Thin film materials exposure to low earth orbit aboard space shuttle

R. A. Synowicki, Jeffrey S. Hale, Blaine Spady, Mike Reiser, S. Nafis, John A. Woollam

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

To study the effects of Atomic Oxygen on various thin film materials, fourteen thin film samples were exposed to the corrosive environment of low Earth orbit. Total exposure was 42 hours, resulting in a nominal atomic oxygen fluence of 2.2 x 1020 atoms/cm2. The films included aluminum, diamondlike carbon, diamond, and multilayer stacks. Included are experimental details of sample preparation, exposure, and post-flight results. Pre-flight characterization techniques included Variable Angle Spectroscopic Ellipsometry, optical reflectance and transmittance, Atomic Force Microscopy, and Raman scattering. Post-flight analysis repeated pre-flight characterization. Aluminum films resisted degradation. Surface contaminants were identified using Auger Electron Spectroscopy. Contaminants were Si02, fluorine, and sulfur which most likely result from degradation of cargo bay lining, waste water dumps, and outgassing. Diamondlike carbon films were completely etched away during exposure. Polycrystalline diamond films were extremely resistant to atomic oxygen degradation, showing no post-flight structural, compositional, or mass changes. Aluminum films 23.5 nm thick simultaneously protect silver reflecting layers from oxidation and increase the ultraviolet reflectance of the stack. Decreasing the aluminum thickness to 7.5 nm resulted in complete oxidation during exposure and failure as a protective coating.

Original languageEnglish (US)
Pages (from-to)97-102
Number of pages6
JournalJournal of Spacecraft and Rockets
Volume32
Issue number1
DOIs
StatePublished - 1995

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science

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