Accession Number : ADA291605

Title :   Design of a Laboratory Study of Contaminant Film Darkening in Space.

Corporate Author : AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS

Personal Author(s) : Judeikis, H. S. ; Arnold, G. S. ; Young Owl, R. C. ; Hall, D. F. ; Hill, M.

PDF Url : ADA291605

Report Date : 01 OCT 1993

Pagination or Media Count : 91

Abstract : One of the most deleterious effects of spacecraft contaminant films is the increase in solar absorptance of optics, such as silvered fused-silica thermal control mirrors or solar cell cover slips. However, this effect cannot currently be predicted with precision. Here we discuss the design of a laboratory program to enhance the quantitative understanding of this effect, as determined by the composition of the contaminant film and subsequent simulated environmental radiation-induced darkening. This effort includes four major elements: the quantitative identification of the classes of organic materials likely to be precursors of photochemically deposited contaminant films; prediction of these materials' sensitivities to energetic irradiation in the space environment; measurement of rates of deposition and optical absorption spectra of photochemically deposited films on fused silica; and the measurements of further film darkening by irradiation with electrons, vacuum ultraviolet light, and ions. Each of these elements is discussed. A set of organic materials that have been chosen as analogs for major classes of spacecraft contaminants is presented, including the rationale for their selection and a prioritization of their potential importance. Apparatus design and performance and early experimental results are also described. jg

Descriptors :   *SPACE ENVIRONMENTS, *FILMS, *FUSED SILICA, *CONTAMINANTS, THERMAL PROPERTIES, MIRRORS, CONTROL, SIMULATION, IONS, OPTICS, OPTICAL PROPERTIES, SPACECRAFT, ENVIRONMENTS, ULTRAVIOLET RADIATION, PHOTOCHEMICAL REACTIONS, SILICON DIOXIDE, IDENTIFICATION, DEPOSITION, ELECTRONS, RADIATION ABSORPTION, SOLAR CELLS, DARKNESS, ORGANIC MATERIALS, VISIBLE SPECTRA, LABORATORIES, IRRADIATION, VACUUM ULTRAVIOLET RADIATION, ENERGETIC PROPERTIES, PHTHALATES, SILVER, RADIATION EFFECTS, OCTYL RADICALS.

Subject Categories : Astronautics
      Organic Chemistry
      Coatings, Colorants and Finishes
      Test Facilities, Equipment and Methods
      Radiation Pollution and Control

Distribution Statement : APPROVED FOR PUBLIC RELEASE