Dynamic Control of Radiative Surface Properties With Origami-Inspired Design

Thermal management systems for space equipment commonly utilize static solutions such as insulation, optical coatings or reflective mirrors. The simplicity of static systems is advantageous, but the inability to adapt to environmental changes leads to systems designed for extreme conditions. Active control of radiative surface properties would increase the operational capabilities of spacecraft thermal management systems. This study investigates a dynamic solution that allows for real-time control of radiative surface properties based on origami-inspired designs. The extent to which the absorptivity and emissivity of a surface may be varied is demonstrated experimentally. Linear actuation of origami-based structures provides the avenue to alternating between flat and cavity-like surface geometries where the number of reflections, and hence the radiative surface properties are controlled. Flat and folded aluminum foil samples were alternately irradiated with a blackbody emitter at 1000 °C then shielded from the radiation source while the transient temperature was recorded using thermocouples and an IR camera. Thermal models relating the apparent absorptivity of the radiation shield to the time-dependent surface temperature are presented, and methods to invert these models are described. Preliminary results show a significant increase in irradiated steady state temperature for a high fold density as compared to unfolded configurations of the same thickness and material. These results indicate that origami-inspired designs have the potential to provide dynamic control of the apparent absorptivity of radiation shields and surfaces.