DELTA 1 R/B

DELTA 1 R/B is a spent rocket body associated with United States, launched on 1965-07-02 from Cape Canaveral Space Force Station, United States on the Tiros OT1 launch. After more than 61 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 657 km and 711 km with an inclination of 98.6°. It travels at approximately 27,060 km/h (7.52 km/s), completing one full orbit every 98 minutes — that’s roughly 14.63 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 ~10–25 years. Spent rocket bodies like DELTA 1 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.

DELTA 1 R/B orbits at an average altitude of 684 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 DELTA 1 R/B’s average altitude, there are currently 342 active payloads and 1,390 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, ONEWEB-0179. With an inclination of 98.6°, DELTA 1 R/B passes over latitudes between 98.6°N and 98.6°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 97 share a similar altitude band with DELTA 1 R/B.