of a cloud of contaminants around the spacecraft. Together with atomic oxygen bombardment, this may lead to gradual deposition of thin layers of carbon-containing silicon dioxide. Their poor transparency is a concern in case of optical systems and solar panels. Deposits of up to several micrometers were observed after 10 years of service on the solar panels of the Mir space station. Other sources of problems for structures subjected to outer space are erosion and redeposition of the materials by sputtering caused by fast atoms and micrometeoroids. Another major concern, though of non-corrosive kind, is material fatigue caused by cyclical heating and cooling and associated thermal expansion mechanical stresses. References External links The Cosmos on a Shoestring: Small Spacecraft for Space and Earth Science, Appendix B: Failure in Spacecraft Systems PDF New Scientist premium article: Space is corrosive NASA Long Duration Exposition Facility: surface contamination in space Corrosion Spaceflight