Investigation of thermal distortion and control of spacecraft based on shape memory materials

Gossamer space structures are relatively large, flimsy, and lightweight. As a result, they are more easily affected or distortion by space thermal environments compared to other space structures. This study examines the structural integrity of a Five-Meter Ka-Band Inflatable/Self-Rigidizable Reflect Antenna under space thermal environments. To maintain the required accuracy of the reflector under orbital temperature changes, the Gossamer space structures will utilize an active control system, consisting of boundary control actuators and an electrostatic figure control system with a real time closed loop feedback. An experimental system is established to verify the control mechanism with photogrammetric measurement technique and Bragg fiber grating (FBG) sensor technique. The shape control experiments are finished by measuring and analyzing small amplitude distortion of Five-Meter Ka-Band Inflatable/Self-Rigidizable Reflect Antenna based on the active components made of shape memory alloy (SMA) and shape memory polymer composite (SMPC) material. Then, simulations are finished by NASTRAN finite element software with active effect which is considered to be deformation applied on the analytical model. The amplitude of distortion is obtained by the simulations. Both the experimental and numerical solution show that the amplitude of accuracy are developed which proves the feasibility of shape control using shape memory materials and this investigation explores the feasibility of utilizing an active cable based control system of shape memory materials to reduce global distortion due to thermal loading. It is found that through proper assemble of cable lengths and attachment points, significant thermal distortion reduction is achieved. Specifically, radial distortion due to on-orbit thermal loading.