Editing Einstein Observatory (section)

{{Short description|X-ray telescope space observatory}}
{{About|the X-ray telescope|the Chinese X-ray telescope|Einstein Probe|the observatory building in Potsdam|Einstein Tower|the proposed gravitational wave detector|Einstein Telescope}}
{{Use American English|date=March 2014}}
{{Use mdy dates|date=March 2014}}
{{Infobox spaceflight
| name                  = Einstein Observatory
| image                 = HEAO-2_High_Energy_Astronomy_Observatory_0102090.jpg
| image_caption         = Einstein Observatory
| insignia              =
| mission_type          = Astronomy
| operator              = [[NASA]]
| website               = [http://heasarc.gsfc.nasa.gov/docs/einstein/heao2.html Einstein Observatory at NASA.gov]
| COSPAR_ID             = 1978-103A
| SATCAT                = 11101
| mission_duration      = 4 years
| spacecraft_bus        = 
| manufacturer          = [[TRW Inc.|TRW]]
| dry_mass              = {{convert|3130|kg}}
| launch_mass           = 
| power                 =
| launch_date           = {{start date|1978|11|13|df=yes}} 05:24&nbsp;UTC
| launch_rocket         = [[Atlas-Centaur|Atlas SLV-3D Centaur-D1AR]]
| launch_site           = [[Cape Canaveral Air Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Space Launch Complex 36|LC-36B]]
| launch_contractor     =
| last_contact          = {{end date|1981|04|17|df=yes}}
| decay_date            = 26 May 1982
| orbit_epoch           = 13 November 1978 05:24:00 UTC
| orbit_reference       = [[Geocentric orbit|Geocentric]]
| orbit_regime          = [[Low Earth orbit|Low Earth]]
| orbit_periapsis       = {{convert|465|km}}
| orbit_apoapsis        = {{convert|476|km}}
| orbit_inclination     = 23.5°
| orbit_period          = 94.0 minutes
| apsis                 = gee
}}

'''Einstein Observatory''' ('''HEAO-2''') was the first fully imaging [[X-ray telescope]] put into space and the second of [[NASA]]'s three [[HEAO Program|High Energy Astrophysical Observatories]]. Named '''HEAO B''' before launch, the observatory's name was changed to honor [[Albert Einstein]] upon its successfully attaining orbit.<ref name=cfa-harvard>{{cite web |title=HEA Heritage Missions: Einstein Observatory |publisher=cfa.harvard.edu |url=http://www.cfa.harvard.edu/hea/hm/heaob.html |access-date=27 March 2014}}</ref>