Abstract: The dependence of ZnO/K2SiO3 thermal control coating optical characteristics upon electron exposure was studied. The test specimens were exposed to 10, 30, 50 and 70keV electrons. The spectral reflectance of each test specimen was measured in situ before and after exposures. The solar absorptance was calculated by assuming a Johnson solar spectral irradiance distribution. The effects of electron energy on spectral reflectance and solar absorptance have been analyzed. The results are discussed relative to the change in spectral reflectance in the near infrared wavelength region. It is found that under the effect of electron exposure, the ZnO/K2SiO3 suffers a big amount of degradation. The magnitude of degradation is electron energy dependent, it goes up as the electron energy increases.