The Infrared Space Observatory (ISO) was launched in 1995 by an Ariane-4 rocket. Its mission was to find and observe distant astronomical objects that are swathed in clouds of dust and gas or give off very faint heat readings. Conventional telescopes cannot see these objects, but ISO uses long wave infrared technology to cut through the haze of galactic dust and pick up distant heat signatures. During its three years in orbit key results have included observations of new-born and dying stars, and the location of water vapour on Saturn, Uranus and Neptune, and at the centre of the Milky Way.
