ION-BEAM TREATMENT OF POTENTIAL SPACE MATERIALS AT THE NASA LEWIS RESEARCH-CENTER

Ion source systems, in different configurations, have been used to generate unique surface morphologies for several NASA space applications. The discharge chamber of a 30 cm ion source was successfully used to texture potential space radiator materials for the purpose of obtaining values of thermal emittance greater than 0.85 at 700 and 900 K. High absorptance surfaces were obtained using ion beam seed-texturing, for space radiator materials that were flown on the long duration exposure facility (LDEF) for 5.8 years in space. An ion source discharge chamber was also used to develop electrode surfaces with suppressed secondary electron emission characteristics for use in collectors in microwave amplifier traveling wave tubes. This was accomplished by sputtering textured carbon onto copper as well as texturing copper using tantalum and molybdenum as sacrificial texture-inducing seeding materials. In a third configuration, a dual-ion-beam system was used to generate high transmittance diamond-like carbon (DLC) films.