Description: NASA Technology Roadmap Area 14 outlines a turn down goal of 6 to 1 by a thermal control system operating at the scale of kilowatts of heat removal. These thermal control systems must be designed to perform this turn-down and turn-up within a required time frame reliably and predictably. Paragon?s innovation will achieve this with lower weight, less complexity, and reduced costs, all while maintaining a highly flexible design. The Controlled Stagnation Radiator offers the ideal combination of maximized radiator performance at high heat loads and a high turndown ratio via controlled, determinate stagnation at low heat loads. By placing one or more passive pressure equalization devices on some of the radiator fluid tubes, that portion of the radiator becomes more resistant to stall, and those tubes without the innovation will be the first to stagnate. In effect, this system provides controlled stagnation by adding local stagnation resistance, rather than by adding mechanical systems which increase complexity and mass, or flow imbalance which impact design load performance. Since the implementation of the innovation has no impact to the flow distribution in the design load case the radiator can both be optimized for full flow performance and be designed to exhibit determinate performance in deep stagnation for high turndown and intermediate loads, as is required of modern spacecraft thermal control system design. This improvement upon the state of the art is expected to mature stagnation technology by giving the system greatly improved performance determinance which will allow the solution to be baselined for use in next generation spacecraft and optimized for any application with minimized design cycle, testing, cost and schedule impact. The innovation concept is also highly compatible with Paragon?s xRad radiator manufacturing technique, meaning that any size and aspect ratio of radiator panel can be easily manufactured without the need for complex tooling.

Benefits: The Controlled Stagnation Radiator is primarily intended for human-rated single loop ATCS applications as most suitable non-toxic fluids are highly viscous and prone to stall under low heat loads in cold environments. As NASA develops deep space mission capabilities there will be a need for new habitat modules that would benefit from the incorporation of this technology. In addition, the developed technology could be incorporated into block upgrades of multiple commercial and NASA spacecraft to save weight and decrease complexity and costs. Additionally, surface habitat modules for the Moon and/or Mars could also benefit from the use of the Controlled Stagnation Radiator, especially as these colonies grow and require more radiator area to support higher maximum heat loads while still being functional at lower loads.

Companies such as Boeing, Lockheed Martin, Orbital ATK and Bigelow are known to be proposing development of habitat or EAM modules for the anticipated NASA missions to deep space. Additionally, Elon Musk of SpaceX is very up-front about his desire to send humans to Mars. All of these represent potential customers. Military customers have varied missions with periods of high and low thermal dissipation needs that would also benefit from the innovation. This includes directed energy, high-powered communication systems and Operationally Responsive spacecraft. Also, Mars One is still pursuing the colonization of Mars and continues development of surface modules. As Paragon is already a partner on this project to provide life support, it would make sense that the Controlled Stagnation Radiator concept could find its way to Mars.