0191-9067/85 $3.00 + .00 Copyright ® 1985 SUNSAT Energy Council ON THE PERFORMANCE AND LIFETIME OF SOLAR MIRROR FOILS IN SPACE D. FINK, J. P. BIERSACK Hahn-Meitner-Institut f. Kernforschung Glienicker Str. 100 D-1000 Berlin 39, F. R. Germany M. STADELE Freie Universitat Berlin D-1000 Berlin 33, F.R. Germany Abstract — The application of solar mirrors in space is discussed for transmission of heat and light to the Earth for various purposes. The mirrors should be lightweight to minimize expenses. This implies the use of thin reflecting foils (polymer foils coated with Al). These foils are subjected to solar wind irradiation. The implantation profiles of the solar wind components as well as radiation damage and ionization profiles in the foil and the substrate profiles after cascade mixing are given, and the performance and lifetime of the foils are discussed in the light of the irradiation effects. It turns out that the foils are subject to a high damage in the critical surface area resulting in a rapid carbonization and blistering, which leads to a degradation of the optical properties. Depending on the mechanical properties of the thus modified foil, the mirror is either destroyed quickly, or can further be used. With regular maintenance, the maximum possible lifetime, determined by solar wind sputtering, is in the order of hundreds of years. INTRODUCTION The recent successful launchings of the Space Shuttle makes the old utopia of solar mirrors in space in geostationary orbits look more realistic for the next decades. By those mirrors, reflecting on both sides and rotating around the Earth once a day and around themselves at half the speed, a preselected terrestrial area can be nearly constantly illuminated and heated (Fig. 1). By positioning the mirror in a non- equatorial orbit, the transition through the Earth's shadow (approx. 80 min) is avoided (in this case, the adjustment of the mirror to the target area is, however, more complicated). By proper focusing of the mirror, any desired brightness and temperature can be created in the illuminated area, thus making the construction of power plants possible. Further, one could illuminate and warm up the centers of cities or agricultural areas in hostile (e.g., arctic) environment. Smaller mirrors could be useful, e.g., in helping to keep the arctic passages ice-free, as well as enabling weatherproof ports, aeroports, or even important streets and railway lines in winter time. Finally, these mirrors may be useful to create daylight in the vicinity of future lunar stations during the two-week long lunar nights. To illuminate larger (terrestrial or lunar) regions, immense mirror areas of typi-
RkJQdWJsaXNoZXIy MTU5NjU0Mg==