IUE has been the most productive astronomical telescope ever: its 18.7 years of operations returned 104 470 high- and low-resolution spectra of 9600 astronomical sources from all classes of celestial objects in the 1150 to 3350 Å UV band.
During IUE's life, more than 1000 European observation programmes were conducted from Villafranca, returning more than 30 000 spectra from about 9000 targets, extending from comets to far away quasars at the early days of the Universe and covering a brightness range of 10 orders of magnitude (extending from Mv =-4 to Mv =21). These spectra were processed and deposited in a public domain archive together with the data collected by the IUE Observatory at NASA's Goddard Space Flight Center. The IUE Data Archive remains the most heavily used astronomical archive in existence: with 500 000 data delivered in archive form and more than 100 000 spectra taken, each IUE spectrum has already been used six times. The IUE Archive, now a Historical Reference Archive, will be transferred by ESA to the Laboratory for Space Astrophysics and Theoretical Physics (LAEFF) in Spain, which will continue to support the INES implementation of the IUE Archive for the Astronomical Community, in 2000.
With more than 250 Ph.D dissertations world-wide using data from the IUE Project, one can say that the project has played an important role in the formation of a complete generation of Astronomers. From launch to 1998, 3585 papers have been published in the refereed scientific literature using IUE results. Currently the IUE Archive is still regularly used, and many publications will continue to use the Archival data from IUE.