This is a centrifugal pump designed and made by U.S. rocket pioneer Robert H. Goddard for forcing the propellants into the combustion chamber of a rocket motor. Most likely its dates from ca. 1938-1941, when he worked at his test site at Roswell, New Mexico, on his so-called P-Series, or pump series of rocket motors. The object was donated to the Smithsonian by the Daniel and Florence Guggenheim Foundation for the Promotion of Aeronautics in 1985.
This object is on display in Barron Hilton Pioneers of Flight at the National Air and Space Museum in Washington, DC.