English: This photograph shows the High Energy Astronomy Observatory (HEAO)-2 experiment level testing after integration at TRW, Inc., the prime contractor for the HEAO. The HEAO-2, the first imaging and largest x-ray telescope built to date, was capable of producing actual photographs of x-ray objects. TRW, Inc. designed and developed the HEAOs under the project management of the Marshall Space Flight Center. The HEAO-2 was originally identified as HEAO-B but the designation was changed once the spacecraft achieved orbit.