Este fue
tu cielo.

A High Energy Fleet

NASA's High Energy Astrophysical Observatory (HEAO) spacecraft appear poised over Earth in this illustration. Labeled A, B, and C, they were known as HEAO-1, HEAO-2, and HEAO-3. HEAO-1 and HEAO-2 revealed the X-ray sky, discovering thousands of celestial sources of high-energy radiation. HEAO-2, also called the Einstein Observatory, was the first X-ray telescope to create focused images.