Every satellite that goes up to orbit is the pride and joy of some company, lab, or nation. But once it has outlived its purpose, it's nothing but junk.

Attaching a hi-tech kite-tail to satellites might seem too simple to work. But electrodynamic tethers could provide a low-cost, lightweight method of debris removal. Best of all, they operate without fuel. Tethers take advantage of the Earth's magnetic field, interacting with the ionosphere via 3-mile-long wires to produce a drag effect, pulling defunct satellites down to lower orbits until they burn up in the atmosphere.

Tethers Unlimited Inc. has a working prototype called the Terminator Tether that could de-orbit large satellites in a matter of months after being deployed. Pictured is an artist's concept of NASA's ProSEDS tether, a variation on this model designed as a source of propulsion.