The past decade of ZERODUR® glass-ceramics in space applications

For the past four decades, ZERODUR (R) glass ceramics has flown on many satellites including the prominent space missions METEOSAT, Hubble Space Telescope, CHANDRA, and LISA pathfinder. Firstly, this unique material is chosen as mirror substrate for high precision optics due to its extreme thermal stability. Its near-zero thermal expansion over a wide temperature range of several tens of Kelvin is homogenous within the entire volume. This enables control of the ZERODUR (R)'s surface profile at the 10-picometer level. SCHOTT has conducted comprehensive material characteristics studies on the mechanical properties and the radiation environment effects experienced in realistic orbits to define the suitability of ZERODUR (R) to survive both high loads during launch and to support long-term missions, respectively. Besides these advantageous material properties, this glass-ceramics can be extremely light-weighted by precision grinding enabled by the new SCHOTT competence center for machining and metrology. In this paper, we will continue to trace the recent developments of ZERODUR (R) glass ceramics as space material in the context of selected missions flown since 2009 and those anticipated. Major milestones such as the LISA pathfinder mission are discussed. Furthermore, we outline the viable use of ZERODUR (R) for great observatory architectures for IR/O/UV spaceborne telescopes. The objective of this paper is to supplement an earlier review of the use of ZERODUR (R) for space applications in the past decade and to summarize the latest progress and results of material studies toward very efficient production capabilities for high-performance light-weighted mirror substrates.