Satellites have a major part to play in the present communication system. These satellites are launched with the help of rockets. Typically a payload will placed by a rocket in to Low Earth Orbit or LEO (around 400 km) and then boosted higher by rocket thrusters. But just transporting a satellite from the lower orbit to its eventual destination can to several thousand dollars per kilogram of payload. To cut expenses space experts are reconsidering the technology used to place payload in their final orbits.
There are over eight thousand satellites and other large objects in orbit around the Earth, and there are countless smaller pieces of debris generated by spacecraft explosions between satellites. Until recently it has been standard practices to put a satellite in to and leave it there. However the number of satellites has grown quickly, and as a result, the amount of orbital debris is growing rapidly. Because this debris is traveling at orbital speed (78km/s), it poses a significant threat to the space shuttle, the International Space Station and the many satellites in Earth orbit.
One method of removing a satellite from orbit would be to carry extra propellant so that the satellite can bring itself down out of orbit. However this method requires a large mass of propellant and every kilo of propellant that must be carried up reduces the weight available for revenue-producing transponders. Moreover this requires that the rocket and satellites guidance systems must be functional after sitting in orbit for ten years or more.
What can, without rockets, deploy satellite to Earth-orbit or fling them in to deep space, can generate electrical power in space, can then catch and eliminate space junk? String! Sounds impossible, but the development in space-tethers may be as significant to future space development as rockets were to its beginnings.
Called an electrodynamic tether provides a simple and reliable alternative to the conventional rocket thrusters. Electrodynamic tethers work by virtue of the force a magnetic field exerts on a current carrying wire
Download seminar docs :