Midway Space Station

From The Stargate Omnipedia

Midwayspacestation.jpg
Space station which marks the halfway-point of a traveler's journey through the intergalactic gate bridge. A Stargate from both the Milky Way and Pegasus gate networks occupy either end of the massive chamber, allowing individuals to step out of one Stargate network, cross a corridor, and re-enter the next.

The station was manned by S.G.C. personnel, including scientists Bill Lee and Kavanagh. It was believed to be secure from access by enemies.

Shortly after the station was completed, Wraith managed to access the station and used it to reach Earth. An error on the part of Kavanagh resulted in the activation of the computer system's self-destruct protocol, which could not be disabled. The Midway station was destroyed, and the gate bridge link between Atlantis and Earth severed -- or at least made more difficult to use, since one must now travel from the Pegasus gate network to the Milky Way network on board a Puddle Jumper.

KEY EPISODES

The Return, Part 1 - Colonel Sheppard is greeted by the Daedalus during his stop at Midway Space Station while traversing the intergalactic gate bridge for the first time.
The Return, Part 2 - Sheppard and the team take a temporary break at the Midway station after stealing a Jumper from Stargate Command, in order to retake Atlantis from the Replicators.
Adrift - Samantha Carter and Bill Lee work to bring the nearly complete Midway station online.
The Seer - Richard Woolsey must spend time in medical quarantine on the Midway station while en route to Atlantis.
Midway - After the Wraith penetrate the station's defenses and use it to reach Earth, Midway is accidentally destroyed.