Tailoring Thin-Film/Lacquer Coatings for Space Applications

Abstract

Thin-film coatings have the capability of obtaining a wide range of thermal radiative properties, but the development of thin-film coatings can sometimes be difficult and costly when trying to achieve highly specular surfaces. Given any space mission’s thermal control requirements, there is often a need for a variation of solar absorptance (α s ), emittance (∊) and/or highly specular surfaces. The utilization of thin-film coatings is one process of choice for meeting challenging thermal control requirements because of its ability to provide a wide variety of α s /∊ ratios. The radiative properties of thin-film coatings can be tailored to meet specific thermal control requirements through the use of different metals and the variation of dielectric layer thickness. Surface coatings can be spectrally selective to enhance radiative coupling and decoupling. The application of lacquer to a surface can also provide suitable specularity for thin-film application without the cost and difficulty associated with polishing.