Iridium coverage at the poles is EXCELLENT because the satellites all converge over the polar regions, being in orbital inclinations of something like 82 to 90 degrees. There are also a lot of unattended weather monitoring and science data M2M things in Antarctica that use Iridium embedded modems.

multilink PPP over Iridium for polar regions: https://www.ittc.ku.edu/publications/documents/Mohammad2004_...