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Universe X-rayed and British science honoured
Universe X-rayed and British science honoured
Keywords: X-ray, Cameras
The first X-ray pictures of the Universe taken by Europe's XMM spacecraft have been received following successful commissioning of the spacecraft's telescopes. At the same time the spacecraft has been renamed "XMM-Newton Observatory" in honour of Sir Isaac Newton, the renowned British mathematician and astronomer.
"These first pictures are tremendously exciting", said Dr Martin Turner of Leicester University, lead scientist on the spacecraft's main X-ray camera, "especially after we have worked for so many years on the project". All three European Photon Imaging Cameras (EPIC) were used to take several X-ray views of two different extra-galactic regions of the Universe, chosen to demonstrate the full functioning of the space observatory.
Dr Martin Turner explained, "In the Large Magellenic Cloud we can clearly see the elements that make up stars and planets being released in giant stellar explosions of enormous energy. This is what we built the EPIC cameras for and they are really fulfilling their purpose".
Commenting on the renaming of the space telescope, Professor Ian Halliday, CEO of the Particle Physics and Astronomy Research Council, the UK's strategic science investment agency, said, "This is a great honour for British science. The UK is involved in all three instruments on XMM and provides the lead scientist on two, clear recognition of the continuing contribution the UK is making to world science".
The Minister for Science, Lord Sainsbury, said, "I am delighted by the initial success of this project, which is of great scientific importance and in which the UK has played such a leading role. The XMM is an excellent example of what can result when European knowledge, people and resources are pooled together. It is a flagship for European space science".
The spacecraft also has an optical camera built by the UK's Mullard Space Science laboratory, which simultaneously took shots of the same area imaged by the X-ray cameras. Inspection of these first images immediately showed unique X-ray views of several celestial objects. Following calibration and performance verification of the spacecraft's instruments in March a full scientific observing programme will begin.
Lord Sainsbury added, "XMM will bring exciting information back to us, measuring and recording the hottest and fastest moving objects in the Universe, including exploding stars and black holes. It will also allow us to see the most distant objects in the Universe and look further back in time than has ever been possible until now. Space science of this calibre amply justifies our commitment to this field of research and our priorities for space - developing technologies to exploit new commercial markets and to excel in science".
ESA's X-ray space observatory is unique. It is the biggest science satellite ever built in Europe, its X-ray telescopes are the most powerful ever developed in the world, and with its sensitive cameras it will see infinitely more than any previous X-ray satellite.
Since the Earth's atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton Observatory will help scientists solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time is being made available to the scientific community, applying for observational periods on a competitive basis.
The mission derives its name from its X-ray multi-mirror design. It also honours Sir Isaac Newton, the English physicist and mathematician (1642-1727) who advanced the principal theories of gravitation and optics and who also made the first working reflecting telescope. The mission was initially called the High Through-put X-ray Spectroscopy Mission because of its great capacity to detect X-rays.
XMM-Newton is a three-axis stabilised spacecraft with a pointing accuracy of 1 arcsec. Launch mass was 3.8 tonnes. The satellite comprises a service module bearing the X-ray mirror modules, propulsion and electrical systems, a long telescope tube, and the focal plane assembly carrying the science instruments. Total length is 10m, and with its solar arrays the satellite has a 16m span.
The prime contractor Domier Satellitensysteme (Friedrichshafen, Germany - part of DaimlerChrysler Aerospace) leads an industrial consortium involving 46 companies from 14 European countries and one in the USA. Media Lario, Como, Italy, developed the X-ray mirror modules.
Although the nominal mission is for two years, XMM has been designed to operate for ten years.
The spacecraft X-ray optics cover a spectral range of 1-120 nanometres (0.1keV-12keV). The telescope consists of three barrel-shaped mirror modules, each containing 58 "Wolter-type" wafer-thin concentric mirrors, 0.3m to 0.7m in diameter and 0.6m in length. The total collecting area is 4,300cm2 at 1.5keV, 1,800cm2 at 8keV. The focal length of the telescope is 7.5m and resolution is 5 arcsec (full width half-maximum), 14 arcsec (half energy width) at all wavelengths. Each X-ray mirror module has a mass of 500kg.
XMM-Newton carries three main science instruments:
The three European photon imaging cameras (EPIC) produced by a consortium made up of ten institutes in four nations: the UK, Germany, Italy, and France. EPIC principal investigator is Professor Martin Turner of the X-ray Astronomy Group at Leicester University, UK. One of the cameras uses a new type of CCD (PN) developed by the Max Planck Institute of Extraterrestrial Physics in Garching, Germany.
The two reflection grating spectrometers (RGS). The principal investigator is Professor Bert Brinkman of the High-Energy Astronomy division SRON, Utrecht, The Netherlands, with co-investigator Steven Kahn from Columbia University, NY, USA.
The optical monitor, co-aligned with the main X-ray telescope, will give the mission a multi-wavelength capacity. The Mullard Space Science Laboratory (MSSL) UK has supplied this 30cm aperture Richtey-Chre¨tien telescope (with a 170-600 nanometre spectral range). OM principal investigator is Professor Keith Mason.
In addition, XMM 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, radiation that might perturb the sensitive CCD detectors of the main science instruments.
The XMM-Newton spacecraft was launched on 10 December 1999 by Arianespace on the first Ariane 5 commercial mission. It was then placed in a 48-hour elliptical orbit around the Earth. Inclined at 40 degrees with a Southern apogee at 114,000km, the perigee altitude is 7,000km. On each revolution, after the satellite has passed through the Earth's radiation belts, astronomers have the observatory at their disposal for some 40 hours.
The spacecraft has an operational lifetime of two to ten years. It is being controlled by the European Space Operations Centre (ESOC, Darmstadt Germany) using ground stations at Perth (Australia) and Kourou (French Guiana).
The XMM-Newton Science Operations Centre situated at VILSPA in Villafranca, Spain is managing observation requests, receiving, processing and distributing XMM data. The XMM Survey Science Centre (SSC), at Leicester University UK, is processing, archiving and correlating all XMM observations with existing sky data held elsewhere in the world.
Programme history and cost
XMM-Newton is the second Cornerstone mission of ESA's long-term Space Science programme. It was proposed by the Agency's Science Programme Committee in 1984 and was approved by the ESA Council of Ministers held in Rome in January 1985.
After the constitution in January 1993 of the XMM Project team based at the ESTEC Technical Centre in Noordwijk, The Netherlands, and selection of the prime contractor in October 1994, the development phase began in March 1996 and effective construction of the spacecraft started in March 1997.
With the end of satellite integration and testing in September 1999, the programme was completed in a remarkably short time for such a major space mission which ventured into industrial production processes never before explored.
The project, under direct ESA management, was achieved within the allocated budget of 689 million Euro at 1999 economic conditions (covering satellite design and construction, launch by Ariane 5 and science mission operations during two years).