Formulation of Electrically Conductive Thermal-Control Coatings

摘要

The development and formulation of electrically conductive thermal-control coatings was undertaken for use on the International Sun-Earth Explorer (ISEE) spacecraft. The primary effort was to develop a coating with an area resistivity of less than 1 X 105 ohm-m2, an optical absorptance of approximately 0.55, and a normal emittance of 0.90. The required stability in space called for an area resistivity of less than 1 X 105 ohm-m2, an absorptance of less than 0.67, and a normal emittance of 0.90 after exposure to approximately 4 X 1016 proton/cm2 of solar-wind particles and 5300 equivalent Sun-hours. These exposures rep¬resent 2 years of ISEE flight conditions.nThis paper describes both the unsuccessful formulation efforts and the successful use of oxide pigments fired at 1448 K and discusses problems relative to the reactivity of specific coating vehicles exposed to high humidity. Although the emphasis of this paper is on coating formulation and application techniques, measurement, testing methods and data results are also mentioned. Methods of varying the optical properties as desired and formulations of white, low-absorptance coatings are also described.