A test model of a solar sail blade before it unfurls in a zero-gravity simulation. Through these tests and experiments, the engineers are determining the final configuration for the solar sail's blades. The Planetary Society. Blade on floor. The Planetary Society.
Sunlight bounces off the mirror-like sail, imparting momentum to the vehicle.
The force is imparted in a direction controlled by the angle of the sail with respect to the sunlight, which can either increase or decrease the velocity of the spacecraft depending on the direction of the force. Louis Friedman, redrawn by B. S. Smith. That's Louis Friedman, Executive Director of The Planetary Society and Project Director for Cosmos 1, walking toward the camera. The Planetary Society. Dr. Louis Friedman, Cosmos I Project Director and Executive Director of The Planetary Society, with sail material-1.