The spacecraft creates a 60 km wide magnetic field behind it. It then pumps ionised gas, known as a plasma, into this magnetic bubble.

The interaction of the plasma with the charged particles carried by the solar wind propels the spaceraft forwards.

The magnetic bubble effectively acts as a sail trapping the solar wind. Scientists calculate that speeds of 288,000 km/h (180,000 mph) will be possible - 10 times faster than the space shuttle.

Faster and lighter

Nasa has awarded Professor Robert Winglee and his team at the University of Washington $500,000 (�330,000) to develop their Mini-Magnetospheric Plasma Propulsion system (M2P2).

Voyager has pushed the limits of human space exploration

"We can go faster and lighter than anyone else," said Professor Winglee.

The solar wind is made up of charged particles travelling at one million mph. An electric coil, or solenoid, the size of a jam jar will generate a magnetic field 1000 times stronger than the Earth's.

This field would contain a bubble of plasma 30 to 60 kilometres across (18 to 36 miles). Plasma injected into the field would interact with the solar wind's particles to propel the spacecraft forward.

High speed

Previous ideas for harnessing the solar wind include using huge folding sails - but these have the big disadvantage of being relatively heavy. M2P2 could power a vehicle for three months using only three kilograms of helium fuel.

Although the force propelling the space craft would be small - about one Newton, or a quarter of a pound - this would act constantly on the vehicle, accelerating it to its extremely high final speed.

If launched in 2003, M2P2 would reach the outer limits of the solar system before Voyager One, currently the most distant man-made object. Voyager One was launched in 1977 and has a 11-billion-kilometre (6.8-billion-mile) head start, but M2P2 could overtake it in 2013.