- "Thirty-four Gates from both the Milky Way and Pegasus Gate systems have been strategically placed in the massive void between our two galaxies. Simply enter on either side -- for example, Atlantis -- and boom! A macro that I have written specially for the occasion will command each Gate in the chain to store you in its buffer and forward you along to the next, and the next, and the next, and the next, and the next until you arrive here. Once at the midway space station you simply exit the Pegasus Gate system and enter the Milky Way Gate system where a similar macro designed by yours truly will forward you along to the SGC. Total travel time, a little over thirty minutes. Cue applause."
- ―Rodney McKay[src]
The McKay/Carter Intergalactic Gate Bridge is a network of interconnected Stargates placed in the void between the Milky Way and Pegasus galaxies, designed to allow fast, convenient travel between Atlantis and Stargate Command without the need for a Daedalus class ship or a Zero Point Module. It is named after the Tau'ri scientists who developed it: Dr. Meredith Rodney McKay, Chief Science Officer of the Atlantis Expedition and a member of the Expedition's flagship team AR-1 (the First Atlantis Reconnaissance Team), and Lt. Colonel Samantha Carter, a member of Stargate Command's flagship team SG-1. (SGA: "Irresistible")
The bridge is composed of 34 Stargates taken from both the Pegasus and Milky Way gate systems, into which has been loaded a macro developed by Dr. Rodney McKay that forwards travelers directly from one Stargate to the next without rematerializing them. While the two gate systems are compatible, a Pegasus Stargate without either an altered dialing program, or a control crystal that allows intergalactic dialing, wouldn't be able to dial the Milky Way, just the "local" galaxy, and vice versa. And, if a Pegasus gate and a Milky Way gate are in proximity to each other, the Pegasus gate holds priority. (SGA: "The Return, Part 1")
Therefore, a space station has been constructed at the midpoint between the two galaxies, where the two chains of Stargates meet, with a workaround allowing the Milky Way gate to hold priority for the Milky Way side and the Pegasus gate to hold priority for the Pegasus side, allowing transfer between them. There, it is intended that one need only step out of one Stargate and into the next. Travel time using the bridge is approximately 30 minutes, a drastic reduction from the weeks-long journey required via ship. (SGA: "The Return, Part 1", "Midway")
Midway space station
- Main article: Midway space station
Structurally, the station was built around the two Stargates, and its interior was dominated by a single, expansive gate room. However, isolated rooms had been installed along either side of the structure, divided into two floors. The gates themselves were located in between these levels, accessible by ramps like in Stargate Command. Because the two gates were in such close proximity to each other, a work-around had to be created so that the Pegasus gate would not supersede the Milky Way gate, allowing both to dial. The other rooms include small living quarters for the personnel and travelers between the galaxies as well as at least one weapons room. Stargate operations are monitored by a control room on the upper level of the station. There also exists an airlock which includes Space suits and a Puddle Jumper in case of an evacuation. (SGA: "Midway")
Millennia ago, the Ancients/Lanteans experimented with the concept of extending the operational distance of Stargates without the need of dialing the eighth chevron. However, these gates can only be reached by Puddle Jumpers that are specially outfitted with energy boosting units. Without the energy reserves, the Puddle Jumper will most likely not make it to their destination. If they do, the Jumper's energy reservoir will be mostly depleted and many internal systems overloaded, thus stranding the travelers on the planet - just as Lt. Colonel John Sheppard and his team were on Khost. Ultimately, the Ancients weren't able to perfect the technology due to the escalating war with the Wraith. However, the concept inspired Dr. Rodney McKay to extend the dialing distance by creating the Intergalactic Gate Bridge that only requires the same power requirements as a seven symbol gate address (Interstellar travel) as compared to an eight symbol gate address (Intergalactic travel). (SGA: Dead End)
As of 2006, the Midway space station was still incomplete, but the gate bridge itself was fully functional; Lt. Colonel John Sheppard performed the inaugural intergalactic voyage using a Puddle Jumper.
When the Asurans briefly took control of Atlantis, Major General Henry Landry expressed concern that the gate bridge might be used to allow them access to the Milky Way. Even though Earth was protected by the Iris, the Asurans could potentially rewrite Dr. Rodney McKay's macro to send them to some other Stargate within the galaxy. When Sheppard and Dr. Elizabeth Weir mounted an operation to retake Atlantis, McKay himself managed to rewrite the macro to take them to the Athosians' new homeworld. (SGA: "The Return, Part 1")
Afterward, Landry wanted a way to disable the gate bridge; Dr. Bill Lee suggested detonating a Mark IX warhead at Midway station. This plan was apparently not carried out, however, and the gate bridge remained intact. (SGA: "The Return, Part 2", "Echoes")
Following a viral outbreak in Atlantis, a 24-hour quarantine period was imposed on bridge travel to prevent such an occurrence resulting in a viral outbreak on Earth, all travelers proceeding to and from Atlantis being required to wait in Midway for the duration of this time. (SGA: "Tabula Rasa", "The Seer")
The gate bridge was rendered inactive at the beginning of 2008 when the Midway station was destroyed during an invasion of the Wraith. Despite its importance, the station was not rebuilt. It is also unlikely that they would open another gate bridge for further risk of invasion. (SGA: "Midway")