How can the sail be used in near-term interplanetary exploration and ultimately in star travel?
For probes to atmosphere-bearing planets and satellites, sail-aided aerocapture might be considered, where the sail decelerates the spacecraft parachute-like during a single pass through that planet’s upper atmosphere. Sails are also useful in conducting out-of-the-ecliptic visits to comets in the inner solar system. Commercially, large sails have application to dragging mined asteroid material to space manufacturing facilities. If we wish to economically deliver payloads to Mars-space to support human exploration and are not concerned with long travel time, the sail is ideal. If we dip inward towards the Sun and unfurl the sail at perihelion, the sail can be blown out of the solar system. Near-term Earth-launched sails can exit the solar system at 50-100 km/sec, and ultimately space-manufactured sails can reach 1,000 km/sec. NASA and several Eureopean study groups have considered using near term sail-technology to explore the Sun’s galactic vicinity out to 200-600 Astronomical Units.
