Skip to Main Content


BBXRT mission graphic

Broad Band X-ray Telescope

Phase: Past

Launch Date: December 02, 1990

Mission Project Home Page -

Pin it

The Broad Band X-ray Telescope (BBXRT) was flown on the space shuttle Columbia (STS-35) on December 2-11, 1990, as part of the ASTRO-1 payload. The flight of BBXRT marked the first opportunity for performing X-ray observations over a broad energy range with a moderate energy resolution. The BBXRT consists of a pair of coaligned thin foil conical X-ray mirrors, with a cryogenically-cooled, Si(Li) spectrometer at the focus of each.

In spite of some well-publicized technical hitches during the mission with the instrument's pointing system, BBXRT successfully performed ~160 observations of ~80 celestial sources including clusters of galaxies, active galaxies, SNR, X-ray binaries, cataclysmic variables, stars, and the X-ray background.

BBXRT was added to the Astro-1 mission, to take advantage of the unique opportunity provided by the bright supernova called SN1987A. The energy resolution (90 eV and 150 eV at 1 and 6 keV, respectively), coupled with an extremely low detector background, made BBXRT a very powerful tool for the study of continuum and line emission from cosmic sources. The observing program was designed to be an even mix of Galactic and extragalactic targets. It was not flown again on the Astro-2 mission.

BBXRT's observing efficiency was reduced due to problems in the spacecraft's pointing systems. However, BBXRT still achieved a total of 157 observations of 82 X-ray sources.

Science Highlights:

  • Resolved iron K line in the binaries Cen X-3 and Cyg X-2
  • Detect evidence of line broadening in NGC 4151
  • Study of cooling flow in clusters

Last Updated Date: May 28, 2015

Related Links
  • Astro-1 Mission -
  • STS-35 info -