The University of Washington in the USA has received a £500,000 grant from NASA to work on a new propulsion system called Mini-Magnetospheric Plasma Propulsion - M2P2 - which could enable a spacecraft to travel at 290,000km/h or 6.5 million km/day.
Solar cells and solenoid coils would be used to create an electromagnetic field around the spacecraft which would be propelled by its interaction with the solar wind.
Source: Flight International