This Ullage solid fuel rocket motor was used on the third stage of the Saturn V launch vehicle that took men to the Moon in Project Apollo. It was one of two such motors fired during the separation of the vehicle's second and third stages. The thrust of the Ullage produced an additional acceleration of the stage during stage separation.
This momentum helped shift the liquid oxygen and liquid hydrogen propellants toward the ends of their tanks in preparation for their entry into the combustion chamber of the main J-2 engine. The Ullage motor produced a thrust of 3,420 pounds. The term "ullage" comes from an old French word, "eullage" meaning "to fill a wine cask." The motor was donated to the Smithsonian in 1976 by Thiokol.
Gift of Thiokol Chemical Corporation