HELIOS 2A

HELIOS 2A is an active satellite operated by Centre National d'Etudes Spatiales (CNES)/Délégation Générale de l'Armement (DGA) (France), launched on 2004-12-18 from Guiana Space Centre, Kourou. With over 22 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 557 km and 560 km with an inclination of 98.3°. It travels at approximately 27,304 km/h (7.58 km/s), completing one full orbit every 96 minutes — that’s roughly 15.03 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 HELIOS 2A in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

HELIOS 2A orbits at an average altitude of 559 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 2A’s average altitude, there are currently 3,246 active payloads and 414 tracked debris or rocket body fragments — notable neighbours include STARLINK-1184, STARLINK-1276, ONEWEB-0050. This makes it one of the more crowded altitude bands, containing roughly 18.6% of all active satellites. With an inclination of 98.3°, HELIOS 2A passes over latitudes between 98.3°N and 98.3°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 115 active satellites in total, of which 24 share a similar altitude band with HELIOS 2A.