Abstract:

It is important for the design of high reliability and long lifetime spacecrafts to study the effect of molecular contamination on spacecrafts in space environment. A summary review of the present molecular contamination phenomena on spacecrafts is presented. The source, formation process, interaction with other space environmental factors of the molecular contamination, such as atomic oxygen and ultraviolet radiation, and the effects on a spacecraft's sensitive surfaces are introduced. The molecular contamination layer is formed by the deposition of the outgassing products of spacecraft materials and the erosion products released by the reaction of atomic oxygen with spacecraft materials. And by the action of atomic oxygen and ultraviolet radiation, the contamination layer is oxidized, fixated, and darkened, and it's surface appearance and composition are changed in a complicated way, which can affect the optical, electronic, and thermal control property of such sensitive surface of a spacecraft as its optical windows, camera lenses, thermal control coatings, solar array, sensors, and infrared instruments.

Key words: molecular contamination, vacuum outgassing, atomic oxygen erosion, space environment, spacecraft