Space elevators appear in three of my stories. In Humanity's Hope, Gus Nicols builds one above the planet Ilium in the opening chapters. In Dust and Memory, a sub-orbital craft launches from one on Mars. In Cog in the Machine, they are everyday infrastructure on Earth, hauling cargo and people into orbit all day long. Readers sometimes ask whether any of this could really happen. As with the heat pumps, the honest answer is that the idea is less far-fetched than it sounds, but one crucial ingredient doesn't exist yet. That ingredient is the part I invented.
The real science
The concept is simple. A cable is anchored at the equator and runs out beyond geostationary orbit, 35,786 km (22,236 miles) up. At that height an object takes exactly a day to circle the planet, so it hangs over the same spot on the ground. A counterweight beyond that point keeps the cable taut, and electric climbers travel up and down it, with no rockets needed. Modern designs picture a thin ribbon rather than a round cable, about a metre wide and 100,000 km long, thickest at geostationary altitude where the tension is greatest and thinnest at the ground.
The favoured way to build one starts in space, not on the ground. A spacecraft carries the tether into geostationary orbit, then lowers one end towards the planet while extending the other end away from it, so the whole assembly stays balanced. In the best-known proposal, the first ribbon is a thin "seed" weighing around 20 tonnes, launched on conventional rockets. Climbers then add material to thicken it. This is a delicate operation: simulations show that an uncontrolled deployment is inherently unstable and can pull the whole system out of orbit, so it needs careful control.
The real obstacle is the material. Estimates of the minimum strength a tether needs run from about 60 to 100 gigapascals, against roughly 0.55 for structural steel. Nothing manufactured at scale today comes close. Carbon nanotubes have the theoretical strength, but the longest one made in publicly disclosed work is about half a metre. Graphene has similar strength, and a 2022 review by Adrian Nixon of the International Space Elevator Consortium noted that it can now be made as a large-area material at two metres per minute, in lengths up to a kilometre, though tether-quality material still needs development. The Consortium currently names single-crystal graphene as its preferred candidate and works with a team at the Graphene Engineering Innovation Centre in Manchester.
Is anyone actually trying to build one? Japan's Obayashi Corporation announced in 2012 a plan for a 96,000 km elevator by 2050, carrying 30 passengers on a climb of about a week. In 2025 the company told an international congress that its research had entered a new phase, though I'm not aware of construction having started. The nearest thing to a real-world test is STARS-Me, launched in 2018: two tiny satellites joined by a 10-metre tether, designed to test a small climber moving along the cable in orbit. It is a very small step.
What I invented: woven graphene
In my novels, the tether's core is made of "woven graphene", and this is where I made the biggest leap. Here is the real problem it answers. Nobody can make a perfect strand of graphene or nanotube long enough for a tether, so the practical route is to spin short pieces into thread, the way cotton is spun. But thread is far weaker than the strands inside it. One Rice University analysis found that bundled nanotube fibres are about 100 times weaker than individual tubes, and Cambridge researchers estimated at least 25 times weaker. What decides the strength is how long the pieces are and how much friction holds them together. (Those studies were of nanotubes rather than graphene ribbons, but any thread spun from short pieces faces the same basic problem.)
So in the story, the core is made of graphene ribbons one atom thick, one nanometre wide and less than a centimetre long, twisted into thread and woven together. I haven't invented new physics. I've assumed that decades of work on friction between strands closes the gap that exists today. Woven graphene of that strength doesn't exist, and I can't promise it's possible.
The same friction idea solves the deployment problem in the book. Here is how Gus's colony ship handles the unspooling:
The friction between each layer of tether on the spool varied as it unspooled. It started low until the ends had accelerated up to speed, then increased to keep the speed constant before increasing again. This meant the tether was played out at a reasonable rate and didn't snap in the middle when it fully unspooled and pulled tight.
Real engineers handle that instability with active control, such as thrusters. A passive, friction-based answer is my own invention, but the problem it solves is real.
The second stage of construction also has a real-world echo. As in the "seed tether" proposals, the first thread is only a core, and machines then climb it to add strengthening layers. Researchers worry that reactive atomic oxygen high in the atmosphere would erode a carbon tether. In the novel, the equivalent threats are wear from the climbers and the oxygen-rich air near Ilium's surface, so Gus coats the core with silicon carbide and winds a second layer of woven graphene over it. The coating is my invention. The worry behind it is real.
One more detail matters. Ilium's gravity is 90% of Earth's, so the strength requirement drops only slightly. That is deliberate: Gus can't rely on a weak-gravity shortcut and has to solve the material problem. Lower-gravity worlds really are easier. Mars is the obvious candidate, and NASA-hosted studies have looked at tethers anchored to its moon Phobos.
Elevators as ordinary infrastructure
By Cog in the Machine, the materials problem has been solved long enough ago that elevators are routine. Here is how Edric Winchester describes one:
The tether was 10 centimetres wide and only half a centimetre thick. Rising vertically from the concrete floor, it disappeared into the bright blue sky above us like a dull white ribbon. The core was woven graphene, but the surface was textured silicon carbide.
That's the speculative leap: not a single heroic elevator, but a mature, industrial-scale system. The real research suggests other hurdles would remain even with a perfect material, including space debris and finding a place to anchor the base at the equator.
Launching from the tether
In Dust and Memory and Cog in the Machine, characters ride the tether part of the way up and then launch a sub-orbital craft from it. I haven’t found a real proposal for that. Real tether-launch ideas work differently: they use a tether that orbits the planet, not one anchored to the ground, to give a rocket or plane a boost into orbit. Releasing a craft from a ground-anchored tether and flying it back down is my own invention.
Why I bother
None of this changes the plot. Nobody needs to know about atomic oxygen to follow Gus lining up a spool above an alien planet. But I think it makes a future feel earned rather than assumed when I can trace a line from real research, through the one thing that doesn't exist yet, to the world on the page. As in my last science post, I want the reader to be able to see the load-bearing wall.
If you'd like to see an elevator in action, Dust and Memory is free on my website and on StoryOrigin.
