SEEDS

SEEDS is an active satellite operated by Nihon University (Japan), launched on 2008-04-28 from SRI. After 18 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Low Earth Orbit (LEO) at altitudes between 467 km and 468 km with an inclination of 97.8°. It travels at approximately 27,485 km/h (7.63 km/s), completing one full orbit every 94 minutes — that’s roughly 15.33 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 ~1–3 years. Orbital Radar tracks SEEDS in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

SEEDS orbits at an average altitude of 468 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 SEEDS’s average altitude, there are currently 8,039 active payloads and 190 tracked debris or rocket body fragments — notable neighbours include STARLINK-1017, STARLINK-1039, STARLINK-1047. This makes it one of the more crowded altitude bands, containing roughly 46.1% of all active satellites. With an inclination of 97.8°, SEEDS passes over latitudes between 97.8°N and 97.8°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. Japan operates approximately 189 active satellites in total, of which 25 share a similar altitude band with SEEDS.