Heat pipes for spacecraft temperature control: An assessment of the state-of-the-art

Spacecraft applications that require the efficient cooling of high-powered components, the precise temperature control of sensitive electronic and optical components, and the protection of cooled components from temporary, adverse environmental conditions are increasing. Heat pipes using gas, vapor, liquid, or voltage control to provide variable conductance or diode thermal behavior have been and are continuing to be developed to meet increasingly difficult requirements. The various control techniques are critically evaluated using characteristic features and properties, including heat transport capability, volume and mass requirements, complexity and ease of fabrication, reliability, and control characteristics. As a result, advantages and disadvantages of specific approaches are derived and discussed. Using four development levels, the state-of-the-art of the various heat pipe temperature control techniques is assessed.