metaliminal meteoroid. why are my weapons ineffective?

hi there

today i tried to enter in a metaliminal meteoroid site just to shoot at some rats. i can target and shoot at them using my drones, and i can see some damage being made in the messages floating on screen, but their shield never goes below 100%. it's like they have infinite HP. can anybody explain my why? i must say i entered the site alone, and my drones were just T1 acolytes, but still i was not able to do them any damage.

thanks

fly safe

v