Introduction to solar sailing

Abstract

For all of its short history, practical spacecraft propulsion has been dominated by the unaltering principles of Newton’s third law. All forms of propulsion, from simple solid rocket motors to complex solar-electric ion drives, rely on a reaction mass which is accelerated into a high velocity jet by some exothermal or electromagnetic means. A unique and elegant form of propulsion which transcends this reliance on reaction mass is the solar sail. Since solar sails are not limited by a finite reaction mass they can provide continuous acceleration, limited only by the lifetime of the sail film in the space environment. Of course, solar sails must also obey Newton’s third law. However, solar sails gain momentum from an ambient source, namely photons, the quantum packets of energy of which Sunlight is composed.