Thermal Vacuum Verification of Origami Inspired Radiators

This effort seeks to provide a unique means of modulating the waste thermal energy radiated by a radiator, and represents a restart of the FY17 effort that had to be terminated early. Two concepts are combined; use of custom, multimaterial-layered films (deposited via conventional sputtering methods and Atomic Layer Deposition (ALD)) and the ability to "fold" the radiator employing origami techniques. The ALD coating technique is new to this radiator application, and has well established stability in electrostatic charging environments. This technology is applicable to the full spectrum of spacecraft platforms from large structures to 1 U CubeSats. Current technology undergoes a solid-state transition at 68 C, which is generally too high to be useful. This CIF will seek to achieve a lower transition temperature through use of an innovative, multi-layered structure involving selective reflectance interference layers, applied via ALD. The material of choice for this interference layer is TiO2 with Ge. Theoretically, the proposed coating results in a surface that transitions around 2 C with a low e = .1 and a high e = .85, and a 5% reversible hysteresis. This coating will be tested to demonstrate performance, Additionally, as a second innovation, this novel coating will be applied onto origami inspired radiators, currently under development at BYU. Fabrication and characterization testing of this variable emissivity, 3D radiator will be performed at GSFC by the end of the FY.