X-ray astronomy satellites - AbsoluteAstronomy.com

X-ray astronomy satellites study X-ray

X-ray

X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

emissions from celestial objects. Satellites, which can detect and transmit data about the X-ray emissions are deployed as part of branch of space science

Space science

The term space science may mean:* The study of issues specifically related to space travel and space exploration, including space medicine.* Science performed in outer space ....

known as X-ray astronomy

X-ray astronomy

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 are needed because 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.

A detector is placed on a satellite

Satellite

In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

which is then put into orbit

Orbit

In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...

well above the Earth's atmosphere

Earth's atmosphere

The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...

. Unlike balloons, instruments on satellites are able to observe the full range of the X-ray spectrum

Dispersion (optics)

In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or alternatively when the group velocity depends on the frequency.Media having such a property are termed dispersive media...

. Unlike sounding rockets, they can collect data for as long as the instruments continue to operate. In one instance, the Vela 5B

Vela (satellite)

Vela was the name of a group of satellites developed as the Vela Hotel element of Project Vela by the United States to monitor compliance with the 1963 Partial Test Ban Treaty by the Soviet Union, and other nuclear-capable states. It means vigil or "watch" in Spanish.Vela started out as a small...

satellite, the X-ray detector remained functional for over ten years.

Active X-ray observatory satellites

Satellites in use today include the XMM-Newton observatory

XMM-Newton

The XMM-Newton is an orbiting X-ray observatory launched by ESA in December 1999 on a Ariane 5 rocket...

(low to mid energy X-rays 0.1-15 keV) and the INTEGRAL

INTEGRAL

The European Space Agency's INTErnational Gamma-Ray Astrophysics Laboratory is an operational Earth satellite, launched in 2002 for detecting some of the most energetic radiation that comes from space. It is the most sensitive gamma ray observatory ever launched.INTEGRAL is an ESA mission in...

satellite (high energy X-rays 15-60 keV). Both were launched by the European Space Agency

European Space Agency

The European Space Agency , established in 1975, is an intergovernmental organisation dedicated to the exploration of space, currently with 18 member states...

. NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

has launched the Rossi X-ray Timing Explorer

Rossi X-ray Timing Explorer

The Rossi X-ray Timing Explorer is a satellite that observes the time structure of astronomical X-ray sources. The RXTE has three instruments—the Proportional Counter Array, the High-Energy X-ray Timing Experiment , and one instrument called the All Sky Monitor...

(RXTE), and the Swift

Swift Gamma-Ray Burst Mission

The Swift Gamma-Ray Burst Mission consists of a robotic spacecraft called Swift, which was launched into orbit on 20 November 2004, 17:16:00 UTC on a Delta II 7320-10C expendable launch vehicle. Swift is managed by the NASA Goddard Space Flight Center, and was developed by an international...

and Chandra observatories. One of the instruments on Swift is the Swift X-Ray Telescope (XRT).
The GOES 14

GOES 14

GOES 14, known as GOES-O prior to reaching its operational orbit, is an American weather satellite, which is part of the US National Oceanic and Atmospheric Administration 's Geostationary Operational Environmental Satellite...

spacecraft carries on board a Solar X-ray Imager to monitor the Sun's X-rays for the early detection of solar flares, coronal mass ejections, and other phenomena that impact the geospace environment. It was launched into orbit on June 27, 2009 at 22:51 GMT from Space Launch Complex 37B at the Cape Canaveral Air Force Station

Cape Canaveral Air Force Station

Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...

.

On January 30, 2009, the Russian Federal Space Agency

Russian Federal Space Agency

The Russian Federal Space Agency , commonly called Roscosmos and abbreviated as FKA and RKA , is the government agency responsible for the Russian space science program and general aerospace research. It was previously the Russian Aviation and Space Agency .Headquarters of Roscosmos are located...

successfully launched the Koronas-Foton

Koronas-Foton

Koronas-Foton , also known as CORONAS-Photon , was a Russian Solar research satellite. It is the third satellite in the Russian Coronas programme, and part of the international Living With a Star programme...

which carries several experiments to detect X-rays, including the TESIS telescope/spectrometer FIAN with SphinX soft X-ray spectrophotometer.

The Italian Space Agency

Italian Space Agency

The Italian Space Agency is a government agency established in 1988 to fund, regulate and coordinate space exploration activities in Italy...

(ASI) gamma-ray observatory satellite Astro-rivelatore Gamma ad Imagini Leggero (AGILE

AGILE (spacecraft)

AGILE is an X-ray and Gamma ray astronomical satellite of the Italian Space Agency .ASI has made contact with AGILE: signals from it have been acquired by the ground station at the Broglio Space Centre near Malindi, Kenya and it has been placed in a sun-pointing mode....

) has on board the Super-AGILE 15-45 keV hard X-ray detector. It was launched on April 23, 2007 by the Indian PSLV-C8.

A soft X-ray solar imaging telescope is on board the GOES-13

Geostationary Operational Environmental Satellite

The Geostationary Satellite system, operated by the United States National Environmental Satellite, Data, and Information Service , supports weather forecasting, severe storm tracking, and meteorology research. Spacecraft and ground-based elements of the system work together to provide a continuous...

weather satellite launched using a Delta IV from Cape Canaveral

Cape Canaveral

Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.It is part of a region known as the...

LC37B on May 24, 2006. However, there have been no GOES 13 SXI images since December 2006.

Although the Suzaku

ASTRO-E

Suzaku is a Japanese X-ray astronomy satellite launched on 10 July 2005 aboard the M-V-6 rocket. The project was renamed Suzaku after its successful launch after the mythical Vermilion bird of the South....

X-ray spectrometer (the first micro-calorimeter in space) failed on August 8, 2005 after launch on July 10, 2005, the X-ray Imaging Spectrometer (XIS) and Hard X-ray Detector (HXD) are still functioning.

Past X-ray observatory satellites

Past observatories include SMART-1

SMART-1

SMART-1 was a Swedish-designed European Space Agency satellite that orbited around the Moon. It was launched on September 27, 2003 at 23:14 UTC from the Guiana Space Centre in Kourou, French Guiana. "SMART" stands for Small Missions for Advanced Research in Technology...

, which contained an X-ray telescope for mapping lunar X-ray fluorescence

X-ray fluorescence

X-ray fluorescence is the emission of characteristic "secondary" X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays...

, ROSAT

ROSAT

ROSAT was a German Aerospace Center-led satellite X-ray telescope, with instruments built by Germany, the UK and the US...

, 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...

(the first fully imaging X-ray telescope), the ASCA observatory

Advanced Satellite for Cosmology and Astrophysics

ASCA is the fourth cosmic X-ray astronomy mission by Japan's , and the second for which the United States is providing part of the scientific payload. The satellite was successfully launched on February 20, 1993. The first eight months of the ASCA mission were devoted to performance verification...

, EXOSAT

EXOSAT

The European X-ray Observatory Satellite , originally named HELOS, was operational from May 1983 until April 1986 and in that time made 1780 observations in the X-ray band of most classes of astronomical object including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs,...

, and BeppoSAX

BeppoSAX

BeppoSAX was an Italian–Dutch satellite for X-ray astronomy which played a crucial role in resolving the origin of gamma-ray bursts , the most energetic events known in the universe...

. Uhuru

Uhuru (satellite)

Uhuru was the first satellite launched specifically for the purpose of X-ray astronomy. It was also known as the X-ray Explorer Satellite, SAS-A , SAS 1, or Explorer 42.The observatory was launched on 12 December 1970 into an initial orbit of about 560 km apogee, 520 km...

was the first satellite launched specifically for the purpose of X-ray astronomy. Copernicus which carried an X-ray detector built by University College London

University College London

University College London is a public research university located in London, United Kingdom and the oldest and largest constituent college of the federal University of London...

's Mullard Space Science Laboratory made extensive X-ray observations. ANS

Astronomical Netherlands Satellite

The Astronomical Netherlands Satellite was a space-based X-ray and ultraviolet telescope. It was launched into Earth orbit on 30 August 1974 at 14:07:39 UTC in a Scout rocket from Vandenberg Air Force Base, United States...

could measure X-ray photons in the energy range 2 to 30 keV. Ariel 5 was dedicated to observing the sky in the X-ray band. HEAO-1 scanned the X-ray sky over 0.2 keV - 10 MeV. Hakucho

Hakucho

Hakucho was Japan's first X-ray astronomy satellite, developed by the Institute of Space and Aeronautical Science...

was Japan's first X-ray astronomy satellite.

Array of low-energy X-ray imaging sensors

The Array of Low Energy X-ray Imaging Sensors

Array of Low Energy X-ray Imaging Sensors

The Array of Low Energy X-ray Imaging Sensors X-ray telescopes feature curved mirrors whose multilayer coatings reflect and focus low-energy X-rays or extreme ultraviolet light the way optical telescopes focus visible light...

(ALEXIS) featured curved mirrors whose multilayer coatings reflect and focus low-energy X-rays or extreme ultraviolet light the way optical telescopes focus visible light. The launch of ALEXIS was provided by the United States Air Force

United States Air Force

The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

Space Test Program on a Pegasus

Pegasus rocket

The Pegasus rocket is a winged space launch vehicle capable of carrying small, unmanned payloads into low Earth orbit. It is air-launched, as part of an expendable launch system developed by Orbital Sciences Corporation . Three main stages burning solid propellant provide the thrust...

Booster on April 25, 1993. The spacing of the molybdenum

Molybdenum

Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...

(Mo) and silicon

Silicon

Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

(Si) layers on each telescope's mirror is the primary determinant of the telescope's photon energy response function. ALEXIS operated for 12 yr.

OSO-3

The third Orbiting Solar Observatory (OSO 3

OSO 3

OSO 3, third Orbiting Solar Observatory was launched on March 8, 1967, into a nearly circular orbit of mean altitude 550 km, inclined at 33° to the equatorial plane...

) was launched on March 8, 1967 into a nearly circular orbit of mean altitude 550 km, inclined at 33° to the equatorial plane, deactivated on June 28, 1968, followed by reentry on April 4, 1982. Its XRT consisted of a continuously spinning wheel (1.7 s period) in which the hard X-ray experiment was mounted with a radial view. The XRT assembly was a single thin NaI(Tl) scintillation crystal plus phototube enclosed in a howitzer-shaped CsI(Tl) anti-coincidence shield. The energy resolution was 45% at 30 keV. The instrument operated from 7.7 to 210 keV with 6 channels. OSO-3 obtained extensive observations of solar flares, the diffuse component of cosmic X-rays, and the observation of a single flare episode from Scorpius X-1

Scorpius X-1

Scorpius X-1 is an X-ray source located roughly 9000 light years away in the constellation Scorpius. Scorpius X-1 was the first extrasolar X-ray source discovered, and, aside from the Sun, it is the strongest source of X-rays in the sky...

, the first observation of an extrasolar X-ray source by an observatory satellite. Among the extrasolar X-ray sources OSO 3 observed were UV Ceti

Luyten 726-8

Luyten 726-8 is a binary star system that is one of Earth's nearest neighbors, at about 8.7 light years from Earth in the constellation Cetus...

, YZ Canis Minoris

YZ Canis Minoris

YZ Canis Minoris is a "flare star" so called due to its solar flares being more powerful than those of Earth's star. It is a Dwarf star roughly 3 times the size of Jupiter, and is 20 light years from earth. The radiation from the star is in a 50mhz bandwidth and is centered on 1464.9mhz....

, EV Lacertae

EV Lacertae

EV Lacertae is a faint red dwarf star 16.5 light years away in the constellation Lacerta. It is the nearest star to the Sun in that region of the sky, although with an apparent magnitude of 10, it is only barely visible with binoculars...

and AD Leonis, yielding upper soft X-ray detection limits on flares from these sources.

ESRO 2B (Iris)

ESRO 2B (Iris) was the first successful ESRO

ESRO

The European Space Research Organization was an international organisation founded by 10 European nations with the intention of jointly pursuing scientific research in space. It was founded in 1964...

satellite launch. Iris was launched on May 17, 1968, had an elliptical orbit with (initially) apogee 1086 km, perigee 326 km, and inclination 97.2°, with an orbital period of 98.9 minutes. The satellite carried seven instruments to detect high energy cosmic rays, determine the total flux of solar X-rays, and measure trapped radiation, Van Allen belt protons and cosmic ray protons. Of special significance for X-ray astronomy were two X-ray instruments: one designed to detect wavelengths 1-20 Å (0.1-2 nm) (consisting of proportional counters with varying window thickness) and one designed to detect wavelengths 44-60 Å (4.4-6.0 nm) (consisting of proportional counters with thin Mylar windows).

Wavelength dispersive X-ray spectroscopy

Wavelength dispersive X-ray spectroscopy

The Wavelength dispersive X-ray spectroscopy is a method used to count the number of X-rays of a specific wavelength diffracted by a crystal. The wavelength of the impinging x-ray and the crystal's lattice spacings are related by Bragg's law and produce constructive interference if they fit the...

(WDS) is a method used to count the number of X-rays of a specific wavelength diffracted

Diffraction

Diffraction refers to various phenomena which occur when a wave encounters an obstacle. Italian scientist Francesco Maria Grimaldi coined the word "diffraction" and was the first to record accurate observations of the phenomenon in 1665...

by a crystal. WDS only counts X-rays of a single wavelength or wavelength band. In order to interpret the data, the expected elemental wavelength peak locations need to be known. For the ESRO-2B WDS X-ray instruments, calculations of the expected solar spectrum had to be performed and were compared to peaks detected by rocket measurements.

Early X-ray detecting satellites

The Global Geospace Science (GGS) Polar Satellite

Polar (satellite)

The Global Geospace Science Polar Satellite was a BABATONDIE science spacecraft launched at 06:23:59.997 EST on February 24, 1996 aboard a BABATONDIE BABATONDIE 7925-10 rocket from launch pad 2W at Vandenberg Air Force Base in BABATONDIE, BABATONDIE, to observe the polar BABATONDIE...

was a NASA

NASA

science spacecraft

Spacecraft

A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

launched at 06:23:59.997 EST on February 24, 1996 aboard a McDonnell Douglas

McDonnell Douglas

McDonnell Douglas was a major American aerospace manufacturer and defense contractor, producing a number of famous commercial and military aircraft. It formed from a merger of McDonnell Aircraft and Douglas Aircraft in 1967. McDonnell Douglas was based at Lambert-St. Louis International Airport...

Delta II

Delta II was an American space launch system, originally designed and built by McDonnell Douglas. Delta II is part of the Delta rocket family and was in service from 1989 until November 1, 2011...

7925-10 rocket from launch pad 2W at Vandenberg Air Force Base

Vandenberg Air Force Base

Vandenberg Air Force Base is a United States Air Force Base, located approximately northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command ....

in Lompoc, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, to observe the Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

's polar magnetosphere

Magnetosphere

A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...

. Polar is in a highly elliptical orbit, at an 86° inclination

Inclination

Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...

with an orbital period

Orbital period

The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...

of ~18 hrs. It gathers multi-wavelength imaging (including X-ray) of the aurora

Aurora (astronomy)

An aurora is a natural light display in the sky particularly in the high latitude regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere...

, and measures the entry of plasma

Plasma (physics)

In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...

into the polar magnetosphere and the geomagnetic tail, the flow of plasma to and from the ionosphere

Ionosphere

The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...

, and the deposition of particle energy in the ionosphere and upper atmosphere

Atmosphere

An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

. Polar Mission Operations were terminated at 14:54:41 EDT on April 28, 2008.

A later satellite of the Intercosmos

Intercosmos

Interkosmos was a space program of the Soviet Union designed to include members of military forces of allied Warsaw Pact countries in manned and unmanned missions...

series, Intercosmos 26, (launched on March 2, 1994) as part of the Coronas-I international project may have conducted X-ray studies of the Sun.

On March 23, 1983, at 12:45:06 UTC, the Astron

Astron (spacecraft)

Astron was a Soviet spacecraft launched on 23 March 1983 at 12:45:06 UTC, using Proton launcher, which was designed to fulfill an astrophysics mission. It was based on the Venera spacecraft design and was operational for six years as the largest ultraviolet space telescope during its lifetime...

spacecraft is launched into an orbit around the Earth withan apogee of 185,000 km allowing it to make observations with an onboard X-ray

X-ray

spectroscope outside the Earth's umbra

Umbra

The umbra, penumbra and antumbra are the names given to three distinct parts of a shadow, created by any light source. For a point source only the umbra is cast.These names are most often used to refer to the shadows cast by celestial bodies....

and radiation belt. Observations of Hercules X-1

Hercules X-1

Hercules X-1 , also known as 4U1656+35, is a moderately strong X-ray binary source first studied by the Uhuru satellite.It is composed of a neutron star accreting matter from a normal star probably due to Roche lobe overflow....

are made from 1983 to 1987 in bith the prolonged low state ("off" state) and "high on" state.

Bhaskara was the second Indian Space Research Organization (ISRO) satellite. It was launched on June 7, 1979 with a modified SS-5 (SKean IRBM) plus upper stage from Kapustin Yar

Kapustin Yar

Kapustin Yar is a Russian rocket launch and development site in Astrakhan Oblast, between Volgograd and Astrakhan. Known today as Znamensk , it was established 13 May 1946 and in the beginning used technology, material, and scientific support from defeated Germany...

in the Soviet Union. A secondary objective was to conduct X-ray astronomy investigations. Bhaskara 2 was launched on November 20, 1981 from Kapustin Yar like its predecessor also in size, mass and design may have conducted X-ray astronomy investigations.

Orbiting Solar Observatory (OSO 8) was launched on June 21, 1975. While OSO 8's primary objective was to observe the Sun, four instruments were dedicated to observations of other celestial X-ray sources brighter than a few milliCrab. A sensitivity of 0.001 of the Crab nebula source (= 1 "mCrab"). OSO 8 ceased operations on October 1, 1978.

Signe 3 (launched on June 17, 1977) was part of the Soviet Union

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

's Intercosmos program.

Almost from the beginning of satellite X-ray studies the Soviet Union began placing a large number of solar X-ray satellites into orbit, including those of the Intercosmos

Intercosmos

Interkosmos was a space program of the Soviet Union designed to include members of military forces of allied Warsaw Pact countries in manned and unmanned missions...

series.

The third US Small Astronomy Satellite (SAS-3)

Third Small Astronomy Satellite

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...

was launched on May 7, 1975, with 3 major scientific objectives: 1) determine bright X-ray source locations to an accuracy of 15 arcseconds; 2) study selected sources over the energy range 0.1-55 keV; and 3) continuously search the sky for X-ray novae, flares, and other transient phenomena. It was a spinning satellite with pointing capability. SAS 3 was the first to discover X-rays from a highly magnetic WD binary system, AM Her, discovered X-rays from Algol and HZ 43, and surveyed the soft X-ray background (0.1-0.28 keV).

To conduct experiments in X-ray astronomy and solar physics among others the Indian Space Research Organization (ISRO) built Aryabhata

Aryabhata (satellite)

Aryabhatta was India's first satellite, named after the great Indian astronomer of the same name. It was launched by the Soviet Union on 19 April 1975 from Kapustin Yar using a Cosmos-3M launch vehicle. It was built by the Indian Space Research Organization to gain experience in building and...

. It was launched by the Soviet Union on April 19, 1975 from Kapustin Yar

Kapustin Yar

. A power failure halted experiments after 4 days in orbit.

Following on the success of Uhuru

Uhuru (satellite)

(SAS 1), NASA launched the Second Small Astronomy Satellite

Second Small Astronomy Satellite

The Small Astronomy Satellite 2, also known also as SAS-2, SAS B or Explorer 48, was a NASA gamma ray telescope. It was launched on 15 November 1972 into low Earth orbit with a periapsis of 443 km and an apoapsis of 632 km...

SAS 2. It was launched from the San Marco platform off the coast of Kenya, Africa, into a nearly equatorial orbit.

TD-1A

TD-1A

TD-1A, or Thor-Delta 1A, was a European astrophysical research satellite which was launched in 1972. Operated by the European Space Research Organisation, TD-1A made astronomical surveys primarily in the ultraviolet, but also using x-ray and gamma ray detectors.-Spacecraft:TD-1A was named after the...

was put in a nearly circular polar sun-synchronous orbit, with apogee 545 km, perigee 533 km, and inclination 97.6°. It was ESRO's first 3-axis stabilized satellite, with one axis pointing to the Sun to within ±5°. The optical axis was maintained perpendicular to the solar pointing axis and to the orbital plane. It scanned the entire celestial sphere every 6 months, with a great circle being scanned every satellite revolution. After about 2 months of operation, both of the satellite's tape recorders failed. A network of ground stations was put together so that real-time telemetry from the satellite was recorded for about 60% of the time. After 6 months in orbit, the satellite entered a period of regular eclipses as the satellite passed behind the Earth—cutting off sunlight to the solar panels. The satellite was put into hibernation for 4 months, until the eclipse period passed, after which systems were turned back on and another 6 months of observations were made. TD-1A

TD-1A

was primarily a UV mission however it carried both a cosmic X-ray and a gamma-ray detector. TD-1A reentered on January 9, 1980.

To continue the intensive X-ray investigation of the Sun and the cosmic X-ray background, OSO 7

OSO 7

OSO 7 is the seventh in the series of American Orbiting Solar Observatory satellites launched by NASA between 1962 and 1975...

was launched on September 29, 1971. OSO 7

OSO 7

OSO 7 is the seventh in the series of American Orbiting Solar Observatory satellites launched by NASA between 1962 and 1975...

made the first observation of solar gamma-ray line emission, due to electron/positron annihilation at 511 keV, from a solar flare in April 1972.

Cosmos 428 was launched by the USSR into Earth orbit on June 24, 1971 and recovered July 6, 1971. The orbit characteristics: apogee/perigee/inclination 208 km, 271 km, and 51.8°, respectively. It was a military satellite on which X-ray astronomy experiments had been added. There was a scintillation spectrometer sensitive to X-rays >30 keV, with a 2° × 17° field of view. In addition, there was an X-ray telescope which operated in the range 2-30 keV. Cosmos 428 detected several X-ray sources which were correlated to already identified Uhuru

Uhuru (satellite)

point sources.

Like the previous Vela 5 satellites, the Vela 6

Vela (satellite)

nuclear test detection satellites were part of a program run jointly by the Advanced Research Projects of the U. S. Department of Defense and the U. S. Atomic Energy Commission, managed by the U. S. Air Force. The twin spacecraft, Vela 6A and 6B, were launched on April 8, 1970. Data from the Vela 6 satellites were used to look for correlations between gamma-ray bursts and X-ray events. At least 2 good candidates were found, GB720514 and GB740723. The X-ray detectors failed on Vela 6A on March 12, 1972 and on Vela 6B on January 27, 1972.

OSO 6 was launched on August 9, 1969. Its orbital period was ~95 min. The spacecraft had a spin rate of 0.5 rps. On board was a hard X-ray detector (27-189 keV) with a 5.1 cm² NaI(Tl) scintillator, collimated to 17° × 23° FWHM. The system had 4 energy channels (separated 27-49-75-118-189 keV). The detector spun with the spacecraft on a plane containing the Sun direction within ± 3.5°. Data were read with alternate 70 ms and 30 ms integrations for 5 intervals every 320 ms.

The Vela satellites 5A and 5B, launched on May 23, 1969, are responsible for significant discoveries of gamma-ray bursts and astronomical X-ray sources including V 0332+53.

OSO 5 was launched on January 22, 1969, and lasted until July 1975. It was the 5th satellite put into orbit as part of the Orbiting Solar Observatory

Orbiting Solar Observatory

The Orbiting Solar Observatory Program was the name of a series of nine American science satellites primarily intended to study the Sun, though they also included important non-solar experiments. Eight were launched successfully by NASA between 1962 and 1975 using Delta rockets...

program. This program was intended to launch a series of nearly identical satellites to cover an entire 11-year solar cycle. The circular orbit had an altitude of 555 km and an inclination of 33°. The spin rate of the satellite was 1.8 s. The data produced a spectrum of the diffuse background over the energy range 14-200 keV.

Cosmos 215 was launched April 19, 1968 and contained an X-ray experiment. Orbit characteristics: 261 × 426 km, at an inclination of 48.5°. The orbital period was ~ 91 minutes. It was intended primarily to perform solar studies, but did detect some non-solar X-ray events. It reentered the atmosphere on June 30, 1968.

OGO 5 was launched on March 4, 1968. The satellite, primarily devoted to Earth observation, was in a highly elliptical initial orbit with a 272 km perigee and an 148,228 km apogee. The orbital inclination was 31.1°. The satellite took 3796 minutes to complete one orbit. The Energetic Radiations from Solar Flares experiment was operational from March 1968 - June 1971. Primarily devoted to solar observations, it detected at least 11 cosmic X-ray bursts in time coincidence with gamma-ray bursts seen by other instruments. The detector was a 0.5 cm thick NaI(Tl) crystal with a 9.5 cm² area. Data were accumulated into energy ranges of: 9.6-19.2, 19.2-32, 32-48, 48-64, 64-80, 80-104, 104-128, and > 128 keV. The data were sampled for 1.15 seconds once every 2.3 seconds.

The fourth successful Orbiting Solar Observatory

Orbiting Solar Observatory

, OSO 4, was launched on October 18, 1967. The objectives of the OSO 4 satellite were to perform solar physics experiments above the atmosphere and to measure the direction and intensity over the entire celestial sphere in UV, X, and gamma radiation. The OSO 4 platform consisted of a sail section (which pointed 2 instruments continuously toward the Sun) and a wheel section which spun about an axis perpendicular to the pointing direction of the sail (which contained 7 experiments). The spacecraft performed normally until a second tape recorder failed in May 1968. OSO 4 was put into a "standby" mode in November 1969. It could be turned on only for recording special events in real-time. One such event occurred on March 7, 1970 during a solar eclipse. The spacecraft became totally inoperable on December 7, 1971.

The first USA satellite which detected cosmic X-rays was the Third Orbiting Solar Observatory, or OSO-3, launched on March 8, 1967. It was intended primarily to observe the Sun, which it did very well during its 2 year lifetime, but it also detected a flaring episode from the source Sco X-1 and measured the diffuse cosmic X-ray background.

Solar X-ray bursts were observed by OSO 2 and an effort was made to map the entire celestial sphere for direction and intensity of X-radiation.

OGO 1, the first of the Orbiting Geophysical Observatories

Orbiting Geophysical Observatory

Orbiting Geophysical Observatory refers to the six satellites launched by the United States that were in use from September 1964 to 1972, designed to study the Earth's magnetosphere. The satellites successfully studied the interactions between the Earth and the Sun, despite a number of technical...

(OGOs), was successfully launched from Cape Kennedy on September 5, 1964 and placed into an initial orbit of 281 × 149,385 km at 31° inclination. A secondary objective was to detect gamma-ray bursts from the Sun in the energy range 80 keV - 1 MeV. The experiment consisted of 3 CsI crystals surrounded by a plastic anti-coincidence shield. Once every 18.5 seconds, integral intensity measurements were made in each of 16 energy channels which were equally spaced over the 0.08-1 MeV range. OGO 1 was completely terminated on November 1, 1971. Although the satellite did not achieve its goals due to electrical interference and secular degradation, searching back through the data after the discovery of cosmic gamma-ray bursts by the Vela satellites revealed the detection of one or more such events in the OGO 1 data.

The first in a series of 8 successfully launched Orbiting Solar Observatories

Orbiting Solar Observatory

(OSO 1, launched on March 7, 1963) had as its primary mission to measure solar electromagnetic radiation in the UV, X-ray, and gamma-ray regions.

The SOLar RADiation satellite program (SOLRAD) was conceived in the late 1950s to study the Sun's effects on Earth, particularly during periods of heightened solar activity. Solrad 1 is launched on June 22, 1960, aboard a Thor Able from Cape Canaveral

Cape Canaveral

at 1:54 a.m. EDT. As the world's first orbiting astronomical observatory, Solrad 1 determined that radio fade-outs were caused by solar X-ray emissions.

Agreement signed by Roscosmos and the German Aerospace Center

Among the contracts negotiated in August at the MAKS International Aviation and Space Salon there was an agreement signed by the Russian Federal Space Agency (Roscosmos) and the German Aerospace Center (DLR). The contract details the creation of the Orbital Astrophysics Observatory Spectrum-X-Gamma

Spectrum-X-Gamma

Spektr-RG is an international high-energy astrophysics observatory, which is being built under the leadership of the Russian Space Research Institute...

(SXG) planned to be launched in 2012.

According to Mikhail Pavlinsky, deputy head of the Space Research Institute (SPI), the total project cost nears €50 million. Under the agreement, Germany will provide the main of the two X-ray telescopes (eROSITA), while Russia will install it on its platform, prepare the spacecraft, and take care of all related issues. Russia will also install an additional telescope (ART-XC) on this platform.

The project is unique not only because of its participants and large scale, but also because of its tasks and possible discoveries. The project will be looking for galaxies, not stars. When it comes to discovering further galaxies, even the telescopes brought beyond the Earth's atmosphere are sometimes blind when compared to X-ray telescopes. Space is permeated by dust and at times it is hard for X-rays to get through it. The new observatory will help scientists perform an all-sky scan survey.

Constellation-X

The Constellation-X Observatory was a mission concept for an X-ray space observatory to be operated by NASA; in 2008 it was merged with ESA and JAXA efforts in the same direction to produce the International X-ray Observatory project, announced on July 24, 2008 .The intention of the Con-X project...

will provide high resolution X-ray spectroscopy to probe matter as it falls into a black hole, as well as probe the nature of dark matter and dark energy by observing the formation of clusters of galaxies. The International X-ray Observatory (IXO) – a joint effort of NASA, ESA, and JAXA supersedes the Constellation-X mission.

International X-ray Observatory

The International X-ray Observatory was a planned X-ray telescope from about 2008 to 2011 by NASA, ESA, and JAXA. In 2011, NASA pulled out and ESA is forking/rebooting the project as the ESA Advanced Telescope for High ENergy Astrophysics ., which is an L-class candidate within the ESA Cosmic...

(IXO) is the result of the merging of NASA's Constellation-X

Constellation-X

and ESA/JAXA's XEUS

XEUS

XEUS, X-ray Evolving Universe Spectroscopy, was space observatory plan developed by the European Space Agency as a successor to the successful XMM-Newton X-ray satellite telescope...

mission concepts. It will feature a single large X-ray mirror with a 3 m² collecting area and 5" angular resolution, and a suite of instrumentation, including a wide field imaging detector, a hard X-ray imaging detector, a high-spectral-resolution imaging spectrometer (calorimeter), a grating spectrometer, a high timing resolution spectrometer, and a polarimeter. Launch is planned for 2021.

ESA Solar Orbiter

The Solar Orbiter

Solar Orbiter

Solar Orbiter is a planned Sun-observing satellite, under development by the European Space Agency . The main mission scenario is a launch by an Atlas V from the Kennedy Space Center in Florida in January 2017...

(SOLO) will approach to 62 solar radii to view the solar atmosphere with high spatial resolution in visible, XUV, and X-rays. The nominally 6 yr mission will be from an elliptical orbit around the Sun with perihelion as low as 0.28 AU and with increasing inclination (using gravity assists from Venus) up to more than 30° with respect to the solar equator. The Orbiter will deliver images and data from the polar regions and the side of the Sun not visible from Earth. The launch date, if selected, could be Jan 2017.

Active X-ray observatory satellites

Past X-ray observatory satellites

Array of low-energy X-ray imaging sensors

OSO-3

ESRO 2B (Iris)

Early X-ray detecting satellites

Agreement signed by Roscosmos and the German Aerospace Center

Constellation-X

International X-ray Observatory

ESA Solar Orbiter

See also