A technology for propelling spacecraft using a “sail” pushed by light has passed an initial test, with the prototype device staying centered in a laser beam.
To snap close-up photos of planets outside our Solar System (exoplanets), some researchers are proposing the use of a fleet of “light sails” propelled by powerful Earth-bound lasers. A new experiment has demonstrated a possible sail design that uses diffraction gratings, rather than the reflective mirrors that have been used in previous sail designs. The gratings deflect an incoming laser beam at an angle, creating a sideways force that keeps the sail aligned with the beam’s center. Further testing is needed, but the team developing the sail is hopeful that their “beam-rider” technology could guide probes to faraway stars or to closer targets in our own Solar System.
