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ATM, Event Analyzer, X-Ray


Display Status:

This object is on display in the James S. McDonnell Space Hangar room at Steven F. Udvar-Hazy Center in Chantilly, VA.

Collection Item Summary:

Engineering prototype for an event analyzer that formed part of the assembly of one (S056; Cat #19840408000) of the three X-ray telescopes that were flown on the Apollo Telescope Mount (ATM)on Skylab. This analyzer (X-REA), built by James E. Milligan and his staff at Marshall, comprises a proportional counter system with beryllium and aluminum windows. The instrument, which contained its own amplifier and preamplifier, also included a pulse height analyzer, rate meter and activity history plotter. It was transferred to NASM from NASA's Marshall Space Flight Center in 1986.

Collection Item Long Description:

Data Source

National Air and Space Museum


Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum


NASA Marshall Space Flight Center

Credit Line

Transferred from NASA/Marshall Space Flight Center


  • Metal case, electronics, wires
  • Electronics


3-D: 76.2 x 16.5 x 14cm (30 x 6 1/2 x 5 1/2 in.)

See more items in

National Air and Space Museum Collection

Country of Origin

United States of America



Inventory Number