HEAO Program

HEAO 1, launched August 12, 1977, was a sky survey mission that included four large X-ray and gamma-ray astronomy instruments, known as A1, A2, A3, and A4, respectively.

HEAO 2, more commonly known as the Einstein Observatory, launched 13 November 1978 into a 23.5 deg inclination orbit.

It carried a single large grazing-incidence focusing X-ray telescope, providing unprecedented levels of sensitivity (hundreds of times better than previously achieved) and arc-second angular resolution for pointed observations of known objects, and operated over the 0.2 to 3.5 keV energy range.

The first was a cryogenically cooled germanium (Ge) high-resolution gamma-ray spectrometer, while the C2 and C3 experiments were large cosmic-ray instruments.

All three satellites were built by TRW Systems of Redondo Beach, California, who won the Nelson P. Jackson Aerospace Award for their work.