The HEAO satellite series

The first of three High Energy Astrophysical Observatories (HEAO-1) was launched by NASA in August of 1977. It was primarily a survey mission designed to scan and map the universe using X-rays. After six months, the entire sky had been observed. In January of 1979, the systems were shut down and HEAO-1 drifted in a decaying orbit until it burned up on re-entry into the Earth's atmosphere.

The second and third HEAO missions continued making images of, and studying various sources of, X-rays and gamma-rays in the sky.

All spacecraft images courtesy NASA
© The Children's Museum of Indianapolis, 1999