Date: ca. 1924-1928
Country of Origin: United States of America
Overall: 1ft 2 7/8in. x 4 1/8in. x 3/4in. (37.78 x 10.48 x 1.91cm)
Overall, glass; sealing wax on end of adjoining tube; two pairs of wires, possibly copper, inside lower tube with the four strands projecting from sealing wax; wooden dowel, possibly bamboo, inside upper tube; strip of a reddish material, possibly thin cardboard, also in this tube below dowel; shiny silver metal ring, possibly aluminum, inside bottom of top tube.
Glass, Copper, Wax, Cork, Aluminum, Wood, Cardboard, Natural Fabric
American rocket pioneer Robert Goddard (1882-1945) used this device between 1924 and 1928 in his experiments to determine the feasibility of ion propulsion for space travel. Ion engines, in which electrically charged particles of atoms are discharged, produce extremely high exhaust velocities. Experiments in space with ion propulsion first took place in 1964.
This ion collector may have been made by one of Goddard's graduate students, Louis M. Sleeper. According to 1964 observations made by Russell B. Hastings, who also helped Goddard on his experiments as a graduate student in physics at Clark, this tube was "probably a low pressure ion research device and an important object…." Mrs. Goddard gave this artifact to the Smithsonian in 1965 as part of a set of laboratory glassware from her husband's pioneering ion-propulsion experiments.
Gift of Mrs. Robert Goddard