Friday, February 14, 2014

Space Elevator

When you think about sending people and things into space, rockets probably come into your mind. However, are there any alternatives to sending people and things into space besides rockets?

In 1895, the idea of a space elevator came into conception by Konstantin Tsiolkovsky. The idea was that we could engineer a building in which the upper levels would reach the top levels of the atmosphere and could be directly connected from the ground into space. But would this building ever be possible to create? And if we could create the building what would we have to look out for?

With current estimates, the projected height of this building would have to be around 50 km tall and would have to be attached to another body in space such as an asteroid to serve as a counterweight insuring that the building would not tumble upon itself. In addition to this, the building would have to be built in an equatorial site in order for the building to remain in a steady stable orbit. This is necessary because with the counterweight at the top of the elevator, if the building was built in any other location, the centrifugal force would cause the elevator to swing.

But with the extremely limited parameters and large dimensions of the building, why would you ever want to build a space elevator? Well, with today’s energy costs, through a space elevator, a 12000 kg object or payload would cost around $17,700 for the items to be sent into space. This means that a person with a maximum weight of 150 kg including their baggage would only cost around $222 to be sent into space. However currently, for a Proton launch into space, this would cost around $4300 per kg and about $40,000 per kg on a Pegasus launch.

The next question that comes to mind is with what materials would we use to build this structure? If the structure were created out of any conductive material, then the material could become charged due to the Earth’s electromagnetic field. Assuming this scenario, this would result in massive electric currents and could potentially electrocute anything in the proximity. However, on the other side of this argument, if the building could tap and collect this energy, then this would create a self-sustaining structure as well. Currently, the most promising material that could be used is graphene rolled into carbon nanotubes. This material is very light compared to other metals and has a tensile strength of over 200 Gigapascals compared to the necessary required tensile strength of 62 Gigapascals. From this, it seems that we have the capabilities of creating a material that could fit the necessary need of the structure, however, there are currently no way to mass produce this graphene considering the current method consists of scratching the material on a paper and then using tape to peel off and create miniscule strands. Then if researchers are able to develop a way to collect the electricity, a conductive material could be placed in the center of the cable to create magnetic field rail cars to ride the elevator.

So is it worth it? Personally, I think that a space elevator is completely worth it. When technology reaches a point where graphene nanotubes can be created en masse, the idea could be a feasible project for the world to create. With our reliance on satellites, and a potential future focused on space travel and exploration, in the long run this space elevator would save an enormous amount of money. However, in the future, I would only support this project given that other variables such as problems concerning the safety of the building from debris and other bodies as well as elements such as solar winds could be solved. In my opinion, the elevator would only be worth the massive creation costs if it could be protected after its creation. Also, compared to spending lots of money over time, a space elevator would be one very large purchase and would make the cost of sending materials into space a lesser matter in the future. With recent budget cuts affecting space related programs, the creation of a space elevator could make space research much cheaper and maybe more socially accepted in our society.

For more information, see this and see this.
Justin Kim

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