FRESR: Freezable Radiator for Efficient, Safe, and Robust Single Loop Thermal Control

This project addresses NASArsquo;s need for low mass, safe, and highly robust single loop active thermal control systems (ATCS).nbsp; The spacecraft ATCS must transport heat loads from inside a space habitat to subsystems that reject heat to the surroundings. Deep space habitats will require ATCS that maintain cabin temperature despite wide fluctuations in heat loads (during crewed and un-crewed periods) and sink temperatures.nbsp; Historically, dual loop architectures have been utilized, because there are no known fluids that are both non-toxic (safe to use inside the habitat) and non-freezable (reliable for use outside of the habitat).nbsp; Thus, a low-freeze point fluid is used in an external loop and a non-toxic fluid (water) in an internal loop, increasing overall mass and complexity.nbsp; These dual loop architectures are safer with a nontoxic internal fluid but hazards still remain. Non-freezable, nontoxic coolants and freezable radiators will enable single loop ATCS architectures that have reduced complexity and mass over dual loop systems.nbsp; Space Lab Technologies proposes FRESR, a Freezable Radiator for Efficient, Safe, and Robust single loop thermal control of crewed vehicles and habitats.nbsp; FRESR builds upon and integrates ground tested heat exchanger/radiator technology, into a realizable single loop architecture with low mass materials and more reliable components. A FRESR ATCS includes human-safe coolant, eliminating the toxic hazard of ammonia or HFE7200; freeze tolerant components that allow thermal expansion during freeze; and self-regulating temperature control, making it robust to fluctuating heat loads and heat sinks.nbsp; Space Lab, supported by the University of Colorado, will establish feasibility of integrating FRESR into a space habitat ATCS for exploration missions (such as Lunar Gateway or a lunar surface habitat).nbsp; In Phase I, lightweight freeze-tolerant coolant tubes and radiator loops will be designed and tested as an integrated system in thermal vacuum.nbsp;