In late August, officials at NASA announced what had already become apparent: Two U.S. astronauts, stranded for nearly three months at the International Space Station, weren't coming home as planned and would have to remain in space for several months.
The Boeing Starliner craft that transported Suni Williams and Barry Wilmore to the ISS in June, the company’s first crewed mission, had experienced multiple problems and was returning to Earth without people on board. A SpaceX rescue craft, meanwhile, couldn’t reach the astronauts until February 2025.
The only option for Williams and Wilmore was to wait. But that may not always be the case. And if and when the scenario changes, it may well be in a direction that is quite literally the stuff of science fiction.
The technology is there
For more than a century in theory and at least a couple of decades in earnest, researchers have pondered the construction of a “space elevator” between Earth and distant space. Now, several scientists–and executives at one major Japanese company–believe the idea has wings.
“The technology is there,” says Bradley Edwards, a physicist who produced the first viable design and engineering report for NASA for the system almost a quarter century ago. (He was mostly politely ignored.)
What’s missing, Edwards adds, is simple: “A will to do it. And funding.”
Right, the money. But first things first. A space elevator? It’s not exactly that. Think, rather, of a cable or ribbon, or perhaps a vertical railway with freight cars that move up and down the stationary cable, transporting payloads.
One plan, Edwards says, would use a spacecraft to carry a spool of the ribbon up to geosynchronous orbit, about 22,000 miles above Earth. There, the spool would deploy downward by gravity and ultimately be anchored in the Pacific Ocean. Meanwhile, the spacecraft would continue its journey upwards to perhaps 60,000 miles in space (the equivalent to about one-fourth of a Moon journey), unspooling the rest of the ribbon as it goes.
The spacecraft would remain up there as a counterweight. A vehicle with massive storage space, called a climber, would then scale the cable, bringing up and attaching more ribbon to the first layer in order to make it thicker and stronger. “And you do that with about 200 climbers,” says Edwards.
The cable, most likely constructed of carbon nanotubes or possibly graphene, would stretch from Earth at a point near the equator. Similar to when one twirls a ball on a string at sufficient speed around one’s head and the string becomes taut, the force generated by the earth’s rotation maintains tension throughout the tether.
“The centrifugal force will balance the force of the gravity,” says Dennis Wright, president of the Seattle-based International Space Elevator Consortium (ISEC), which has studied and hosted conferences on the topic for two decades. “And it will stretch this cable tight and provide a vertical railroad, if you will, for vehicles that can grip the cable to climb up and down and deliver payloads.”
These climbers, traveling at speeds of a fast train, perhaps around 120 to 200 mph, could carry, for example, a 15-ton satellite every day or every other day. It could bring back from space, satellites and elements mined from asteroids. Such a vehicle might also carry tourists, of course, and it would be available every day, unburdened by rocket launch windows dependent on ideal conditions. “It changes everything. It’s just a completely different world,” says Edwards.
Because the top end (apex) of the space elevator is moving so fast, payloads can be launched into the solar system quickly and inexpensively. A trip to Mars—for colonization, perhaps—could be cut from around six to eight months on a rocket ship to three to four months. More importantly, it would open the Mars launch window to more than six months in a 26-month cycle, compared to rockets’ current two-week launch window for the same period.
“A space elevator becomes a bridge to the entire solar system,” says Stephen Cohen, who teaches physics at Vanier College in Montreal and has conducted extensive research on the mechanics of space elevators.
Too, such mass-transport deliveries could prime the pump for asteroid mining, building a village on the moon, and establishing space-based solar power that could beam clean power to, say, New York or France. All might begin to be realized via a system that can get massive amounts of material to and from space quickly and at a low enough cost not to scare away investors, companies, or governments.
Theoretically.
If this sounds like something a novelist might imagine, understand that it once was. The late sci-fi writer Arthur C. Clarke made the construction of a space elevator the centerpiece of his novel The Fountains of Paradise in 1979, almost half a century ago. In 2001, Clark wrote to Edwards to say he’d once predicted that it would be “50 years after everyone stops laughing” before the elevator would be built. After reading Edwards’ NASA report, Clark wrote, “They just stopped.”
Clarke wasn’t the first, either. The notion of a tower that could extend from Earth thousands of miles into space was suggested in 1895 by a Russian scientist and astronautics pioneer, Konstantin E. Tsiolkovsky. At that time, one of the strongest and most widely used construction materials in the world was steel, and so for a variety of reasons–too heavy and not strong enough—the concept remained a thought exercise.
For the longest time, the material engineering question—how to make strong enough ribbon or cable—remained elusive. But the discovery in 1991 of carbon nanotubes, with strength far surpassing steel and other materials, took the notion of a space elevator from distant to plausible.
“It surprised me that somebody hadn’t dumped a ton of money into carbon nanotubes, because carbon nanotubes are an absolute game changer,” says Edwards. “They’re easily 20 to 30 times stronger than carbon fiber (Kevlar) and anything else. They would revolutionize a lot of industries.”
Edwards hopes so. His new company, Industrial CNT, is in the process of rounding up funding to make longer and longer carbon nanotubes, which eventually could form the tether. He believes a space elevator could be completed in eight to 10 years, including the time it would take to ramp up the carbon nanotube production. (Other experts suggest the use of graphene and note that China has been making large graphene molecules.)
Whoever develops this first is going to control space
“I think whoever develops this infrastructure first is going to really control space,” says ISEC’s Wright, whose next conference is set for early September in Chicago. “If that message can be brought out in America, then I think people would be more willing to look at the idea and say, well, I think some people are actually working on it. We should be too, otherwise, we're going to be behind the eight ball.”
In part because of the unknown expense of various items, including exactly what types of devices might be engineered to climb the cable, the potential price tag rendered the space elevator a nonstarter for a long time. The Japanese construction conglomerate Obayashi Corp., which has touted plans for an elevator since 2012, has pegged its more elaborate version of the project at around $100 billion.
Edwards sees it far differently: $8 billion to build the first elevator. “That’s about the same cost as two launches of the Boeing SLS Rockets, which were $4 billion each,” the physicist says. As for the once-mysterious climbers, the electric motors that would be needed for them are already in production at Tesla at roughly $12,000 each, with two such motors likely required per climber. The second elevator would cost less, about $3 billion, "because you’d already have the first one up there and you could use that to build the second,” Edward says.
Companies like LeoLabs also are perfecting their ability to track space debris particles down to the level they’d need in order to help prevent them from striking the elevator. Edwards says he hopes to ramp up carbon nanotube manufacturing, grow CNTs at length (they are originally a billionth of a meter in diameter), and then use machines to spin them into threads in hopes of one day creating a spool that is many thousands of miles long.
“I think we have overcome the major problems (related to the space elevator),” says Yoji Ishikawa, an aerospace engineer in Japan who played a key role in developing Obayashi’s concept. The company’s planned 2025 construction start is on hold, Ishikawa says, as he looks for both international support and "many different industries to come together.”
A space elevator could be used to get objects up to geosynchronous orbit (GEO), possibly as fast as a week’s time. At GEO, the orbital period matches Earth’s one-day rotation, allowing things to remain where they are positioned above us. Right now, most missions and man-made objects in space remain in low earth orbit. The stranded astronauts are currently stuck about 250 miles above us, where the International Space Station is located. Rockets need lots of fuel to go much farther, but the extra fuel then makes the rockets heavier, costing even more fuel and money.
With the space elevator, no such fuel loads are needed. “You'll just use whatever electrical mechanism you have (on climbers) to get you up there,” plus a little fuel to correct positioning from time to time, Cohen said. “Right now, we have astronauts stuck 400 kilometers away and we're like help is on the way, just wait six months.”
NASA, fairly famously risk-averse, heard out Edwards but hasn’t moved on the idea. (The agency was not able to immediately respond to questions, but recommended Edwards as a source.) Wright says several countries have at least studied the concept, including China and Japan—the Obayashi Corp. commitment is real enough.
But it may take international cooperation to actually get a space elevator built, in part because, without nations working together, there is always the chance of piracy or use of the idea for military advantage. There are also basic concerns like weather-related events, problems largely mitigated by locating the base, or the “Earth port,” near the equator in a specific region of the Pacific Ocean. “None of these seems to be showstoppers,” says Cohen. "So until someone finds one that has no solution, then I think onward.”
A 2019 report by the International Academy of Astronautics said “a broad group of space professionals” concluded that the space elevator seemed not only feasible but that the “development initiation is nearer than most think.” Still, Cohen says, “I think an appetite to build a space elevator is sort of the wildcard in this,” and there certainly has been no heavy public or governmental push for the project.
To Edwards, that’s where more widespread information would help, including more details on how close the idea is to reality. “We can build it now,” he says. “It is an economic win now.”
It isn’t, of course, until entities invest. But for the first time in nearly 150 years, the space elevator is out of the realm of sci-fi and into the orbit of mission possible. Stuck in space, waiting for a rocket launch to bring them home, Suni Williams and Barry Wilmore might have been thrilled to have the option of just pushing the down button.
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