An indirect optimization method is applied to minimize the trip time of interplanetary and escape missions using a grey (i.e., non-perfectly reflective) solar sail. The sail is assumed to be flat and the optical properties of its material (transmittance, absorptance, and reflectance) are taken into account; the reflection is not perfectly specular, but diffuse and back reflectance are also considered. The theory of optimal control and, in particular, Pontryagin’s maximum principle provide the optimal orientation of the sail at each point of the trajectory. A real sail with non-unit reflectivity is feathered during some particular phases of the mission. A sail, which reemits the absorbed energy mainly from the rear side, may present jumps in the sail orientation for maximum performance. Numerical examples, concerning transfers to Mars and escape from the solar system, are presented to highlight the differences in control law and performance of ideal and real sails.
Optimal Control of a Grey Solar Sail for Interplanetary Missions
J of Astronaut Sci
The Journal of the Astronautical Sciences ; 51 , 4 ; 405-418
2003-12-01
14 pages
Article (Journal)
Electronic Resource
English
Optimal Control of a Grey Solar Sail for Interplanetary Missions
Online Contents | 2003
|Optimal Control of a Grey Solar Sail for Interplanetary Missions
Online Contents | 2003
|