This study proposes a new method for shape control of non-spinning solar sails, in which Shape Memory Alloy (SMA) wires are exploited. An SMA wire is one of soft actuators that contracts at temperatures above its design value. In the proposed framework, the whole shape of a solar sail membrane is deformed via the contraction of SMA wires distributed over the membrane. The deformation results in the change in solar radiation pressure (SRP) torque acting on the solar sail-craft, which is applicable to fuel-free attitude control. In this paper, we investigate the theory of shape control using SMA wires. It is shown that a membrane under shape control behaves similarly both in a ground experiment and in a finite element method (FEM) analysis, demonstrating the validity of numerical modeling. With this result, the performance of shape control for a large membrane in a space environment is simulated by another FEM analysis. Results demonstrate that the proposed method is capable of producing SRP torque at an effective level for attitude control.
