XMM-Newton

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 clusters, the environment of supermassive black holes and mapping of the mysterious dark matter. In 1982, even before the launch of XMM-Newton predecessor EXOSAT 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 groups were established to determine the feasibility of such a mission, 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 three flight mirror modules for the X-ray telescopes were delivered by Italian subcontractor Media Lario in December 1998, The Toucan docked at the French Guianese town of Kourou on 23 September, and was transported to Guiana Space Centre 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 5 rocket, and placed into a highly elliptical, 40-degree orbit that had a perigee of and an apogee of . 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, 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. Including all construction, spacecraft launch, and two years of operation, the project was accomplished within a budget of (1999 conditions). 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 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's antenna at the Goldstone Deep Space Communications Complex 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 (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. An eighth extension was approved in March 2023, continuing operations through the end of 2026, with indicative extension up to 2029. == Spacecraft ==

'', Toulouse XMM-Newton is a long space telescope, and is wide with solar arrays deployed. At launch it weighed . == 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 chips (one in the centre and six circling it), with each chip containing a matrix of 600 × 600 pixels, giving the camera a total resolution of about 2.5 megapixels. 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 Space Research Centre and EEV Ltd. 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 curves, 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 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. 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, 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 substrate covered with a gold film, and is supported by five beryllium 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. 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 with contributions from organisations in the United States and Belgium. == Telescopes ==

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 and at 8 keV. == Subsystems ==

Attitude & Orbit Control System Spacecraft three-axis attitude control is handled by the Attitude & Orbit Control System (AOCS), composed of four reaction wheels, four inertial measurement units, two star trackers, three fine Sun sensors, and three Sun acquisition sensors. The AOCS was provided by Matra Marconi Space of the United Kingdom. Coarse spacecraft orientation and orbit maintenance is provided by two sets of four hydrazine thrusters (primary and backup). 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 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. == Ground systems ==

XMM-Newton mission control is located at the European Space Operations Centre (ESOC) in Darmstadt, Germany. Two ground stations, located in Perth and Kourou, 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, and Dongara. Because XMM-Newton contains no on-board data storage, science data is transmitted to these ground stations in real time. and distributed to mirror archives at the Goddard Space Flight Center and the XMM-Newton Survey Science Centre (SSC) at the Institut de Recherche en Astrophysique et Planétologie. Prior to June 2013, the SSC was operated by the University of Leicester, 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 XMMXCS 2215-1738, 10 billion light years away from Earth. The object SCP 06F6, discovered by the Hubble Space Telescope (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, 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 star shed a plume of matter that was partly ingested by a smaller companion neutron star 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, 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 clusters, and several scenarios of dark matter 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. In November 2025 it was announced that in May 2016 XMM-Newton had observed the first confirmed coronal mass ejection on a star other than the sun using its low frequency array. == See also ==