Einstein Observatory

Einstein Observatory (HEAO-2) was the first fully imaging X-ray telescope put into space and the second of NASA's three High Energy Astrophysical Observatories. Named HEAO B before launch, the observatory's name was changed to honor Albert Einstein upon its successfully attaining orbit.

Launch
The Einstein Observatory, HEAO-2, was launched on November 13, 1978, from Cape Canaveral, Florida, on an Atlas-Centaur SLV-3D booster rocket into a near-circular orbit with an initial altitude slightly above 500 km. Its orbital inclination orbit was 23.5 degrees. The Einstein Observatory satellite re-entered the Earth's atmosphere and burned up on March 25, 1982.

Instrumentation
The Einstein Observatory carried a single large grazing-incidence focusing X-ray telescope that provided unprecedented levels of sensitivity (hundreds of times better than previously achieved) and arc-second angular resolution of point sources and extended objects. It had instruments sensitive in the 0.2 to 3.5 keV energy range. A collection of four focal-plane instruments was installed in the satellite:


 * HRI, or High Resolution Imaging camera, 0.15-3 keV
 * IPC, or Imaging Proportional Counter, 0.4 to 4 keV
 * SSS, or Solid State Spectrometer, 0.5 to 4.5 keV
 * FPCS, or Bragg Focal Plane Crystal Spectrometer
 * MPC, Monitor Proportional Counter, 1-20 keV
 * BBFS, Broad Band Filter Spectrometer
 * OGS, Objective grating spectrometer