Advanced composite materials are an excellent option for flexible deployable space structures, such as deployable antennas and booms. However, the harsh environment in space can degrade the performance of composite materials, thus limiting their wider application. In low Earth orbit (LEO), atomic oxygen (AO) resistance is a key limitation to service longevity. In this work, the AO resistance is examined for three commercial composite materials, which undergo exposure in a ground-based facility which simulates the AO environment of space. The degradation of the performance of the materials is determined by measuring selected properties (e.g. surface chemistry, and flexural stiffness) before and after exposure. The results indicated that the resin on the surface of all laminates has almost been entirely eroded and suffered significant degradation after exposure. The results presented in this work can act as a benchmark for the development of new composite systems or protection technologies which can provide an extended service life for flexible deployable structures in LEO.