HST

HST is an active satellite operated by European Space Agency (ESA)/NASA (United States), launched on 1990-04-24 from Cape Canaveral, Florida. With over 36 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 472 km and 475 km with an inclination of 28.5°. It travels at approximately 27,473 km/h (7.63 km/s), completing one full orbit every 94 minutes — that’s roughly 15.31 orbits per day. 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 ~1–3 years. Orbital Radar tracks HST in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

HST orbits at an average altitude of 474 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 HST’s average altitude, there are currently 8,007 active payloads and 205 tracked debris or rocket body fragments — notable neighbours include STARLINK-1017, STARLINK-1039, STARLINK-1047. This makes it one of the more crowded altitude bands, containing roughly 45.9% of all active satellites. With an inclination of 28.5°, HST passes over latitudes between 28.5°N and 28.5°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 12,360 active satellites in total, of which 7,433 share a similar altitude band with HST.