DMSP 5D-3 F17 (USA 191)

DMSP 5D-3 F17 (USA 191) is an active satellite operated by DoD/NOAA (United States), launched on 2006-11-04 from Vandenberg SFB, California. With over 20 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 834 km and 850 km with an inclination of 98.7°. It travels at approximately 26,762 km/h (7.43 km/s), completing one full orbit every 102 minutes — that’s roughly 14.15 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. Orbital Radar tracks DMSP 5D-3 F17 (USA 191) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

DMSP 5D-3 F17 (USA 191) orbits at an average altitude of 842 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-3 F17 (USA 191)’s average altitude, there are currently 251 active payloads and 2,125 tracked debris or rocket body fragments — notable neighbours include NOAA 20, ONEWEB-0179, ONEWEB-0455. With an inclination of 98.7°, DMSP 5D-3 F17 (USA 191) 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 12,360 active satellites in total, of which 48 share a similar altitude band with DMSP 5D-3 F17 (USA 191).