circumpolar

What does it mean for an orbiter to support circumpolar orbits, and why is it crazy?

They surveyed well and they used the two near-polar circumpolar start available to them at the time.

And the high arctic at the time of this find 130k years ago was pretty much one cold dry circumpolar ecosystem as ocean levels were much lower than today.

And the military demanded an orbiter that could do circumpolar orbits--which was totally crazy from an engineering standpoint.

Antarctica and South America were connected as recently as 30 MYa, blocking the circumpolar current and allowing water in the southern oceans to be much more mixed.

Or rephrased something like the boring circumpolar stars are always "naturally" going to be one corner of the circle of your map so you'd tend to write the seasonal star names right side up across the map, sorta.

A possible reason for it to "go north" is mentioned here: [2].> Environmental scientists at Harvard have discovered that the Arctic accumulation of mercury ... is caused by both atmospheric forces and the flow of circumpolar rivers that carry the element north into the Arctic Ocean.

Or rephrased the natural way to figure out a star map is to pattern match the circumpolar stars, hold up your star map matching the circumpolar stars on the map with the world, and you "naturally" end up with the north side up, more or less, so you can read the star names with the "boring" circumpolar stars matched up and the zenith at the center of the page.