Solar sail attitude control and dynamics, part 1

Results of a study of developing attitude control systems for solar sail spacecraft are presented. The study objective was to advance sailcraft attitude control technology so that a solar sail spaceflight experiment for validating sail attitude stability, as well as thrust-vector pointing performance, can be conducted in the near future. An overview of sail-attitude-control issues, solar-radiation-pressure models, and dynamic modeling and control analyses of a sailcraft in an Earth-centered elliptic orbit is presented. A simple spin-stabilization approach is emphasized, whereas other active three-axis control approaches, employing a gimbaled control boom, control vanes, or sail shifting/tilting, are presented in the companion paper. A 40 x 40 m, 160-kg sailcraft with a nominal solar-pressure force of 0.01 N, an uncertain center-of-mass/center-of-pressure offset of +/-0.1 to (i.e., +/-0.25% of 40 m), and moments of inertia of (6000, 3000, 3000) kg (.) m(2) is used to illustrate the various concepts and principles involved in dynamic modeling and attitude control design.