(High Energy Astrophysics Observatory 2, Einstein Observatory, HEAO-B, High Energy Astronomy Observatory 2)
(1978 X-ray observatory space mission)
HEAO-2 (for High Energy Astrophysics Observatory 2, aka
High Energy Astronomy Observatory 2,
Einstein Observatory or HEAO-B)
was a NASAX-ray observatory in space from 1978 to 1982.
It was part of a program that included HEAO-1 and HEAO-3.
HEAO-2 instruments: