26 January
1978: On 26 January 1978, ESA launched IUE, the world's longest-lived and most productive satellite.
It worked non-stop from launch until it was switched off in September 1996, 14 years later than originally planned. Although IUE produced no images, it provided invaluable data by measuring the energies of ultraviolet rays coming from celestial objects, giving insight into the physical conditions of these objects.
