Helicopters for Interplanetary Space Flight

The Jet Propulsion Laboratory in Pasadena has recently completed a design study of solar sail propulsion systems for the Halley Comet Rendezvous Mission. The configuration selected by JPL as best suited for the Halley mission is a vehicle known as the Heliogyro, which resembles a conventional helicopter rotor both in appearance and in function. Solar sails derive their propulsive thrust from solar radiation pressure. The reflective area must be very large to provide a useful thrust; for example, the area of the solar sail proposed for the Halley Comet Rendezvous Mission is 625,000 m2. The paper describes the mechanical and functional characteristics of the Heliogyro with particular emphasis on structural dynamics and control. It also reviews potential applications of the Heliogyro to planetary missions.