The SiC technology is ready for the next generation of extremely large telescopes

Beside the baseline glass-ceramics, the sintered silicon carbide (SSiC) technology appears as a valid and very attractive alternative for the mass production of the next generation extremely large mirror segments. The specific stiffness of SSiC ceramic is about four times better than the one of glass-ceramics. Furthermore, the SSiC manufacturing process allows lightweighing the blanks at very cost effective condition. The spectacular expected gain in mass will dramatically relax the requirements of the moving, structure, which supports the mirror segments. Boostec team has got two different and very useful experiences in SSiC, components that are serial production of low cost parts and the manufacturing of the largest space telescopes particularly through Herschel ESA program. A paper study has clearly shown that the thousands of OWL segments could be made of SSiC at competitive costs. The needed investments are easily affordable and they do not require any technological development. On the other hand, four hexagonal segments have been designed (1 m flat to flat, only 44 kg/m(2)) and successfully manufactured in order to qualify this technology.