Highly elliptical orbit

Such extremely elongated orbits have the advantage of long dwell times at a point in the sky during the approach to, and descent from, apogee.

Geostationary orbits cannot serve polar latitudes because their elevation above the horizon from these ground sites is too low.

[2] Many GEO comm sats have custom "foot prints" and focus their signals at their primary service areas, so above 60 degrees a larger ground antenna and clear line of sight is needed.

The longitude above which the satellites dwell at apogee in the small loop remains relatively constant as Earth rotates.

The three separate orbits are spaced equally around the Earth, but share a common ground track.