SORCE

SORCE is an active satellite operated by National Aeronautics and Space Administration (NASA) Earth Science Office/Laboratory for Atmospheric and Space Physics, Univ. of Colorado (United States), launched on 2003-01-25 from Esrange, Sweden. With over 23 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 544 km and 567 km with an inclination of 40.0°. It travels at approximately 27,310 km/h (7.59 km/s), completing one full orbit every 96 minutes — that’s roughly 15.04 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~3–10 years. Orbital Radar tracks SORCE in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

SORCE orbits at an average altitude of 556 km in the core of Low Earth Orbit, the most heavily utilised altitude band. The balance of moderate drag (limiting debris accumulation) and short signal path (enabling low-latency links and high-resolution imaging) makes this regime the default for most commercial and government missions. Within ±50 km of SORCE’s average altitude, there are currently 3,346 active payloads and 390 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 19.2% of all active satellites. With an inclination of 40.0°, SORCE passes over latitudes between 40.0°N and 40.0°S, covering the tropical and temperate zones where most of the world’s population resides. Low-to-mid inclination orbits are efficient to reach from equatorial and mid-latitude launch sites. United States operates approximately 12,339 active satellites in total, of which 2,767 share a similar altitude band with SORCE.