Passive Two-Phase Deployable Radiator for CubeSats and SmallSats

CubeSats and SmallSats have long been increasing the onboard electronics capabilities, resulting in high heat fluxes with inherently reduced surface area for rejection to deep space (as compared with traditional larger satellite designs).  This creates challenges for thermal management specifically relating to limited available thermal radiator area.  A new generation of thermal control technologies called for by DoD 22.1 SBIR topic AF221-0020 will thus require significant improvements in deployable radiator heat rejection surfaces.  ThermAvant Technologies (TAT) proposes a passive deployable radiator oscillating heat pipe (DR-OHP) to address this thermal challenge.  TAT expects the following key advantages to be provided by the DR-OHP:  Improved system level thermal conductance (100s of W/°C), as three-dimensional microchannel routing enables the reduction of thermal interfaces from conventional systems; Two and three-dimensional spreading capabilities in a single package, as compared to the one-dimensional, tubular format of conventional heat pipe embedded radiators, enables new system designs and capabilities, and can reduce mass; High heat flux acquisition and heat load capability, e.g., over 10 W/cm2 and 100’s W per panel, which reduces reliability concerns associated with conventional heat pipes heat flux limits; Working fluids capable of operating over a broad range of operating temperatures, e.g., up to +150 °C and without freezing at -60 °C; Integral phase change or energy storage materials can be easily integrated for increased thermal capacitance; Enhanced wattage rejected by isothermalizing temperature of radiator (with isothermal heat rejection surface with gradients of say 2-5°C) as compared with solid aluminum conductors, thus raising average temperature of radiator.  Structural integration of DR-OHP with deployment mechanism > 25% mass reduction of radiator TAT has experience with non-deployable radiator technologies which have structurally integrated oscillating heat pipes embedded.  Specifically in NASA Ph I Radiator, contract #80NSSC19C0206, and NASA Ph II Radiator, contract #80NSSC19C0206, and ongoing commercial development work with several of the nation’s leading aero-defense contractors.  Case study indicates radiator surface would isothermalize with use of OHP as compared with solid aluminum from 83C dT down to less than 3C dT.  This is in close alignment with the work TAT has already performed and aligns with the experimental test data from those programs. Proposal includes a half dozen categories of deployment mechanism with details around those which are being emphasized for pursuit within this Phase I scope of work and which are fodder for future Phase II an/dor Phase III work