Sunday, November 11, 2012

A space elevator



vignetteYou enter the elevator. Then you press the button and presto! More than 200 km / h, you're in space, aboard the International Space Station. A dream? Not so much!




The idea of ​​an elevator to space is not new: it is a Russian mathematician Yuri Artsutanov, who had imagined in 1960. But today, NASA believes very strong, and even launched a contest last year to validate the concept.

Must first set up the cable. It will be carried, rolled into geosynchronous orbit by small rockets, and deployed vertically from the base platform of 1500 tons located in the Pacific (at the equator).

space elevator
 
Along almost 100 000 km, will be attached to the Earth at a base station. At the other end, a counterweight (eg a small asteroid) will keep the cable taut. Basically, it will be stretched by gravity, and centripetal forces and acceleration at the other end. © Nasa
 
Remains to find a material capable of withstanding such constraints. Carbon nanotubes seem to be the only possibility: these hoses 10,000 times thinner than a human hair is 100 times stronger than steel.

Risk of collision

Elevator cars will be powered by parabolic antennas of 13 m diameter, which receive electricity through the laser beam. The main risks collision with meteorites, and corrosion due to free oxygen atoms found at very high altitudes. According to experts, the problem can be solved by different methods (form ribbon, metal reinforcement ...). According to their calculations, the cable can withstand impacts of objects up to 10 cm in diameter.
The space elevator would send into space all types of objects, provided they are not too heavy: solar satellites, space stations bags, supplies, etc..

Cheap and easily exploitable

While space shuttles burn more than 2 million liters of fuel just to break away from Earth's orbit, the elevator is it relatively cheap. The cost to orbit would be reduced to $ 48 per kilogram, against $ 22 000 per kilogram on a rocket. More than 5 tons of goods may well be sent each day in this way. In short, a highly profitable project, whose total cost is still estimated at $ 7 or $ 10 billion, including start-up costs. Other lifts could then see the light from the Moon, Mars, Venus or even ...