There's been a bit of a
hubbub on the interwebs about the name.
The short and skinny of it: The term (Ultima) Thule dates back to antiquity (as a label for some distant faraway place - probably an island? - in the extreme north; you'll find it in some shape or form in many a map all the way up to the Renaissance (as an island somewhere up in the north). There are ongoing debates what people in antiquity were actually referring to. Pytheas of Massalia pinned some things on Thule that imply actual knowledge from faraway northern lands: his accounts include references to strange celestial phenomenon up there like strange lights dancing in the sky at night, and insanely long days in the summer and nights in the winter. But esp. since the original sources were lost, we don't actually know WHAT he was talking about: Greenland? Gotland (huge island in Sweden)? Saaremaa (huge island in Estonia)? It's a pretty salient term in Northern Europe, with Greenlanders really wanting it to be Greenland, Swedes Gotland, and Estonia Saaremaa. This is kinda an envy thing IMO: we don't actually have any ancient records from Northern Europe dating back to antiquity (there was NO literacy in Estonia before the Baltic crusades of the 13th century, for example), so Ultima Thule is seen as a chance to get a longer historical record - which for some reason seems to matter to people. Whatever the reason is, though, you will see the term thrown around a lot in Northern Europe, but all we really know about the original reference is "faraway cold place".
That's the reference the makers of Space: 1999 were making, and the reference NASA people were making when agreeing on the nickname.
BUT ... the Nazis picked up on the same term too, and declared Thule as the home of the Aryan race in their pseudo-mythology. Hence, hubbub.
Personally, I find is silly - at least given the information that I have right now. "Anything touched by Nazis has Nazi all over it for all eternity" is an inane stance. The Nazis produced a massive amount of insane and self-contradictory propaganda and pseudo-mythology over more than two decades, so they got their Nazi fingers over a whole lot of shit. More relevant is the question if they used a symbol or term so extensively that it either ( 1 ) entered the public consciousness as a symbol associated with Nazism (see the swastika), or ( 2 ) continues to be used as an "in-group code" of some sort in right-wing groupings.
As for ( 1 ): definitely not.
As for ( 2 ): I don't know, but I suspect the answer is: No, but it might be NOW. Nice job breaking it, Internet drama llamas.