My modules say they're offline. Why?

tactical inner bypass, or you cant afford ur upkeep and they broke

are they attack/defense, or something else?

Attack/ Defense but my force shield is still online and I have 15 million credits

then it was a tactial inner bypass. that automatically uninstalls 5 attack or defense systems on an enemy ship making them easier to take down.

Does it go away or is it permanent
?

just click install

Thanks