I have maxed out milestones in everything, but surviving extreme environments. That is stuck at milestone 8 with 27.6 hours with 28 being the next milestone. No matter how long I stay on extreme environment planets, it will not budge and hasn't for months. I walk around on the planet, don't get into an exocraft of ship and that milestone just won't budge. I started a new game when Beyond came out and just can't get this last milestone... I guess it's not really a big deal, but the completionist in me gets a little twitchy at seeing it.

The internal counter for the Survival milestone is reset on a player's "death." The displayed counter, however, continues to show the maximum time accumulated. It's a little (okay, a lot) deceptive.

So if there was a player death (that blasted plasma grenade) when the milestone achievement was at 27.6 sols (about 7 real world hours) then the displayed counter won't advance until the post-death accumulated time exceeds that number.

Time off-planet (obviously) or in a vehicle (starship, exocraft) doesn't count. I think that time in a building or on a Trading Post platform does count, as does time in a cave or (also obvously) time spent in the open.

This explains why I haven't made any progress on this achievement for over a year, thanks for the info.

So many aspects of this game are poorly explained (if at all), it's an endless source of frustration.

Ah, that would make sense. Yes, I've been killed by my own plasma, as well as glitched to death... It's the last milestone that isn't maxed out, and I'd like to see it finished. :)

Thanks for the info.

That's another thing that, if I recall correctly, was an early design decision by HG. All a piece of the scenario where you wake up near a crashed ship on some random planet and have to figure out how to survive. Partly a puzzle that you need to solve and also partly to encourage the development of communty support and a knowledge base.

That's incorrect. See dashiichi's explanation, which is the way it works.

*edit* To be clear: the counter stops when you leave the extreme environment, but start again as soon as you enter another one. I've gotten this achievement and did not stay in consecutive hours in one extreme environment. I warped to other systems, explored non-extreme planets, and just did a whole lot of exploring in between my times on extreme worlds to get this achievement.