Could A Space Elevator Be Coming Soon?
Could A Space Elevator Be Coming Soon?
A space elevator is exactly what it sounds like: a massive elevator to space. While it wouldn’t function exactly like a traditional elevator, the concepts are similar. People and materials would be able to “ride” the elevator from the surface of earth to outer space.
Other than being really cool, why would we want to do this?
As I mentioned in my article on SpaceX, cost is one of the biggest challenges of space travel. Finding a way to reduce difficulty and cost is crucial to humanity becoming a space-faring species. A space elevator could solve this cost problem.
The Economics of the Space Elevator
It takes an enormous amount of rocket fuel to get even a small amount of material to space. This material is known as a payload. To get a single kilo (about 2.5 lbs) into space costs $20,000. That means it takes about $1.3 million to fly a single person into space.
Some estimates suggest that a space elevator would decrease the cost a hundred-fold. Now the cost to reduce a 1 kilo payload would be only $200 instead of $20,000. The cost to send a human to space would fall from $1.3 million to $13,000. You can see why the elevator would be worth it.
Which brings us to the first of the two major types of problems facing the space elevator.
The space elevator would be huge and expensive. It could cost hundreds of billions to build the elevator. However, that cost could be worth it.
If it cost $200 billion to build the space elevator, humanity would recover the invest after shipping 10 million tons into space. That’s about the size of 20 International Space Stations.
So the risk/reward might be worth it.
Which brings us to problem two: technology. The biggest hurdles are technological. If we can solve the technological problems, it’s likely that building a space elevator is possible. But those solutions are by no means guaranteed.
How A Space Elevator Would Work
To understand the technological problems faced by a space elevator, it’s helpful to understand how the elevator would work.
The Design: Four Major Parts
All the designs for a space elevator have four major parts: tether, anchor, counterweigh, and climber.
The tether and climber act like a regular elevator in some ways. The tether is the long string that the climber (the elevator box) climbs up and down.
The tension between the anchor and the counterweight keeps the tether taught. Tension keeps the tether taught. Say that five times fast!
The counterweight would need to be about 36,000 km (convert to miles) away from Earth. This allows the counterweight to be in a stable orbit and utilized the energy of the Earth.
Orbits are complicated, but the concept is simple. They rely on gravity (which is the pull of a heavy object). An orbit is essentially falling towards something but moving sideways fast enough to stop from actually falling. Once something is moving in space, it keeps moving. So, an object in a geostationary orbit will continue to circle the Earth indefinitely.
This is why the “space end” of the elevator (counterweight) would need to be in a stable orbit with the Earth.
The Counterweight and The Anchor
What would the counterweight be? There have been numerous proposals for what we could make the counterweight out of. There are four major ideas, each of which come with their own advantages and challenges.
First, we could just pile up whatever space junk happens to be around. This has the advantage of being cheap because much of it is already in space. But gathering and stabilizing it could be a challenge.
Second, we could capture an asteroid or meteor of some kind. This has the advantage of being cool and the disadvantage of being difficult. You may have suspected that.
Third, we could build a space station to act as the counterweight. One of the major advantages of this is that it would be functional.
Fourth, we could just add a lot more tether. Essentially, if you extended the tether well beyond where the counterweight would be, it could act like a counterweight by creating the necessary tension.
The anchor would likely be a large submerged object in the ocean. It would have a floating platform above it to serve as the Earth loading and docking bay.
The Climber and The Tether
There have been numerous ideas for the climber. Because climbing the elevator would take several days and require a lot of energy, design is uncertain. The climber could climb using nuclear energy, friction, lasers, or magnetism. But the climber isn’t the focal point because the biggest technological issue lies with the tether.
The tether needs to be made of something that is light, strong, and cheap. But, there is no material currently made by man that is strong enough to act as a tether. There are some promising leads.
Diamond nanothreads are one idea. A Penn State lab created these in 2014. Supercomputers from Australia modeled them and the results suggest they could be incredibly strong and flexible.
Carbon nanotubes are another. They were discovered by a Japanese researcher called Sumio Iijima in 1991. This may be why the Japanese have the strongest commitment to building a space elevator.
But neither have been created at a length longer than a few inches. It’s also still uncertain if they’re strong enough.
Is An Ambitious Project Good?
Documentaries like Sky Line help capture the public’s attention and remind us of humanity’s space-faring dreams. Although work on the space elevator isn’t popular currently, advances elsewhere may help reignite interest.
At the moment, there isn’t a ton of institutional support. This may change, but if reusable rockets are able to drop the cost of bringing payloads to space, the space elevator may not be worth the cost.
But its also possible that an ambitious project is exactly what is needed. Much like the Olympics, there are some moments that help unite humanity as a single species.
A great example of an ambitious scientific project was the Human Genome Project. This project was started in the late 1980s. The U.S. government primarily funded it, along with support from other governments and institutions. It was declared complete ahead of schedule and underbudget.
The Project was able to do so because technological advancements were made along the way. It was a huge moment for humanity, and much of the discussion of human genetics that happens now is a result of the Human Genome Project. It was an accomplishment of international cooperation and benefits all of humanity.
A space elevator could be the same. Despite the cost and the challenges, an ambitious, international effort might be exactly what we need.
The Future of the Space Elevator: Off-Planet?
Because of the risks, costs, and technical limitations, there may not be a space elevator for some time. At least, not on Earth.
Both the moon and Mars have significantly less gravity than earth does. This means that building a space elevator on either of those would be significantly easier. A space elevator on the moon might allow us to test the concept more cheaply. It would also make building other installations on the moon easier. The lower gravity on the moons means existing material, like Kevlar, could be used as the tether.
The payoff would be immense. It’s possible that a space elevator would be the first big step in becoming a space-faring species.
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