Far Ultraviolet Spectroscopic Explorer 939966 220931964 2008-06-22T07:49:07Z DOI bot 6652755 Citation maintenance. Initiated by [[User:Fconaway|Fconaway]]. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. {{Infobox Space telescope |name = Far Ultraviolet Spectroscopic Explorer (FUSE) |image = [[Image:FUSE prelaunch crop.jpg|250px|FUSE in a pre-launch clean room]] |caption = FUSE in a pre-launch [[clean room]] |organization = [[Johns Hopkins University|Johns Hopkins]]&nbsp;[[Applied Physics Laboratory|APL]]{{\}}[[NASA]] |major_contractors = |alt_names = Explorer 77<br/>MIDEX/FUSE<br/>25791 (NORAD ID)<ref name="nssdc-master"/> |nssdc_id = 1999-035A<ref name="nssdc-master"/> |location = |orbit_type = Circular [[low Earth orbit]] |height = 746&nbsp;[[Kilometre|km]] (402.8&nbsp;[[Nautical mile|nmi]]) to 760&nbsp;km (410.4&nbsp;nmi){{lower|0.2em|<ref name="n2yo-25791"/>}} |period = 99.9 minutes<ref name="n2yo-25791"/> |velocity = |accel_gravity = |launch_date = [[June 24]], [[1999]] at 15:44&nbsp;[[Coordinated Universal Time|UTC]]<ref name="nssdc-launch"/> |launch_location = [[Cape Canaveral]]<br/>[[Florida]], [[United States|USA]]<ref name="nssdc-launch"/> |launch_vehicle = [[Delta II|Delta II 7320]]<ref name="nssdc-launch"/> |mission_length = Three years (design){{lower|0.2em|<ref name="nssdc-master"/>}}<br/>Eight years (actual){{lower|0.2em|<ref name="sr25334"/>}} |deorbit_date = |wavelength = 90.5 to 119.5&nbsp;[[Nanometre|nm]]<ref name="nssdc-master"/> |mass = 1400&nbsp;[[Kilogram|kg]] (3086.5&nbsp;[[Pound (mass)|lb]])<ref name="nssdc-master"/> |style = Far [[ultraviolet]]<ref name="nssdc-master"/> |diameter = |area = |focal_length = |coolant = |website = http://fuse.pha.jhu.edu/ |as_of = September 2007 |stats_ref = <!-- --><ref name="nssdc-master">{{cite web |url=http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1999-035A |title=NSSDC Master Catalog Display: Spacecraft |work=NASA.gov |date=[[2007-05-18]] |accessdate=2007-09-07}}</ref> <!-- --><ref name="nssdc-launch">{{cite web |url=http://nssdc.gsfc.nasa.gov/nmc/tmp/1999-035A-traj.html |title=NSSDC Master Catalog Display: Spacecraft Launch/Orbital Information |work=NASA.gov |date=[[2007-05-18]] |accessdate=2007-09-07}}</ref> <!-- --><ref name="sr25334">{{cite web |url=http://www.spaceref.com/news/viewsr.html?pid=25334 |title=ROSES-07 Amendment 20: Cancel FUSE Legacy Science Program |work=Spaceref.com |author=NASA HQ |date=[[2007-09-06]] |accessdate=2007-09-07}}</ref> <!-- --><ref name="n2yo-25791">{{cite web |url=http://www.n2yo.com/satellite.php?s=25791 |title=FUSE 1 Satellite details |work=N2YO.com |accessdate=2007-09-07}}</ref> }} The '''Far Ultraviolet Spectroscopic Explorer''' ('''FUSE''') is a space-based [[telescope]] operated by the [[Johns Hopkins University]] [[Applied Physics Laboratory]]. ''FUSE'' was launched on a [[Delta II]] rocket on [[June 24]], [[1999]], as a part of [[NASA]]'s [[Origins program]]. ''FUSE'' detected light in the far [[ultraviolet]] portion of the electromagnetic spectrum, between 90.5-119.5&nbsp;[[nanometre]]s, which is mostly unobservable by other telescopes. Its primary mission was to characterize universal [[deuterium]] in an effort to learn about the stellar processing times of deuterium left over from the [[Big Bang]]. ''FUSE'' resides in a [[low Earth orbit]], approximately 760&nbsp;[[kilometre|km]] (410&nbsp;[[nautical mile|nmi]]) in altitude, with an inclination of 25&nbsp;degrees and just less than a 100 minute orbital period. Its [[Explorer program|Explorer]] designation is ''Explorer 77''. On [[July 12]], [[2007]], ''FUSE'''s final [[momentum wheel|reaction wheel]], which is required for accurately pointing a spacecraft, failed and efforts to restart it were unsuccessful. An announcement was made on [[September 6]] that because the fine control needed to perform its mission had been lost, the ''FUSE'' mission would be terminated.<ref name="sr25334"/> == Optical design == Although the original specification was to have a [[Wolter telescope |Wolter]]-type grazing incidence telescope,<ref name="ia7-1">{{cite journal |url=http://adsabs.harvard.edu/abs/1994SPIE.2011...34K |title=Optical design of Lyman/FUSE |journal=Instrumentation in Astronomy VII |first=David A. |last=Content |coauthors=et al |month=July |year=1990 |pages=pp. 943–952 |doi=10.1117/12.19157 |volume=1235}}</ref> the final design of the ''FUSE'' telescope comprises four individual mirrors. Each of the four mirrors is a 39-by-35&nbsp;[[centimetre|cm]] (15.4-by-13.8&nbsp;[[inch|in]]) off-axis parabola. Two mirror segments are coated with [[silicon carbide]] for reflectivity at the shortest ultraviolet wavelengths, and two mirror segments are coated with [[lithium fluoride]] over [[aluminum]] that reflects better at longer wavelengths. This optimizes performance over the entire spectral range.<ref name="nssdc-master"/> Each mirror has a corresponding [[astigmatism]]-corrected, [[holography|holographically]]-ruled [[diffraction grating]], each one on a curved substrate so as to produce four 1.65&nbsp;[[metre|m]] (5.4&nbsp;[[foot (unit of length)|ft]]) [[Henry Augustus Rowland|Rowland]] circle [[spectrograph]]s. The dispersed ultraviolet light is detected by two [[microchannel plate detector|microchannel plate]] intensified double delay-line detectors, whose surfaces are curved to match the curvature of the focal plane.<ref name="fuse-aas95">{{cite web |url=http://fuse.pha.jhu.edu/papers/technical/aas95/aas95.html |title=The Far Ultraviolet Spectroscopic Explorer Mission |work=JHU.edu |first=D.J. |last=Sahnow |coauthors=et al |date=[[1995-07-03]] |accessdate=2007-09-07}}</ref> == Science results == Over 400 scientific papers have been written using data from ''FUSE'',<ref name="fuse-pub">{{cite web |url=http://fuse.pha.jhu.edu/~awf/fusepubs/JHU/ |title=FUSE Publications |work=JHU.edu |accessdate=2007-09-07}}</ref> with subjects ranging from cool stars to the intergalactic medium. One of the primary science goals of ''FUSE'' was to study the abundance of deuterium, an isotope of [[hydrogen]]. Because of the large number of atomic absorption and emission lines in the far-ultraviolet, ''FUSE'' enabled many studies of galactic, extragalactic and intergalactic chemistry and chemical evolution. == References == {{reflist}} == External links == * [http://fuse.pha.jhu.edu/ ''FUSE'' website] at Johns Hopkins University * [http://www2.iap.fr/Fuse/ ''FUSE'' website] at Institut d'Astrophysique de Paris * [http://archive.stsci.edu/fuse ''FUSE'' archive] at Multimission Archive at STScI (MAST) {{Space telescopes}} {{Explorer program}} [[Category:1999 in space exploration]] [[Category:2007 disestablishments]] [[Category:Artificial satellites currently orbiting Earth]] [[Category:Explorer program]] [[Category:Space telescopes]] [[Category:Ultraviolet telescopes]] [[de:Far Ultraviolet Spectroscopic Explorer]] [[fr:Télescope spatial FUSE]] [[zh:远紫外分光探测器]]