Dr Pekka Janhunen of the Finnish Meteorological Institute in Helsinki thinks he has invented a method to make space faring much easier and cheaper than before. In 2004 he put forward the idea of a sail that harnesses the solar wind, a stream of charged particles emanating from the sun which manifests itself on Earth in the dramatic displays of the aurorae.
With the electric solar wind sail a spacecraft could make a round trip to the asteroid belt in little more than three years. A fleet of 50 such craft, weighing about 5kg each and thus capable of being launched by a single rocket, could visit 300 asteroids, survey them and return to Earth.
Read the story (The Economist)