The Citadel is a massive construct, similar in shape to a pentagram. It consists of a central ring 7.2 kilometers in diameter, from which five arms protrude, each 43.6 km long and 330m thick. The station is capable of closing in on itself, via the convergence of its five arms, transforming it into a long, impenetrable cylinder. However, the Citadel is only closed in times of emergency, and normally the station retains its ‘open’ appearance. The central ring and five arms are home to the Presidium and Wards respectively; the spaceports are also located on the central ring, as it is the center of rotation, facilitating easier access for ships attempting to dock with the station.