8. Conclusions

Forty years after the development of the first rigidimers based on glass or asbestos fibers in the USA, ablative composites with carbon and silica fibers continue to be used in the nozzles of solid rocket motors in France (strategic missiles, Ariane) and the USA (MX (missile X) and Trident divergents, STAR and IUS (Interim Upper Stage) rocket motors and space shuttle boosters).

The ability to manufacture very large parts, such as the boosters for the US space shuttle and Ariane 5, and extensive industrial experience in their use and understanding are strong assets, but ablative phenolic composites are only one of the possible materials for use in nozzles.

Carbon/carbon composites are the most suitable materials for parts that have to guarantee thermostructural stability, or for parts that are subject to the most severe ablation stresses....