The key to conquering the solar system is inside a black plastic briefcase on Brad Edwards’s desk. Without ceremony, he pops open the case to reveal it: a piece of black ribbon about a foot long and a half-inch wide, stretched across a steel frame.
Huh? No glowing infinite-energy orb, no antigravity disk, just a hunk of tape with black fibers. “This came off a five-kilometer-long spool,” says Edwards, tapping it with his index finger. “The technology is moving along quickly.”
The ribbon is a piece of carbon-nanotube composite. In as little as 15 years, Edwards says, a version that’s three feet wide and thinner than the page you are reading could be anchored to a platform 1,200 miles off the coast of Ecuador and stretch upward 62,000 miles into deep space, kept taut by the centripetal force provided by Earth’s rotation. The expensive, dangerous business of rocketing people and cargo into space would become obsolete as elevators climb the ribbon and hoist occupants to any height they fancy: low, for space tourism; geosynchronous, for communications satellites; or high, where Earth’s rotation would help fling spacecraft to the moon, Mars, or beyond. Edwards contends that a space elevator could drop payload costs to $100 a pound versus the space shuttle’s $10,000. And it would cost as little as $6 billion to build—less than half what Boston spent on the Big Dig highway project.
Science fiction writers, beginning with Arthur C. Clarke in his 1979 novel, The Fountains of Paradise, and a few engineers have kicked around fantastic notions of a space elevator for years. But Edwards’s proposal—laid out in a two-year $500,000 study funded by the NASA Institute for Advanced Concepts—strikes those familiar with it as surprisingly practical. “Brad really put the pieces together,” says Patricia Russell, associate director of the institute. “Everyone is intrigued. He brought it into the realm of reality.”
“It’s the most detailed proposal I have seen so far. I was delighted with the simplicity of it,” says David Smitherman, technical manager of the advanced projects office at NASA’s Marshall Space Flight Center. “A lot of us feel that it’s worth pursuing.”
Still, there’s many a slip between speculative space proposals and the messy real world. The space shuttle, to name one example, was originally projected to cost $5.5 million per launch; the actual cost is more than 70 times as much. The International Space Station’s cost may turn out to be 10 times its original $8 billion estimate. While NASA takes the space elevator seriously, the idea is officially just one of dozens of advanced concepts jostling for tight funding, and it was conspicuously absent from President Bush’s January 14 address, in which he laid out plans for returning to the moon by 2020, followed by a manned mission to Mars.
So the United States does not appear to be in a mad rush to build an elevator to heaven anytime soon. On the other hand, for reasons Edwards makes abundantly clear, the United States cannot afford to dither around for decades with his proposal. “The first entity to build a space elevator will own space,” he says. And after several hours spent listening to Edwards explain just how and why that is so, one comes away persuaded that he is probably right.
The office of the world’s leading space elevator designer is across the street from the Foxx Pawn Shop in the somewhat frayed downtown of Fairmont, West Virginia. The little mining community of 19,000—hit hard by the 1990 Clean Air Act, which made the local sulfurous coal a tough sell—aims to become a high-tech hub, helped by lashings of funds from Congressman Alan Mollohan, a ranking member of the House Appropriations Committee. Edwards is director of research for the Institute for Scientific Research, a four-year-old technology development house headquartered here in a new, cool, rather spartan office building. The space elevator is the most prominent of a dozen projects on the institute’s agenda.
Edwards is not the first to contemplate a great structure rising from Earth’s equator, flinging payloads into space like David’s sling. That distinction probably goes to Russian space visionary Konstantin Tsiolkovsky, who in 1895 imagined a tower so tall that when an elevator occupant reached 22,000 miles, gravity “would be completely annihilated, and then it would again be detected . . . but its direction would be reversed, so that a person would have his head turned towards the earth.” Throughout the 20th century, the visions came thick and fast, replete with fanciful names: Skyhook, Heavenly Ladder, Beanstalk, Orbital Tower, even Cosmic Funicular. But every serious study concluded that the elevator’s track could not be built, because no known material was strong enough to support itself, much less legions of freight-hauling elevators, over such a yawning expanse.
Then in 1991, while studying the unique atomic structures called buckyballs, which are created by electrically charging carbon soot, Sumio Iijima of Meijo University in Nagoya, Japan, discovered the first nanotubes—fantastically strong cylindrical carbon-atom constructions less than two nanometers wide and of varying lengths. If such nanotubes could be chained together with no loss of strength, a piece as thin as sewing thread could lift a large automobile.
During the 1990s, several scientists speculated that a space elevator ribbon could be made from nanotubes, but “it was just an idea mentioned in passing,” says Edwards. Then came a day in 1998 when Edwards chanced to read a interview with a scientist—he does not recall the name—who declared that the space elevator would be completed in “300 years to never.”
“Yet he didn’t give any reasons why it couldn’t be done,” says Edwards. “That got me going.” A wunderkind of astronautical engineering during his 11 years at the Los Alamos National Laboratory, Edwards led the development of the world’s first optical cryocooler, a breakthrough device that achieved supercold temperatures with no moving parts (“It breaks two, if not all three, laws of thermodynamics,” he says), and designed missions to the moon and Jupiter’s moon Europa. Intense and energetic, he used to hang glide for fun and wanted to be an astronaut. NASA rejected him because he has asthma. “I’m not timid. My feeling is, you can do a nine-to-five job, or you can take on something larger. At 29, I designed a lunar mission to map out all the elements and look for water. This seemed like a natural progression.”
In 1999 Edwards published a paper on the space elevator in the journal Astronautica, then spent two years writing a detailed plan for NASA. The plan calls for using a deployment booster assembled in low Earth orbit to carry two spools of 5- to 10-inch-wide pilot ribbon into geosynchronous orbit, 22,000 miles above the equator. The ribbons will unwind down toward Earth as the spools simultaneously ascend to 62,000 miles into space, always keeping the center of the ribbons’ mass near the geosynchronous point. The dangling ends of the ribbons will be anchored to a platform similar to an offshore oil rig in the Pacific Ocean. From there, an unmanned device called a climber, equipped with traction treads, will “zip” the ribbons together as it is powered heavenward by lasers focused on solar cells.
INSIDE THE EXPRESS CAR
The space shuttle is an ear-splitting, bone-rattling ride, beginning with eight minutes of inertial forces peaking at three g’s (three times an individual astronaut’s weight) followed by a near-instant, stomach-churning flip to zero gravity.
By contrast, the space elevator would offer gracious access from Earth to space.
The first five miles would seem familiar to air travelers, but at the seven-mile mark, Earth’s curvature would become noticeable, and by 30 miles the sky would turn black and the stars would become visible, even in daytime, on the climber’s shaded side. Windows would need to be thick and coated for pressure containment and radiation protection, but a tourist-oriented climber would no doubt feature a high-resolution television screen providing panoramic views.
At 100 miles, Earth would clearly appear as a partial sphere. By 215 miles, gravity would drop by a noticeable 10 percent; by 456 miles, it would drop 20 percent. And at around 1,642 miles—roughly 13 hours into the trip—it would drop by 50 percent. “We can’t test it before we actually build a ribbon, but the slow reduction of gravity during a multiday trip may well serve to significantly reduce the number of people adversely affected by zero gravity by the time they get to the geosynchronous orbit station,” Brad Edwards says.
At the 22,000-mile-high geosynchronous orbit stop, Earth would appear the size of a baseball held at arm’s length. A permanent station floating nearby could offer a variety of tourist attractions, such as wild zero-gravity versions of ball-and-stick sports, or even the possibility of a visitor flying like a bird though large open spaces using wings strapped to the arms.
Someday, Edwards says, an entire ribbon might be devoted to the tourist trade with a hotel permanently affixed at 8,700 miles, where there is one-tenth of Earth’s gravity for comfort. By that point, he says, a ribbon would cost just $2 billion to build, bringing the price of a trip to roughly $6,000 in today’s dollars.
Then 229 more climbers will follow, adding more nanofiber-composite filaments until, after two years, the ribbon reaches a width of roughly three feet. All 230 climbers will cluster under the deployment booster to serve as a permanent counterweight. The completed ribbon and counterweight can support a steady stream of climbers, each capable of hoisting 13 tons of cargo and/or people at 125 miles per hour and reaching geosynchronous orbit in seven days. In the early stages, ascended climbers can be put into parking orbits. As more ribbons are constructed and operating costs drop, the climbers can be rounded up and brought back down.
Several ribbons in full-scale operation will open the heavens for solar satellites that can beam power back to Earth, large-scale zero-gravity manufacturing, space tourism, better global environmental monitoring, orbiting observatories, removal of man-made debris from Earth orbit, asteroid mining, and Mars-colonizing ships filled with hundreds of people. “The space elevator could be a catalytic step in our history,” Edwards wrote in his 2002 book (coauthored with Eric Westling), The Space Elevator: A Revolutionary Earth-to-Space Transportation System.
The plan is slowly building an audience of fans. Since he joined the Institute for Scientific Research last year, Edwards has been spending a good deal of his time flying around the world, laying out the blueprint to scientific groups in presentations that take up to five hours. “I go to a place like the Center for Astrophysics, and the room is packed because people have been saying, ‘Let’s go heckle this guy about the space elevator,’” he says with a grin. “They say to me, ‘You didn’t think about this. You forgot about that,’ and I say, ‘Yes, we covered that,’ and I show them. At the end, they come up, give me their cards, and ask if they can help.”
Edwards will need all the assistance he can get. The very first step—making the ribbon—still strikes some as too difficult. “I was overcome by the giggle factor,” says Rodney Andrews, associate director in carbon materials at the University of Kentucky’s Center for Applied Energy Research, as he recalls talking to Edwards two years ago. The physicist had called Andrews about the nanotubes he makes in his lab. “I drive Brad nuts, because he wants me to say we can do this. What I will say is that it’s an interesting project, and there is nothing yet that says you can’t do it.”
Andrews’s skepticism stems not from doubts about the nanotubes themselves—they are more than strong enough for a space elevator—but from the difficulty of embedding them in high concentrations in a material like polypropylene. The little sample in Edwards’s briefcase came from Andrews’s lab. It’s just 1 percent nanotubes; the rest is a polymer matrix. The stresses on the space elevator’s ribbon will require it to consist of 50 percent nanotubes. To get to that point, Andrews says, the nanotube-matrix bond has to improve. “The question is, can we make a system where the nanotube is chemically bonded to the matrix?” To this, he can only say, “Lots of people are working on it.”
Assuming this large problem is solved, many only slightly smaller ones wait their turn. “The one people bring up most often is debris,” says Edwards. Since the dawn of the space age in the late 1950s, low Earth orbit has become a junkyard, with about 110,000 hunks of old spacecraft one half inch or larger hurtling at speeds as high as 30,000 miles per hour. Pieces moving 20 times faster than a high-powered rifle bullet would damage even the space elevator’s superstrong fibers. Edwards’s response: Make the ribbon’s base mobile so that it can dodge the biggest pieces that NASA tracks (a 30- to 60-foot movement would be needed every six days); make the ribbon wider in low Earth orbit, where debris is most plentiful; and regularly patch small gashes.
Other concerns include the viability of laser-powered climbers. In Edwards’s scenario, ground-based solid-state lasers would beam at photovoltaic cells on the climbers’ undersides. Edwards says each 20-ton climber will require 2.4 megawatts of power, roughly the amount needed to power 650 U.S. homes. Is it possible to beam that much power with current technology? At least one expert is optimistic. “Yes, absolutely,” says Neville Marzwell, advanced concepts and technology innovation manager at the Jet Propulsion Laboratory. He points out that the space-based defense investments of the Reagan years led to huge advancements in laser development and that “the technology has made quantum jumps in the last 20 years.” He says ground-based tests have shown it is possible to beam “five times as much power as the space elevator would need.”
One by one, Edwards continues to bat away objections. Corrosion from atomic oxygen in the upper atmosphere can be forestalled with a coating of gold or platinum a few microns thick in the danger zone. Hurricanes can be thwarted by making the ribbon’s face narrower (and increasing its thickness) for the first five miles. Terrorists are a concern, but the anchor station in the equatorial Pacific would be remote, with “no way to sneak up on it,” he says. “It would be protected like any other valuable piece of property, in this case probably by the U.S. military.”
What if the thing should snap and fall? Most of it would stay in space or burn up in Earth’s atmosphere, says Edwards, adding that because the ribbon would weigh just 26 pounds per mile, any pieces that fell to Earth would have “about the same terminal velocity as that of an open newspaper page falling.” And would it really cost just $6 billion? “The technical cost is $6 billion,” he says. “That’s different from full program cost. It could easily be twice that, even three or four times that when you get into political issues.” Still, compared with recent estimates for a rocket mission to Mars, which run as high as $1 trillion, even $24 billion for a space elevator looks cheap.
If the elevator works, it means nothing less than a revolution in human destiny. Humans have lived at the bottom of a gravity well for millennia; a space elevator would be a rope dangling into that well. Many people would clamber out. Some, eventually thousands or even millions, would never go back.
In Edwards’s vision, the first project undertaken by a completed space elevator should be building more elevators. While he estimates that constructing the first one would be a six-year $6 billion task, the second could cost as little as $2 billion and take just seven months because it could employ the first to boost construction materials into space. The requisite time and money would shrink for each subsequent elevator, and payload size could increase dramatically. Edwards’s long-term plan calls for climbers on the third and fourth elevators, each hoisting 140 tons.
He says that’s why NASA needs to get serious now: “The guy who builds the first one can have several built before anybody else can build a second one. Now the first guy has so much capacity, his payload price is down to zero. He can run the other guy out of business. Talk about grabbing the brass ring.”
And Edwards emphasizes that the United States is by no means fated to win this race. The first builder might not even be a government. “We have actually been told by private investors, ‘If you can reduce the risk and prove it can be done, getting $10 billion is nothing.’” Having an international consortium of public and private entities pitch in may be the best scenario for ensuring the common good. A world blessed with a half-dozen space elevators constructed cooperatively, radiating from the equator like lotus petals, could provide near-universal access to space at a payload cost of as little as $10 a pound.
In the long run, “you wouldn’t want the elevator only on Earth. A similar system would work on Mars or some other planetary body,” says NASA’s David Smitherman. Indeed, says Edwards, any large object in the solar system that spins could become a candidate for a space elevator.
But for now, Edwards remains focused on getting the first one built. Along with all the other boons it would deliver to humankind, the elevator also has the potential to realize Edwards’s personal dream of voyaging into space. “In 20 years, I’ll be 60. I should still be plenty healthy enough to go on the space elevator. Maybe it will turn out that the only way I can get into space is to build the way to get there myself.”
A refurbished oil-drilling platform displacing 46,000 tons of water would serve as both the anchor station for the space elevator and a platform for a laser to propel the climbers. A key advantage of an offshore anchorage is mobility; the entire station could be moved every few days to allow the ribbon to avoid large chunks of space junk. Edwards’s plan calls for placing the station off the coast of Ecuador, which has the advantage of being a relatively lightning-free zone and also fairly accessible to the United States.
RIBBON OF NANOTUBES
Carbon nanotubes, discovered in 1991 and now synthesized in many laboratories worldwide, have a tensile strength 100 times stronger than steel at one-fifth the weight. The space elevator’s ribbon will consist of thousands of 20-micron-diameter fibers made of carbon nanotubes in a composite matrix. The fibers will be cross-linked with polyester tape at roughly three-foot intervals.
Ascent vehicles will vary in size, configuration, and power, depending on function. All will climb via tractorlike treads that pinch the ribbon like the wringers of an old-fashioned washing machine. Power for the motors will come from photovoltaic cells on the climbers’ undersides that are energized by a laser beamed up from the anchor station. At least two additional lasers will be located elsewhere in case clouds block the anchor station’s beam.
A deployment booster, carried aloft in pieces by a vehicle such as the space shuttle and assembled in low Earth orbit, will unfurl two thin strips of ribbon stretching from Earth to deep space. Once the strips are anchored to a site on Earth, 230 unmanned climbers will “zip” together and widen the strips. Those climbers will then remain permanently at the far end of the ribbon, just below the deployment booster, to serve as a counterweight. >