Capital ships can be found in the space and actively shooting at the enemies. BUT this huge piece of dangerous metal can be also damaged and destroyed. But it would have to be a very determined and numerous group of players to achieve it.
Taken from the official forum written by Gedemon:
It would, you can destroy modules on it, and it's hull is taking damage too, but I have no idea on how much torpedoes would be needed to destroy one, it has fled with 95% hull left after losing every weapons...
Below is a video showing peacefully the ship:
But in the next one Gedemon is trying to fight it with Viper. The video ends abruptly because the game crashes if the capital ship enters or leaves the area.