Simple deployable radiator with autonomous thermal control function

The concept, detailed design, fabrication, and test results of a reversible thermal panel, which is a new, passive, and lightweight 100 W-class deployable radiator with an environment-adaptive function, is described. The reversible thermal panel changes its function reversibly from a radiator to a solar absorber by deploying/stowing the radiator/ absorber reversible fin upon changes in the heat dissipation and thermal environment, and is effective for the thermal control of high power density small satellites, lenders, and interplanetary spacecrafts. Parametric studies were conducted with detailed simulation models, and the reversible thermal panel configuration that satisfies thermal requirements with the restraints of weight and fin efficiency variation was determined. Based on the analytical results, a reversible thermal panel engineering model was fabricated using high thermal conductivity graphite sheets in the reversible fin and a shape-memory alloy in the passive deployment/stowing actuator. Test results indicated excellent performance of the reversible thermal panel as a passive radiator from the standpoints of heat-rejection capability, specific heat rejection, and variation of the fin efficiency. The effectiveness of the reversible thermal panel as a solar absorber that can be substituted for a survival heater was also demonstrated.