If its absolutely necessary to keep it for fairness, though i see no fairness in the design of this type of weapon personally. the orbital cannon should probably be on a glass tank with a lot of energy that cant soak up more damage than anything else in the galaxy. to add a balanced option, there should be another ship (Hello Enforcer 
) that is middle of the road for both armor and energy but can use say 8 spitters or 6 beams or the like. thats a little more tankish but less devastating.
The idea that it is both the most devastating weapon and the best defended is kinda overboard.
When you can make a landing zone in a couple hits usually on some planet in the system because they are rarely all high level and then just disappear and only need to shoot once and there's no time to retaliate what exactly is the defense against that weapon??
) that is middle of the road for both armor and energy but can use say 8 spitters or 6 beams or the like. thats a little more tankish but less devastating. The idea that it is both the most devastating weapon and the best defended is kinda overboard.
When you can make a landing zone in a couple hits usually on some planet in the system because they are rarely all high level and then just disappear and only need to shoot once and there's no time to retaliate what exactly is the defense against that weapon??