There have been several instances where by I was majorly out numbered, and being attacked, so I thought to hide behind a large asteroid. Apparently enemy vessels can still target me and fire upon me, the phase fire and torpedos passing through the asteroids themselves. However, when I try to fire at them, I cannot because of the asteroid.
Wow i'm glad that I posted this, for a while I thought I was the only one!
I have experienced this in multiple different boards.
I have also experienced aan enemy ship getting stuck in an asteroid, and being able to fire upon it... bot as mentioned by the other player if its in a specific spot i might be able to fire phasers on them.