Polymerization process of an inflatable composite balloon in LEO space environment

This paper presents the results of the design of an inflatable rigidizable space structure. The structure is a balloon, about 5 m in diameter, made of a composite material that rigidizes by curing of the epoxy resin from whic h it is made, under the action of the typical thermal loads of LEO orbits. The balloon is covered by a metallic layer which, must be a continuum elect ric conductor. An analysis will be presented of a one-dimensional continuum to validate th e hypothesis that the thermal gradients through the thickness of the materi al are negligible so that it is possible to study a two-dimensional model. A model of the LEO orbit environment has been studied in order to define th e thermal fluxes on the structure surface. The considered thermal loads are : sun radiation, albedo radiation, earth radiation. The numerical simulation of the polymerization process of the complete stru cture during the motion of the system along the orbit was made considering several materials for the metallic cover layer (pure aluminum, pure copper, aluminum + oxide, copper + oxide). A different material for the metallic l ayer may influence the polymerization process, because the different optica l properties of each material determine the thermal flux on the composite.