This article contains orbital elements but does not include an epoch, or date when those elements, which typically vary over time, were correct. Please help by adding the epoch for the current data, or changing the orbital elements to ones with a known epoch. Unsourced materials may be challenged and remove.
This article is about the X-ray telescope. For the gravitational wave detector, see Einstein Telescope.
Einstein Observatory (HEAO-2) was the first fully imaging X-raytelescope 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.
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.
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
Payloads are separated by bullets ( · ), launches by pipes ( | ). Manned flights are indicated in bold text. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets).
This article about a specific observatory, telescope or astronomical instrument is a stub. You can help Wikipedia by expanding it.