Diffractive Solar Sails Could Hit a Killer Asteroid at 100 km/s

Researchers at Beihang University propose using diffractive solar sails to send an impactor onto a retrograde trajectory and strike a hazardous asteroid head-on at about 100 km/s. That delivers roughly 230 times more energy per kilogram than the DART mission, and could reach Apophis in 200–300 days after launch.

• A 100 km/s impact delivers ~230x more energy per kg than DART's 6 km/s
• Diffractive sails bend light sideways without tilting the sail away from the Sun
• A simulated mission reaches 340m asteroid Apophis in 200–300 days
• That is nearly a year faster than a standard reflective solar sail