Antimatter starship. Artist's impression of a space vehicle for exploring other star systems. The vehicle is 700 metres long, has a mass of 15,000 tonnes and is powered by an antimatter rocket engine. In this concept, matter and antimatter are allowed to mix in a 'combustion' chamber. Matter particles annihilate with their antimatter counterparts producing very energetic charged particles (mostly pions and electrons). These may be directed into the exhaust nozzle by magnetic fields. This vehicle's cruising velocity would be about 10% of the speed of light, so even the nearest star will be a 43-year journey from Earth.