The first company in the United States dedicated solely to the production of the liquid rocket engine, Reaction Motors, Inc. (RMI) was formed in 1941.  Its four founders were rocket enthusiasts and members of the American Rocket Society. RMI developed the rocket motors that powered the first supersonic flight, that of the X-1; the retro rockets for five NASA surveyor lunar soft landers; and prepackaged liquid rocket engines for the U.S. Navy Bullpup A & B air to ground missiles, among many other pioneering programs. RMI became a division of Thiokol Chemical Corporation in 1958 and closed in 1972.