Unflown example of an ion mass spectrometer tube of the type flown on Aerobee sounding rockets by the Aeronomy group at the Naval Research Laboratory (NRL). This radio frequency mass spectrometer tube was transferred to NASM by NRL in March 1986.

During the early 1950s the NRL carried out studies of the upper atmosphere by sending specialized instruments to extreme altitudes on Aerobee sounding rockets. Maximum altitude for these rockets was close to 230 kilometers. This radiofrequency mass spectrometer, which was designed by Willard H. Bennett when he was at the National Bureau of Standards, was used to determine the identity of the gases present in the near vacuum at extreme altitudes. The compact size and light weight of this mass spectrometer makes it suitable for use in sounding rockets. This tube does not incorporate the element that ionizes gases found in a neutral mass spectrometer (Catalogue #1987016000). It consequently determines the identity of atoms and molecules present in already ionized form. This instrument is the same as those that NRL sent aloft in the late 1950s in connection with the International Geophysical Year.