusiasts who will touch down later this month at the Loews L'Enfant Plaza Hotel in Washington, D.C., to attend the third annual international space elevator conference. Though the assemblage could be written off as a bunch of crackpots, some of the expected attendees boast good credentials, millions in financing, and because of new nanotechnology, a reasonable-sounding rebuttal to those would dismiss them. Their mission: to build two platforms (one in the ocean and one in orbit) between which a capsule not unlike an elevator could travel.

The idea for an elevator to space is not new. In 1895, a Russian scientist named Konstantin Tsiolkovsky, inspired by the Eiffel Tower, conceived of a "celestial castle" tethered to our planet by a cable. More recently, the sci-fi novelist Arthur C. Clarke gave the concept play in his 1978 book The Fountains of Paradise. The author, who lives in Sri Lanka, is widely quoted as having predicted that an elevator could actually be built "about 50 years after everyone stops laughing." Last year in a speech, Clarke shortened the forecast to a decade.

For folks like Michael Laine, the mirth has already subsided. The former Marine and three-time entrepreneur hopes that his new business, LiftPort Group, will complete a space elevator by 2018. Though the company runs on a shoestring budget and employs only five people, its founder says he is poised to raise $500,000. From there, he hopes to pursue a half dozen elevator-related businesses, from nano- to laser technology. When it is finally completed, the elevator could compete with NASA and the Russian Space Agency as the prime mover (literally) in the solar system. A lot of people are rooting for Laine to succeed. "People are hungry," says Thomas Olson, who is launching the Colony Fund, a mutual fund that invests in space companies. "After people walked on the moon, the universe had been opened to us. We're trying to reclaim that birthright."

"I kept saying, 'What's your return on investment -- your ROI?' And they'd give these puzzled responses: 'What's ROI?"

Michael Laine, is the founder of the LiftPort Group.

The modern conception of the space elevator is simple if audacious. First, you build a platform in the ocean along the equator -- a spot 2,500 miles south of San Diego is the top choice. Then you launch a few rockets into Low Earth Orbit, where they deploy either robots or people who assemble a platform (see sidebar). When that structure is complete, it starts unspooling an ultra-strong ribbon back down to the Pacific.

The ribbon is at first about eight inches wide, but once secured at both ends, devices called "lifters" ascend with more material that widens it. Meanwhile, the platform in space slowly starts rising to 62,000 miles from Earth so that the portion at geosynchronous orbit remains tautly in place. Once the ribbon is three feet wide, it's ready to start hauling payloads of five tons per day. Currently, the cost to deliver a pound of stuff into space is $10,000. If the elevator were operative 200 days per year, it could deliver two million pounds of materiel per year -- resulting in billions in sales.

Of course, in any technology business -- and certainly any that has to do with spacecraft -- things get complicated quickly. First of all, there's the start-up cost. Laine thinks the construction of the elevator will cost between $7 billion and $10 billion over five years, with an extra $1 billion needed just to service debt. Then there's the fact that the ribbon needs to be stronger than anything in industrial use today -- about 30 times the strength of steel. Veteran space industry analyst John Pike, director of GlobalSecurity.org, likes to joke that the required substance should be dubbed "unobtainium."

Elevator boosters counter that newly developed carbon nanotubes -- rolled-up sheets of carbon hexagons -- have been proven in the lab to be about 20 times steel strength. But the ribbon cannot be made solely from nanotubes -- it must be blended with a material like plastic into a composite, which would dilute its strength considerably. Still, Laine is encouraged that large corporations DuPont and Mitsui are throwing money into nanotube R&D.

It wasn't so long ago that Laine himself was skeptical of the potential for making money in space. Four years ago, he was living off a smart real estate investment, having just shuttered a dot-com. In his downtime, he served as the resident curmudgeon on space enthusiast message boards, especially at Lou Dobbs's Space.com. "All of these people were saying, 'Let's go to the moon' or 'Let's go to Mars," he recalls. "I kept saying 'What's your return on investment -- your ROI?' And they'd give these puzzled responses: 'What's ROI?"

Laine's posts elicited an e-mail from a man named Brad Edwards, who wanted to build a space elevator. At first, "I thought it was ridiculous," says Laine, "that this was yet another crackpot." When he learned that Edwards was a physicist who had worked at Los Alamos National Laboratories for 11 years -- and that he had raised $570,000 from NASA to study the feasibility of a space elevator -- Laine reconsidered. The two men met for lunch, which lasted for eight hours. Soon they co-founded a company called High Lift Systems.

The business lasted only about a year. While Edwards preferred to conduct pure scientific research, funded by the government, Laine wanted to build a market-driven company. Edwards, who held 51% of the stock, decided they should split. "I was pretty mad," says Laine, "but looking back, it was the right decision."

Today the former partners are competing to get elevator projects off the ground. Laine says he is trying to negotiate a round of $60 million in private equity from Canadian investors. He is also setting up a website that encourages people to join investment clubs that focus on space (think "The Beardstown Ladies Go to Mars!").

Edwards still doubts an entrepreneurial elevator venture is long for this world. Since jettisoning Laine, he has gained $2.5 million in funding from the government to set up a lab in West Virginia. Uncle Sam's backing has helped him make key contacts while, he says, his former partner spins his wheels. "If Michael Laine is standing there with something, Boeing and the Air Force won't even notice him," he scoffs. That may be. But for many of today's space pioneers, the profit motive seems to be less important than the sheer possibility of what they're trying to do.