DELTA 1 DEB

DELTA 1 DEB is a tracked piece of space debris attributed to United States, launched on 1972-07-23 from Vandenberg SFB, California on the ERTS A launch. After more than 54 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 601 km and 817 km with an inclination of 98.8°. It travels at approximately 27,012 km/h (7.50 km/s), completing one full orbit every 99 minutes — that’s roughly 14.55 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 ~25–100 years. As orbital debris, DELTA 1 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.

DELTA 1 DEB orbits at an average altitude of 709 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 DEB’s average altitude, there are currently 255 active payloads and 1,533 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, LANDSAT 9. With an inclination of 98.8°, DELTA 1 DEB passes over latitudes between 98.8°N and 98.8°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 62 share a similar altitude band with DELTA 1 DEB.