This glass tube device was used in experiments by U.S. rocket pioneer Robert H. Goddard during 1924-1928 to determine the feasibility of ion propulsion for space flight. Ion propulsion, in which electrically charged particles of atoms called ions are discharged, produces extremely rapid exhaust velocities. Because of this and their long duration of operation, ion engines are ideal for deep space propulsion.
However, they produce very low thrusts and must be placed in space by larger conventional chemical propellant rocket boosters. Experiments with ion propulsion in space occured when the first succesful Space Electric Test (SERT-1) took place in 1964. This object was donated to the Smithsonian in 1965 by Esther C. Goddard.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.