Starbase Athena has a good security system, even a cloaking device, but having extra eyes out of rang of sensors are a necessity even more so in this part of the galaxy that we don't know much about.  Considering that we are alone in this quadrant, there is a lot more ships, but when they are gone exploring, only 2 remains around the station.  USS Drake, Excelsior class who had been modified internally but externally had kept the shape of his predecessor.  USS London, Defiant Class who proved themselves to be a formidable little ship.