\<COLOUR 1> COMMENTS: \<COLOUR 0> Designed for a maximum 5-year lifetime, IUE (international ultraviolet explorer) is still returning valuable data in 1992 after 15 years; the first satellite to map the sky in the ultraviolet, it mainly studies stars, but can be switched to observe other phenomena when they occur, eg Halley's comet in 1986 and the 1987 supernova in the Large Magellanic Cloud.