Newbie Combat Question

[Aaragorn]

Ok call me stupid but..............
I've just entered a system with an enemy satallite which I'm trying to attack with my capital ship missiles but everytime I try to attack I'm given a 0% message over my weapon indicating that i'm unable to attack!
I have been able to attack another enemy "ship" and destroy it with these weapons so why can't I destroy the satallite?
Also can anyone tell me what the % over the weapon in combat actually means with missiles?
Is it my % chance of hitting the enemy or the % of damage I will do to the enemy ship?

Any help appreciated with this great game!
Aaragorn.