STARS-AO

STARS-AO is an active satellite operated by Japan, launched on 2018-10-29 from TNSTA. It orbits in Low Earth Orbit (LEO) at altitudes between 513 km and 517 km with an inclination of 98.0°. It travels at approximately 27,390 km/h (7.61 km/s), completing one full orbit every 95 minutes — that’s roughly 15.17 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 STARS-AO in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

STARS-AO orbits at an average altitude of 515 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 STARS-AO’s average altitude, there are currently 8,325 active payloads and 266 tracked debris or rocket body fragments — notable neighbours include STARLINK-1017, STARLINK-1039, STARLINK-1184. This makes it one of the more crowded altitude bands, containing roughly 47.8% of all active satellites. With an inclination of 98.0°, STARS-AO passes over latitudes between 98.0°N and 98.0°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. Japan operates approximately 189 active satellites in total, of which 40 share a similar altitude band with STARS-AO.