This is a nozzle from a 1-inch solid fuel rocket which U.S. rocket pioneer Robert H. Goddard made during 1917-1918 for the U.S. Army as a weapon during World War I. The spiral grooves on the nozzle caused the rocket to rotate during its flight thereby helping to counteract deviations in its flight path and making it more stable in its flight.
A trial was later undertaken at the Army's Aberdeen Proving Grounds, Aberdeen, Maryland, on 6 November 1918. However, the following day the armistice was signed that ended the war as well as the Army's interest in this project. In 1921 Goddard switched to liquid propellants. This nozzle was donated to the Smithsonian by the Guggenheim Foundation for the Promotion of Aeronautics in 1985.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.