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Imager, ROSAT Engineering model


Display Status:

This object is on display in the Explore the Universe exhibition at the National Air and Space Museum in Washington, DC.

Collection Item Summary:

Engineering model for the high-resolution imager (HRI) flown on the ROSAT (Roentgen Satellite) spacecraft, one of two detectors on the spacecraft. This imager consists of a pair of stacked microchannel plates backed by a grid of crossed wires. This HRI was developed for NASA by the Harvard-Smithsonian Center for Astrophysics. It comprises an improved version of an imager used on the earlier Einstein Observatory. ROSAT, named after the discoverer of X-rays, Wilhem Roentgen, was an international mission aimed at exploring the high-energy universe. It was developed in a cooperative effort between Germany, the United States and Great Britain. The satellite, which was designed and operated by Germany, was placed in orbit board a Delta II launch vehicle in June 1990 and collected data until February 1999. During that time it obtained an all sky survey in the X-ray region as well as detailed observations of many galaxies.

The orbiting x-ray telescope ROSAT used sets of wide metallic cylinders to "scoop up" incoming x-rays and focus them onto a detector like this one. The x-rays ricocheted down the cylinders and into a bundle of microscopic metallic straws in the HRI. The x-rays knocked electrons off the sides of the straws, which channeled the electrons onto a fine wire mesh screen. The resulting electrical impulses were used to create an image showing the intensity and distribution of the x-ray energy.

Transferred from the Smithsonian Astrophysical Observatory, courtesy of NASA

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

Credit Line

Transferred from the Smithsonian Astrophysical Observatory, Harvard University.


  • Mixed metals
  • Electronics


3-D: 45.7 x 30.5 x 61cm (18 x 12 x 24 in.)

Country of Origin

United States of America



Inventory Number