ISO - the Infrared Space Observatory

Fig.1: MPIA delivered the ISOPHOT-Instrument to Europe’s ISO-Satellite.

ISO was the first versatile infrared space observatory. This European mission was launched in November 1995, following the infrared survey mission IRAS by NASA in 1983. ISO’s 60 cm telescope and four scientific focal plane instruments were inside a huge cryostat containing as coolant 2300 l of superfluid helium at a temperature close to absolute zero (-273°C). Beyond IRAS, ISO opened a new window in the far infrared (FIR) and allowed diffraction limited imaging and spectroscopy in the entire IR (2.5...240 μm). Moreover, ISO achieved a sensitivity up to 100 times better than the exploring IRAS mission. During the Postoperation Phase (1998...2002) and Active Archive Phase (2002...2006), the huge ISO data base obtained during 29 months of observations was reprocessed with the final calibration corrections and transformed into the ISO Data Archive, which will become part of the International Virtual Observatory.