How to code spaceship evasive maneuvers?

Hello all!

I'm designing a small real-time tactical space combat game for an university project, but there's a problem that I didn't get to the bottom of: the evasive maneuvers. When my spaceship A attacks an enemy one, I would like it to "flying around" to avoid enemy torpedos.

An extension of this problem is: If A and B are fighting, how do avoid them to collide with other spaceships?

My demo probject will allow to control only one spaceship and you'll be against another spaceship, so the second problem is more importantly a curiosity.

I know that this is not an easy one, but how would you solve ( or simplify ) the problem?

Note: I'm sorry if my English isn't perfect. Moreover, I'm new to Unity, but I did study C++, Java and Processing, so I can feel the potential!