Potpourri of Stuff!
What the hell is a space elevator? Well, let me explain. Don’t even think of saying or thinking that we are getting ahead of ourselves. A space elevator is a plan on paper right now and it will come to life soon. A space elevator is a model that is proposed so as to facilitate transporting stuff from earth to space and vice-verse. Instead of using gallons of rocket fuel and billions of dollars of taxpayer’s money, this elevator would be anchored to a place around the equator of the Earth and the other end that lies beyond the geostationary altitude, which is approximately an altitude of 35,800 km above Earth’s surface. A geostationary orbit is an orbit that is equal to the time taken by the Earth to complete one rotation. Because of this, the object in such an orbit seems to be motionless to observers from Earth. Communication and weather satellites are usually given a geostationary orbit.
It is amazing that this concept has been introduced in 1895 by Konstantin Tsiolkovsky. He proposed a standing tower from the surface to the geostationary orbit. Earth, being a source of good gravity can keep the structure under tension and hence supporting the weight. But unfortunately, any of the proposed models today are practically impossible because we do not have a material that is strong enough to make the tether. But fortunately, researchers have implied that materials like the carbon nano tubes can be used to make a tether of the required strength.
The base stations on earth would be mobile stations. The plans for a land based anchor have been called off in order to avoid huge storms and space debris. The materials required for making the tether is under debate but carbon nano tubes would be the preferred candidate. We need to consider the breaking lengths of materials before we can decide the candidate. The metals that we know of like titanium and aluminum alloys all have a breaking length of only 20-30km. Quartz fibers can be extended up to a few hundreds of kilometers but it still isn’t enough. So, Carbon Nano tubes can make that have a breaking lengths above 5000 to 6000 km.
Check out this video to get an insight of how the space elevator would operate like.
Now, launching objects into deep space can be done by this elevator. The logic is that any object attached to the space elevator at a height of 53,100 km will be at escape velocity when released. Escape velocity is the velocity that is required to make the object float off into space, free from the gravity of a planet or a moon. The escape velocity of Earth is 11.2km/s. So, objects launched will have enough momentum to make it as far as up to Jupiter.
These space elevators can also be tethered to other planets, asteroids or moons. A Martian elevator would be much shorter than the one that is on earth. The construction of these giant elevators involve risk factors. Advancements in the field of materials engineering and physical technology is required in order to make sure that these elevators do not fail.
The risks with building space elevators are significant. For instance, there would have to be 24×7 strict air traffic monitoring so that the planes do not crash on the tether. Also, spaceships would have to check their orbit for any possibilities of collisions. When passengers cross the Van Allen Radiation belt containing extremely deadly doses of radiation from which they must be protected from, they have to have advanced suits which increases the mass/crew member and decreases the payload. The cable must be equipped with technology to safely maneuver from the impact of asteroids, micrometeorites, and man made debris without breaking.
With the current rocket designs, the cost/kg of payload to be taken up to the geostationary orbit is a whooping $25,000/kg ($11,000/pound)! But with a space elevator, the cost is just a fraction of the current costs $220/kg ($100/pound).
Philip Ragan, co-author of the book “Leaving the Planet by Space Elevator“, states that “The first country to deploy a space elevator will have a 95 percent cost advantage and could potentially control all space activities.”