Editing Einstein Observatory (section)

==Project conception and design==
The [[HEAO Program|High Energy Astronomy Observatory]] (HEAO) program originated in the late 1960's within the Astronomy Missions Board at NASA, which recommended the launch of a series of satellite observatories dedicated to high-energy astronomy. In 1970, NASA requested proposals for experiments to fly on these observatories, and a team organized by [[Riccardo Giacconi]], [[Herbert Gursky]], [[George W. Clark]], [[Elihu Boldt]], and Robert Novick responded in October 1970 with a proposal for an X-ray telescope. NASA approved four missions in the HEAO program, with the X-ray telescope planned to be the third mission.{{sfn |Tucker |Tucker |1986 |p=61-64}}

One of the three missions of the HEAO program was cancelled in February 1973, due to budgetary pressures within NASA that briefly resulted in the cancellation of the entire program, and the x-ray observatory was moved up to become the second mission of the program, receiving the designation HEAO B (later HEAO-2), and scheduled to launch in 1978.{{sfn |Tucker |Tucker |1986 |p=72-75}}

HEAO-2 was constructed by [[TRW Inc.]] and shipped to [[Marshall Space Flight Center]] in [[Huntsville, AL]] for testing in 1977.{{sfn |Tucker |Tucker |1986 |p=83}}