Space Elevators

Why Space Elevators Could Be the Future of Space Travel

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IN BRIEF
  • Expensive, unsustainable rockets have served as our primary means to exit Earth, but space elevators present a cheaper way to enter outer space.
  • Although new materials are needed, space elevator missions are in motion and we could see the first elevator constructed in the next several decades.

THE SPACE ELEVATOR

Getting into space with rockets is ridiculously expensive. A NASA Inspector General report says the agency will pay Russia $491.2 million to send six astronauts into space in 2018. That’s almost $82 million a seat.

And depending on what company you launch a satellite with, it costs between $10 to $30 million for every metric ton you send into space, The Motley Fool reported this year. But there’s a vastly more affordable answer to rockets — space elevators.

Futurists have flirted with the idea of space elevators since 1895 when the Eiffel Tower inspired Russian scientist Konstantin Tsiolkovsky. Tsiolkovksy reasoned if a tower was built 35,800 kilometers (22,236 miles) high, it would reach geostationary orbit and could carry payloads to outer space. His concept isn’t too far off from current thinking.

A 2002 NASA study by Dr. Brad Edwards re-invigorated the scientific community with what’s considered today’s modern day space elevator. According to the study, a flexible and durable cable with a space station counterweight could serve as a viable space elevator.

A mechanical “climber” — using magnetic levitation or rollers along the tether — would then carry many tons of equipment or people into orbit. Although such a project would cost in the tens of billions, it would eventually pay for itself by providing much cheaper space travel to a greatly expanded market.

Space Elevator
The anatomy of a space elevator. 

A 2014 report by the International Academy of Astronautics (IAA) proposes a “ribbon” tether stretching well past geostationary orbit that’s roughly one hundred million times longer than its width. The “ribbon,” held down by an anchor as heavy as about 170 school buses, could carry 1 kilogram to geosynchronous orbit for $500, opposed to the current price of $20,000 per kilogram via rocket, according to the IAA report.

Dr. Peter Swan, who helped author the IAA report, is the president of the International Space Elevator Consortium, a professional society of space elevator enthusiasts advocating for the megastructure. He said space elevators offer an “opening of our vision towards humanity’s future.”

“There’s a tremendous movement of moving off-planet,” Swan told Futurism. “Space elevators could jump in and help the whole process by lowering the cost to geosynchronous and beyond.”

Swan, a satellite engineer by trade, said a functioning elevator would decrease the cost of launching satellites and missions by 99 percent.

A different concept by Thoth aims to build an elevator just 20 kilometers (12.4 miles) high to launch rocket trips that would cost less fuel. But Thoth and the IAA face the same obstacle as all other space elevator designs: materials.

THE MATERIALS PROBLEM

To build a tether capable of reaching tens of kilometers from Earth, an incredibly strong, dense, and flexible material is needed. This is because gravity decreases the farther away from Earth you are, so the tensile strength for the cable has to support roughly 5,000 kilometers (3,000 miles) of itself.

Engineers thought the tether could be made of ultra flexible and tough carbon nanotubes, but a study by Hong Kong Polytechnic University ruled them out this year. It’s also possible a version of the diamond nanothreads researchers discovered in late 2015 could be the key.

Carbon Nanotubes Space Elevator
Types of carbon nanotubes.

Swan said diamond nanothreads or boron nitride might work but still believes carbon nanotubes will be crucial in building the space elevator tether, despite the new Hong Kong Polytechnic University study.

“I don’t believe that any of the space elevator people that are working with carbon nanotubes to have been scared by that statement,” Swan said.

Point being: The materials don’t exist — yet. But we could see the right materials come out before 2030, according to a study published in the journal New Space.

space elevator
How Earth could look from a space elevator. 

The materials problem isn’t stopping the Japanese from trying to build a space elevator. The STAR-C orbiter from Shizouka University is on its way to the ISS and will test Kevlar in space to see if the material could work as a tether.

“They’re going to simulate what a tether climber could do on Kevlar. That would be a major step forward in the knowledge of space tethers and space elevators,” Swan said. “I applaud their activity.”

The Obayashi construction company has also committed to building a space elevator by 2050.

And since gravity isn’t as strong on the Moon or Mars as it is on Earth, we already have the materials — like Kevlar — to build space elevator tethers on these smaller celestial bodies. So space colonists in the immediate future could make use of the technology.

SOLAR SPACE ELEVATORS

Space elevators also present a way to generate potentially massive amounts of solar electricity. This is because solar panels in outer space — where the Sun’s light is unfiltered — can absorb vastly more energy than on Earth. The array could then radiate electricity down to Earth, bypassing power lines completely, Swan said.

“The key is to put acre-size solar arrays at geosynchronous (altitude), and radiate the energy down to the Earth at very, very low cost,” Swan said.

Solar space elevator
Solar towers could scale the sides of space elevators and generate massive amounts of energy for earth.

The 2009 sci-fi anime “Gundam 00” portrays a world where humans depend on a few orbital elevators to almost completely power the planet with solar power. Could something like it be in our future?

Swan ultimately believes space elevators will expand “the aperture of the human spirit.”

“By having extremely low-cost access to space, you can open up the human mind, so moving off-planet is not a dream, but a reality,” Swan said. “We can talk about going to Mars, going to the Moon, having a colony orbiting around the Earth.”

Space Elevators Are Totally Possible.

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and Will Make Rockets Seem Dumb…

It’s the scourge of futurists everywhere: The space elevator can’t seem to shake its image as something that’s just ridiculous, laughed off as the stuff of sci-fi novels and overactive imaginations. But there are plenty of scientists who take the idea quite seriously, and they’re trying to buck that perception.

How to Build a Space Elevator

To that end, a diverse group of experts at the behest of the International Academy of Astronautics completed an impressively thorough study this month on whether building a space elevator is doable. Their resulting report, “Space Elevators: An Assessment of the Technological Feasibility and the Way Forward,” found that, in a nutshell, such a contraption is both totally feasible and a really smart idea. And they laid out a 300-page roadmap detailing how to make it happen.

The “why build a space elevator?” part is easy. First up, it’s because rockets aren’t cutting it. Rocket technology is such that 80 percent of the mass is fuel and 14 percent is structure, leaving just 6 percent for the payload. Then the rocket takes off, spews a bunch of chemicals into the atmosphere, and never comes back. A cable-based transportation system, by comparison, would have no constraints on the size or shape of the payload, and at a fraction of the energy and cost, the study explains.

Image: IAA

 

Moreover, once the elevator’s cargo can safely switch from large payloads to transporting people into orbit, that could usher in a new era of space exploration that would lead to a “renaissance” that would transform the Earth, researchers write:

The facility to provide power to any location on the surface [space solar power satellites] will enable development across the world. Several examples are that Africa could skip the 20th century of wires while the outback of countries like India or China would not have to burn coal and the  Amazon region could retain more of its rain forests. In addition, the increase in communications and Earth resource satellites will remake the emergency warning systems of the world. Some intractable problems on the Earth’s surface would also have solutions, such as the safe and secure delivery—and thus disposal—of nuclear waste to solar orbit.

Naturally, how to build a space elevator is more difficult to answer. The gist of the idea is this: A long, strong tether is anchored at the equator and extends into geosynchronous orbit some 62,000 miles above the Earth. At the other end is a counterweight far enough away to keep the center of mass in orbit with the Earth so the cable stays over the same point above the equator as the planet rotates. The rotation keeps the cable taut, to counter the gravitational pull as robotic, electric “climbers” ride the line up into space carrying the payload. Boom.

This basic concept hasn’t changed much since Arthur C. Clark’s 1979 novel The Fountains of Paradise first popularized the idea of an elevator to space—though no one took it seriously. Decades later, in 2003, Clarke stated, “The space elevator will be built ten years after they stop laughing … and they have stopped laughing.”

What made people stop laughing? Nanotech. Carbon nanotubes were developed in the 90s and promised to be the uber-strong, light, flexible supermaterial needed to build the kind of 62,000-mile cable that could transport humans into space. By the end of the 90s, NASA had released its report on the technological progress: “Space Elevators: An Advanced Earth-Space Infrastructure for the New Millennium.”

This month’s IAA report gives something of an update. “The materials currently being tested in the laboratory have surpassed that level and promise a tether that can withstand the environmental and operational stresses necessary,” it states. “Will it end up being carbon nanotubes, or boron nitrite materials, or something else?”

Nanomaterials are strong and light enough, but the rub is that scientists can’t get them to scale yet. Luckily, billions of dollars are being poured into this area of research. The report predicts a suitable material will be ready by the 2020s.

As material engineering research continues, experts are feeling increasingly comfortable putting an ETA on the long-imagined space elevator. A couple years agoJapan predicted it could create the machine “by 2050”. Rumors that the secretive Google X lab was building a space elevator sparked at least one prediction that it would “replace rockets in 50 years.”

RELATED: This Hypnotic Animation Makes Space Rocks Look BeautifulGoogle has since denied any such project, but plenty of other attempts to make the journey into space easier and cheaper are still on the table. There is the research out of the International Space Elevator Consortium, the ambitious Kickstarter project to build a vehicle that travels from the Earth to the Moon, the Japanese space elevator that runs on solar power cells attached to the ISS, Elon Musk’s reusable rockets, NASA’s plan to launch objects into space with rail guns and magnetic levitation, and acclaimed sci-fi author Neil Stephenson’s moonshot project to build a tower so tall it reaches to the stars.

The IAA report, for its part, is ready to put the rubber to the road. It lays out everything from the technological infrastructure of the machine and the physics of defying gravity, to the funding profiles of the future space markets it would open up, and when investors should expect a return on investment from the elevator. “No doubt all the space agencies of the world will welcome such a definitive study that investigates new ways of transportation with major changes associated with inexpensive routine access to GEO and beyond,” IAA president Gopalan Madhavan Nair writes in the report.

Be it 20, 50, or 100 years from now, if the elevator/bridge/gun/train/tower next-gen celestial transport system comes to fruition, it could be rockets that people are laughing about in the future.