The Infrared Space Observatory

The first true infrared observatory in space, ESA's Infrared Space Observatory (ISO), was launched 17 November 1995. Since one and a half years, it has made more than 15,000 observations with its four versatile instruments: a camera, a photo-polarimeter and two spectrometers. This paper presents an overview of the satellite, its payload, the operations of the observatory and gives an outlook of the events to come.