IRS 1C

IRS 1C is an active satellite operated by ISRO (India), launched on 1995-12-28 from Baikonur Cosmodrome, Kazakhstan on the IRS-1C launch. With over 31 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 812 km and 814 km with an inclination of 99.0°. It travels at approximately 26,816 km/h (7.45 km/s), completing one full orbit every 101 minutes — that’s roughly 14.24 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. Its near-circular orbit (eccentricity close to zero) means it maintains a very consistent altitude throughout each revolution. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~100–500 years. Orbital Radar tracks IRS 1C in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

IRS 1C orbits at an average altitude of 813 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 IRS 1C’s average altitude, there are currently 454 active payloads and 2,530 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0455. With an inclination of 99.0°, IRS 1C passes over latitudes between 99.0°N and 99.0°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. India operates approximately 109 active satellites in total, of which 11 share a similar altitude band with IRS 1C.