Thermosetting polyimide (TPI) composite with better wear resistance and lower friction was obtained with various functional fillers after a high-low temperature cycle test. Nevertheless, taking into consideration of harsh space condition, the friction and wear behavior of TPI composite were also explored after atomic oxygen (AO) irradiation. It reveals that TPI composite behaves excellent properties against AO mainly attributed to g-C3N4 with more negative electronegativity N than carbon atom. Moreover, the mechanism of friction and wear demonstrated that degradation caused by AO led to TPI composite surface with special carpet-like morphology and this resulted into lubrication failure, especially when temperature was increased from 200 degrees C to 350 degrees C. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48441.