Design, fabrication, and evaluation of a passive deployment mechanism for deployable space telescope

This article presents a high precise deployment mechanism for a deployable space telescope to facilitate satellite miniaturization. It is designed with a passive deployment mechanism utilizing a spring hinge. In particular, the customized modules and an assembly jig are specifically designed to reduce alignment errors. To confirm the feasibility of the designed mechanism, three alignment errors that influence the optical performance of the structure-tilt, de-center, and despace-are theoretically analyzed for quarter, half, and full model, respectively. In the case of quarter model, significant results are obtained as a tilt of 21.12 mu rad, a de-center of 2.20 mu m, and a de-space of 1.71 mu m. Based on the theoretical analysis, a deployment mechanism of the quarter model is fabricated, and the alignments of the deployment mechanism are experimentally investigated with a measurement platform consisting of five non-contact-based laser displacement sensors. In addition, the influence of gravity on the alignment error is analyzed and compensated by investigating the tendency of the alignment error according to the rotation degree of the measurement model for the direction of gravity. As a result of the gravity compensation, the proposed mechanism gives acceptable alignment errors as a tilt of 30.04 mu rad, de-center of 8.92 mu m, and de-space of 4.03 mu m, which are controllable by employing the conventional focusing mechanism.