NISAR

NISAR is an active satellite operated by India, launched on 2025-07-30 from SRI. As a relatively recent addition to the catalogue, its orbital elements are well-characterised. It orbits in Low Earth Orbit (LEO) at altitudes between 749 km and 751 km with an inclination of 98.4°. It travels at approximately 26,934 km/h (7.48 km/s), completing one full orbit every 100 minutes — that’s roughly 14.43 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 ~25–100 years. Orbital Radar tracks NISAR in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

NISAR orbits at an average altitude of 750 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 NISAR’s average altitude, there are currently 356 active payloads and 1,947 tracked debris or rocket body fragments — notable neighbours include LANDSAT 9. With an inclination of 98.4°, NISAR passes over latitudes between 98.4°N and 98.4°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 7 share a similar altitude band with NISAR.