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Space environmental testing of flexible coverglass alternatives based on siloxanes,

Polymer degradation and stability 98, 12 (2013) 2503-2511

N.J. Smeenk, C. Mooney, J. Feenstra, P. Mulder, T. Rohr, C.O.A. Semprimoschnig, E. Vlieg, J. Schermer,

Abstract: With the development of thin-film, high-efficient III–V solar cells using the epitaxial lift-off technique, flexible solar panels for space applications can be designed. Besides new deployment options, this also reduces the mass and thus launch costs of a satellite. One requirement for such a flexible panel configuration is the replacement of the brittle coverglass, which shields the solar cells from the harsh space environment, by a flexible alternative. In this work we have tested several compositions of a polysiloxane candidate material for a flexible shielding layer by exposing them to high energy UV and electron radiation at elevated temperatures. It was found that irradiation by electrons with a fluence corresponding to 15 years in space produces little degradation. UV radiation, on the other hand, has a more pronounced impact on the material properties, causing a discolouration of the transparent material and for some compositions even cracking of the samples.