According to CNES, Hermes would have been subject to more extreme re-entry conditions than the Space Shuttle due to its smaller size resulting in the vehicle being subject to higher aerothermal pressures. The baseline thermal protection, which was to be capable of withstanding temperatures of 1,400-1,600 °C for a minimum of 20 minutes and studied by Dassault and SEP, would have consisted of carbon elements with an anti-oxidant coating applied to portions of the nose and leading edges of the wings, while thermal tiles were to have covered the underside of the wing and fuselage. These tiles, which were to be fastened into place, would have employed thin, reinforced ceramic-carbon honeycomb composite insulating layers separated by thin sheets of metal alloy to reflect the heat; an alternative concept for the tiles would have employed higher metallic portions in place of ceramics. The upper surfaces of the vehicle, which would have been subject to less heat than the lower surfaces, would have used flexible blanket-like low-density, glassfibre-ceramic layers.