EOS-4

EOS-4 is an active satellite operated by Indian Space Research Organization (ISRO) (India), launched on 2022-02-14 from SRI. It orbits in Low Earth Orbit (LEO) at altitudes between 527 km and 529 km with an inclination of 97.5°. It travels at approximately 27,364 km/h (7.60 km/s), completing one full orbit every 95 minutes — that’s roughly 15.13 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 ~3–10 years. Orbital Radar tracks EOS-4 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

EOS-4 orbits at an average altitude of 528 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 EOS-4’s average altitude, there are currently 6,788 active payloads and 286 tracked debris or rocket body fragments — notable neighbours include STARLINK-1039, STARLINK-1184, STARLINK-1231. This makes it one of the more crowded altitude bands, containing roughly 38.9% of all active satellites. With an inclination of 97.5°, EOS-4 passes over latitudes between 97.5°N and 97.5°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 15 share a similar altitude band with EOS-4.