Just sail through the infinite expanse of space? Like a sailboat that uses the wind to cross a lake or even the ocean, solar sails use the pressure exerted by sunlight to propel a spacecraft through space. NASA has developed an innovative solar sail concept for this purpose, which is now to be tested. The Diffractive Solar Sailing project was selected for a Phase III study as part of the NASA Innovative Advanced Concepts (NIAC) programme. Phase III aims to implement NIAC concepts with high potential for NASA, other government agencies or commercial partners. The Phase III grant will provide the research team with two million dollars over two years to further develop the technology for use in a possible future demonstration mission. The project is led by Amber Dubill of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.
Previous reflective solar sails are usually very large and very thin. Their use is limited by the direction of the sunlight, forcing compromises between performance and navigation. Diffractive light sails, on the other hand, would use small gratings embedded in thin films to exploit a property of light called diffraction. This causes light to spread out as it passes through a narrow aperture. In this way, a spacecraft could use sunlight more efficiently without being hampered in its manoeuvrability. “As we venture further into the cosmos than ever before, we need innovative, breakthrough technologies to advance our missions,” said NASA Administrator Bill Nelson. “NASA’s Innovative Advanced Concepts programme helps develop visionary ideas – like novel solar sails – and bring them closer to reality.”