The Infrared Space Observatory (ISO) is designed to provide detailed infrared properties of selected Galactic and extragalactic sources. The sensitivity of the telescopic system is about one thousand times superior to that of the Infrared Astronomical Satellite (IRAS), since the ISO telescope enables integration of infrared flux from a source for several hours. Density waves in the interstellar medium, its role in star formation, the giant planets, asteroids, and comets of the solar system are among the objects of investigation.
ISO was operated as an observatory with the majority of its observing time being distributed to the general astronomical community. One of the consequences of this is that the data set is not homogeneous, as would be expected from a survey. The observational data underwent sophisticated data processing, including validation and accuracy analysis. In total, the ISO Data Archive contains about 30,000 standard observations, 120,000 parallel, serendipity and calibration observations and 17,000 engineering measurements. In addition to the observational data products, the archive also contains satellite data, documentation, data of historic aspects and externally derived products, for a total of more than 400 GBytes stored on magnetic disks. The ISO Data Archive is constantly being improved both in contents and functionality throughout the Active Archive Phase, ending in December 2006.