Analysis and optimization of micro-switch actuation in spacecraft deployable antenna pointing mechanisms

During the deployment test of a spacecraft's deployable antenna, a fault was observed in the hold-down and release mechanism's micro-switch. The micro-switch failed to transition its actuation state correctly. This paper investigates the root cause of the failure and identifies excessive initial compression of the micro-switch leaf spring as the primary factor. A detailed fault mechanism analysis was conducted. It examined the contact and actuation state of the switch. A finite element simulation model of the leaf spring and micro-switch assembly was developed to analyze stress distribution and actuation forces. The simulation revealed that the excessive pre-load placed the micro-switch in a critical, unreliable actuation state. Based on these findings, optimization objectives were defined, which led to the proposal of two specific design improvements. Post-optimization simulation results demonstrated a significant reduction in both leaf spring stress and contact forces, confirming the efficacy of the proposed measures. Subsequent deployment tests validated the optimization approach, successfully verifying its correctness and effectiveness. This work provides a critical foundation for the reliable actuation design and precise quantitative control of micro-switches in pointing mechanisms and other space-borne mechanisms.