HEAO Program
Encyclopedia
The High Energy Astronomy Observatory Program was a NASA program of the late 1970s and early 1980s that included a series of three large low-Earth-orbiting
spacecraft for X-ray and Gamma-Ray astronomy and Cosmic-Ray investigations. After launch, they were denoted HEAO 1, HEAO 2 (also known as The Einstein Observatory
), and HEAO 3, respectively. The large (~3000 kg) satellites were 3-axis stabilized to arc-minute accuracy, with fixed solar panels. All three observatories were launched from Cape Canaveral, Florida
on Atlas-Centaur
SLV-3D launch vehicles into near-circular orbits with initial altitudes slightly above 500 km.
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. HEAO 2 differed from HEAO 1 and HEAO 3 in that it was used for pointed, deep, small-field-of-view observations rather than sky-survey studies.
A suite of four focal plane instruments were provided:
as well as a 1-20 keV Monitor Proportional Counter (MPC), a Broad Band Filter Spectrometer (BBFS), and an objective grating spectrometer (OGS). The observatory re-entered the Earth's atmosphere and burned up on March 25, 1982.
, while the C2 and C3 experiments were large cosmic-ray instruments. The satellite re-entered the Earth's atmosphere and burned up on December 7, 1981.
of Redondo Beach, California, who won the Nelson P. Jackson Aerospace Award for their work. The total program cost was roughly $250 million.
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
spacecraft for X-ray and Gamma-Ray astronomy and Cosmic-Ray investigations. After launch, they were denoted HEAO 1, HEAO 2 (also known as The Einstein Observatory
Einstein Observatory
Einstein Observatory was the first fully imaging X-ray telescope put into space and the second of NASA's three High Energy Astrophysical Observatories...
), and HEAO 3, respectively. The large (~3000 kg) satellites were 3-axis stabilized to arc-minute accuracy, with fixed solar panels. All three observatories were launched from Cape Canaveral, Florida
Cape Canaveral, Florida
Cape Canaveral is a city in Brevard County, Florida, United States. The population was 8,829 at the 2000 census. As of 2008, the estimated population according to the U.S. Census Bureau was 10,147...
on Atlas-Centaur
Atlas-Centaur
The Atlas-Centaur was an American expendable launch system designed and built by General Dynamics Convair Division in San Diego, CA. It was derived from the SM-65 Atlas missile. It was a member of the Atlas family of rockets, and was used for 61 orbital launches between 1962 and 1983. It was...
SLV-3D launch vehicles into near-circular orbits with initial altitudes slightly above 500 km.
HEAO 1
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. Inclination was about 22.7 degrees. It re-entered the Earth's atmosphere and burned up on March 15, 1979.- The A1, or Large-Area Sky Survey (LASS) instrument, was managed by the Naval Research Laboratory and used large proportional counters to cover the 0.25 to 25 keV energy range.
- The A2, or Cosmic X-ray Experiment (CXE), from the Goddard Space Flight CenterGoddard Space Flight CenterThe Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...
, covered the 2-60 keV energy range with high spatial and spectral resolution.
- The A3, or Modulation Collimator (MC) instrument, provided high-precision positions of X-ray sources, accurate enough to permit follow-up observations to identify optical and radio counterparts. It was provided by the Center for Astrophysics (Smithsonian Astrophysical ObservatorySmithsonian Astrophysical ObservatoryThe Smithsonian Astrophysical Observatory is a research institute of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory to form the Harvard-Smithsonian Center for Astrophysics .-History:The SAO was founded in 1890 by...
and the Harvard College ObservatoryHarvard College ObservatoryThe Harvard College Observatory is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, USA, and was founded in 1839...
, SAO/HCO).
- The A4, Hard X-ray / Low Energy Gamma-ray experiment, used scintillation counters to cover the energy range from about 20 keV to 10 MeV. It was provided and managed by the University of California at San Diego, in collaboration with MIT.
HEAO 2 A/K/A Einstein Observatory
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-incidenceWolter telescope
A Wolter telescope is a telescope for X-rays using only grazing incidence optics. Visible light telescopes are built with lenses or parabolic mirrors at nearly normal incidence. Neither works well for X-rays. Lenses for visible light are made of a transparent material with an index of refraction...
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. HEAO 2 differed from HEAO 1 and HEAO 3 in that it was used for pointed, deep, small-field-of-view observations rather than sky-survey studies.
A suite of four focal plane instruments were provided:
- HRI, or High Resolution Imaging camera, 0.15-3 keV.
- IPC, or Imaging Proportional Counter, 0.4 to 4 keV.
- SSS, or Solid State Spectrometer, 0.5 to 4.5 keV.
- FPCS, or Bragg Focal Plane Crystal Spectrometer,
as well as a 1-20 keV Monitor Proportional Counter (MPC), a Broad Band Filter Spectrometer (BBFS), and an objective grating spectrometer (OGS). The observatory re-entered the Earth's atmosphere and burned up on March 25, 1982.
HEAO 3
HEAO 3, launched on 20 September 1979 into a 43.6-degree inclination orbit, carried three experiments, known as C1, C2, and C3. The first was a cryogenically cooled germanium (Ge) high-resolution gamma-ray spectrometerSpectrometer
A spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization...
, while the C2 and C3 experiments were large cosmic-ray instruments. The satellite re-entered the Earth's atmosphere and burned up on December 7, 1981.
Program
The experiment designations A1, A2, A3, A4, for HEAO A, thru C1, C2, C3 for HEAO C, were most common before launch, but also often appear in the later scientific literature. The overall HEAO program was managed out of NASA's Marshall Space Flight Center in Huntsville, AL. NASA Program Manager was Mr. Richard E. Halpern; NASA Program Scientist was Dr. Albert G. Opp. All three satellites were built by TRW SystemsTRW
TRW Inc. was an American corporation involved in a variety of businesses, mainly aerospace, automotive, and credit reporting. It was a pioneer in multiple fields including electronic components, integrated circuits, computers, software and systems engineering. TRW built many spacecraft,...
of Redondo Beach, California, who won the Nelson P. Jackson Aerospace Award for their work. The total program cost was roughly $250 million.