Launch and Orbit
ISO was launched by an Ariane 44P launcher from Europe's spaceport in Kourou, French Guiana, on 17 November 1995 at 01:20 UT.
ISO's highly elliptical orbit had a perigee of about 1000 km, an apogee at 70 500 km, and a period of almost 24 hours. The orbital plane was inclined at 5° to the ecliptic. The lowest parts of the orbit lay inside the Earth's Van Allen Belt, which is made up of trapped electrons and protons. Inside these regions ISO's detectors were scientifically unusable, due to effects caused by radiation impacts. The period that ISO spent outside the radiation belts each orbit, and during which the scientific observations were made, lasted almost 17 hours per day.
Diagram of ISO's orbit
Last Update: 1 September 2019