Vid MIT astro brainboxes say they're on the track of tech which could greatly prolong the life of satellites, as well as helping them avoid banging into each other. They have illustrated this by fashioning a crude plasma thruster out of a Coke can and a glass bottle.

Needless to say, the MIT vid of the Coke bottle-rocket is available on YouTube:

The recycled-materials space thruster was assembled Dr Oleg Batishchev and his team, of the MIT Department of Aeronautics and Astronautics. Batishchev's mob are working on a heavily simplified version of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR), which might soon be used to adjust the orbit of the International Space Station - or one day carry astronauts beyond Mars.

Batishchev believes, however, that full-on VASIMR plasma drives are too complex for use on the most common of humanity's spacecraft today - normal Earth-orbiting satellites. But satellites need a propulsion system. They carry small chemical rockets, used for adjusting their orbit - either to keep on track, to change what ground they pass over, or to avoid collision with other objects in space.