Well I bough Orion and bolted rear turret to it. In space I encountered one pirate and assigned it as target for the turret, seemed to work OK and the turret was firing at the pirate when it could.
But later I encountered several enemies and at some point noticed that the turret simply stopped functioning no matter how I hitted Alt-t or Ctrl-t, it didn't shoot even if the turret-targeted enemy was right there shooting my arse. It just spinned around like it was crazy or something...