Study of sealing effect about the Shape Memory Alloy-based Knife-edge Seal System in extraterrestrial soil sample return mission

Deep space exploration missions critically require reliable sealing system for extraterrestrial sample containment and return. This study presents a Shape Memory Alloy-based Knife-edge Seal System (SMAKSS) designed specifically for this demanding application. Through an integrated approach combining numerical modeling and experimental validation, we systematically investigated the system's sealing performance. A thermo-mechanical finite element model is developed in COMSOL Multiphysics to simulate the Shape Memory Alloy (SMA) ring's thermally-induced contraction behavior and stress distribution during sealing. Moreover, the experiment investigates trends in both leakage rates and knife-edge penetration depths in SMAKSS systems with four different blade angles and tip radius under increasing heating temperatures. Experimental results demonstrate that the configuration with a 45° blade angle and a 0.1 mm tip radius achieves the deepest penetration depth and generates the highest compressive stress, achieving a minimal leakage rate of 3.53 × 10⁻¹¹ Pa m³/s at a heating temperature of 150 °C. This leakage rate meets the stringent sealing requirements for extraterrestrial sample containment, establishing SMAKSS as a promising solution for planetary exploration applications.