Space elevator: A fiction or future of human space flight?
The Space Elevator
Getting into space is HARD! As much as we wish there were an easy and affordable way to see our planet floating in the dark. As of right now, the only way is to become an astronaut or a billionaire but there is a concept that might make it possible while serving as the starting point for the exploration of the universe; The Space Elevator but how exactly does it work? Let’s find out!
To understand how a space elevator will get us into space we must first understand what an orbit is. Being in an orbit means falling towards something but it’s fast enough to miss. When you throw a ball on Earth, it makes an arc through the air and then hits the ground. In space, gravity makes you move much the same way but if you move sideways fast enough the curvature of the earth makes the ground fall away beneath you as fast as gravity pulls you towards it. Similarly, to enter earth’s orbit rockets have to go up and sideways fast. By contrast, a space elevator taps into energy from the Earth’s rotation to get the cargo going fast. Imagine a child spinning a toy on a rope with an Ant on the child’s hand as the Ant climbs out along the rope it starts to move faster and faster as it ascends. Compared to rockets, with cargo launched on the elevator, you only need to provide the energy to go up. The fast sideways movement comes free with the earth’s rotation. BUT a space elevator would without a doubt be the single largest and most expensive structure ever built by humans. So, is it worth it?
It all comes down to costs. rockets burn a huge amount of rocket fuel just to get a small amount of cargo into space. At current prices, it costs about $20,000 to put one kilogram of payload into space; that’s $1.3 million for the average human, $40 million for your car, billions for an International Space Station. This immense cost is one of the major limitations of human spaceflights. Even with advancing technology as the cost isn’t likely to be compatible with the price of an airline ticket anytime soon. A space elevator would solve this problem. After construction a space elevator, its projected to reduce the cost 100-fold i: e $200 per kilogram. If an expensive space elevator costs $20 billion then we can recoup our losses after launching only 1000 tons which is close to the weight of two International Space stations.
What would a space elevator look like in real life?
A space elevator has four major components: the tether, an anchor, counterweight, and a climber. The elevator part of the space elevator is the tether and the climber. It extends from the surface of the earth to space. The climber is like a conventional elevator carriage; a chamber that works its way up and down the tether. The base would be an anchor pinning the tether to the earth along with a port for climbers. At the top is the counterweight which holds up the tether. The tether is held tight like a rope and supported from above by the tension from the counterweight located higher than 36,000 kilometers above the earth’s surface. At the counterweight could be a space station, a launching point for all missions from the spaceport elevator.
Can we build one? Unanswered Questions
The biggest challenge is that the tether needs to be light, affordable, and more stable than any material we can produce right now. There are promising materials like Graphene and Diamond nanothreads but even they may not be strong enough. Aside from being incredibly strong, the tether would also have to withstand atmospheric corrosion, radiation and micrometeorites, and debris impacts. Additionally, it takes several days to climb the elevator. It requires a lot of energy to go up. Maybe a nuclear reactor on our elevator carriage or do we beam power from the ground with a super-powered laser? and where do we get the raw materials for a 36,000 kilometer-long tether? Do we make it on earth and launch into space or do we make it in space and lower it down to the earth? Could asteroid mining is the answer? But simply there are still some major technological hurdles to overcome.
A space elevator has a long-range of risks involved. Should the tether ever break the entire megastructure would collapse in spectacular style. If it breaks near the anchor, the force exerted by the counterweight will cause the entire elevator to rise and ascend into space. Should it break near the counterweight the tether will fall wrapping around the world and whipping the end off! The resulting debris in orbit could pose serious problems to future spaceflights. If we build a space elevator on earth, we must do it right the first time. For these reasons, some experts have proposed first building a space elevator on the moon. The moon’s gravity is much weaker than the earth so a flimsier but existing material like Kevlar could serve as a tether. Even with all these challenges, the payoff of having a working space elevator would be immense. It might be the first step to truly becoming a spacefaring civilization.