This device was used by the American rocket pioneer Dr. Robert H. Goddard (1882-1945) during the period 1924-28 to determine the feasibility of ion propulsion for space travel. Ion propulsion, in which electrically charged particles of atoms called ions are discharged, produce extremely high exhaust velocities. Because of that and potential long duration of operation, ion engines are ideal for deep space propulsion. However, ion engines produce very low thrust and must be placed in space by conventional rocket boosters. Experiments in space with ion propulsion first took place in 1964.
According to a 1964 tag written by Russell B. Hastings, one of Goddard's graduate students at Clark who helped make these kinds of tubes, they were "probably a type of ion collecting apparatus." Mrs. Goddard gave them to the Smithsonian in 1965.
Gift of Mrs. Robert Goddard