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Space Research Journal

Year: 2014 | Volume: 7 | Issue: 1 | Page No.: 1-13
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Authors

S.W. Samwel

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Research Article

Low Earth Orbital Atomic Oxygen Erosion Effect on Spacecraft Materials

S.W. Samwel
The presence of Atomic Oxygen (AO) in the Low Earth Orbit (LEO) environment is considered one of the main reasons for the degradation of the surfaces exposed to the Space Environment A spacecraft’s orbital velocity of 7.8 km sec-1 may expose a spacecraft to a stream of AO at energy of approximately 5 eV. At this energy, atomic oxygen initiates a number of chemical and physical reactions with the materials. The degree of surface degradation is directly proportional to AO fluence which, in turn, varies with several factors, such as: Spacecraft altitude, orientation, orbital inclination, mission duration and solar activity variation. The present paper concerns study the variation of the atomic oxygen erosion with the previous mentioned factors. In addition a comparative study of the atomic oxygen erosion effect of different spacecraft materials which are widely used for space application is performed. The atomic oxygen interaction model (ATOMOX) has been employed to evaluate the atomic oxygen flux, fluence and material erosion, based on reference atmosphere and wind models. The computation of neutral atmosphere composition is achieved using the standard NRLMSISE-00 model. Values of erosion yields have been established based on flight data. The results obtained represent that the exposed materials onboard spacecraft experience the most intense degradation at low earth orbit with lower altitudes and inclination, for surfaces in the ram direction, for prolonged exposure and at high solar activity. Also, it is found that according to the material sample understudy, Teflon shows the higher resistivity for AO erosion, for polymers; while it is Tungsten, in case of metals.
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