THOR BURNER 2 R/B

THOR BURNER 2 R/B is a spent rocket body associated with United States, launched on 1971-10-14 from Vandenberg Space Force Base, United States on the DMSP Block 5B F-1 (SV-2) launch. After more than 55 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Low Earth Orbit (LEO) at altitudes between 768 km and 855 km with an inclination of 99.1°. It travels at approximately 26,818 km/h (7.45 km/s), completing one full orbit every 101 minutes — that’s roughly 14.24 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 ~100–500 years. Spent rocket bodies like THOR BURNER 2 R/B are among the largest pieces of uncontrolled space debris and are priority targets for collision avoidance manoeuvres and future active debris removal efforts.

THOR BURNER 2 R/B orbits at an average altitude of 812 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 THOR BURNER 2 R/B’s average altitude, there are currently 453 active payloads and 2,512 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0455. With an inclination of 99.1°, THOR BURNER 2 R/B passes over latitudes between 99.1°N and 99.1°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. United States operates approximately 13,206 active satellites in total, of which 176 share a similar altitude band with THOR BURNER 2 R/B.