THOR BURNER 2 R/B

THOR BURNER 2 R/B is a spent rocket body associated with United States, launched on 1975-05-24 from Vandenberg Space Force Base, United States on the DMSP Block 5C F-2 launch. After more than 51 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 788 km and 864 km with an inclination of 98.7°. It travels at approximately 26,791 km/h (7.44 km/s), completing one full orbit every 101 minutes — that’s roughly 14.20 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 826 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 399 active payloads and 2,455 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0455. With an inclination of 98.7°, THOR BURNER 2 R/B passes over latitudes between 98.7°N and 98.7°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 152 share a similar altitude band with THOR BURNER 2 R/B.