High Energy Astronomy Observatory 3

The High Energy Astronomy Observatory 3 (also HEAO HEAO -3 or C) was optimized for sky surveys in the hard X-ray and gamma-ray range Space Telescope NASA.

HEAO -3 was launched on 20 September 1979, an Atlas - Centaur rocket from Cape Canaveral and was until 29 May 1981 in operation. The satellite entered into force on December 7, 1981 back into the Earth's atmosphere.

Main instrument was a gamma spectrometer for the energy range 50 keV to 10 MeV with an energy resolution of about 3 keV at 1:46 MeV energy and a field of view of 30 °. There were experiments on frequency of nuclei of heavy elements in cosmic rays and isotope composition of the cosmic radiation. The depletion of the coolant for the four germanium detectors of the spectrometer mid 1980's ended this most important part of the mission. Main result was a sky survey in emission lines of the gamma radiation.