Apparent Radiative Properties of Reconfigurable, Diffuse-Specular Origami-Inspired Cavities

Dynamic control of apparent radiative surface properties enhances the design and optimization of spacecraft thermal management systems. This work focuses on engineered surfaces that achieve dynamic variation in effective radiative properties through cavity effects. Specifically, the objective is to demonstrate how actuation of origami-inspired cavities with mixed diffuse–specular reflectance can be used to dynamically control apparent radiative properties. The collapsible nature of these cavities enables a transition between intrinsic and apparent radiative behavior through surface actuation. This study presents a Monte Carlo Ray Tracing (MCRT) investigation of the apparent radiative properties of several isothermal, opaque, and gray origami-inspired geometries, namely, a V-groove, Miura-Ori, and Barreto's Mars tessellations. Results demonstrate how geometry and specularity ratio influence the apparent absorptivity of complex surfaces under collimated and diffuse irradiation. For V -grooves exposed to collimated radiation, apparent absorptivity is generally higher at small actuation angles and for specular surfaces; for example, with intrinsic absorptivity α = 0.3 and γ = 40°, the apparent absorptivity increases by approximately 27% as the specularity ratio increases from 0 to 1. Fully folded Miura-Ori tessellations with specular surfaces approximate a black surface, similar to the V -groove as it collapses. In contrast, Barreto's Mars tessellations exhibit peak apparent absorptivity at intermediate actuation angles, with maxima occurring at γ = 40° (0.82), 35° (0.65), 30° (0.47), and 20° (0.22) for intrinsic absorptivities of 0.7, 0.5, 0.3, and 0.1, respectively.