DMSP 5D-2 F9 (USA 29)

DMSP 5D-2 F9 (USA 29) is an active satellite operated by United States, launched on 1988-02-03 from Vandenberg SFB, California. With over 38 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 790 km and 801 km with an inclination of 98.4°. It travels at approximately 26,848 km/h (7.46 km/s), completing one full orbit every 101 minutes — that’s roughly 14.29 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. Its near-circular orbit (eccentricity close to zero) means it maintains a very consistent altitude throughout each revolution. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~25–100 years. Orbital Radar tracks DMSP 5D-2 F9 (USA 29) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

DMSP 5D-2 F9 (USA 29) orbits at an average altitude of 796 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 DMSP 5D-2 F9 (USA 29)’s average altitude, there are currently 427 active payloads and 2,265 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0179, ONEWEB-0455. With an inclination of 98.4°, DMSP 5D-2 F9 (USA 29) passes over latitudes between 98.4°N and 98.4°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 12,339 active satellites in total, of which 162 share a similar altitude band with DMSP 5D-2 F9 (USA 29).