I thought about it, and doesnt it sound strange that the huge motheships cannot defend themselves? It's particularly sad when you are attackes by ship with 1 space and 1 marine onboard 

So here's my suggestion- can we make constructible turrets/barracks/missile silos? They would be using segments to be constructed, and can be upgraded in research window. For example:
1 laser turret- cost- 5 segs
                            1000000 creds
                            100 000 nominal attack @ 75% acc.
1 marine barracks- cost-  10 segs
                                    1 000 000 creds
                                     holds 100 000  marines
1 missile silo- cost- 50 segs
                             5 000 000 credits
                             allows construction and storage of 5000 missiles.
1missile( cost 50 creds, attack 100, acc- 99%)
Thank you for your time. 
