HELIOS 1B

HELIOS 1B is an active satellite operated by France, launched on 1999-12-03 from Guiana Space Centre, Kourou. With over 27 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 602 km and 606 km with an inclination of 98.2°. It travels at approximately 27,214 km/h (7.56 km/s), completing one full orbit every 97 minutes — that’s roughly 14.88 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 ~10–25 years. Orbital Radar tracks HELIOS 1B in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

HELIOS 1B orbits at an average altitude of 604 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 HELIOS 1B’s average altitude, there are currently 1,633 active payloads and 682 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 9.4% of all active satellites. With an inclination of 98.2°, HELIOS 1B passes over latitudes between 98.2°N and 98.2°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. France operates approximately 114 active satellites in total, of which 49 share a similar altitude band with HELIOS 1B.