Radiator Heat Pipes with Carbon‐Carbon Fins and Armor for Space Nuclear Reactor Power Systems

Technologies for Space Reactor Power Systems are being developed to enable future NASA’s missions early next decade to explore the farthest planets in the solar system. The choices of the energy conversion technology for these power systems require radiator temperatures that span a wide range, from 350 K to 800 K. Heat pipes with carbon‐carbon fins and armor are the preferred choice for these radiators because of inherent redundancy and efficient spreading and rejection of waste heat into space at a relatively small mass penalty. The performance results and specific masses of radiator heat pipes with cesium, rubidium, and potassium working fluids are presented and compared in this paper. The heat pipes operate at 40% of the prevailing operation limit (a design margin of 60%), typically the sonic and/or capillary limit. The thickness of the carbon‐carbon fins is 0.5 mm but the width is varied, and the evaporator and condenser sections are 0.15 and 1.35 m long, respectively. The 400‐mesh wick and the heat p...