These stations had initial success in maintaining the peace and protecting rimward Imperial worlds in the aftermath of the Clone Wars, but were frequently taken over by pirates and criminal groups, forcing Kuat Drive Yards to produce more heavily armed and protected models.
However, Star Wars: Empire at War is the only souce to depict the Cardan series of space stations and it would be unlikely that an Imperial installation would be this minimally equipped to deal with Rebellion and pirate assaults. It is more probable that the Cardan I would possess at least 10 defensive batteries.
The Cardan I could hold off small capital ships and starfighters, and sometimes accompanied defense with corvette-sized capital ships, Ton-Falk-class escort carriers, and other small ships of their own.
The Cardan I was able to produce both TIE/LN starfighters, TIE/IN interceptors and TIE/sa bombers. These starfighters could be built in limited numbers and only one squadron could actually be stored in the hangar of the space station.