Changes of Solar Array Surfaces on Orbital Station Mir

Several fragments (front and back protective glasses) of a solar array were investigated after its return from the orbital station Mir to Earth in 1998 after functioning in the low-Earth-orbit environment for 10.5 years. Three methods of surface analysis were applied: scanning electron microscopy, local x-ray microanalysis, and x-ray photoelectron spectroscopy. The main changes to solar array surfaces after prolonged exposition in low Earth orbit are caused by contamination layers (thicknesses up to 3μm3μm) that deposit from the intrinsic outer atmosphere of the station. Besides contamination deposits, some surface damages are observed (dimensions of 5-20μm5-20μm), caused by micrometeoroid and/or debris impacts. The outer layers of the contamination deposits consist of spheroid particles with dimensions of 0.3-0.5μm0.3-0.5μm. The main components of the deposits are carbon (three chemical forms were observed by x-ray photoelectron spectroscopy) and silicon (two chemical forms: silicon dioxide and linear organosilicon). A silicon carbide presence is possible. [PUBLISHER ABSTRACT] We thank the late Vladimir Alexeevich Letin (11 September 1939-18 August 2008), the former Vice Designer of Research and Development Enterprise "Kvant," who initiated this work.