Microwave beam-driven sail flight experiments

We have observed flight of ultralight sails of Carbon-Carbon microtruss material at several gees acceleration. To propel the material we sent a 10 kW, 7 GHz beam into a 10(-6) Torr vacuum chamber and onto sails of mass density 5-10 g/m(2). At microwave power densities of similar to kW/cm(2) we saw upward accelerations of several gees and flights of up to 60 cm. Sails so accelerated reached > 2000 K from microwave absorption, a capability of carbon which rules out most materials for high acceleration missions. Diagnostics were optical and IR video photography, reflected microwave power and residual gas analysis. Data analysis and comparison with candidate acceleration mechanisms shows that photonic pressure can account for 3 to 30% of the observed acceleration, so another cause must be present. Future research will measure the thrust precisely using a pendulum to try to identify the acceleration mechanism. In the future, microwave-driven acceleration might be used to propel probes to very high speeds for science missions to the outer salar system, the interstellar region and the nearby stars.