View source for XEUS


{{short description|European X-ray space observatory}}
{{Use British English|date=March 2021}}
{{Use dmy dates|date=September 2019}}
{{other uses}}
{{Infobox spaceflight
| name              = X-ray Evolving Universe Spectroscopy
| names_list        = XEUS
| image             =
| image_caption     =
| image_size        =
| mission_type      = [[Space telescope]]
| operator          = [[European Space Agency]] (ESA)
| COSPAR_ID         =
| SATCAT            =
| website           =
| mission_duration  =
| launch_date       =
| launch_rocket     =
| launch_site       =
| launch_contractor =
| orbit_reference   = [[Lagrange point|L2 orbit]]
| instruments       = Wide-Field X-ray Imager (WFXI)
| insignia          =
| insignia_caption  =
| insignia_size     =
| programme         = '''[[Cosmic Vision]]'''
| previous_mission  = [[XMM-Newton]]
| next_mission      = [[Advanced Telescope for High-ENergy Astrophysics]] (ATHENA)
}}
'''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 [[Electronvolt|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&nbsp;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,  [[baryon]]s 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|Cosmic Vision programme]] of the European Space Agency.<ref>{{Cite web |title=New facility development underway for ATHENA telescope calibration |url=https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Shaping_the_Future/New_facility_development_underway_for_ATHENA_telescope_calibration |access-date=2024-02-21 |website=www.esa.int |language=en}}</ref>
== Recent developments ==
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 Observatory|Constellation-X]] (Con-X) projects.<ref name="Announcement">{{cite web|url=https://ixo.gsfc.nasa.gov/news/2008/ixo_announcement.html|title=Announcing the International X-ray Observatory (IXO)|publisher=NASA|date=24 July 2008|access-date=13 March 2021|archive-date=18 January 2017|archive-url=https://web.archive.org/web/20170118124903/https://ixo.gsfc.nasa.gov/news/2008/ixo_announcement.html|url-status=dead}}</ref> This proposed the start of a joint study for the [[International X-ray Observatory]] (IXO).<ref name="IXO">{{cite web|url=https://ixo.gsfc.nasa.gov/|title=The International X-Ray Observatory|publisher=NASA|date=2012|access-date=13 March 2021|archive-date=31 January 2017|archive-url=https://web.archive.org/web/20170131172251/https://ixo.gsfc.nasa.gov/|url-status=dead}}</ref>
== See also ==
{{Portal|Spaceflight}}
* [[Calorimeter]]
== References ==
{{Reflist|30em}}
== External links ==
* [https://web.archive.org/web/20020306060837/http://xeus.esa.int/ ESA International X-Ray Observatory Mission Site]
* [https://web.archive.org/web/20110714090712/http://www.micronit.com/en/about_us/news.php?BasicNieuwsItemID=103 Press Release] Micronit and Cosine Develop Next-Generation ESA X-ray Telescope
* [http://ixo.gsfc.nasa.gov/ NASA International X-Ray Observatory Mission Site] {{Webarchive|url=https://web.archive.org/web/20120814083958/http://ixo.gsfc.nasa.gov/ |date=14 August 2012 }}
{{ESA projects}}
{{Space observatories}}
{{DEFAULTSORT:Xeus}}
[[Category:European Space Agency space probes]]
[[Category:Cancelled spacecraft]]
[[Category:Space telescopes]]
[[Category:X-ray telescopes]]