ESA's X-ray space observatory XMM-Newton is unique. It is the biggest scientific satellite ever built in Europe, its telescope mirrors are amongst the most powerful ever developed in the world, and with its sensitive cameras it can see much more than any previous X-ray satellite.
Since Earth's atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is made available to the scientific community who apply to the regular announcements of opportunity on a competitive basis.
The mission was initially known as XMM after its X-ray Multi-Mirror design, and was formally called the High Throughput X-ray Spectroscopy Mission because of its great capacity to detect X-rays. The name was later modified to XMM-Newton in honour of Sir Isaac Newton.
Announcing the new name on 9 February 2000, ESA's former Director of Science Prof. Roger Bonnet explained: "We have chosen this name because Sir Isaac Newton was the man who invented spectroscopy and XMM is a spectroscopy mission. The name of Newton is associated with the falling apple, which is the symbol of gravity and with XMM I hope that we will find a large number of black hole candidates which are of course associated with the theory of gravity. There was no better choice than XMM-Newton for the name of this mission".
XMM-Newton is a three-axis stabilised spacecraft with a pointing accuracy of one arcsec. The satellite, which had a launch mass of 3.8 tonnes, is made up of: a service module bearing the three X-ray mirror modules, propulsion and electrical systems, a long telescope tube and the focal plane assembly carrying the science instruments.
The total length of XMM-Newton is 10 metres, and its solar arrays give the satellite a 16 metres span. The Prime contractor Dornier Satellitensysteme (Friedrichshafen, Germany - part of DaimlerChrysler Aerospace) led an industrial consortium involving 46 companies from 14 European countries and one in the United States. Media Lario, Como, Italy, developed the X-ray mirror modules. Although the nominal mission was for two years, XMM-Newton has been designed and built to perform well beyond that period. Mission operations have been extended until end-2025, with a mid-term review in 2022.
There are three main scientific instruments on board XMM-Newton:
The European Photon Imaging Camera (EPIC)
The Reflection Grating Spectrometer (RGS)
The Optical Monitor (OM)
In addition, XMM-Newton is equipped with a particle detector, the EPIC Radiation Monitor System (ERMS), developed by the Centre d'Etude Spatiale des Rayonnements (CESR) in Toulouse, France. Its role is to measure the radiation levels in the Earth's radiation belts and from solar flares; this radiation can perturb the sensitive CCD detectors of the main science instruments.
|Spacecraft X-ray optics||Cover a spectral range of 1 - 120 Å (12 keV - 0.15 keV)|
|Telescope||Consists of three barrel-shaped mirror modules, each containing 58 "Wolter-type I" wafer-thin concentric mirrors, 0.3 metres to 0.7 metres in diameter and 0.6 metres in length|
|Total collecting area||Is 4650 cm² at 1.5 keV (1550 cm² for each telescope), about 1800 cm² at 8 keV (600 cm² for each telescope).|
|Telescope||Focal length is 7.5 m
Resolution is about 5 arcsec (full width half-maximum), and about 14 arcsec (half energy width), at all wavelengths
|Each X-ray mirror module||Weight 500 kg|
XMM-Newton was launched on an Ariane 5 on 10 December 1999, at 14:32 UT, from Kourou, French Guiana. After launch, the spacecraft was placed into a 48-hour elliptical orbit around the Earth, with an inclination of 40°, a Southern apogee at an altitude of 114 000 km, and a perigee altitude of 7000 km. The orbital parameters evolve as the mission progresses. As an example, the perigee altitude has varied between 6000 km and 22 000 km, while the apogee altitude has varied between 99 000 km and 115 000 km. However, the orbital period is always kept at 48 hours.
The XMM-Newton spacecraft is controlled by the Mission Operations Centre (MOC) at the European Space Operations Centre (ESOC) in Darmstadt, Germany, using ground stations at Perth (Australia) and Kourou (French Guiana), with of number of back-up ground stations. The Science Operations Centre (SOC), located at the European Space Astronomy Centre (ESAC) in Villanueva de la Cañada, near Madrid, Spain, manages observation requests, scientific mission planning and data analysis and also receives, processes, delivers and archives XMM-Newton science data. The XMM-Newton Survey Science Centre, a consortium of several European institutes, correlates all XMM-Newton observations with existing sky data from other observatories and compiles the catalogue of detected X-ray sources.