Solar Array Deployment Mechanism: Study and Redesign of a Space-Grade Hinge Aerospacelab

Abstract

As the small satellite industry grows, spacecraft manufacturers face increasing pressure to produce reliable hardware at industrial scale. Aerospacelab (ASL) addresses this challenge buy providing vertically integrated spacecraft structure, relying on versatile and scalable components. Their Versatile Satellite Platform (VSP) is a concrete example of a modular and standardized satellite design. This thesis was conducted within the Solar Array Assembly (SAA) team during the final production and delivery phase of the first batch of in-house solar wings. The subject of the work is the root hinge latching mechanism of the SAA. A formal analysis of the baseline design, grounded in the theory of form and force closure for unilat- eral contact systems, reveals that the deployed bracket degree of freedom is maintained in force closure by the actuation torque of the driving clock spring rather than by geometric locking. This results in conditional backlash: a dead motion zone that appears when the spring load is removed or overcame, which constitutes a latent non-conformance with the zero-backlash requirement. A subsequent analysis then identifies a proper redesign direction, preventing any back- lash on the hinge bracket. This design choice, however, involves submitting the latch to disengaging loads. One must therefore enforce that the latch remains locked in through force closure. The specific condition of self-locking through friction between mechanical parts in contact is studied as the answer to that problematic. To study the resulting contact, a complete geometric model is built, limiting the number of design parameters left and allowing to mathematically define the conditions under which a proper contact can be established at the latching interface while achieving self-locking of the mechanism. The resulting parameter space is then explored before selecting a redesign candidate and putting it to experimental testing. The results show that the redesign is achievable and can indeed suppress the backlash observed in the baseline design, while making sure that the latch can not disengage. The work combines a rigorous theoretical framework, through contact mechanics, self-locking analysis, and convex geometries, with concrete engineering deliverables: a parametric Computer-Aided Design (CAD) model in Siemens NX and a reusable Python toolbox that can be updated as the design evolves.