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IUE

IUE mission graphic

International Ultraviolet Explorer

Phase: Past

Launch Date: January 26, 1978

Mission Project Home Page - http://archive.stsci.edu/iue/

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The IUE satellite was launched on January 26, 1978. It had an expected lifetime of 3 years, with a goal of 5 years, but exceeded that beyond anyone's wildest dreams. When it was shut down on September 30, 1996, it had been in continuous operation for 18 years and 9 months.

IUE was an international collaboration between three groups: NASA, the European Space Agency (ESA), and the United Kingdom's Science and Engineering Research Council (SERC; now Particle Physics and Astronomy Research Council, or PPARC ). NASA provided the launch, spacecraft engineering support and software. ESA provided the solar panels and a satellite command station outside of Madrid, Spain, and the UK provided the Vidicon cameras. Observing time was split between two spacecraft command stations. NASA operated the spacecraft for 16 hours a day from Goddard Space Flight Center, and VILSPA (the Villafranca satellite control station) operated it for 8 hours a day.

IUE Short Wavelength spectra of the
Jupiter southern aurora on 17 July 1994



The two pictures show the spatially resolved spectrum of the south aurora of Jupiter on July 17 1994 after the impacts with the SL-9 comet fragments have started. The spectra were obtained with the SWP camera (1100-2000 A) using the large aperture which was centered at -60 degrees latitude on the Jovian central meridian.

The signature of the aurora are the emission-like features at the top edge of the spectra near the center of the image and those close to the Lyman alpha line (on the left) which fills in the whole aperture. These are the Werner and Lyman bands produced by H2. The change of these features is apparent between the two spectra taken four hours apart. This shows the temporal and spatial evolution of the auroral emission.

IUE's geosynchronous orbit allowed for real-time operation, which made IUE very flexible. Astronomers came to the spacecraft command stations to direct their observations and inspect the data as they were collected, much as they do at ground-based observatories. Two on-board spectrographs covered ultraviolet wavelengths from 1200 to 3350 Å.

Observers from around the world took advantage of this workhorse observatory, gathering data from a wide variety of astronomical sources. Short and long wavelength spectrographic cameras covered ultraviolet wavelengths from about 120 to 340 nanometers. These wavelengths of electromagnetic radiation are obscured from the ground by the Earth's protective ozone layer.

Objects observed by IUE include virtually every type of object in the universe, from planets and stars to galaxies. One of IUE's strengths was the ability to rapidly respond to targets of opportunity such as comets, novae, and supernovae. IUE obtained the only ultraviolet data of the outburst of Supernova 1987a in the Large Magellanic Cloud. By tracking on the nucleus of fast-moving Comet IRAS-Araki-Alcock, IUE was able to obtain the first detection of molecular sulfur in a comet. During July 1994, IUE (along with the rest of the globe) spent a good deal of time observing Jupiter when Comet Shoemaker-Levy collided with the planet.

Astronomers study multiple wavelengths in order to learn more about the objects of the universe. Simultaneous data acquisition is essential in order to gain the most knowledge of certain transient events. Thus, very often IUE was used in conjunction with other telescopes from around the world. These collaborations have involved spacecraft such as the Hubble Space Telescope, the ROSAT, the Compton Gamma Ray Observatory, the Voyager probes, the Space Shuttle's ASTRO-1 and ASTRO-2 missions, the Extreme Ultraviolet Explorer, Japan's ASCA satellite, as well as numerous ground-based observatories.

Last updated: March 30, 2012

Related Links
  • ESA IUE Website - http://sci.esa.int/science-e/www/area/index.cfm?fareaid=22