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129-608: 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 March 2023 and is scheduled to operate until the end of 2026. ESA plans to succeed XMM-Newton with the Advanced Telescope for High Energy Astrophysics (ATHENA), the second large mission in the Cosmic Vision 2015–2025 plan, to be launched in 2035. XMM-Newton

258-414: 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

387-545: A 40' x 40' instantaneous sky area, with a separate Fast Detector tailored to observe the brightest point sources of the X-ray sky with high throughput and low pile-up. These capabilities, in combination with the unprecedented effective area and wide field of the Athena telescope, will provide breakthrough capabilities in X-ray imaging spectroscopy. The WFI is developed by an international consortium composed of ESA member states. It

516-404: A body is proportional to the product of the masses of the two attracting bodies and decreases inversely with the square of the distance between them. To this Newtonian approximation, for a system of two-point masses or spherical bodies, only influenced by their mutual gravitation (called a two-body problem ), their trajectories can be exactly calculated. If the heavier body is much more massive than

645-427: A certain time called the period. This motion is described by the empirical laws of Kepler, which can be mathematically derived from Newton's laws. These can be formulated as follows: Note that while bound orbits of a point mass or a spherical body with a Newtonian gravitational field are closed ellipses , which repeat the same path exactly and indefinitely, any non-spherical or non-Newtonian effects (such as caused by

774-562: A good angular resolution. It also benefits from a high technology readiness level and a modular design highly amenable to mass production necessary to achieve the unprecedented telescope collecting area. A movable mirror assembly can focus X-rays onto either one of Athena 's two instruments (WFI and X-IFU, see below) at any given time. Both the WFI and X-IFU successfully passed their Preliminary Requirements Reviews, on 31 October 2018 and 11 April 2019 respectively. The Wide Field Imager (WFI)

903-516: A high resolution X-ray spectrum, the defocussing capability of the Athena mirror will enable the focal beam to be spread over hundreds of sensors. The X-IFU will thus be able to observe very bright X-ray sources. It will do so either with the nominal resolution, e.g. for detecting the baryons thought to reside in the Warm Hot Intergalactic Medium , using bright gamma-ray burst afterglows, as background sources shining through

1032-492: A planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point . Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits , with the center of mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion . For most situations, orbital motion

1161-420: A practical sense, both of these trajectory types mean the object is "breaking free" of the planet's gravity, and "going off into space" never to return. In most situations, relativistic effects can be neglected, and Newton's laws give a sufficiently accurate description of motion. The acceleration of a body is equal to the sum of the forces acting on it, divided by its mass, and the gravitational force acting on

1290-518: A re-point manoeuvre within 4 hours for 50% of any randomly occurring events in the sky. The Athena X-ray observatory consists of a single X-ray telescope with a 12 m focal length , with an effective area of approx. 1.4 m (at 1 keV) and a spatial resolution of 5 arcseconds on-axis, degrading gracefully to less than 10 arcseconds at 30 arcminutes off-axis. The mirror is based on ESA's Silicon Pore Optics (SPO) technology. SPO provides an excellent ratio of collecting area to mass, while still offering

1419-507: 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

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1548-421: A sensitive X-ray space observatory. Its combination of scientific performance exceeds any existing or planned X-ray missions by over one order of magnitude on several parameter spaces: effective area, weak line sensitivity, survey speed, just to mention a few. Athena will perform very sensitive measurements on a wide range of celestial objects. It will investigate the chemical evolution of the hot plasma permeating

1677-456: A series of mechanical coolers, with interface temperatures at 15 K, 4 K and 2 K and 300 mK, pre-cooling a sub Kelvin cooler made of a 3He adsorption cooler coupled with an Adiabatic Demagnetization Refrigerator . Calibration data are acquired along with each observation from modulated X-ray sources to enable the energy calibration required to reach the targeted spectral resolution. Although an integral field unit where each and every pixel delivers

1806-410: A single point called the barycenter. The paths of all the star's satellites are elliptical orbits about that barycenter. Each satellite in that system will have its own elliptical orbit with the barycenter at one focal point of that ellipse. At any point along its orbit, any satellite will have a certain value of kinetic and potential energy with respect to the barycenter, and the sum of those two energies

1935-424: 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

2064-477: A target with an accuracy of 0.25 to 1 arcseconds . 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 Spectrometers (RGS), and an Optical Monitor. The spacecraft

2193-491: A technical sense—they are describing a portion of an elliptical path around the center of gravity—but the orbits are interrupted by striking the Earth. If the cannonball is fired with sufficient speed, the ground curves away from the ball at least as much as the ball falls—so the ball never strikes the ground. It is now in what could be called a non-interrupted or circumnavigating, orbit. For any specific combination of height above

2322-822: A technology that was new at the time of XMM-Newton 's development. The cameras were developed by OIC–Delft and IMEC , both of Belgium. 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

2451-402: A total collecting area of 4,425 cm (686 sq in) at 1.5 keV and 1,740 cm (270 sq in) at 8 keV. The mirrors range from 0.47 mm (0.02 in) thick for the innermost mirror to 1.07 mm (0.04 in) thick for the outermost mirror, and the separation between each mirror ranges from 1.5 to 4 mm (0.06 to 0.16 in) from innermost to outermost. Each mirror

2580-568: Is Prof. Kirpal Nandra, Director of the High-Energy Group at MPE. The X-ray Integral Field Unit is the cryogenic X-ray spectrometer of Athena X-IFU will deliver spatially resolved X-ray spectroscopy , with a spectral resolution requirement of 2.5 eV up to 7 keV over a hexagonal field of view of 5 arc minutes (equivalent diameter). The prime detector of X-IFU is made of a large format array of Molybdenum Gold transition-edge sensors coupled to absorbers made of Au and Bi to provide

2709-432: Is a 30 cm (12 in) Ritchey–Chrétien optical/ultraviolet telescope designed to provide simultaneous observations alongside the spacecraft's X-ray instruments. The OM is sensitive between 170 and 650 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 3.8 m (12 ft) and a focal ratio of ƒ/12.7. The instrument

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2838-505: Is a constant value at every point along its orbit. As a result, as a planet approaches periapsis , the planet will increase in speed as its potential energy decreases; as a planet approaches apoapsis , its velocity will decrease as its potential energy increases. There are a few common ways of understanding orbits: The velocity relationship of two moving objects with mass can thus be considered in four practical classes, with subtypes: Orbital rockets are launched vertically at first to lift

2967-528: Is a convenient approximation to take the center of mass as coinciding with the center of the more massive body. Advances in Newtonian mechanics were then used to explore variations from the simple assumptions behind Kepler orbits, such as the perturbations due to other bodies, or the impact of spheroidal rather than spherical bodies. Joseph-Louis Lagrange developed a new approach to Newtonian mechanics emphasizing energy more than force, and made progress on

3096-572: Is a large field of view spectral-imaging camera based on the unique Silicon DEPFET technology developed in the semiconductor laboratory of the Max Planck Society . The DEPFETs provide an excellent energy resolution (<170eV at 7keV), low noise, fast readout and high time resolution, with good radiation hardness. The instrument combines the Large Detector Array, which is optimized for a wide field of view observations over

3225-410: Is achieved by the addition of a second cryogenic detector underneath the prime focal plane array. This way non-X-ray events such as particles can be vetoed using the temporal coincidence of detecting energy in both detectors simultaneously. The focal plane array, the sensors and the cold front end electronics are cooled at a stable temperature less than 100 mK by a multi-stage cryogenic chain, assembled by

3354-418: Is adequately approximated by Newtonian mechanics , which explains gravity as a force obeying an inverse-square law . However, Albert Einstein 's general theory of relativity , which accounts for gravity as due to curvature of spacetime , with orbits following geodesics , provides a more accurate calculation and understanding of the exact mechanics of orbital motion. Historically, the apparent motions of

3483-407: Is adopted of taking the potential energy as zero at infinite separation, the bound orbits will have negative total energy, the parabolic trajectories zero total energy, and hyperbolic orbits positive total energy. An open orbit will have a parabolic shape if it has the velocity of exactly the escape velocity at that point in its trajectory, and it will have the shape of a hyperbola when its velocity

3612-464: Is also a vector. Because our basis vector r ^ {\displaystyle {\hat {\mathbf {r} }}} moves as the object orbits, we start by differentiating it. From time t {\displaystyle t} to t + δ t {\displaystyle t+\delta t} , the vector r ^ {\displaystyle {\hat {\mathbf {r} }}} keeps its beginning at

3741-419: Is composed of 1 mm (0.039 in) thick silicon carbide substrate covered with a 2,000- ångström (7.9 × 10 in) 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 Optical Monitor (OM)

3870-530: 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 −120 °C (−184 °F). They were developed and built by the University of Leicester Space Research Centre and EEV Ltd . The pn-CCD camera

3999-645: 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

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4128-556: Is formed by more than 800 members spread around the world . The ACO is meant to become a focal point to facilitate the scientific exchange between the Athena activities and the scientific community at large, and to disseminate the Athena science objectives to the general public. The main tasks of the ACO can be divided into three categories: The ACO is led by the Instituto de Física de Cantabria (CSIC-UC) . Further ACO contributors are

4257-404: Is greater than the escape velocity. When bodies with escape velocity or greater approach each other, they will briefly curve around each other at the time of their closest approach, and then separate, forever. All closed orbits have the shape of an ellipse . A circular orbit is a special case, wherein the foci of the ellipse coincide. The point where the orbiting body is closest to Earth is called

4386-854: Is led by the Max Planck Institute for Extraterrestrial Physics (DEU) with partners in Germany (ECAP, IAA Tübingen), Austria ( University of Vienna ), Denmark (DTU), France ( CEA Saclay , Strasbourg ), Italy ( INAF , Bologna , Palermo ), Poland (SRC PAS, NCAC PAS), the United Kingdom ( University of Leicester , Open University ), the United States ( Pennsylvania State University (Penn State), SLAC, Massachusetts Institute of Technology (MIT), SAO), Switzerland ( University of Geneva ), Portugal (IA), and Greece (Athens Observatory, University of Crete ). The principal investigator

4515-581: Is located in the plane using vector calculus in polar coordinates both with the standard Euclidean basis and with the polar basis with the origin coinciding with the center of force. Let r {\displaystyle r} be the distance between the object and the center and θ {\displaystyle \theta } be the angle it has rotated. Let x ^ {\displaystyle {\hat {\mathbf {x} }}} and y ^ {\displaystyle {\hat {\mathbf {y} }}} be

4644-637: 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 trackers . Surrounding this component is the Service Module , which carries various spacecraft support systems: computer and electric busses , consumables (such as fuel and coolant ), solar arrays ,

4773-427: Is similar to NASA 's Chandra X-ray Observatory , 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. 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 ,

4902-402: Is that it was able to account for the remaining unexplained amount in precession of Mercury's perihelion first noted by Le Verrier. However, Newton's solution is still used for most short term purposes since it is significantly easier to use and sufficiently accurate. Within a planetary system , planets, dwarf planets , asteroids and other minor planets , comets , and space debris orbit

5031-661: 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. 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 0.15 and 15 keV ( 82.7 to 0.83 ångströms ). Each camera contains

5160-815: Is transmitted to these ground stations in real time. Data is then forwarded to the European Space Astronomy Centre 's 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

5289-414: 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 2.5 to 0.35 keV ( 5 to 35 ångström ) 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

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5418-421: 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 36 cm (5.6 sq in). A radiator cools the camera to −90 °C (−130 °F). This system

5547-674: 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. 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,

5676-480: The Université de Genève , Max Planck Institute for Extraterrestrial Physics (MPE) and L'Institut de Recherche en Astrophysique et Planétologie (IRAP). Orbit This is an accepted version of this page In celestial mechanics , an orbit (also known as orbital revolution ) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around

5805-464: The apoapsis is that point at which they are the farthest. (More specific terms are used for specific bodies. For example, perigee and apogee are the lowest and highest parts of an orbit around Earth, while perihelion and aphelion are the closest and farthest points of an orbit around the Sun.) In the case of planets orbiting a star, the mass of the star and all its satellites are calculated to be at

5934-467: The eccentricities of the planetary orbits vary over time. Mercury , the smallest planet in the Solar System, has the most eccentric orbit. At the present epoch , Mars has the next largest eccentricity while the smallest orbital eccentricities are seen with Venus and Neptune . As two objects orbit each other, the periapsis is that point at which the two objects are closest to each other and

6063-453: The perigee , and when orbiting a body other than earth it is called the periapsis (less properly, "perifocus" or "pericentron"). The point where the satellite is farthest from Earth is called the apogee , apoapsis, or sometimes apifocus or apocentron. A line drawn from periapsis to apoapsis is the line-of-apsides . This is the major axis of the ellipse, the line through its longest part. Bodies following closed orbits repeat their paths with

6192-737: The three-body problem , discovering the Lagrangian points . In a dramatic vindication of classical mechanics, in 1846 Urbain Le Verrier was able to predict the position of Neptune based on unexplained perturbations in the orbit of Uranus . Albert Einstein in his 1916 paper The Foundation of the General Theory of Relativity explained that gravity was due to curvature of space-time and removed Newton's assumption that changes in gravity propagate instantaneously. This led astronomers to recognize that Newtonian mechanics did not provide

6321-446: The three-body problem ; however, it converges too slowly to be of much use. Except for special cases like the Lagrangian points , no method is known to solve the equations of motion for a system with four or more bodies. Rather than an exact closed form solution, orbits with many bodies can be approximated with arbitrarily high accuracy. These approximations take two forms: Differential simulations with large numbers of objects perform

6450-560: 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

6579-528: The EPIC MOS-CCD detectors were cooled from their initial operating temperature of −100 °C (−148 °F) to a new setting of −120 °C (−184 °F). 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

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6708-403: 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 90 cm (35 in), are 250 cm (98 in) in length, and have a base weight of 425 kg (937 lb). The two telescopes with Reflection Grating Arrays weigh an additional 20 kg (44 lb). Components of

6837-410: The Earth at the point half an orbit beyond, and directly opposite the firing point, below the circular orbit. At a specific horizontal firing speed called escape velocity , dependent on the mass of the planet and the distance of the object from the barycenter, an open orbit (E) is achieved that has a parabolic path . At even greater speeds the object will follow a range of hyperbolic trajectories . In

6966-495: The Focal Plane Assembly looking forward. The first is FUGA-15, a black and white camera with high dynamic range and 290 × 290 pixel resolution. The second is IRIS-1, a colour camera with a variable exposure time and 400 × 310 pixel resolution. Both cameras measure 6 × 6 × 10 cm (2.4 × 2.4 × 3.9 in) and weight 430 g (15 oz). They use active pixel sensors ,

7095-681: The Hot and Energetic Universe science theme. The scientific advice for the Athena mission is provided by the Athena Science Study Team (ASST) composed of expert scientists from the community. The ASST was appointed by ESA on 16 July 2014. The ESA Study Scientist and Study Manager are Dr Matteo Guainazzi and Dr Mark Ayre respectively. Athena completed successfully its Phase A with the Mission Formulation Review on 12 November 2019. The next key milestone will be

7224-638: The Hot and Energetic Universe scientific theme. Athena will operate in the energy range of 0.2–12 keV and will offer spectroscopic and imaging capabilities exceeding those of currently operating X-ray astronomy satellites – e.g. the Chandra X-ray Observatory and XMM-Newton – by at least one order of magnitude on several parameter spaces simultaneously. The primary goals of the mission are to map hot gas structures, determine their physical properties, and search for supermassive black holes . The mission has its roots in two concepts from

7353-646: The Netherlands. When direct sunlight is unavailable, power is provided by two nickel–cadmium batteries providing 24 A·h and weighing 41 kg (90 lb) each. The batteries were provided by SAFT of France. 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

7482-427: The Sun, their orbital periods respectively about 11.86 and 0.615 years. The proportionality is seen by the fact that the ratio for Jupiter, 5.2 /11.86 , is practically equal to that for Venus, 0.723 /0.615 , in accord with the relationship. Idealised orbits meeting these rules are known as Kepler orbits . Isaac Newton demonstrated that Kepler's laws were derivable from his theory of gravitation and that, in general,

7611-539: The Telescope Sun Shield, and two S-band antennas. Behind these units is the Telescope Tube , a 6.8-metre (22 ft) long, hollow carbon fibre structure which provides exact spacing between the mirrors and their detection equipment. This section also hosts outgassing equipment on its exterior, which helps remove any contaminants from the interior of the satellite. At the aft end of spacecraft

7740-412: The United Kingdom. Coarse spacecraft orientation and orbit maintenance is provided by two sets of four 20- newton (4.5  lb f ) 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

7869-470: The United States. More than 50 research institutes are involved in the X-IFU consortium. The principal investigator of X-IFU is Dr Didier Barret, Director of research at the research institute in astrophysics and planetology of Toulouse ( IRAP -OMP, CNRS UT3-Paul Sabatier/ CNES , France). Dr Jan-Willem den Herder ( SRON , The Netherlands) and Dr Luigi Piro ( INAF -IAPS, Italy) are co-principal investigators of

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7998-485: The X-IFU. CNES manages the project, and on behalf of the X-IFU consortium, is responsible for the delivery of the instrument to ESA. The "Hot and Energetic Universe" science theme revolves around two fundamental questions in astrophysics : How does ordinary matter assemble into the large-scale structures that we see today? And how do black holes grow and shape the Universe ? Both questions can only be answered using

8127-557: The X-ray contribution to the fleet of large-scale observational facilities to be operational in the 2030s (incl. SKA , ELT , ALMA , LISA ...). The Athena Science Study Team (ASST) established the Athena Community Office (ACO) to obtain support in performing its tasks assigned by ESA, and most especially in the ASST role as "a focal point for the interests of the broad scientific community". Currently, this community

8256-613: 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,

8385-403: The accelerations in the radial and transverse directions. As said, Newton gives this first due to gravity is − μ / r 2 {\displaystyle -\mu /r^{2}} and the second is zero. Equation (2) can be rearranged using integration by parts. We can multiply through by r {\displaystyle r} because it is not zero unless

8514-586: The aim of saving propellant to extend the spacecraft lifetime. In 2019 the fuel was predicted to last until 2030. Primary power for XMM-Newton is provided by two fixed solar arrays. The arrays are composed of six panels measuring 1.81 × 1.94 m (5.9 × 6.4 ft) for a total of 21 m (230 sq ft) and a mass of 80 kg (180 lb). 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

8643-462: The atmosphere, in an act commonly referred to as an aerobraking maneuver. As an illustration of an orbit around a planet, the Newton's cannonball model may prove useful (see image below). This is a ' thought experiment ', in which a cannon on top of a tall mountain is able to fire a cannonball horizontally at any chosen muzzle speed. The effects of air friction on the cannonball are ignored (or perhaps

8772-466: The calculations in a hierarchical pairwise fashion between centers of mass. Using this scheme, galaxies, star clusters and other large assemblages of objects have been simulated. The following derivation applies to such an elliptical orbit. We start only with the Newtonian law of gravitation stating that the gravitational acceleration towards the central body is related to the inverse of the square of

8901-545: The camera pixels . 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 −80 °C (−112 °F) down to −113 °C (−171 °F), and a few hours later to −115 °C (−175 °F). After analysing the results, it was determined the optimal temperature for both RGS units would be −110 °C (−166 °F), and during 13–14 November, both RGS-1 and RGS-2 were set to this level. During 6–7 November,

9030-486: The cameras to an operating temperature of −110 °C (−166 °F). 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

9159-517: The center of gravity and mass of the planet, there is one specific firing speed (unaffected by the mass of the ball, which is assumed to be very small relative to the Earth's mass) that produces a circular orbit , as shown in (C). As the firing speed is increased beyond this, non-interrupted elliptic orbits are produced; one is shown in (D). If the initial firing is above the surface of the Earth as shown, there will also be non-interrupted elliptical orbits at slower firing speed; these will come closest to

9288-407: The concurrent cosmological evolution of accreting black holes and galaxies. Among them are highly obscured and high-redshift (z≥6) AGN. Furthermore, Athena will be an X-ray observatory open to the whole astronomical community, poised to provide wide-ranging discoveries in almost all fields of modern astrophysics, with a large discovery potential of still unknown and unexpected phenomena. It represents

9417-459: The coordinate system at the center of the mass of the system. Energy is associated with gravitational fields . A stationary body far from another can do external work if it is pulled towards it, and therefore has gravitational potential energy . Since work is required to separate two bodies against the pull of gravity, their gravitational potential energy increases as they are separated, and decreases as they approach one another. For point masses,

9546-565: The cosmic web, or with a spectral resolution of 3–10 eV, e.g. for measuring the spins and characterizing the winds and outflows of bright X-ray binaries at energies where their spectral signatures are the strongest (above 5 keV). As of December 2018, when the X-IFU consortium was formally endorsed by ESA as being responsible for the procurement of the instrument to Athena , the X-IFU consortium gathered 11 European countries ( Belgium , Czech Republic , Finland , France, Germany, Ireland, Italy, Netherlands, Poland, Spain, Switzerland), plus Japan and

9675-683: The distance r {\displaystyle r} of the orbiting object from the center as a function of its angle θ {\displaystyle \theta } . However, it is easier to introduce the auxiliary variable u = 1 / r {\displaystyle u=1/r} and to express u {\displaystyle u} as a function of θ {\displaystyle \theta } . Derivatives of r {\displaystyle r} with respect to time may be rewritten as derivatives of u {\displaystyle u} with respect to angle. Plugging these into (1) gives So for

9804-434: The distance between them, namely where F 2 is the force acting on the mass m 2 caused by the gravitational attraction mass m 1 has for m 2 , G is the universal gravitational constant, and r is the distance between the two masses centers. From Newton's Second Law, the summation of the forces acting on m 2 related to that body's acceleration: where A 2 is the acceleration of m 2 caused by

9933-472: 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

10062-430: The early 2000s, XEUS of ESA and Constellation-X Observatory (Con-X) of NASA . Around 2008, these two proposals were merged into the joint NASA/ESA/JAXA International X-ray Observatory (IXO) proposal. In 2011, IXO was withdrawn and then ESA decided to proceed with a cost-reduced modification, which became known as ATHENA. Athena was selected in 2014 to become the second (L2) L-class Cosmic Vision mission, addressing

10191-473: The electroforming and final assembly were performed by Media Lario with contributions from Kayser-Threde . 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

10320-428: The entire analysis can be done separately in these dimensions. This results in the harmonic parabolic equations x = A cos ⁡ ( t ) {\displaystyle x=A\cos(t)} and y = B sin ⁡ ( t ) {\displaystyle y=B\sin(t)} of the ellipse. The location of the orbiting object at the current time t {\displaystyle t}

10449-680: The environment of supermassive black holes and mapping of the mysterious dark matter . In 1982, even before the launch of XMM-Newton 's 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

10578-637: The feasibility of such a mission, and mission objectives were presented at a workshop 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

10707-408: The force of gravitational attraction F 2 of m 1 acting on m 2 . Combining Eq. 1 and 2: Solving for the acceleration, A 2 : where μ {\displaystyle \mu \,} is the standard gravitational parameter , in this case G m 1 {\displaystyle Gm_{1}} . It is understood that the system being described is m 2 , hence

10836-417: The gravitational energy decreases to zero as they approach zero separation. It is convenient and conventional to assign the potential energy as having zero value when they are an infinite distance apart, and hence it has a negative value (since it decreases from zero) for smaller finite distances. When only two gravitational bodies interact, their orbits follow a conic section . The orbit can be open (implying

10965-490: The highest accuracy in understanding orbits. In relativity theory , orbits follow geodesic trajectories which are usually approximated very well by the Newtonian predictions (except where there are very strong gravity fields and very high speeds) but the differences are measurable. Essentially all the experimental evidence that can distinguish between the theories agrees with relativity theory to within experimental measurement accuracy. The original vindication of general relativity

11094-493: The intergalactic space in cluster of galaxies, search for elusive observational features of the Warm-Hot Intergalactic Medium , investigate powerful outflows ejected from accreting black holes across their whole mass spectrum, and study their impact on the host galaxy, and identify sizeable samples of comparatively rare populations of Active Galactic Nuclei (AGN)   that are key to understanding

11223-542: 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. 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

11352-498: 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. Feeding

11481-720: The mission adoption by ESA's Science Programme Committee (SPC) expected in 2023 , leading to launch in 2035. In 2023, the mission was rescoped as NewAthena, with launch date moved to 2037. In 2035, an Ariane 64   launch vehicle will lift Athena into a large amplitude halo orbit around the L 2 point of the Sun-Earth system . The orbit around L 2 was selected due to its stable thermal environment, good sky visibility, high observing efficiency, and stable particle background.  Athena will perform pre-planned scheduled observations of up to 300 celestial locations per year. A special Target of Opportunity mode will allow

11610-427: The model was capable of reasonably accurately predicting the planets' positions in the sky, more and more epicycles were required as the measurements became more accurate, hence the model became increasingly unwieldy. Originally geocentric , it was modified by Copernicus to place the Sun at the centre to help simplify the model. The model was further challenged during the 16th century, as comets were observed traversing

11739-504: The mountain is high enough that the cannon is above the Earth's atmosphere, which is the same thing). If the cannon fires its ball with a low initial speed, the trajectory of the ball curves downward and hits the ground (A). As the firing speed is increased, the cannonball hits the ground farther (B) away from the cannon, because while the ball is still falling towards the ground, the ground is increasingly curving away from it (see first point, above). All these motions are actually "orbits" in

11868-411: 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

11997-410: The object never returns) or closed (returning). Which it is depends on the total energy ( kinetic + potential energy ) of the system. In the case of an open orbit, the speed at any position of the orbit is at least the escape velocity for that position, in the case of a closed orbit, the speed is always less than the escape velocity. Since the kinetic energy is never negative if the common convention

12126-445: The on-board propulsion systems to fire a total of five times, which, between 10 and 16 December, changed the orbit to 7,365 × 113,774 km (4,576 × 70,696 mi) with a 38.9-degree inclination. This resulted in the spacecraft making one complete revolution 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,

12255-471: The orbital speed of each planet is not constant, as had previously been thought, but rather that the speed depends on the planet's distance from the Sun. Third, Kepler found a universal relationship between the orbital properties of all the planets orbiting the Sun. For the planets, the cubes of their distances from the Sun are proportional to the squares of their orbital periods. Jupiter and Venus, for example, are respectively about 5.2 and 0.723 AU distant from

12384-498: The orbiting object crashes. Then having the derivative be zero gives that the function is a constant. which is actually the theoretical proof of Kepler's second law (A line joining a planet and the Sun sweeps out equal areas during equal intervals of time). The constant of integration, h , is the angular momentum per unit mass . In order to get an equation for the orbit from equation (1), we need to eliminate time. (See also Binet equation .) In polar coordinates, this would express

12513-411: The orbits of bodies subject to gravity were conic sections (this assumes that the force of gravity propagates instantaneously). Newton showed that, for a pair of bodies, the orbits' sizes are in inverse proportion to their masses , and that those bodies orbit their common center of mass . Where one body is much more massive than the other (as is the case of an artificial satellite orbiting a planet), it

12642-421: The origin and rotates from angle θ {\displaystyle \theta } to θ + θ ˙   δ t {\displaystyle \theta +{\dot {\theta }}\ \delta t} which moves its head a distance θ ˙   δ t {\displaystyle {\dot {\theta }}\ \delta t} in

12771-614: 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 10 × 20 cm (4 × 8 in) grating

12900-627: The perpendicular direction θ ^ {\displaystyle {\hat {\boldsymbol {\theta }}}} giving a derivative of θ ˙ θ ^ {\displaystyle {\dot {\theta }}{\hat {\boldsymbol {\theta }}}} . We can now find the velocity and acceleration of our orbiting object. The coefficients of r ^ {\displaystyle {\hat {\mathbf {r} }}} and θ ^ {\displaystyle {\hat {\boldsymbol {\theta }}}} give

13029-477: The planets were described by European and Arabic philosophers using the idea of celestial spheres . This model posited the existence of perfect moving spheres or rings to which the stars and planets were attached. It assumed the heavens were fixed apart from the motion of the spheres and was developed without any understanding of gravity. After the planets' motions were more accurately measured, theoretical mechanisms such as deferent and epicycles were added. Although

13158-435: 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

13287-548: The radial and transverse polar basis with the first being the unit vector pointing from the central body to the current location of the orbiting object and the second being the orthogonal unit vector pointing in the direction that the orbiting object would travel if orbiting in a counter clockwise circle. Then the vector to the orbiting object is We use r ˙ {\displaystyle {\dot {r}}} and θ ˙ {\displaystyle {\dot {\theta }}} to denote

13416-442: The required stopping power. The pixel size corresponds to slightly less than 5 arc seconds on the sky, thus matching the angular resolution of the X-ray optics. A large part of the X-IFU related Athena science objectives relies on the observation of faint extended sources (e.g. hot gas in cluster of galaxies to measure bulk motions and turbulence or its chemical composition), imposing the lowest possible instrumental background. This

13545-408: The rocket above the atmosphere (which causes frictional drag), and then slowly pitch over and finish firing the rocket engine parallel to the atmosphere to achieve orbit speed. Once in orbit, their speed keeps them in orbit above the atmosphere. If e.g., an elliptical orbit dips into dense air, the object will lose speed and re-enter (i.e. fall). Occasionally a space craft will intentionally intercept

13674-516: The satellite, confirming the process had worked and that the satellite was back under control. 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

13803-531: The sensitive camera CCDs and associated electronics. The ERMS was built by the Centre d'Etude Spatiale des Rayonnements of France. 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

13932-509: The slight oblateness of the Earth , or by relativistic effects , thereby changing the gravitational field's behavior with distance) will cause the orbit's shape to depart from the closed ellipses characteristic of Newtonian two-body motion . The two-body solutions were published by Newton in Principia in 1687. In 1912, Karl Fritiof Sundman developed a converging infinite series that solves

14061-440: The smaller, as in the case of a satellite or small moon orbiting a planet or for the Earth orbiting the Sun, it is accurate enough and convenient to describe the motion in terms of a coordinate system that is centered on the heavier body, and we say that the lighter body is in orbit around the heavier. For the case where the masses of two bodies are comparable, an exact Newtonian solution is still sufficient and can be had by placing

14190-537: The spacecraft left Rotterdam for French Guiana aboard Arianespace 's transport ship MN Toucan . The Toucan docked at the French Guianese town of Kourou on 23 September, and was transported to Guiana Space Centre 's 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

14319-510: The spacecraft's Radio Frequency switch had failed. After troubleshooting a solution, ground controllers used NASA 's 34 m (112 ft) 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

14448-437: The spheres. The basis for the modern understanding of orbits was first formulated by Johannes Kepler whose results are summarised in his three laws of planetary motion. First, he found that the orbits of the planets in our Solar System are elliptical, not circular (or epicyclic ), as had previously been believed, and that the Sun is not located at the center of the orbits, but rather at one focus . Second, he found that

14577-730: The standard Euclidean bases and let r ^ = cos ⁡ ( θ ) x ^ + sin ⁡ ( θ ) y ^ {\displaystyle {\hat {\mathbf {r} }}=\cos(\theta ){\hat {\mathbf {x} }}+\sin(\theta ){\hat {\mathbf {y} }}} and θ ^ = − sin ⁡ ( θ ) x ^ + cos ⁡ ( θ ) y ^ {\displaystyle {\hat {\boldsymbol {\theta }}}=-\sin(\theta ){\hat {\mathbf {x} }}+\cos(\theta ){\hat {\mathbf {y} }}} be

14706-412: The standard derivatives of how this distance and angle change over time. We take the derivative of a vector to see how it changes over time by subtracting its location at time t {\displaystyle t} from that at time t + δ t {\displaystyle t+\delta t} and dividing by δ t {\displaystyle \delta t} . The result

14835-443: The subscripts can be dropped. We assume that the central body is massive enough that it can be considered to be stationary and we ignore the more subtle effects of general relativity . When a pendulum or an object attached to a spring swings in an ellipse, the inward acceleration/force is proportional to the distance A = F / m = − k r . {\displaystyle A=F/m=-kr.} Due to

14964-463: The system's barycenter in elliptical orbits . A comet in a parabolic or hyperbolic orbit about a barycenter is not gravitationally bound to the star and therefore is not considered part of the star's planetary system. Bodies that are gravitationally bound to one of the planets in a planetary system, either natural or artificial satellites , follow orbits about a barycenter near or within that planet. Owing to mutual gravitational perturbations ,

15093-511: 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. The Reflection Grating Spectrometers (RGS) are composed of two Focal Plane Cameras and their associated Reflection Grating Arrays. This system

15222-432: 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 600 mm (24 in) long and ranging in diameter from 306 to 700 mm (12.0 to 27.6 in), producing

15351-498: The way vectors add, the component of the force in the x ^ {\displaystyle {\hat {\mathbf {x} }}} or in the y ^ {\displaystyle {\hat {\mathbf {y} }}} directions are also proportionate to the respective components of the distances, r x ″ = A x = − k r x {\displaystyle r''_{x}=A_{x}=-kr_{x}} . Hence,

15480-626: 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. XMM-Newton is a 10.8-metre (35 ft) long space telescope, and is 16.16 m (53 ft) wide with solar arrays deployed. At launch it weighed 3,764 kilograms (8,298 lb). The spacecraft has three degrees of stabilisation, which allow it to aim at

15609-437: Was built by vapour-depositing a 250 nm layer of gold reflecting surface onto a highly polished aluminium mandrel , followed by electroforming a monolithic nickel support layer onto the gold. The finished mirrors were glued into the grooves of an Inconel 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 , and

15738-516: Was established at the University of Leicester 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 then by the barge Emeli to Rotterdam . On 12 September,

15867-544: 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 35-metre (115 ft) antenna in New Norcia, Western Australia , and communication with XMM-Newton suggested that

15996-621: Was formed in January 1993 and based at the European Space Research and Technology Centre (ESTEC) in Noordwijk , Netherlands. Prime contractor Dornier Satellitensysteme (a subsidiary of the former DaimlerChrysler Aerospace ) 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

16125-482: Was lofted into space aboard an Ariane 5 rocket, and placed into a highly elliptical, 40-degree orbit that had a perigee of 838 km (521 mi) and an apogee of 112,473 km (69,887 mi). 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

16254-500: 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 curves , which projects the number of X-rays that arrive over time and shows changes in the brightness of

16383-425: 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 € 689 million (1999 conditions). 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

16512-425: 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

16641-450: 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

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