Getting to space is not easy. As much as many of us want for there to be an affordable way to travel up to witness the beauty of planet Earth, that would call for us to be astronauts or billionaires, of which most of us are neither. But there’s a concept that might make this possible, while serving as the starting point for the exploration of the universe.
Space elevators are one of those technologies that sci-fi geeks like me obsess over. Even if I wasn’t a sci-fi nerd, seeing technologies that you would only witness in futuristic movies cross into the realm of science reality would still have me on the edge of my toes. It’s the kind of experiment that could very much be possible, if we continued on with the exponential growth of our current technologies.
A space elevator?
Yes, it’s exactly what you’re thinking. Think of it as a giant pole, or elevator shaft that climbs all the way up from Earth’s ground where the destination on the other side is literally space.
But to understand how this space elevator will even get us to space, we must first grasp an understanding of how orbit works. Anything in orbit maintains its curved routes by balancing two factors: its velocity and the gravitational pull that Earth has on it. While gravity wants to drag you down, if you move fast enough sideways, that momentum is enough to counterbalance that gravity force.
So to enter Earth’s orbit, rockets have to travel up and sideways as fast as possible.
But the way space elevators work is by taking advantage of the Earth’s rotation. Imagine a tennis ball on the end of a rope and you are spinning the rope around. An ant is climbing from your hand to the tennis ball along the string. While it would have to walk up, by the time it reaches the end, it won’t have to do anything to move around the Earth.
If you’re launching a rocket, it would take energy for the rocket to move up as well as travel sideways. However, with space elevators, the only energy needed would be to move up — the movement around the Earth comes along with Earth’s rotation.
Maybe our wallets won’t have to break
If humanity could actually build an elevator to space, this could provide a solution to one of the largest barriers of space travel: cost.
It takes more than $160 million to launch a satellite into orbit. At current prices, it takes about $20,000 to put one kilogram of payload into space, and $1.3 million to put a human. Because of the immense amount of fuel needed to transport even such a small amount into orbit means the price of a ticket to space will be far from the price of an airline one.
However, after the construction of a space elevator, the shaft would expect the reduce costs to only $200 per kilogram.
Parts of a space elevator
A space elevator has four major components: the anchor, counterweight, tether, and climber.
The tether is the massive rod or elevator line that extends from Earth to space. The climber can be imagined as the conventional elevator carriage, which climbs up and down the tether. The anchor is attached as a base to Earth where material and people would board the climber, and the counterweight would be on the other side of the tether, where a space station would be located approximately 36,000 km above the surface.
But designing isn’t as easy as we think
Many of our buildings are restricted in height as a result of the compressive strength of our materials. The higher we build, the more weight is piled onto the foundations. This is why structures like the great pyramids in Egypt were able to be constructed to their towering heights: the widened bases allowed for the weight of the entire building to be held.
While the Earth’s rotation will solve this problem as the momentum from the spinning will attempt pull the structure from the ground, lessening the pressure on the base, we still have to consider something else as a result from this dynamic.
Picture a game of tether ball. The objective of the game is to wrap the string around the pole by swinging the ball. If the string can’t rotate around the centre of spin, it will wrap itself around the poll. This means we need to implant our tether on a very specific location of Earth, or the tether will swing itself into the Earth like the tether ball.
We haven’t come by the ideal material either
But the challenge I explained above can be solved with a mathematical equation. The real challenge lies with what we’re going to build the physical elevator with, specifically the tether.
Obviously building a rod extending into the middle of space can’t be done with what we currently use to build buildings in New York or Toronto. It would need to be light and cheap and be able to withstand extreme weather conditions, radiation, and atmospheric corrosion. Diamond nano threads and graphene are our best bet, but it’s highly likely that even those materials can’t fulfill our promises.
Besides, where would we even get enough material to build a 36,000 km pole? Whatever it is, the material would have to be one that we have produced more than any other.
We also need to consider loads more including where we gather the power to push the elevator cartridge up the massive pole, directly against the force of gravity for multiple days on end.
In the end, we only get one ticket
We could all imagine that if the tether breaks, hell would wreak out. If it snaps in half near the anchor, the force exerted by the counterweight would cause the tether to rise up like a ballon into the rest of space. If space debris collides with the tether near the counterweight, the rest of the tether below will wrap itself around Earth like the tether ball string and crash. And any tech waste that remains would pose serious barriers to any future space flights and cause a loss of billions worth of material.
So if we were to actually build a space elevator, we would technically only have one shot.
But that’s not to say it isn’t impossible. Yes, it will be one the hardest things we as humans will ever build, but with technology moving at the speed of light, new discoveries are only at our finger tips. We’ve already come so far as a civilization and who knows, what if we actually do it someday? That would be beyond exciting.
- Ashley
