The Polar satellite, launched on February
24, 1996, is in a highly elliptical, 86 deg inclination orbit with a period of about 17.5 hours.
Within the Sun-Earth Connections fleet, Polar has the responsibility for
multi-wavelength imaging of the aurora, measuring the entry of plasma into
the polar magentosphere and the geomagnetic tail, the flow of plasma to
and from the ionosphere, and the deposition of particle energy in the
ionosphere and upper atmosphere. Polar was launched to observe the polar
magnetosphere and, as its orbit has precessed with time, has observed the
equatorial inner magnetosphere and is now progressing toward an extended
southern hemisphere campaign.