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Carrying the largest X-ray telescope ever built, HEAO-B was
the second in a series on three large observatories designed to study
the "high energy universe," i.e., X-rays, gamma rays, and cosmic
particles. The scientific objectives of the HEAO program were to
learn more about some of the most puzzling objects in the universe:
pulsars, neutron stars, black holes, quasars, radio galaxies, and
supernovas. Many of these radiate only in the X-ray, gamma ray, and
cosmic ray regions of the electromagnetic spectrum and cannot be
studied from the ground because of the obscuring effects of the
Earth's atmosphere.
The X-ray telescope had a 584mm wide mirror and a focal
length of 3.3 meters. Images acquired by the telescope were
transmitted to ground stations. The experiment also contained five
other instruments, four of which shared the use of the telescope to
make a variety of measurements of X-rays emitted by stellar objects.
The fifth instrument, independent of the telescope, measured
properties of X-rays beyond the telescope's energy range.
HEAO-B was built by TRW Defense and Space Systems Group,
Redondo Beach, California, under the direction of NASA's Marshall
Space Flight Center, Huntsville, Alabama. It was launched from
Kennedy Space Center on November 13, 1978, by an Atlas-Centaur launch
vehicle. The spacecraft was injected into a near-circular orbit with
an inclination of 23.5 degrees and a period of 95.3 minutes.