SOCRATES

SOCRATES is an active satellite operated by National Institute of Information and Communications Technology (JPN) (Japan), launched on 2014-05-24 from TNSTA. After 12 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Low Earth Orbit (LEO) at altitudes between 579 km and 587 km with an inclination of 97.9°. It travels at approximately 27,255 km/h (7.57 km/s), completing one full orbit every 96 minutes — that’s roughly 14.95 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 SOCRATES in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

SOCRATES orbits at an average altitude of 583 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 SOCRATES’s average altitude, there are currently 3,257 active payloads and 572 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0050, STARLINK-3005, STARLINK-3090. This makes it one of the more crowded altitude bands, containing roughly 18.7% of all active satellites. With an inclination of 97.9°, SOCRATES passes over latitudes between 97.9°N and 97.9°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 41 share a similar altitude band with SOCRATES.