To make this thread an all-around help for people, here's my understanding when the other modifiers kick in.
Low/High Gravity, Extreme Pressure and Extreme Temperature are not absolute modifiers but relative. As in, when they kick in depends on your species tolerance.
![](https://i.imgur.com/1oVNort.png)
So as default humans:
Low Gravity modifier activates when fighting on a body with less than 0.10 G
High Gravity modifier activates when fighting on a body with more than 1.90 G
Extreme Pressure activates when atmospheric pressure on a body is above 4.00 atm - but does it kick in when there is no atmosphere? If yes, where is the cut-off point?
Extreme Temperature activates when average body temperature is either below -10.00 Celsius or above 38.00 Celsius
So, fighting on Luna, for example, would utilize ET and probably EP too but nothing else as default Luna is Barren, ie without terrain.