IRAS

IRAS is an active satellite operated by United States, launched on 1983-01-26 from Vandenberg SFB, California. With over 43 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 878 km and 904 km with an inclination of 99.1°. It travels at approximately 26,671 km/h (7.41 km/s), completing one full orbit every 103 minutes — that’s roughly 14.01 orbits per day. Its near-polar, sun-synchronous orbit means it passes over any given point on Earth at approximately the same local solar time, ideal for consistent Earth observation lighting conditions. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Orbital Radar tracks IRAS in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

IRAS orbits at an average altitude of 891 km in a sun-synchronous orbit (SSO), a specialised subset of LEO where the orbital plane precesses to maintain a constant angle relative to the Sun. This provides consistent lighting conditions on every pass — essential for Earth observation, weather monitoring and environmental science. Within ±50 km of IRAS’s average altitude, there are currently 201 active payloads and 1,490 tracked debris or rocket body fragments. With an inclination of 99.1°, IRAS passes over latitudes between 99.1°N and 99.1°S, providing near-global coverage including the polar regions. Polar and near-polar orbits are used for reconnaissance, weather monitoring and Earth-observation missions that need to image every part of the planet. United States operates approximately 12,339 active satellites in total, of which 32 share a similar altitude band with IRAS.