| Names | XEUS |
|---|---|
| Mission type | Space telescope |
| Operator | European Space Agency (ESA) |
| Orbital parameters | |
| Reference system | L2 orbit |
| Instruments | |
| Wide-Field X-ray Imager (WFXI) | |
XEUS (X-ray Evolving Universe Spectroscopy) was a space observatory plan developed by the European Space Agency (ESA) as a successor to the successful XMM-Newton X-ray satellite telescope. It was merged to the International X-ray Observatory (IXO) around 2008, but as that project ran into issues in 2011, the ESA component was forked off into Advanced Telescope for High Energy Astrophysics (Athena).
XEUS consisted of a mirror spacecraft that carried a large X-ray telescope, with a mirror area of about 5 m² and an imaging resolution better than 5 arcsec; for X-ray radiation with an energy of 1 keV. A detector spacecraft would have flown in formation with the telescope at a distance of approximately 50 m, in the focus of the telescope. The detectors would have included a wide-field X-ray imager with an energy resolution of 150 eV at 6 keV, as well as a cryogenic narrow-field imager with an energy resolution of 2 eV at 1 keV.
XEUS could have measured the X-ray spectrum and thereby the composition, temperature and velocities of hot matter in the early universe. It would address diverse questions like the origin and nature of black holes, their relation with star formation, baryons evolution, and the formation of the heavy elements in the Universe.
The technology required for the follow-on project of XEUS, the International X-ray Observatory, eventually leading to Advanced Telescope for High Energy Astrophysics (Athena) which is currently under development. XEUS was one of the candidates for the Cosmic Vision programme of the European Space Agency.
In May 2008, ESA and NASA established a coordination group involving three agencies - ESA, NASA and JAXA - with the intent of exploring a joint mission merging the ongoing XEUS and Constellation-X (Con-X) projects. [1] This proposed the start of a joint study for the International X-ray Observatory (IXO). [2]
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 Space ShuttleColumbia during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, enabled by the high angular resolution of its mirrors. Since the Earth's atmosphere absorbs the vast majority of X-rays, they are not detectable from Earth-based telescopes; therefore space-based telescopes are required to make these observations. Chandra is an Earth satellite in a 64-hour orbit, and its mission is ongoing as of 2023.
XMM-Newton, also known as the High Throughput X-ray Spectroscopy Mission and the X-ray Multi-Mirror Mission, is an X-ray space observatory 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 programme. Named after physicist and astronomer Sir Isaac Newton, 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 wavelengths.
NASA's series of Great Observatories satellites are four large, powerful space-based astronomical telescopes launched between 1990 and 2003. They were built with different technology to examine specific wavelength/energy regions of the electromagnetic spectrum: gamma rays, X-rays, visible and ultraviolet light, and infrared light.
The Herschel Space Observatory was a space observatory built and operated by the European Space Agency (ESA). It was active from 2009 to 2013, and was the largest infrared telescope ever launched until the launch of the James Webb Space Telescope in 2021. Herschel carries a 3.5-metre (11.5 ft) mirror and instruments sensitive to the far infrared and submillimetre wavebands (55–672 µm). Herschel was the fourth and final cornerstone mission in the Horizon 2000 programme, following SOHO/Cluster II, XMM-Newton and Rosetta.
Reuven Ramaty High Energy Solar Spectroscopic Imager was a NASA solar flare observatory. It was the sixth mission in the Small Explorer program (SMEX), selected in October 1997 and launched on 5 February 2002, at 20:58:12 UTC. Its primary mission was to explore the physics of particle acceleration and energy release in solar flares.
The Constellation-X Observatory was a mission concept for an X-ray space observatory to be operated by NASA; in 2008 it was merged with ESA and JAXA efforts in the same direction to produce the International X-ray Observatory project, announced on 24 July 2008.
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 including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies, and supernova remnants.
The INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) is a space telescope for observing gamma rays of energies up to 8 MeV. It was launched by the European Space Agency (ESA) into Earth orbit in 2002, and is designed to provide imaging and spectroscopy of cosmic sources. In the MeV energy range, it is the most sensitive gamma ray observatory in space. It is sensitive to higher energy photons than X-ray instruments such as NuSTAR, the Neil Gehrels Swift Observatory, XMM-Newton, and lower than other gamma-ray instruments such Fermi and HESS.
An X-ray telescope (XRT) is a telescope that is designed to observe remote objects in the X-ray spectrum. In order to get above the Earth's atmosphere, which is opaque to X-rays, X-ray telescopes must be mounted on high altitude rockets, balloons or artificial satellites.
The International Astrophysical Observatory "GRANAT", was a Soviet space observatory developed in collaboration with France, Denmark and Bulgaria. It was launched on 1 December 1989 aboard a Proton rocket and placed in a highly eccentric four-day orbit, of which three were devoted to observations. It operated for almost nine years.
Hitomi, also known as ASTRO-H and New X-ray Telescope (NeXT), was an X-ray astronomy satellite commissioned by the Japan Aerospace Exploration Agency (JAXA) for studying extremely energetic processes in the Universe. The space observatory was designed to extend the research conducted by the Advanced Satellite for Cosmology and Astrophysics (ASCA) by investigating the hard X-ray band above 10 keV. The satellite was originally called New X-ray Telescope; at the time of launch it was called ASTRO-H. After it was placed in orbit and its solar panels deployed, it was renamed Hitomi. The spacecraft was launched on 17 February 2016 and contact was lost on 26 March 2016, due to multiple incidents with the attitude control system leading to an uncontrolled spin rate and breakup of structurally weak elements.
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 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.
Gamma-ray astronomy is the astronomical observation of gamma rays, the most energetic form of electromagnetic radiation, with photon energies above 100 keV. Radiation below 100 keV is classified as X-rays and is the subject of X-ray astronomy.
An X-ray astronomy satellite studies X-ray emissions from celestial objects, as part of a branch of space science known as X-ray astronomy. Satellites are needed because X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites.
The International X-ray Observatory (IXO) is a cancelled X-ray telescope that was to be launched in 2021 as a joint effort by NASA, the European Space Agency (ESA), and the Japan Aerospace Exploration Agency (JAXA). In May 2008, ESA and NASA established a coordination group involving all three agencies, with the intent of exploring a joint mission merging the ongoing XEUS and Constellation-X Observatory (Con-X) projects. This proposed the start of a joint study for IXO. NASA was forced to cancel the observatory due to budget constraints in fiscal year 2012. ESA however decided to reboot the mission on its own developing Advanced Telescope for High Energy Astrophysics as a part of Cosmic Vision program.
The X-Ray Imaging and Spectroscopy Mission, formerly the X-ray Astronomy Recovery Mission (XARM), is an X-ray space telescope mission of the Japan Aerospace Exploration Agency (JAXA) in partnership with NASA to provide breakthroughs in the study of structure formation of the universe, outflows from galaxy nuclei, and dark matter. As the only international X-ray observatory project of its period, XRISM will function as a next generation space telescope in the X-ray astronomy field, similar to how the James Webb Space Telescope, Fermi Space Telescope, and the Atacama Large Millimeter Array (ALMA) Observatory are placed in their respective fields.
The Lynx X-ray Observatory (Lynx) is a NASA-funded Large Mission Concept Study commissioned as part of the National Academy of Sciences 2020 Astronomy and Astrophysics Decadal Survey. The concept study phase is complete as of August 2019, and the Lynx final report has been submitted to the Decadal Survey for prioritization. If launched, Lynx would be the most powerful X-ray astronomy observatory constructed to date, enabling order-of-magnitude advances in capability over the current Chandra X-ray Observatory and XMM-Newton space telescopes.
Imaging X-ray Polarimetry Explorer, commonly known as IXPE or SMEX-14, is a space observatory with three identical telescopes designed to measure the polarization of cosmic X-rays of black holes, neutron stars, and pulsars. The observatory, which was launched on 9 December 2021, is an international collaboration between NASA and the Italian Space Agency (ASI). It is part of NASA's Explorers program, which designs low-cost spacecraft to study heliophysics and astrophysics.
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 succeeded the Horizon 2000 Plus campaign and envisioned a number of missions in the fields of astronomy and solar system exploration beyond 2015. Ten missions across four funding categories are planned to be launched under Cosmic Vision, with the first being CHEOPS in December 2019. A mission to the Galilean moons (JUICE), the first deep space mission with an opportunistic target, and one of the first gravitational-wave space observatories (LISA), are planned for launch as part of the Cosmic Vision campaign.
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