Future space nuclear power systems will require large radiators to dissipate excess thermal energy. Such radiators may be composed of carbon‐carbon composite fins made from high thermal conductivity graphite fibers or may be a more traditional honeycomb structure with face sheets composed of a suitable high temperature metal. In either case, the surface of the radiator must have a high emittance at the desired operating temperature, envisioned to be in the range of 400 to 900 K, and must be durable for the length of the mission, envisioned to be ten years. Existing thermal control paints and coatings may be applicable at the low end of the envisioned temperature range, but may not be applicable at elevated temperatures. Hence, other avenues of emittance enhancement need to be explored. Previous work has identified a number of promising technologies that may be useful for enhancing the emittance of candidate surfaces, including texturing the radiator surface via sand blasting, oxidation at elevated temperature, and exposure to atomic oxygen. This paper will review existing candidate thermal control paints and coatings to identify their strengths and weaknesses and will review other promising technologies that have been proposed in the past few years to enhance the emittance of radiator surfaces. © 2004 American Institute of Physics