Concept illustration and experimental setup of the thermosyphon-based adaptive thermal control system, highlighting two-phase heat transport and SMA-actuated radiator behavior.
Future space missions require highly reliable and efficient thermal management systems to support surface power generation, energy storage, and in-situ resource utilization. Conventional thermal control architectures for fuel cell systems rely on actively pumped loops, introducing failure modes associated with moving parts, control complexity, and limited operational lifetime.
This research investigates a fully passive thermal control system that integrates a two-phase thermosyphon for heat transport with a shape memory alloy (SMA) actuated adaptive radiator for heat rejection. The thermosyphon enables efficient heat transfer through phase change without mechanical pumping, while the SMA torque tube provides temperature-dependent actuation of the radiator geometry. Together, these mechanisms enable adaptive, temperature-driven heat rejection in response to changing thermal loads and environmental conditions.
This effort is funded through NASA Johnson Space Center and is part of a broader initiative to couple passive thermal management with fuel cell technologies. By replacing actively controlled thermal subsystems, this concept improves reliability and operational life while reducing system complexity. The SMA-driven actuation also enables high thermal turndown capability, supporting operation across dynamic environments such as lunar day-night cycles.
Ongoing work focuses on the development of reduced-order models and high-fidelity multiphysics simulations to capture the coupled thermal, fluid, and structural behavior of the system. Experimental validation is ongoing through benchtop testing of a thermosyphon prototype with integrated SMA actuation, enabling comparison between model predictions and system-level performance.
This work addresses key NASA technology gaps in long-duration surface energy systems, including variable heat rejection and adaptive radiators, with applications to lunar and other planetary missions.
Graduate Student: Priscilla Nizio Ho