Infrared Space Observatory
An ESA satellite for infrared astronomy, launched in 1995 November into a 24-hour elliptical orbit. ISO carried a 0.6-m helium-cooled Ritchey–Chrétien telescope equipped with a camera (2.5–17 μm), an imaging photopolarimeter (2.5–240 μm), and two spectrometers (2.5–45 μm and 43–198 μm). It ceased operation in 1998 May.
http://sci.esa.int/science-e/www/area/index.cfm?fareaid=18ESA ESA mission website.