Search

State-of-the-art (SOTA) EDS technology includes the addition of a dielectric substrate, the EDS electrodes, and a dielectric cover layer. Typically, this multilayer stack-up for thermal radiator EDSs are built as a stand-alone and placed directly on top of the thermal radiator base and covered with the thermal control material. This new coating system represents an alternative EDS approach that integrates with the thermal radiator's thermal control coating system. The approach involves utilizing the thermal control coating in multiple functional capacities within the EDS configuration. The thermal control coating properties are leveraged to provide electrical insulation characteristics suitable for EDS operation while maintaining thermal performance requirements. The EDS configuration incorporates conductive elements positioned within the thermal control coating structure. The thermal control coating is applied using processes compatible with standard thermal radiator construction methods. The conductive elements are integrated during the coating application sequence. This integrated EDS approach incorporated into a thermal radiator system reduces certain components compared to SOTA EDS systems. The reduction in components offers potential benefits in system mass, thermal performance characteristics, and manufacturing complexity. The approach may reduce certain failure modes associated with interface layers and thermal expansion effects. This EDS configuration allows for enhanced flexibility in thermal radiator design parameters.

The new composite developed by NASA incorporates PGS and CNTs to enhance its thermal conductivity while preserving the mechanical properties of the underlying carbon fiber polymer composite. NASA has also improved the composite manufacturing process to ensure better thermal conductivity not only on the surface, but also through the thickness of the material. This was achieved by adding perforations that enable the additives to spread through the composite. The process for developing this innovative, highly thermally conductive hybrid carbon fiber polymer composite involves several steps. Firstly, a CNT-doped polymer resin is prepared to improve the matrix's thermal conductivity, which is then infused into a carbon fiber fabric. Secondly, PGS is treated to enhance its mechanical interface with the composite. Thirdly, perforation is done on the pyrolytic graphite sheet to improve the thermal conductivity through the thickness of the material by allowing CNT-doped resin to flow and better interlaminar mechanical strength. Finally, the layup of PGS and CNT-CF polymer is optimized. Initial testing of the composite has shown significant increases in thermal conductivity compared to typical carbon fiber composites, with a more than tenfold increase. The composite also has higher thermal conductivity than aluminum alloys, with more than twice the thermal conductivity of the Aluminum 6061 typically used in the aerospace industry. For this new material, NASA has completed a proof-of-concept demonstration and work continues to use the material in a heat exchanger system and further characterize the properties including longevity and radiation impact analysis.