IRS B3

IRS B3 is an active satellite operated by India, launched on 1996-03-21 from SRI. With over 30 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 811 km and 814 km with an inclination of 99.0°. It travels at approximately 26,817 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 B3 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

IRS B3 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 B3’s average altitude, there are currently 429 active payloads and 2,303 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0179, ONEWEB-0455. With an inclination of 99.0°, IRS B3 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 108 active satellites in total, of which 11 share a similar altitude band with IRS B3.