An Etymological Dictionary of Astronomy and Astrophysics

A satellite that revolves around the Earth in an almost north-south orbit, passing close to both poles. The orbits are sun synchronous, allowing the satellite to cross the equator at the same local time each day.
These satellites orbit at a height of 830-880 km and
take about 100 minutes to complete a turn around the Earth.

See also: → polar; → orbit; → satellite.