20 September 2000 Modeling of transmittance degradation caused by optical surface contamination by atomic oxygen reaction with adsorbed silicones
Author Affiliations +
Abstract
A numerical procedure is presented to calculate transmittance degradation caused by contaminant films on spacecraft surfaces produced through the interaction of orbital atomic oxygen (AO) with volatile silicones and hydrocarbons from spacecraft components. In the model, contaminant accretion is dependent on the adsorption of species, depletion reactions due to gas-surface collisions, desorption, and surface reactions between AO and silicon producing SiOx (where x is near 2). A detailed description of the procedure used to calculate the constituents of the contaminant layer is presented, including the equations that govern the evolution of fractional coverage by specie type. As an illustrative example of film growth, calculation results using a prototype code that calculates the evolution of surface coverage by specie type is presented and discussed. An example of the transmittance degradation caused by surface interaction of AO with deposited contaminant is presented for the case of exponentially decaying contaminant flux. These examples are performed using hypothetical values for the process parameters.
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Aaron Snyder, Aaron Snyder, Bruce A. Banks, Bruce A. Banks, Sharon K. Miller, Sharon K. Miller, Thomas Stueber, Thomas Stueber, Edward Sechkar, Edward Sechkar, "Modeling of transmittance degradation caused by optical surface contamination by atomic oxygen reaction with adsorbed silicones", Proc. SPIE 4096, Optical Systems Contamination and Degradation II: Effects, Measurements, and Control, (20 September 2000); doi: 10.1117/12.400826; https://doi.org/10.1117/12.400826
PROCEEDINGS
12 PAGES


SHARE
Back to Top