NS Savannah was the first nuclear-powered merchant ship, launched on July 21, 1959, two years after the Soviet ice-breaker Lenin, the first nuclear-powered civilian vessel. A demonstration project for the potential peacetime uses of nuclear energy, she was built in the late 1950s at a cost of $46.9 million. Savannah was given the new designation "NS" for "Nuclear Ship", replacing the traditional commercial vessel prefix "SS" for "Screw Steamer", and was named after SS Savannah, the first steamship to cross the Atlantic Ocean. She was funded by United States government agencies as part of President Dwight D. Eisenhower's 1955 "Atoms for Peace" program, and was in service between 1962 and 1972 as one of only four nuclear-powered cargo ships ever built.