Is anyone else still stuck with this Milestone? Today, after almost 400 hours on this file, I warped back to my original Next base. When I arrived, I was awarded with level 5. Is there a trick to this? Do I need to be back in Euclid? I don’t know. I have spent many hours on extreme worlds. At least I am still progressing. 
2 Likes
The only thing I know about the extreme survival milestone is that, at one time, it was bugged.
Apparently it was supposed to aggregate time spent on extreme worlds - but it didn’t. To get the achievement, you had to accumulate the hours all in one session. If you stopped, rebooted, or left the extreme environment, your total was reset to zero, and you had to start again.
This was reported as being fixed a long time ago - but you know how it is with NMS bugs.
4 Likes
Back when I did it for the last time, the counter was bugged. If i died at any point the sols would reset to zero but the counter stayed at wherever it was. I ended up going to an extreme sentinel planet and camping inside a building overnight.
4 Likes
While doing the Expedition I noticed it only counted distance walked to get that award.
Jet pack boosting didn’t count.
Maybe the milestone has a similar bug…?
In the past I’ve just stayed on an extreme world until I reach all the milestones (usually collecting Storm Crystals while there). It just takes a bit of preparation beforehand with suit mods & a stack of batteries.
4 Likes
Normally when I get this milestone, It’s during normal exploration, usually when trying to find all animals on extreme weather or sentinel planets.
I have seen others build a base on an extreme planet to get this milestone. It seems to have worked for them if you just hang out inside. This can be easily checked.
2 Likes
Ok. Thanks everyone! I will just hang out on this Death Fog planet at Traveller’s Rest. Need to re-catalogue all the flora, fauna and minerals anyway. Hopefully, this will work.
Looks like it will take a while.
Tried swimming 
Sitting inside
Sitting outside
Got into my ship and back out
Made it to level 6
9 Likes