The U.S. military has been experimenting with energy weapons for quite some time. Heck, working examples already exist. I am certain that future spaceships that will likely need to defend themselves will have laser turrets, which would make an excellent defense against missiles and fighters.
I'm not certain if it is already too late to say anything that will make any difference, but I figure I'd better speak my mind or forever hold my peace. I think that given the armaments that the Polaris currently has, and the fact that they are all forward facing, she would need some laser turrets for defense. I think that 4-8 placed somewhere on the saucer should be sufficient to give her an adequate coverage.
And what's your heat dissipation plan? Or are you planning on letting the laser emplacements cook themselves?
defenses consist mainly of trying not to get hit.
Dennis has got the right idea. This is really the most realistic way to defend yourself in space, especially if your ship isn't a warship. You only need point defenses if your ECM and maneuverability are hilariously sad, and you decide for whatever reason, to directly confront your opponent. Space combat is wildly impractical if both
participants aren't trying to engage one another, because space is just so darn big.