Solar sails have been considered on and off as a way of propelling spacecraft ever since Konstantin Tsiolkovsky first put forward the idea early in the 20th century. By using sunlight or lasers aimed at gigantic, gossamer-like sails, the pressure of photons hitting the sails could generate thrust, pushing the craft along like a sailing ship.
To see if graphene has any promise as a sail material, researchers took a patch of graphene sheet 3 mm across and dropped it inside a 100-meter-high (330-ft) vacuum tower. As it went into free-fall, the little sail was hit by a series of 1-watt lasers, which accelerated it by as much as 1 m/s². That's only a small fraction of one gravity, but ESA says that in space, this acceleration would eventually build up to tremendous speed.
"Making graphene is relatively simple and could be easily scaled up to kilometer-wide sails, though the deployment of a giant sail will be a serious challenge," says Santiago Cartamil-Bueno, leader of the GrapheneSail team and director of SCALE Nanotech.