The combined effect of hypervelocity space debris impacts and atomic oxygen (AO) on the fracture of polyimide films reinforced with polyhedral oligomeric silsesquioxanes (POSS) was studied. A laser-driven flyer (LDF) system was used to accelerate aluminum flyers to impact velocities of up to 3 km/s, and the impacted films were exposed to an RF plasma AO source. Scanning electron microscopy (SEM) was used to characterize the fracture morphology. The extent of damage in POSS-polyimide impacted films was found to be much smaller compared to POSS-free films, insinuating on a toughening mechanism developed due to POSS incorporation. When exposed to AO, the impacted POSS-free film revealed synergistic effect associated with a large increase in the erosion rate, while impacted POSS-containing samples showed improved resistance toward AO. The increased erosion rate of the impacted POSS-free film is explained by formation of residual stresses that affect the oxidation mainly by increasing the diffusivity of oxygen.