I like the idea of emps. They don't necessarily have to be an item but maybe the center of some planets can send out high amounts of electromagnetic rays and disable electronics. The sun in some solar systems could send out theys waves and disable electronics for the whole solar system, but to avoid this with you spacecraft you could only be able to enter with an emp sheild, allowing you to "dock" on planets. Ps: I'm putting this in mechanics AND in environments This fits into making some planets harder that others, as said under the game description Tell me what you think!
It would make for an interesting new mechanic. EMP on a given world could limit which weapons and equipment a player could use, restricting them to quite primitive equipment. However, a player should have a means of resisting EMP, such as time-limited EMP shields for use outdoors, and EMP-resistant panelling for structures, allowing the use of advanced gear indoors.
I like that idea of electromagnetic-stopping blocks or shelds a character can carry. That way characters can still use needed epuipment on difficult planets.