International Ultraviolet Explorer (IUE) was the first satellite totally dedicated to ultraviolet astronomy. Launched in January 1978, IUE was a joint mission of NASA and the European Space Agency; it carried a 45-centimeter-diameter telescope and two spectrographs for use in the range 115 to 320 nanometers. It operated successfully for more than 18 years – the longest-lived astronomical satellite – until it was switched off in 1996.