International Ultraviolet Explorer

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IUE (Explorer 57)
IUE (Explorer 57)
Type: Space telescope
Country: United StatesUnited States United States
Operator: National Aeronautics and Space AdministrationNASA NASA ESA SERC
European space agencyESA 
COSPAR-ID : 1978-012A
Mission dates
Dimensions: 672 kg
Begin: January 26, 1978, 17:36 UTC
Starting place: Cape Canaveral , LC-17A
Launcher: Delta 2914
Status: Switched off on 09/30/1996, 18:42 UTC
Orbit data
Rotation time : 24 hours
Orbit inclination : 32.7 °
Eccentricity : 0.24

The International Ultraviolet Explorer ( IUE ), also Explorer 57 , was a space telescope for astronomical observations in the ultraviolet range of electromagnetic radiation.


IUE was a joint project of NASA , ESA and the UK SERC and was launched into geosynchronous orbit on January 26, 1978 with a Delta 2914 rocket . Instead of the originally planned three to five years, IUE was in operation until September 30, 1996. By then, four of the original six control gyroscopes had failed, but the telescope was still operational with reduced efficiency. The final failure of the control elements was not waited for, IUE was previously taken out of service, essentially for financial reasons, by being switched off by radio command in September 1996. It was one of the most successful and effective space telescopes.

Launch of IUE on a Delta rocket


IUE had a relatively small telescope with a primary mirror diameter of 45 cm. IUE did not have a camera, the instruments were two spectrographs for wavelengths between 115 and 320 nm with a spectral resolution of 0.01 nm and 0.6 nm respectively. Over 104,000 spectra of various astronomical objects were obtained. IUE was operated from two ground stations in the US and Spain. In contrast to many other space telescopes, it could be controlled directly by the observing astronomers .

A variety of questions were investigated with the spectra of IUE, for example

As an ultraviolet observatory, IUE was the direct forerunner of the Hubble space telescope .

Individual evidence

  1. ^ Explorer: IUE. Gunter's Space Page, December 11, 2017, accessed January 5, 2018 .

Web links

Commons : International Ultraviolet Explorer  - collection of images, videos and audio files