![Animation of XMM-Newton trajectory](https://upload.wikimedia.org/wikipedia/commons/0/00/Animation_of_XMM-Newton_trajectory.gif)
''XMM-Newton'', also known as the High Throughput X-ray Spectroscopy Mission and the X-ray Multi-Mirror Mission, is an
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
space observatory
A space telescope or space observatory is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO-2 launche ...
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
The Science Programme of the European Space Agency is a long-term programme of space science and space exploration missions. Managed by the agency's Directorate of Science, The programme funds the development, launch, and operation of missions ...
programme. Named after physicist and astronomer Sir
Isaac Newton
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a " natural philosopher"), widely recognised as one of the grea ...
, 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 (
visible and
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
) wavelengths.
Initially funded for two years, with a ten-year design life, the spacecraft remains in good health and has received repeated mission extensions, most recently in October 2020 and is scheduled to operate until the end of 2022. ESA plans to succeed ''XMM-Newton'' with the
Advanced Telescope for High Energy Astrophysics
Advanced Telescope for High-ENergy Astrophysics (''Athena'') is an X-ray observatory mission selected by European Space Agency (ESA) within its Cosmic Vision program to address the Hot and Energetic Universe scientific theme. ''Athena'' will ...
(ATHENA), the second large mission in the
Cosmic Vision
Cosmic Vision is the third campaign of space science and space exploration missions in the Science Programme of the European Space Agency (ESA). Formulated in 2005 as ''Cosmic Vision: Space Science for Europe 2015–2025'', the campaign succee ...
2015–2025 plan, to be launched in 2035. ''XMM-Newton'' is similar to
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
's
Chandra X-ray Observatory
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 during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 1 ...
, also launched in 1999.
As of May 2018, close to 5,600
papers have been published about either ''XMM-Newton'' or the scientific results it has returned.
Concept and mission history
The observational scope of ''XMM-Newton'' includes the
detection of X-ray emissions from astronomical objects, detailed studies of star-forming regions, investigation of the formation and evolution of
galaxy cluster
A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-lar ...
s, the environment of
supermassive black hole
A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions of times the mass of the Sun (). Black holes are a class of astronomical ob ...
s and mapping of the mysterious
dark matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not a ...
.
In 1982, even before the launch of ''XMM-Newton'' predecessor ''
EXOSAT
The European X-ray Observatory Satellite (EXOSAT), originally named HELOS, was an X-ray telescope 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 includi ...
'' in 1983, a proposal was generated for a "multi-mirror" X-ray telescope mission.
The ''XMM'' mission was formally proposed to the ESA Science Programme Committee in 1984 and gained approval from the Agency's Council of Ministers in January 1985.
That same year, several
working group
A working group, or working party, is a group of experts working together to achieve specified goals. The groups are domain-specific and focus on discussion or activity around a specific subject area. The term can sometimes refer to an interdis ...
s were established to determine the feasibility of such a mission,
and mission objectives were presented at a
workshop
Beginning with the Industrial Revolution era, a workshop may be a room, rooms or building which provides both the area and tools (or machinery) that may be required for the manufacture or repair of manufactured goods. Workshops were the on ...
in Denmark in June 1985.
At this workshop, it was proposed that the spacecraft contain 12 low-energy and 7 high-energy X-ray telescopes.
The spacecraft's overall configuration was developed by February 1987, and drew heavily from lessons learned during the ''EXOSAT'' mission;
the Telescope Working Group had reduced the number of X-ray telescopes to seven standardised units.
In June 1988 the European Space Agency approved the mission and issued a call for investigation proposals (an "announcement of opportunity").
Improvements in technology further reduced the number of X-ray telescopes needed to just three.
In June 1989, the mission's instruments had been selected and work began on spacecraft hardware.
A project team was formed in January 1993 and based at the
European Space Research and Technology Centre
The European Space Research and Technology Centre (ESTEC) is the European Space Agency's main technology development and test centre for spacecraft and space technology. It is situated in Noordwijk, South Holland, in the western Netherlands, alt ...
(ESTEC) in
Noordwijk
Noordwijk () is a town and municipality in the west of the Netherlands, in the province of South Holland. The municipality covers an area of of which is water and had a population of in .
On 1 January 2019, the former municipality of Noordwij ...
, Netherlands.
Prime contractor Dornier Satellitensysteme (a subsidiary of the former
DaimlerChrysler Aerospace
''Dasa'' ( sa, दास, Dāsa) is a Sanskrit word found in ancient Indian texts such as the ''Rigveda'' and ''Arthasastra''. It usually means "enemy" or "servant" but ''dasa'', or ''das'', also means a " servant of God", "devotee," " votary" or ...
) was chosen in October 1994 after the mission was approved into the implementation phase, with development and construction beginning in March 1996 and March 1997, respectively.
The XMM Survey Science Centre was established at the
University of Leicester
, mottoeng = So that they may have life
, established =
, type = public research university
, endowment = £20.0 million
, budget = £326 million
, chancellor = David Willetts
, vice_chancellor = Nishan Canagarajah
, head_lab ...
in 1995.
The three flight mirror modules for the X-ray telescopes were delivered by Italian subcontractor Media Lario in December 1998,
and spacecraft integration and testing was completed in September 1999.
''XMM'' left the ESTEC integration facility on 9 September 1999, taken by road to
Katwijk
Katwijk (), also spelled Katwyk, is a coastal municipality and town in the province of South Holland, which is situated in the mid-western part of the Netherlands.
The Oude Rijn ("Old Rhine") river flows through the town and into the North Se ...
then by the barge ''Emeli'' to
Rotterdam
Rotterdam ( , , , lit. ''The Dam on the River Rotte'') is the second largest city and municipality in the Netherlands. It is in the province of South Holland, part of the North Sea mouth of the Rhine–Meuse–Scheldt delta, via the ''"Ne ...
. On 12 September, the spacecraft left Rotterdam for
French Guiana
French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas department/region and single territorial collectivity of France on the northern Atlantic coast of South America in the Guianas. ...
aboard
Arianespace
Arianespace SA is a French company founded in 1980 as the world's first commercial launch service provider. It undertakes the operation and marketing of the Ariane programme. The company offers a number of different launch vehicles: the heavy ...
transport ship MN ''Toucan''.
The ''Toucan'' docked at the French Guianese town of
Kourou
Kourou () is a commune in French Guiana, an overseas region and department of France in South America. Kourou is famous for being the location of the Guiana Space Centre, the main spaceport of France and the European Space Agency (ESA). It i ...
on 23 September, and was transported to
Guiana Space Centre
The Guiana Space Centre (french: links=no, Centre spatial guyanais; CSG), also called Europe's Spaceport, is a European spaceport to the northwest of Kourou in French Guiana, a region of France in South America. Kourou is located approximatel ...
Ariane 5 Final Assembly Building for final launch preparation.
Launch of ''XMM'' took place on 10 December 1999 at 14:32 UTC from the Guiana Space Centre.
''XMM'' was lofted into space aboard an
Ariane 504 rocket, and placed into a highly elliptical, 40-degree orbit that had a
perigee
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any ell ...
of and an
apogee
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any ell ...
of .
Forty minutes after being released from the Ariane upper stage, telemetry confirmed to ground stations that the spacecraft's solar arrays had successfully deployed. Engineers waited an additional 22 hours before commanding the on-board propulsion systems to fire a total of five times, which, between 10 and 16 December, changed the orbit to with a 38.9-degree inclination. This resulted in the spacecraft making one complete
revolution
In political science, a revolution (Latin: ''revolutio'', "a turn around") is a fundamental and relatively sudden change in political power and political organization which occurs when the population revolts against the government, typically due ...
of the Earth approximately every 48 hours.
Immediately after launch, ''XMM'' began its
Launch and Early Orbit phase of operations.
On 17 and 18 December 1999, the X-ray modules and Optical Monitor doors were opened, respectively.
Instrument activation started on 4 January 2000,
and the Instrument Commissioning phase began on 16 January.
The Optical Monitor (OM) attained first light on 5 January, the two European Photon Imaging Camera (EPIC)
MOS-
CCDs followed on 16 January and the EPIC
pn-CCD on 22 January, and the Reflection Grating Spectrometers (RGS) saw first light on 2 February.
On 3 March, the Calibration and Performance Validation phase began,
and routine science operations began on 1 June.
During a press conference on 9 February 2000, ESA presented the first images taken by ''XMM'' and announced that a new name had been chosen for the spacecraft. Whereas the program had formally been known as the High Throughput X-ray Spectroscopy Mission, the new name would reflect the nature of the program and the originator of the field of spectroscopy. Explaining the new name of ''XMM-Newton'', Roger Bonnet, ESA's former Director of Science, said, "We have chosen this name because Sir Isaac Newton was the man who invented spectroscopy and XMM is a spectroscopy mission." He noted that because Newton is synonymous with gravity and one of the goals of the satellite was to locate large numbers of black hole candidates, "there was no better choice than XMM-Newton for the name of this mission."
Including all construction, spacecraft launch, and two years of operation, the project was accomplished within a budget of (1999 conditions).
Operation
The spacecraft has the ability to lower the operating temperature of both the EPIC and RGS cameras, a function that was included to counteract the deleterious effects of ionising
radiation on the camera
pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device.
In most digital display devices, pixels are the ...
s. In general, the instruments are cooled to reduce the amount of
dark current within the devices. During the night of 3–4 November 2002, RGS-2 was cooled from its initial temperature of down to , and a few hours later to . After analysing the results, it was determined the optimal temperature for both RGS units would be , and during 13–14 November, both RGS-1 and RGS-2 were set to this level. During 6–7 November, the EPIC MOS-CCD detectors were cooled from their initial operating temperature of to a new setting of . After these adjustments, both the EPIC and RGS cameras showed dramatic improvements in quality.
On 18 October 2008, ''XMM-Newton'' suffered an unexpected communications failure, during which time there was no contact with the spacecraft. While some concern was expressed that the vehicle may have suffered a catastrophic event, photographs taken by amateur astronomers at the
Starkenburg Observatory
The Starkenburg Observatory (german: Starkenburg-Sternwarte) is an astronomical observatory in Heppenheim, Germany. It was founded in 1970, and currently has about 150 members.
The observatory was the venue for the 1997 and 2003 meetings of the ...
in Germany and at other locations worldwide showed that the spacecraft was intact and appeared on course. A weak signal was finally detected using a antenna in
New Norcia, Western Australia, and communication with ''XMM-Newton'' suggested that the spacecraft's Radio Frequency switch had failed. After troubleshooting a solution, ground controllers used
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
's antenna at the
Goldstone Deep Space Communications Complex
The Goldstone Deep Space Communications Complex (GDSCC), commonly called the Goldstone Observatory, is a satellite ground station located in Fort Irwin in the U.S. state of California. Operated by NASA's Jet Propulsion Laboratory (JPL), its m ...
to send a command that changed the switch to its last working position. ESA stated in a press release that on 22 October, a ground station at the
European Space Astronomy Centre
The European Space Astronomy Centre (ESAC) near Madrid in Spain is the ESA's centre for space science (astronomy, solar system exploration and fundamental physics). It hosts the science operation centres for all ESA astronomy and planetary miss ...
(ESAC) made contact with the satellite, confirming the process had worked and that the satellite was back under control.
Mission extensions
Because of the spacecraft's good health and the significant returns of data, ''XMM-Newton'' has received several mission extensions by ESA's Science Programme Committee. The first extension came during November 2003 and extended operations through March 2008.
The second extension was approved in December 2005, extending work through March 2010.
A third extension was passed in November 2007, which provided for operations through 2012. As part of the approval, it was noted that the satellite had enough on-board consumables (fuel, power and mechanical health) to theoretically continue operations past 2017.
The fourth extension in November 2010 approved operations through 2014.
A fifth extension was approved in November 2014 and affirmed in November 2016, continuing operations through 2018.
A sixth extension was approved in December 2017, continuing operations through the end of 2020. A seventh extension was approved in November 2018, continuing operations through the end of 2022.
Spacecraft
![XMM-Newton](https://upload.wikimedia.org/wikipedia/commons/4/40/XMM-Newton.jpg)
''XMM-Newton'' is a long space telescope, and is wide with solar arrays deployed. At launch it weighed .
The spacecraft has three degrees of stabilisation, which allow it to aim at a target with an accuracy of 0.25 to 1
arcseconds
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The ...
. This stabilisation is achieved through the use of the spacecraft's
Attitude & Orbit Control Subsystem. These systems also allow the spacecraft to point at different celestial targets, and can turn the craft at a maximum of 90 degrees per hour.
The instruments on board ''XMM-Newton'' are three European Photon Imaging Cameras (EPIC), two Reflection Grating
Spectrometer
A spectrometer () is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the ...
s (RGS), and an Optical Monitor.
The spacecraft is roughly cylindrical in shape, and has four major components. At the fore of the spacecraft is the ''Mirror Support Platform'', which supports the X-ray telescope assemblies and grating systems, the Optical Monitor, and two
star tracker
A star tracker is an optical device that measures the positions of stars using photocells or a camera.
As the positions of many stars have been measured by astronomers to a high degree of accuracy, a star tracker on a satellite or spacecraft may ...
s. Surrounding this component is the ''Service Module'', which carries various spacecraft support systems:
computer and
electric bus
An electric bus is a bus that is propelled using electric motors as opposed to an internal combustion engine. Electric buses can store the needed electricity on-board, or be fed continuously from an external source. The majority of buses ...
ses, consumables (such as fuel and
coolant
A coolant is a substance, typically liquid, that is used to reduce or regulate the temperature of a system. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, chemically inert and neither causes nor promotes corrosi ...
),
solar arrays, the Telescope Sun Shield, and two
S-band antennas. Behind these units is the ''Telescope Tube'', a long, hollow
carbon fibre
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
structure which provides exact spacing between the mirrors and their detection equipment. This section also hosts
outgassing
Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen, or absorbed in some material. Outgassing can include sublimation and evaporation (which ...
equipment on its exterior, which helps remove any contaminants from the interior of the satellite. At the aft end of spacecraft is the ''Focal Plane Assembly'', which supports the Focal Plane Platform (carrying the cameras and spectrometers) and the data-handling, power distribution, and radiator assemblies.
Instruments
European Photon Imaging Cameras
The three ''European Photon Imaging Cameras'' (EPIC) are the primary instruments aboard ''XMM-Newton''. The system is composed of two
MOS-
CCD cameras and a single
pn-CCD camera, with a total field of view of 30
arcminutes and an energy sensitivity range between (). Each camera contains a six-position
filter wheel, with three types of X-ray-transparent filters, a fully open and a fully closed position; each also contains a radioactive source used for internal calibration. The cameras can be independently operated in a variety of modes, depending on the image sensitivity and speed needed, as well as the intensity of the target.
The two MOS-CCD cameras are used to detect low-energy X-rays. Each camera is composed of seven
silicon chip
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
s (one in the centre and six circling it), with each chip containing a matrix of 600 × 600
pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device.
In most digital display devices, pixels are the ...
s, giving the camera a total resolution of about 2.5
megapixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device.
In most digital display devices, pixels are the sm ...
s. As
discussed above, each camera has a large adjacent
radiator which cools the instrument to an operating temperature of . They were developed and built by the
University of Leicester
, mottoeng = So that they may have life
, established =
, type = public research university
, endowment = £20.0 million
, budget = £326 million
, chancellor = David Willetts
, vice_chancellor = Nishan Canagarajah
, head_lab ...
Space Research Centre and
EEV Ltd.
The pn-CCD camera is used to detect high-energy X-rays, and is composed of a single silicon chip with twelve individual embedded CCDs. Each CCD is 64 × 189 pixels, for a total capacity of 145,000 pixels. At the time of its construction, the pn-CCD camera on ''XMM-Newton'' was the largest such device ever made, with a sensitive area of . A radiator cools the camera to . This system was made by the
Astronomisches Institut Tübingen, the
Max Planck Institute for Extraterrestrial Physics, and PNSensor, all of Germany.
The EPIC system records three types of data about every X-ray that is detected by its CCD cameras. The time that the X-ray arrives allows scientists to develop
light curve
In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...
s, which projects the number of X-rays that arrive over time and shows changes in the brightness of the target. Where the X-ray hits the camera allows for a visible image to be developed of the target. The amount of energy carried by the X-ray can also be detected and helps scientists to determine the physical processes occurring at the target, such as its temperature, its chemical make-up, and what the environment is like between the target and the telescope.
Reflection Grating Spectrometers
The ''Reflection Grating Spectrometers'' (RGS) are a secondary system on the spacecraft and are composed of two Focal Plane Cameras and their associated Reflection Grating Arrays. This system is used to build
X-ray spectral data and can determine the
elements present in the target, as well as the temperature, quantity and other characteristics of those elements. The RGS system operates in the () range, which allows detection of carbon, nitrogen, oxygen, neon, magnesium, silicon and iron.
[ den Herder (2001) states that the RGS system operates in the range, but the majority of sources, including official ESA websites, contradict this.]
The Focal Plane Cameras each consist of nine MOS-CCD devices mounted in a row and following a curve called a
Rowland circle. Each CCD contains 384 × 1024 pixels, for a total resolution of more than 3.5 megapixels. The total width and length of the CCD array was dictated by the size of the RGS spectrum and the wavelength range, respectively. Each CCD array is surrounded by a relatively massive wall, providing heat conduction and
radiation shielding. Two-stage radiators cool the cameras to an operating temperature of . The camera systems were a joint effort between
SRON, the
Paul Scherrer Institute
The Paul Scherrer Institute (PSI) is a multi-disciplinary research institute for natural and engineering sciences in Switzerland. It is located in the Canton of Aargau in the municipalities Villigen and Würenlingen on either side of the River ...
, and
MSSL, with EEV Ltd and Contraves Space providing hardware.
The Reflection Grating Arrays are attached to two of the primary telescopes. They allow approximately 50% of the incoming X-rays to pass unperturbed to the EPIC system, while redirecting the other 50% onto the Focal Plane Cameras. Each RGA was designed to contain 182 identical gratings, though a fabrication error left one with only 181. Because the telescope mirrors have already focused the X-rays to converge at the focal point, each grating has the same angle of incidence, and as with the Focal Plane Cameras, each grating array conforms to a Rowland circle. This configuration minimises focal aberrations. Each grating is composed of thick
silicon carbide
Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal s ...
substrate covered with a
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile me ...
film, and is supported by five
beryllium
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form m ...
stiffeners. The gratings contain a large number of grooves, which actually perform the X-ray deflection; each grating contains an average of 646 grooves per millimetre. The RGAs were built by
Columbia University
Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...
.
Optical Monitor
The ''Optical Monitor'' (OM) is a
Ritchey–Chrétien optical/ultraviolet telescope designed to provide simultaneous observations alongside the spacecraft's X-ray instruments. The OM is sensitive between nanometres in a 17 × 17 arcminute square field of view co-aligned with the centre of the X-ray telescope's field of view. It has a
focal length of and a
focal ratio
In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill Pro ...
of ƒ/12.7.
The instrument is composed of the Telescope Module, containing the optics, detectors, processing equipment, and power supply; and the Digital Electronics Module, containing the instrument control unit and data processing units. Incoming light is directed into one of two fully redundant detector systems. The light passes through an 11-position
filter wheel (one opaque to block light, six broad band filters, one white light filter, one magnifier, and two
grisms), then through an intensifier which amplifies the light by one million times, then onto the CCD sensor. The CCD is 384 × 288 pixels in size, of which 256 × 256 pixels are used for observations; each pixel is further subsampled into 8 × 8 pixels, resulting in a final product that is 2048 × 2048 in size. The Optical Monitor was built by the
Mullard Space Science Laboratory
The UCL Mullard Space Science Laboratory (MSSL) is the United Kingdom's largest university space research group. MSSL is part of the Department of Space and Climate Physics at University College London (UCL), one of the first universities in the ...
with contributions from organisations in the United States and Belgium.
Telescopes
![xray_telescope_lens](https://upload.wikimedia.org/wikipedia/commons/5/59/Xray_telescope_lens.svg)
Feeding the EPIC and RGS systems are three telescopes designed specifically to direct X-rays into the spacecraft's primary instruments. The telescope assemblies each have a diameter of , are in length, and have a base weight of . The two telescopes with Reflection Grating Arrays weigh an additional . Components of the telescopes include (from front to rear) the mirror assembly door, entrance and X-ray
baffles, mirror module, electron deflector, a Reflection Grating Array in two of the assemblies, and exit baffle.
Each telescope consists of 58 cylindrical, nested
Wolter Type-1 mirrors developed by Media Lario of Italy, each long and ranging in diameter from , producing a total collecting area of at 1.5
keV Kev can refer to:
Given name
* Kev Adams, French comedian, actor, screenwriter and film producer born Kevin Smadja in 1991
* Kevin Kev Carmody (born 1946), Indigenous Australian singer-songwriter
* Kev Coghlan (born 1988), Scottish Grand Prix moto ...
and at 8 keV.
The mirrors range from thick for the innermost mirror to thick for the outermost mirror, and the separation between each mirror ranges from from innermost to outermost.
Each mirror was built by vapour-depositing a 250 nm layer of gold reflecting surface onto a highly polished aluminium
mandrel, followed by
electroforming
Electroforming is a metal forming process in which parts are fabricated through electrodeposition on a model, known in the industry as a mandrel. Conductive (metallic) mandrels are treated to create a mechanical parting layer, or are chemically p ...
a monolithic
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...
support layer onto the gold. The finished mirrors were glued into the grooves of an
Inconel
Inconel is a registered trademark of Special Metals Corporation for a family of austenitic nickel-chromium-based superalloys.
Inconel alloys are oxidation-corrosion-resistant materials well suited for service in extreme environments subjected ...
spider, which keeps them aligned to within the five-micron tolerance required to achieve adequate X-ray resolution. The mandrels were manufactured by
Carl Zeiss AG
Carl Zeiss AG (), branded as ZEISS, is a German manufacturer of optical systems and optoelectronics, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe (joined 1866) and Otto Schott (joined 1884) he laid the f ...
, and the electroforming and final assembly were performed by Media Lario with contributions from
Kayser-Threde
Kayser-Threde GmbH based in Munich, Germany is a systems house specializing in applications in manned and unmanned space missions, optics, telematics, crash test data acquisition, and process control for the rail sector. On September 1, 2014, Breme ...
.
Subsystems
Attitude & Orbit Control System
Spacecraft three-axis
attitude control
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
Controlling vehicle ...
is handled by the ''Attitude & Orbit Control System'' (AOCS), composed of four
reaction wheels, four
inertial measurement units, two
star tracker
A star tracker is an optical device that measures the positions of stars using photocells or a camera.
As the positions of many stars have been measured by astronomers to a high degree of accuracy, a star tracker on a satellite or spacecraft may ...
s, three fine
Sun sensor
A sun sensor is a navigational instrument used by spacecraft to detect the position of the sun. Sun sensors are used for attitude control, solar array pointing, gyro updating, and fail-safe recovery.
In addition to spacecraft, sun sensors fin ...
s, and three Sun acquisition sensors. The AOCS was provided by
Matra Marconi Space
Matra Marconi Space (MMS) was a Franco-British aerospace company.
History
Matra Marconi Space was established in 1990 as a joint venture between the space and telecommunication divisions of the Lagardère Group ( Matra Espace) and the GEC ...
of the United Kingdom.
Coarse spacecraft orientation and orbit maintenance is provided by two sets of four
hydrazine thrusters (primary and backup).
The hydrazine thrusters were built by
DASA-RI of Germany.
The AOCS was upgraded in 2013 with a software patch ('4WD'), to control attitude using the 3 prime reaction wheels plus the 4th, spare wheel, unused since launch, with the aim of saving propellant to extend the spacecraft lifetime. In 2019 the fuel was predicted to last until 2030.
Power systems
Primary power for ''XMM-Newton'' is provided by two fixed solar arrays. The arrays are composed of six panels measuring for a total of and a mass of . At launch, the arrays provided 2,200 W of power, and were expected to provide 1,600 W after ten years of operation. Deployment of each array took four minutes. The arrays were provided by
Fokker Space
Fokker was a Dutch aircraft manufacturer named after its founder, Anthony Fokker. The company operated under several different names. It was founded in 1912 in Berlin, Germany, and became famous for its fighter aircraft in World War I. In 1919 t ...
of the Netherlands.
When direct sunlight is unavailable, power is provided by two
nickel–cadmium batteries providing 24
A·h and weighing each. The batteries were provided by
SAFT of France.
Radiation Monitor System
The cameras are accompanied by the ''EPIC Radiation Monitor System'' (ERMS), which measures the radiation environment surrounding the spacecraft; specifically, the ambient proton and electron flux. This provides warning of damaging radiation events to allow for automatic shut-down of the sensitive camera CCDs and associated electronics. The ERMS was built by the
Centre d'Etude Spatiale des Rayonnements of France.
Visual Monitoring Cameras
The ''Visual Monitoring Cameras'' (VMC) on the spacecraft were added to monitor the deployment of solar arrays and the sun shield, and have additionally provided images of the thrusters firing and outgassing of the Telescope Tube during early operations. Two VMCs were installed on the Focal Plane Assembly looking forward. The first is FUGA-15, a black and white camera with high
dynamic range
Dynamic range (abbreviated DR, DNR, or DYR) is the ratio between the largest and smallest values that a certain quantity can assume. It is often used in the context of Signal (electrical engineering), signals, like sound and light. It is measured ...
and 290 × 290 pixel resolution. The second is IRIS-1, a colour camera with a variable
exposure time
In photography, shutter speed or exposure time is the length of time that the film or digital sensor inside the camera is exposed to light (that is, when the camera's shutter is open) when taking a photograph.
The amount of light that re ...
and 400 × 310 pixel resolution. Both cameras measure and weight . They use
active pixel sensors, a technology that was new at the time of ''XMM-Newton'' development. The cameras were developed by and
IMEC
Interuniversity Microelectronics Centre (IMEC) is an international research & development organization, active in the fields of nanoelectronics and digital technologies, with headquarters in Belgium. Luc Van den hove has served as President an ...
, both of Belgium.
Ground systems
''XMM-Newton'' mission control is located at the
European Space Operations Centre
The European Space Operations Centre (ESOC) serves as the main mission control centre for the European Space Agency (ESA) and is located in Darmstadt, Germany. ESOC's primary function is the operation of unmanned spacecraft on behalf of ESA and ...
(ESOC) in
Darmstadt, Germany. Two
ground stations, located in
Perth
Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth i ...
and
Kourou
Kourou () is a commune in French Guiana, an overseas region and department of France in South America. Kourou is famous for being the location of the Guiana Space Centre, the main spaceport of France and the European Space Agency (ESA). It i ...
, are used to maintain continuous contact with the spacecraft through most of its orbit. Back-up ground stations are located in
Villafranca del Castillo,
Santiago
Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whos ...
, and
Dongara. Because ''XMM-Newton'' contains no on-board data storage, science data is transmitted to these ground stations in real time.
Data is then forwarded to the
European Space Astronomy Centre
The European Space Astronomy Centre (ESAC) near Madrid in Spain is the ESA's centre for space science (astronomy, solar system exploration and fundamental physics). It hosts the science operation centres for all ESA astronomy and planetary miss ...
Science Operations Centre in Villafranca del Castillo, Spain, where pipeline processing has been performed since March 2012. Data is archived at the ESAC Science Data Centre,
and distributed to mirror archives at the
Goddard Space Flight Center and the XMM-Newton Survey Science Centre (SSC) at the
L'Institut de Recherche en Astrophysique et Planétologie. Prior to June 2013, the SSC was operated by the
University of Leicester
, mottoeng = So that they may have life
, established =
, type = public research university
, endowment = £20.0 million
, budget = £326 million
, chancellor = David Willetts
, vice_chancellor = Nishan Canagarajah
, head_lab ...
, but operations were transferred due to a withdrawal of funding by the United Kingdom.
Observations and discoveries
The space observatory was used to discover the
galaxy cluster
A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-lar ...
XMMXCS 2215-1738, 10 billion light years away from Earth.
The object
SCP 06F6
SCP 06F6 is (or was) an astronomical object of unknown type, discovered on 21 February 2006 in the constellation Boötes[Hubble Space Telescope
The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...]
(HST) in February 2006, was observed by ''XMM-Newton'' in early August 2006 and appeared to show an X-ray glow around it
two orders of magnitude more luminous than that of
supernovae.
In June 2011, a team from the
University of Geneva
The University of Geneva (French: ''Université de Genève'') is a public research university located in Geneva, Switzerland. It was founded in 1559 by John Calvin as a theological seminary. It remained focused on theology until the 17th centur ...
,
Switzerland, reported ''XMM-Newton'' seeing a flare that lasted four hours at a peak intensity of 10,000 times the normal rate, from an observation of
Supergiant Fast X-ray Transient IGR J18410-0535, where a
blue supergiant
A blue supergiant (BSG) is a hot, luminous star, often referred to as an OB supergiant. They have luminosity class I and spectral class B9 or earlier.
Blue supergiants are found towards the top left of the Hertzsprung–Russell diagram, above ...
star shed a plume of matter that was partly ingested by a smaller companion
neutron star
A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. w ...
with accompanying X-ray emissions.
In February 2013 it was announced that ''XMM-Newton'' along with
NuSTAR have for the first time measured the spin rate of a
supermassive black hole
A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions of times the mass of the Sun (). Black holes are a class of astronomical ob ...
, by observing the black hole at the core of galaxy
NGC 1365. At the same time, it verified the model that explains the distortion of X-rays emitted from a black hole.
In February 2014, separate analyses extracted from the spectrum of X-ray emissions observed by ''XMM-Newton'' a monochromatic signal around 3.5 keV.
This signal is coming from different
galaxy cluster
A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-lar ...
s, and several scenarios of
dark matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not a ...
can justify such a line. For example, a 3.5 keV candidate annihilating into 2 photons,
or a 7 keV dark matter particle decaying into photon and neutrino.
In June 2021, one of the largest X-ray surveys using the European Space Agency's XMM-Newton space observatory published initial findings, mapping the growth of 12,000 supermassive black holes at the cores of galaxies and galaxy clusters.
See also
*
List of X-ray space telescopes
X-ray telescopes are designed to observe the x-ray region of the electromagnetic spectrum. X-rays from outer space cannot be observed from the ground due to absorption by the atmosphere, and so x-ray telescopes must be launched into orbit. Their m ...
References
External links
''XMM-Newton'' websiteby ESA
''XMM-Newton'' Operations websiteby ESA
''XMM-Newton'' Science Operations Centre websiteby ESA
''XMM-Newton'' Survey Science Centre websiteby the L'Institut de Recherche en Astrophysique et Planétologie
''XMM-Newton'' Guest Observer Facility websiteby NASA/Goddard Space Flight Center
{{EngvarB, date=February 2016
Spacecraft launched in 1999
Satellites orbiting Earth
European Space Agency satellites
Space telescopes
X-ray telescopes