Tuesday, 16 January 2007
Solar sails and artificial Lagrange orbits for remote sensing, telecommunications, and space weather applications
Exhibit Hall C (Henry B. Gonzalez Convention Center)
Solar sails are a propulsion technology that uses large, lightweight mirrors to propel a spacecraft using the momentum inherent in sunlight. This continuous source of propellantless propulsion enables new families of orbits that are otherwise impossible. These orbits have a variety of applications to remote sensing, space environment monitoring, and telecommunications. Sun-Earth Lagrange points are equilibrium solutions of the rotating sun-Earth system between the gravity of the Earth and sun and the centripetal acceleration of the rotating system. Solar sails add a controllable force that expands the Lagrange points into three-dimensional surfaces upon which spacecraft can be stationed called artificial Lagrange orbits. Artificial Lagrange orbits sunward of L1 permit early detection of solar wind conditions that lead to geomagnetic storms. Artificial Lagrange orbits north or south of the L1 or L2 Lagrange points allow year-round coverage of a polar region with a single satellite. The resolution is sufficient to meet many remote sensing requirements from these orbits, and the temporal coverage is continuous. The stable thermal and dynamic environment may benefit sensor design. Telecommunications to the South Pole may be met with a single satellite providing a data connection to the mainland. Polar satellites may have global realtime data downlink through two satellite crosslinks in natural or artificial Lagrange orbits to a small number of ground stations. Solar sail technology that can perform these missions has matured greatly in the past few years from government and private investment, and is ready for flight demonstration.