TRANSIT 18 DEB

TRANSIT 18 DEB is a tracked piece of space debris attributed to United States, launched on 1968-03-02 from Vandenberg SFB, California on the NNS O-18 launch. After more than 58 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 992 km and 1,086 km with an inclination of 90.0°. It travels at approximately 26,404 km/h (7.33 km/s), completing one full orbit every 106 minutes — that’s roughly 13.59 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~500–1,000 years. As orbital debris, TRANSIT 18 DEB poses a potential collision risk to operational satellites in nearby orbits and is continuously monitored by the U.S. Space Surveillance Network and other tracking systems.

TRANSIT 18 DEB orbits at an average altitude of 1,039 km in the upper LEO band, where atmospheric drag is negligible and objects can persist for centuries to millennia. This altitude is used by broadband constellations like OneWeb and by scientific missions requiring stable orbits far from the densest debris bands. Within ±50 km of TRANSIT 18 DEB’s average altitude, there are currently 198 active payloads and 504 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0041. With an inclination of 90.0°, TRANSIT 18 DEB passes over latitudes between 90.0°N and 90.0°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. United States operates approximately 12,358 active satellites in total, of which 18 share a similar altitude band with TRANSIT 18 DEB.