Einstein Observatory

Last updated

Einstein Observatory
HEAO-2 High Energy Astronomy Observatory 0102090.jpg
Einstein Observatory
Mission typeAstronomy
Operator NASA
COSPAR ID 1978-103A OOjs UI icon edit-ltr-progressive.svg
SATCAT no. 11101
Website Einstein Observatory at NASA.gov
Mission duration4 years
Spacecraft properties
Manufacturer TRW
Dry mass3,130 kilograms (6,900 lb)
Start of mission
Launch date13 November 1978, 05:24 (1978-11-13UTC05:24) UTC
Rocket Atlas SLV-3D Centaur-D1AR
Launch site Cape Canaveral LC-36B
End of mission
Last contact17 April 1981 (1981-04-18)
Decay date26 May 1982
Orbital parameters
Reference system Geocentric
Regime Low Earth
Perigee altitude 465 kilometres (289 mi)
Apogee altitude 476 kilometres (296 mi)
Inclination 23.5°
Period 94.0 minutes
Epoch 13 November 1978 05:24:00 UTC
 

Einstein Observatory (HEAO-2) was the first fully imaging X-ray telescope put into space and the second of NASA's three High Energy Astrophysical Observatories. Named HEAO B before launch, the observatory's name was changed to honor Albert Einstein upon its successfully attaining orbit. [1]

Contents

Project conception and design

The High Energy Astronomy Observatory (HEAO) program originated in the late 1960's within the Astronomy Missions Board at NASA, which recommended the launch of a series of satellite observatories dedicated to high-energy astronomy. In 1970, NASA requested proposals for experiments to fly on these observatories, and a team organized by Riccardo Giacconi, Herbert Gursky, George W. Clark, Elihu Boldt, and Robert Novick responded in October 1970 with a proposal for an x-ray telescope. NASA approved four missions in the HEAO program, with the x-ray telescope planned to be the third mission. [2]

One of the three missions of the HEAO program was cancelled in February 1973, due to budgetary pressures within NASA that briefly resulted in the cancellation of the entire program, and the x-ray observatory was moved up to become the second mission of the program, receiving the designation HEAO B (later HEAO-2), and scheduled to launch in 1978. [3]

HEAO-2 was constructed by TRW Inc. and shipped to Marshall Space Flight Center in Huntsville, AL for testing in 1977. [4]

History

HEAO-2 was launched on November 13, 1978, from Cape Canaveral, Florida, on an Atlas-Centaur SLV-3D booster rocket into a near-circular orbit at an altitude of approximately 470 km and orbital inclination of 23.5 degrees. [5] The satellite was renamed Einstein upon achieving orbit, in honor of the centenary of the scientist's birth.

Einstein ceased operations on April 26 1981, when the exhaustion of the satellite's thruster fuel supply rendered the telescope inoperable. [6] The satellite reentered Earth's atmosphere and burned up on March 25, 1982. [7]

Instrumentation

HEAO 2 diagram: B-1: Gas proportional counter, B-2: High definition camera detector, B-3: Crystal spectrometer, B-4: Gas proportional counter, B-5: Gas spectrometer solid detector, 1: Platform/bus, 2: Solar panel, 3: Optical bench, 4: Rear pre-collimator, 5: Wolter optics, 6: Front pre-collimator, 7: Sun visor, 8: Filters and spectrometer grids, 9: Star finders, 10: Locations reserved for experiments, 11: Central electronics, 12: Focal plane HEAO-2-Configuration.png
HEAO 2 diagram: B-1: Gas proportional counter, B-2: High definition camera detector, B-3: Crystal spectrometer, B-4: Gas proportional counter, B-5: Gas spectrometer solid detector, 1: Platform/bus, 2: Solar panel, 3: Optical bench, 4: Rear pre-collimator, 5: Wolter optics, 6: Front pre-collimator, 7: Sun visor, 8: Filters and spectrometer grids, 9: Star finders, 10: Locations reserved for experiments, 11: Central electronics, 12: Focal plane

Einstein carried a single large grazing-incidence focusing X-ray telescope that provided unprecedented levels of sensitivity. It had instruments sensitive in the 0.15 to 4.5 keV energy range. Four instruments were installed in the satellite, mounted on a carousel arrangement that could be rotated into the focal plane of the telescope: [8]

Additionally, the Monitor Proportional Counter (MPC) was a non-focal plane, coaxially-mounted proportional counter that monitored the x-ray flux of the source being observed by the active focal plane instrument.

Two filters could be used with the imaging detectors:

Riccardo Giacconi was the principal investigator for all of the experiments on board Einstein. [9]

Scientific results

Einstein discovered approximately five thousand sources of x-ray emission during its operation [10] and was the first x-ray experiment able to resolve an image of the observed sources.

X-ray background

Surveys by early x-ray astronomy experiments showed a uniform diffuse background of x-ray radiation across the sky. The uniformity of this background radiation indicated that it originated outside of the Milky Way Galaxy, with the most popular hypotheses being a hot gas spread uniformly throughout space, or numerous distant point sources of x-rays (such as quasars) that appear to blend together due to their great distance. Observations with Einstein showed that a large portion of this x-ray background originated from distant point sources, and observations with later x-ray experiments have confirmed and refined this conclusion. [11]

Stellar x-ray emissions

Observations with Einstein showed that all stars emit x-rays. [12] Main sequence stars emit only a small portion of their total radiation in the x-ray spectrum, primarily from their corona, while neutron stars emit a very large portion of their total radiation in the x-ray spectrum. [11] Einstein data also indicated that coronal x-ray emissions in main sequence stars are stronger than was expected at the time. [13]

Galaxy clusters

The Uhuru satellite discovered x-ray emissions from a hot, thin gas pervading distant clusters of galaxies. Einstein was able to observe this gas in greater detail. Einstein data indicated that the containment of this gas within these clusters by gravity could not be explained by the visible matter within those clusters, which provided further evidence for studies of dark matter. Observations by Einstein also helped to determine the frequency of irregularly-shaped clusters compared to round, uniform clusters. [11]

Galactic jets

Einstein detected jets of x-rays emanating from Centaurus A and M87 that were aligned with previously-observed jets in the radio spectrum. [13]

See also

Sources

Related Research Articles

<span class="mw-page-title-main">X-ray astronomy</span> Branch of astronomy that uses X-ray observation

X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy uses a type of space telescope that can see x-ray radiation which standard optical telescopes, such as the Mauna Kea Observatories, cannot.

<span class="mw-page-title-main">Chandra X-ray Observatory</span> NASA space telescope launched in 1999

The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the Space ShuttleColumbia during STS-93 by NASA on July 23, 1999. Chandra was sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, enabled by the high angular resolution of its mirrors. Since the Earth's atmosphere absorbs the vast majority of X-rays, they are not detectable from Earth-based telescopes; therefore space-based telescopes are required to make these observations. Chandra is an Earth satellite in a 64-hour orbit, and its mission is ongoing as of 2023.

<span class="mw-page-title-main">XMM-Newton</span> X-ray space observatory

XMM-Newton, also known as the High Throughput X-ray Spectroscopy Mission and the X-ray Multi-Mirror Mission, is an X-ray space observatory launched by the European Space Agency in December 1999 on an Ariane 5 rocket. It is the second cornerstone mission of ESA's Horizon 2000 programme. Named after physicist and astronomer Sir Isaac Newton, the spacecraft is tasked with investigating interstellar X-ray sources, performing narrow- and broad-range spectroscopy, and performing the first simultaneous imaging of objects in both X-ray and optical wavelengths.

<span class="mw-page-title-main">Compton Gamma Ray Observatory</span> NASA space observatory designed to detect X-rays and gamma rays (1991–2000)

The Compton Gamma Ray Observatory (CGRO) was a space observatory detecting photons with energies from 20 keV to 30 GeV, in Earth orbit from 1991 to 2000. The observatory featured four main telescopes in one spacecraft, covering X-rays and gamma rays, including various specialized sub-instruments and detectors. Following 14 years of effort, the observatory was launched from Space Shuttle Atlantis during STS-37 on April 5, 1991, and operated until its deorbit on June 4, 2000. It was deployed in low Earth orbit at 450 km (280 mi) to avoid the Van Allen radiation belt. It was the heaviest astrophysical payload ever flown at that time at 16,300 kilograms (35,900 lb).

<span class="mw-page-title-main">Great Observatories program</span> Series of NASA satellites

NASA's series of Great Observatories satellites are four large, powerful space-based astronomical telescopes launched between 1990 and 2003. They were built with different technology to examine specific wavelength/energy regions of the electromagnetic spectrum: gamma rays, X-rays, visible and ultraviolet light, and infrared light.

<span class="mw-page-title-main">ROSAT</span> Satellite X-ray telescope

ROSAT was a German Aerospace Center-led satellite X-ray telescope, with instruments built by West Germany, the United Kingdom and the United States. It was launched on 1 June 1990, on a Delta II rocket from Cape Canaveral, on what was initially designed as an 18-month mission, with provision for up to five years of operation. ROSAT operated for over eight years, finally shutting down on 12 February 1999.

<span class="mw-page-title-main">High Energy Astronomy Observatory 1</span> X-ray telescope launched in 1977

HEAO-1 was an X-ray telescope launched in 1977. HEAO-1 surveyed the sky in the X-ray portion of the electromagnetic spectrum, providing nearly constant monitoring of X-ray sources near the ecliptic poles and more detailed studies of a number of objects by observations lasting 3–6 hours. It was the first of NASA's three High Energy Astronomy Observatories, HEAO 1, launched August 12, 1977 aboard an Atlas rocket with a Centaur upper stage, operated until 9 January 1979. During that time, it scanned the X-ray sky almost three times

<span class="mw-page-title-main">Advanced Satellite for Cosmology and Astrophysics</span>

The Advanced Satellite for Cosmology and Astrophysics was the fourth cosmic X-ray astronomy mission by JAXA, and the second for which the United States provided part of the scientific payload. The satellite was successfully launched on 20 February 1993. The first eight months of the ASCA mission were devoted to performance verification. Having established the quality of performance of all ASCA's instruments, the spacecraft provided science observations for the remainder of the mission. In this phase the observing program was open to astronomers based at Japanese and U.S. institutions, as well as those located in member states of the European Space Agency.

<span class="mw-page-title-main">X-ray telescope</span> Telescope designed to observe remote objects by detecting X-rays

An X-ray telescope (XRT) is a telescope that is designed to observe remote objects in the X-ray spectrum. X-rays are absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites.

<span class="mw-page-title-main">Hinode (satellite)</span> Japanese satellite

Hinode, formerly Solar-B, is a Japan Aerospace Exploration Agency Solar mission with United States and United Kingdom collaboration. It is the follow-up to the Yohkoh (Solar-A) mission and it was launched on the final flight of the M-V rocket from Uchinoura Space Center, Japan on 22 September 2006 at 21:36 UTC. Initial orbit was perigee height 280 km, apogee height 686 km, inclination 98.3 degrees. Then the satellite maneuvered to the quasi-circular Sun-synchronous orbit over the day/night terminator, which allows near-continuous observation of the Sun. On 28 October 2006, the probe's instruments captured their first images.

Herbert Gursky was the Superintendent of the Naval Research Laboratory's Space Science Division and Chief Scientist of the E.O. Hulburt Center for Space Research.

<i>AstroSat</i> Space observatory

AstroSat is India's first dedicated multi-wavelength space telescope. It was launched on a PSLV-XL on 28 September 2015. With the success of this satellite, ISRO has proposed launching AstroSat-2 as a successor for AstroSat.

Leon P. Van Speybroeck was an American astronomer who served as Telescope Scientist for the Chandra X-Ray Observatory, which was launched into space aboard the Space Shuttle Columbia in 1999. Van Speybroek designed the mirrors that made possible its spectacular X-ray images of nearby and remote celestial objects, including comets, exploding stars, jets of gas spewing from nearby black holes, and powerful quasars more than 10 billion light years from Earth. The data from Chandra prompted new discoveries about the evolution of stars and galaxies, the nature of the black holes, dark matter, and the shape and dimensions of the universe.

<span class="mw-page-title-main">High Energy Astronomy Observatory 3</span>

The last of NASA's three High Energy Astronomy Observatories, HEAO 3 was launched 20 September 1979 on an Atlas-Centaur launch vehicle, into a nearly circular, 43.6 degree inclination low Earth orbit with an initial perigeum of 486.4 km. The normal operating mode was a continuous celestial scan, spinning approximately once every 20 min about the spacecraft z-axis, which was nominally pointed at the Sun. Total mass of the observatory at launch was 2,660.0 kilograms (5,864.3 lb).

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, 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.

<span class="mw-page-title-main">Small Astronomy Satellite 3</span>

The Small Astronomy Satellite 3 was a NASA X-ray astronomy space telescope. It functioned from May 7, 1975 to April 1979. It covered the X-ray range with four experiments on board. The satellite, built by the Johns Hopkins University Applied Physics Laboratory (APL), was proposed and operated by MIT's Center for Space Research (CSR). It was launched on a Scout vehicle from the Italian San Marco launch platform near Mombasa, Kenya, into a low-Earth, nearly equatorial orbit. It was also known as Explorer 53, as part of NASA's Explorer program.

<i>Hitomi</i> (satellite) Failed Japanese X-ray astronomy satellite

Hitomi, also known as ASTRO-H and New X-ray Telescope (NeXT), was an X-ray astronomy satellite commissioned by the Japan Aerospace Exploration Agency (JAXA) for studying extremely energetic processes in the Universe. The space observatory was designed to extend the research conducted by the Advanced Satellite for Cosmology and Astrophysics (ASCA) by investigating the hard X-ray band above 10 keV. The satellite was originally called New X-ray Telescope; at the time of launch it was called ASTRO-H. After it was placed in orbit and its solar panels deployed, it was renamed Hitomi. The spacecraft was launched on 17 February 2016 and contact was lost on 26 March 2016, due to multiple incidents with the attitude control system leading to an uncontrolled spin rate and breakup of structurally weak elements.

<span class="mw-page-title-main">History of X-ray astronomy</span>

The history of X-ray astronomy begins in the 1920s, with interest in short wave communications for the U.S. Navy. This was soon followed by extensive study of the earth's ionosphere. By 1927, interest in the detection of X-ray and ultraviolet (UV) radiation at high altitudes inspired researchers to launch Goddard's rockets into the upper atmosphere to support theoretical studies and data gathering. The first successful rocket flight equipped with instrumentation able to detect solar ultraviolet radiation occurred in 1946. X-ray solar studies began in 1949. By 1973 a solar instrument package orbited on Skylab providing significant solar data.

<span class="mw-page-title-main">International X-ray Observatory</span> Cancelled American-ESA-Japanese space telescope project

The International X-ray Observatory (IXO) is a cancelled X-ray telescope that was to be launched in 2021 as a joint effort by NASA, the European Space Agency (ESA), and the Japan Aerospace Exploration Agency (JAXA). In May 2008, ESA and NASA established a coordination group involving all three agencies, with the intent of exploring a joint mission merging the ongoing XEUS and Constellation-X Observatory (Con-X) projects. This proposed the start of a joint study for IXO. NASA was forced to cancel the observatory due to budget constraints in fiscal year 2012. ESA however decided to reboot the mission on its own developing Advanced Telescope for High Energy Astrophysics as a part of Cosmic Vision program.

References

  1. "HEA Heritage Missions: Einstein Observatory". cfa.harvard.edu. Retrieved March 27, 2014.
  2. Tucker & Tucker 1986, p. 61-64.
  3. Tucker & Tucker 1986, p. 72-75.
  4. Tucker & Tucker 1986, p. 83.
  5. "HEAO-2 Launch Information". nssdc.gsfc.nasa.gov/. Retrieved July 14, 2021.
  6. Tucker & Tucker 1986, p. 90.
  7. "Einstein Observatory (HEAO-2)". ecuip.lib.uchicago.edu. Retrieved March 27, 2014.
  8. Giacconi, R.; Branduardi, G.; Briel, U.; Epstein, A.; Fabricant, D.; et al. (1979). "The Einstein /HEAO 2/ X-ray Observatory". The Astrophysical Journal. adsabs.harvard.edu. 230: 540. Bibcode:1979ApJ...230..540G. doi: 10.1086/157110 . S2CID   120943949.
  9. "HEAO-2 Experiments". nssdc.gsfc.nasa.gov/. Retrieved July 14, 2021.
  10. Schlegel 2002, p. 22-23.
  11. 1 2 3 Tucker & Tucker 1986, p. 93-95.
  12. Schlegel 2002, p. 31.
  13. 1 2 "The Einstein Observatory (HEAO-2)". National Aeronautics and Space Administration. 2020. Retrieved July 8, 2021.