Engineering topics
Publications and source records attributed to Heggen, Philip M..
Paper summarizes available knowledge about glass mirrors for use in outer space. Strengths and weaknesses of various types of first and second reflective surfaces identified. Second-surface glass mirrors used in outer space designed to different criteria more stringent for terrestrial mirrors. Protons, electrons, cosmic rays, meteorites, and orbiting space debris affect longevities of components. Contamination also factor in space.
Large mirrors intended for long-term operation in orbital space will have to retain high reflectance in the presence of contamination or destruction by high-energy particles, meteorites, and orbiting debris. These conditions require the use of low-energy outer surfaces that resist the buildup of contamination, the use of small mirror segments that restrict local damage and facilitate replacement, and the use of surface coatings that minimize the effects of atomic oxygen and/or charge buildup. The present recommendations are based on experience accumulated with terrestrial solar-concentrator mirror materials.