Diffractive Lightsails

Unlike a reflective solar sail, a sun-facing diffractive solar sail uses a component of force perpendicular to the sun line. This allows navigation without sacrificing the amount of solar power on the sail. The angular deviation of light from a diffractive film may be engineered to provide electronic, rather than mechanical, navigation protocols, e.g. by electro-optic beam steering. They can use liquid crystal systems to turn the diffraction system on and off and to manipulate the light forces.

The researchers propose using diffractive solar sails for controlling and placing satellites in difficult but useful orbits around the earth and for interesting and useful orbits around the sun.

An update on the diffractive solar sail work was presented at the NASA NIAC 2020 virtual meeting.