Forty-eight test flights of Regulus II prototypes were carried out, 30 of which were successful, 14 partially successful and four failures. A production contract was signed in January 1958 and the only submarine launch was carried out from Grayback in September 1958.
Forty-eight test flights of Regulus II prototypes were carried out, 30 of which were ?successful, 14 pa,rtially successful and four failures. A production contract was signed in January 1958 and the only submarine launch was carried out from G.rayback in September 19:58.