Hi, Since I restarted a new campaign I went for a little EVA in the upper atmosphere to get that little bit of science. It's perfectly safe, right? *poof* That poor Kerbal instantly explodes from overheating. So I investigated a little bit to find what's happening and the problem unfortunately is this mod's overheating fix. If I remove just that my Kerbals are fine (at least for a while, they overheat but it takes time), with the overheating fix they just die either instantly or very soon :/ I saw somebody else mentioned this issue already but they thought that was related to FAR. This is not the case, I tested with no other mod installed, it's just the overheating fix. Here's a save file for your testing convenience, with a ship that has just barely entered the atmosphere on a very shallow trajectory. I hope that helps, thanks for all the fixes!