Arcturus Station

Arcturus Station is a human space station located in the system of the same name. It is the capital of the Systems Alliance, home to both its parliament and the headquarters of the Alliance Navy, built before contact with the Citadel. It is where David Anderson is first introduced into the story, Mass Effect: Revelation, after graduating from the N7 program at the Academy there.

Arcturus Station is a 5-kilometer diameter Stanford Torus-type space station, at the trailing Lagrange point (L5) of the gas giant Themis. Construction on Arcturus Station began in 2151 and concluded in 2162, utilising many metal-rich asteroids that remain nearby, housing transient populations. Arcturus Station was inaugurated in 2156, and has served as the military and political headquarters of the Systems Alliance since the First Contact War. Arcturus Station currently has a permanent population of 45,000, and is where Joker grew up before joining the Academy.

As the headquarters of the Alliance military, Arcturus Station is the command center of the fleet, and is conveniently located at the nexus of several mass relays. Furthermore, it guards the mass relay leading to Earth. Arcturus's centralized location makes it an ideal choke point for defense as well as a jumping-off point for further exploration.

Admiral Hackett commands the Fifth Fleet from Arcturus, and provides several missions to Commander Shepard throughout the course of the game.

Trivia

 * The fleet stationed at Arcturus was intended to be the First Fleet. Admiral Hackett and the Fifth Fleet were to be stationed out of the Citadel - this is why Rear Admiral Mikhailovich shows up there to annoy Shepard. Due to lack of coordination between the writers, this point was muddled in the final game.