If launched in 2010, the probe would overtake Voyager in 2018, going as far in eight years as Voyager will have journeyed in 41 years. Les Johnson says speed is the crucial issue for any interstellar mission. He envisages ultra-thin, reflective sails that could be propelled through space by sunlight, microwave beams or laser beams just like the wind pushes sailboats on Earth. Rays of light from the Sun would provide tremendous momentum to a gigantic structure. Nothing this big has ever been deployed in space.
Researchers are optimistic about recent breakthroughs with strong, lightweight composite materials.
A leading candidate for sails is a low-density carbon fibre material.