Improvement of Coating Emittance at Temperatures up to 1200°C for Re-Entry Vehicles

The thermo-optical properties of thermal protection systems for spaceplanes or capsules mainly govern the temperature of the aerothermally heated outer surface during ascent and re-entry. High emissivities are favourable to achieve significant surface temperature reduction. Adding of filler materials to a coating is a potential method to improve the emissivity at higher temperatures. When the refraction index of the coating material varies only slightly with temperature, it is demonstrated that overlapping of the spectral emissivities determined at RT with the Planckian spectrum at temperatures T predicts the temperature behaviour of the coating emissivity within a technically acceptable uncertainly bandwidth.