Advanced Solar- and Laser-pushed Lightsail Concepts Final Report May 31, 1999 NASAInstitute for Advanced Concepts 1998 Phase I Advanced Aeronautical/Space Concept Studies Principle Investigator: Geoffrey A. Landis Ohio Aerospace Institute 22800 Cedar Point Road Brook Park, OH 44142 Phone: (216) 433-2238 Fax: (216) 433-6106 e-mail:
[email protected] Advanced Solar- and Laser-pushed Lightsail Concepts Geoffrey A. Landis Abstract Beam-pushed propulsion systems, such as solar- laser-, or microwave- pushed sails, allow the possibility of fuel-free propulsion in space. This makes possible missions of extremely high delta=V, potentially as high as 30,000 km/sec (0.1c), which is required for an fly-by mission to a nearby star. This project analyzed the potential use of dielectric thin films for solar and laser sails. The advantages are extremely light weight and good high temperature properties, which are necessary for both for solar-sail missions inward toward the sun, for solar sail missions outward from the sun that use a close perihelion pass to build speed, and for high velocity laser-pushed missions for the outer solar system and for interstellar probes. Because of the higher temperature capability, the sails can operate under higher laser illumination levels, and hence achieve higher acceleration. This allows large decreases in the minimum size of the sail required. The project also made an analysis of the possibility of microwave-pushed sail propulsion. Microwave sails have the advantage that high-power microwave sources are already existing technology. The study made a new re-analysis of a concept proposed by Robert Forward, and found that a carbon mesh sail is preferable to the aluminum sail proposed by Forward, due to better high-temperature properties.