<title>Thin film coatings with variable emittance</title>

Abstract

The temperature of a nanosatellite in orbit varies strongly as it goes into earth shadow or solar radiation. A variable emittance panel built with an electrochromic material, could improve the temperature control by providing an adaptive thermal control. The active function is due to an electrochromic layer, WO3, deposited by sputtering. Intercalation of Li+ leads to a change in the electron configuration, which modulates the radiation properties. Thin WO3 films were deposited onto Indium Tin Oxide (ITO) coated glass by reactive dc sputtering. IR measurements were done in a Perkin-Elmer 983 spectrophotometer. The IR emittance modulation, (Delta) (epsilon) of WO3 films, deposited on ITO coated glass, has been investigated. The emittance, (epsilon) , is computed from the reflectance, at 25 degrees C. Initial results show emittances in the range from 0.2 to 0.5 crystalline film has (Delta) (epsilon) equals 0.12, and the amorphous film has (Delta) (epsilon) equals 0.3. IR properties of WO3 need to be further investigated as well as the construction of a whole device.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.