PROBA 1

PROBA 1 is an active satellite operated by European Space Agency (ESA) (ESA (European Space Agency)), launched on 2001-10-22 from SRI. With over 25 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 505 km and 583 km with an inclination of 98.0°. It travels at approximately 27,332 km/h (7.59 km/s), completing one full orbit every 96 minutes — that’s roughly 15.07 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. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~3–10 years. Orbital Radar tracks PROBA 1 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

PROBA 1 orbits at an average altitude of 544 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 PROBA 1’s average altitude, there are currently 3,513 active payloads and 342 tracked debris or rocket body fragments — notable neighbours include STARLINK-1184, STARLINK-1276, STARLINK-1451. This makes it one of the more crowded altitude bands, containing roughly 20.1% of all active satellites. With an inclination of 98.0°, PROBA 1 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. ESA (European Space Agency) operates approximately 93 active satellites in total, of which 8 share a similar altitude band with PROBA 1.