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"We need to get back out there; do what we came to do."
Elizabeth Weir[src]

The Atlantis expedition is an international contingent of Tau'ri that explores Pegasus, a galaxy beyond the Milky Way. Its first mission was to discover the lost Ancient City-ship of Atlantis. The impetus for the expedition's creation was the discovery of an Ancient outpost in Antarctica.

Its international origin stems from feelings that a project of such importance (the study of the Ancient outpost in Antarctica, which predates the expedition's founding) could not be the exclusive province of one nation, as well as the fact that according to American and international law, Antarctica is international territory and hence it would be technically illegal for the United States of America to operate any facilities without international participation or at least international knowledge. An international committee, originally called the Atlantis Committee was established, creating the first truly international body for the management of Earth's off world affairs.

The Expedition is currently led by Richard Woolsey with his predecessors having been Colonel Samantha Carter and Dr. Elizabeth Weir.

Like Stargate Command which is home to the Stargate Program, the Expedition also deploys several highly trained teams composed of military personnel and civilians from every country in the world with the Expedition's flagship team, the Atlantis Reconnaissance 1 or AR-1 which is led by Lieutenant Colonel John Sheppard who also serves as the Expedition's military commander.



"We are about to evacuate this city in the hope that it will lie safe for many years and then, one day, our kind will return. And they have."

When the Atlantis expedition arrived from Earth through Atlantis' Stargate in July 2004, they started to explore the lost city until Dr. Meredith Rodney McKay, the expedition's Chief Science Officer discovered that the city's Zero Point Modules were nearly depleted and that the city's shield would fail, causing a massive flood. After searching Athos for safe refuge due to the inevitable shield failure, the search team eventually brought the Athosians back after a Wraith culling occurred. When the team and refugees returned, Janus's fail-safe mechanism activated and Atlantis rose to the surface just as the shield finally ran out of power and failed. With Atlantis safe from the risk of flooding, the expedition continued to settle down and set up home for both themselves and the Athosian refugees. (SGA: "Rising")

Tau'ri encounters with the Wraith[]

Main article: Tau'ri-Wraith war

Having learned of the existence of Earth as a more densely populated feeding ground, the Wraith sent three Hive ships to attack Atlantis. The Atlantis expedition was able to send a message to Earth, which sent its newest battlecruiser, the USS Daedalus, to assist them. Together, they managed to destroy the three ships, but the Wraith sent another twelve. Seeing no way of destroying them, the expedition used a cloak adapted from a Puddle Jumper, and a timed Nuclear warhead to make it appear that the city had been destroyed. The Wraith fell for the ruse, causing them to fall into Civil War. The secret of Atlantis is now a top priority for the expedition members. (SGA: "The Siege, Part 1", "The Siege, Part 2", "The Siege, Part 3")

Battle of Atlantis 9

The second wave bombarding Atlantis from orbit.

In 2006, SG-1, the SGC's flagship team except for Teal'c of Chulak arrived in Atlantis on the Odyssey as a step in their war against the Ori. Lt. Colonel Samantha Carter and Lt. Colonel Cameron Mitchell took McKay on a mission to connect a Pegasus Stargate to the Supergate back in the Milky Way, preventing its further use by the Ori. Meanwhile, Dr. Daniel Jackson and Vala Mal Doran accessed the Atlantis database in the hope of discovering the location of the Sangraal, a weapon designed by Merlin for use against the Ori. However, the ascended Lantean Morgan Le Fay, who masqueraded as the database's holographic interface, was stopped by the Others before she could reveal it. (SG1: "The Pegasus Project")

Later in the same year, live Lanteans were discovered in the void between Pegasus and the Milky Way, who subsequently reclaimed the city and forced the expedition out. Shortly afterwords, the Asurans attacked the city, killing the Lanteans and taking Major General Jack O'Neill and Richard Woolsey hostage. Lt. Colonel John Sheppard, Dr. Elizabeth Weir, McKay, Dr. Carson Beckett, Teyla Emmagan, and Ronon Dex launched a daring rescue mission, using the city's shield generators to emit a massive Replicator disruptor wave. The expedition was then able to reclaim Atlantis, keeping one of the Zero Point Modules installed by the Asurans and sending the other two back to Earth to help with the battle against the Ori. (SGA: "The Return, Part 1", "The Return, Part 2", "Echoes")

The Asuran conflict[]

Asuran Council

The Atlantis Expedition meet the Asuran Council and it's leader Oberoth.

Sometime later, after a massive preemptive strike on Asuras by Earth's new battle cruiser, the Apollo, the Asurans launched an attack on Atlantis. They sent a satellite housing a Stargate to Lantea, and after dialing in from Asuras, directed a powerful energy beam at Atlantis. Unable to evacuate by Stargate, and unable to fully dissipate the beam after submerging the city, the expedition used the Stardrive to leave Lantea. The recently discovered Mobile drilling platform, located on the ocean floor gave Atlantis the power boost it needed to lift off, as the expedition only had one Zero Point Module instead of the 3 which the city was designed to use. The shield had to be lowered so that more power could be diverted to the Stardrive for the crucial first few moments of flight. As the shield was being raised after this initial phase however the Asurans beam grazed the side of the main tower, causing serious damage to the main power conduits. Because of this Atlantis dropped out of hyperspace prematurely and far from the new intended homeworld, with the city's single ZPM nearly depleted, having only twenty four hours of energy left. With the aid of a replacement ZPM, stolen in a daring raid on the Asuras, the city eventually settled on M35-117. (SGA: "First Strike", "Lifeline")

Alliance against the Asurans[]

Main article: Battle of Asuras
Be All My Sins Remember'd

The allied fleet in battle over Asuras

Knowing that the Atlantis team had re-activated the attack command in the Asurans, the Wraith, Todd, allied himself with them in an attempt to stop the Asurans once and for all as they were a common enemy between the Wraith and the humans of the Tau'ri. After McKay came up with a plan that would destroy the Asurans for good, the humans of Atlantis formed an alliance with the Wraith to forge an attack fleet to hold off the Asuran fleet long enough for the plan to be put into play. In the battle that followed, the Tau'ri, Wraith, and Travelers, worked side by side against the Asurans and finally destroyed them with the loss of a single Hive ship and a single Travelers ship. Afterwords the alliance was ended and the war resumed. (SGA: "Be All My Sins Remember'd")

Clashes with the Wraith[]

Although the Tau'ri-Wraith war continues, the Tau'ri have made considerable progress despite terrible odds. With the addition of Daedalus-class battlecruisers and Asgard plasma beam weapons, the Tau'ri are slowly gaining the upper hand in terms of technology, but they still lack anywhere near enough ships to actually start a full-scale war. Since the alliance against the Asurans, there have only been a few skirmishes (mostly with Michael Kenmore), but the Tau'ri gained a major victory when they destroyed the Wraith cloning facility that had created the army that had overwhelmed the Ancients before the Wraith could clone a new one, and took another Hive ship with it. (SGA: "Spoils of War")

Michael Kenmore, an enemy of the Expedition invaded Atlantis in the hope of kidnapping Teyla Emmagan's son to perfect his armies but he was ultimately defeated with Teyla sending Michael to his death. (SGA: "The Prodigal")

With the help of Todd, the expedition has made some headway and even found a way to cause the Wraith to lose their feeding organs with the result of a deadly disease. Todd is the only survivor of that disease. He had also stolen an unknown number of Zero Point Modules (at least six) from Asuras before it was destroyed and has used them to his own ends. Three were used to power the cloning facility and were destroyed when it was destroyed, at least one was used to power a hive ship and two more were given to Atlantis to fully power it. The ZPM used to power the Hive ship caused it to become the Super-hive and was so powerful that it was nearly invincible and not even two Daedalus class ships could destroy it. This led to the Battle of the Super-hive where that particular hive ship went after Earth. After a massive battle where Earth lost its weapons platform and Atlantis even fought, the Hive ship was destroyed by Sheppard and the team as well as Major Evan Lorne using a nuke Sheppard managed to sneak aboard. Atlantis was forced to land on Earth in the Pacific Ocean near San Francisco Bay as a result of being pushed into Earth's atmosphere during the battle and not having enough power to pull out. (SGA: "Enemy at the Gate")

On Earth[]

On Earth, the IOA began efforts to seize Atlantis for themselves and began shutting down the expedition. Many, such as Rodney McKay quit or transferred away. Others began to join the crew of the George Hammond which would be going to Pegasus to continue the fight against the Wraith. Eventually, the IOA shut down the expedition entirely and began plans to dismantle Atlantis for the technology within. In a last desperate attempt to force the IOA to stop, General Jack O'Neill seized control of Atlantis, using the fact that it was in US territorial waters to claim it for the US Air Force. At the same time, he made sure all transfers were to the George Hammond where Colonel Carter, who was working with him, could transfer the people back. Richard Woolsey also began spinning the situation from a political angle, reminding the IOA that as long as Atlantis was off the coast of California, it fell under United States jurisdiction. Not wanting Atlantis under full US control, the IOA eventually caved and restored the expedition, claiming that they had always planned to allow Atlantis to return to Pegasus. O'Neill restored command to Woolsey, having used his brief tenure as commander to stock Atlantis with supplies and bring in "half the Air Force", Doctor Bill Lee and his team and the entire SGC maintenance section to effect repairs to the Atlantis hyperdrive that would've taken months otherwise. Thanks to O'Neill, the Atlantis expedition now numbered around four hundred people, about one hundred of which were new Air Force personnel. As he could not hire new civilian contractors during the time the expedition was shut down, Woolsey welcomed these new people. Two days after the IOA caved, the restored Atlantis expedition began its return trip to Pegasus. (SGA: "Legacy: Homecoming")

Return to Pegasus[]

Seven days into a nine-day journey back to Lantea, Atlantis' hyperdrive developed a malfunction due to battle damage that was never fully repaired. The malfunction drained most of the ZPMs power, leaving Atlantis with only 20% power in the ZPMs and stranded in space once more as the malfunction fried an irreplaceable control crystal for the hyperdrive. Using the sublight drive, Atlantis was able to reach a marginally habitable planet and land, but was left with only 9% power in the ZPMs as a result. The expedition also discovered a new Wraith Queen had risen to power in their absence, Queen Death and posed a very great threat to the galaxy. (SGA: "Legacy: Homecoming")

Things took a turn for the worse, though as during a raid, McKay was eventually captured by a Wraith Dart, leaving his team devastated and vowing to search for him. They eventually found him but were shocked to discover that he had been turned into a Wraith named "Quicksilver" and that McKay/Quicksilver had also developed severe memory loss, believing that he had always been a Wraith who loyally served the Wraith Queen, Death. (SGA: "The Lost")

Atlantis Committee[]

Main article: List of nations of the Atlantis Committee

The Atlantis Committee is composed of the representatives of several nations, but the leaders of the committee seem to be the United States of America, the United Kingdom, France, Russia and China. Though the members are from numerous nations, it is unclear how many nations are aware of the Stargate Program as it is possible they are simply employed by other governments as Doctor McKay is employees by the United States Air Force despite being a Canadian Citizen.


"Every one of you volunteered for this mission and you represent over a dozen countries. You are the world's best and brightest! And in light of the adventure we are about to embark're also the bravest. I hope we all return one day having discovered a whole new realm for humanity to explore."
Elizabeth Weir[src]
Main article: List of Atlantis personnel
Main article: Atlantis teams

Certain personnel have special duties within the Stargate program, an example of these are the Atlantis teams. When the Atlantis expedition was formed there has been at least 11 active teams in the Pegasus galaxy. Atlantis personnel varies heavily in nationality, role, and rank. They all have different colors on their uniforms depending on their role.

In addition to this, each member has a flag patch that contains the flag of the member's home country. Though the most common uniforms are almost all charcoal black, some members have been seen with all-khaki uniforms. They are also color coded. The colors indicate what specialty the members are part of:

  • Red (command/civilian)
  • Blue (scientist)
  • Yellow (medical)
  • Black (military)
  • Green (technician)

The original uniforms featured the science and medical uniforms being a light color unlike military, command and technician uniforms. The first changed had the light color removed and the final also featured less of the colors and had special jackets for missions. John Sheppard also had a special variation. (SGA: "This Mortal Coil")


Atlantis has always had a clear chain of command, with one member of the expedition being in charge. Even though Atlantis is not part of the military, orders from the commander were generally expected to be followed within reason.

There have been three leaders since the Atlantis expedition was first launched.

Doctor Elizabeth Weir[]

Doctor Elizabeth Weir was the first leader of the Atlantis expedition and the first human to set foot onto Atlantis since it was abandoned by the Ancients. Her background as a diplomat and her having negotiated many difficult treaties in hostile areas successfully. Despite her more than capable management of Atlantis both during its initial days and once they were able to establish communication with Earth, she was disliked by many of the military officers who felt that a civilian was not fit to command such a mission. She lead the Atlantis expedition for about three years before being critically injured in a Replicator attack and ultimately sacrificed herself to allow Sheppard's team to escape from the Replicator home world with a ZPM needed to save the city. Weir was ultimately respected by all the expedition members.

Colonel Samantha Carter[]

Took command shortly after Weir's death. Unlike Weir, her military background earned her the respect of most of the star ship commanding officers such as Colonel Ellis and Caldwell. Although her time in command of Atlantis was short she had earned the respect of many of the crew. She was reassigned by the IOA.

Richard Woolsey[]

Initially disliked by both the Expedition crew and military officers but he ultimately came to be respected by the crew, with the star ship commanding officers not warming up to him. Woolsey took great pride in his job and showed great dedication to protecting Earth, which ultimately led him to risk the city to defend Earth from the Super-hive. His actions led to the city landing back on Earth.

Lieutenant General Jack O'Neill[]

Whist Atlantis was stuck on Earth pending IOA approval - which seemed unlikely to come. Both Woolsey and O'Neill tried anything they could to get approval to return. Including an appeal to the President. All of which failed. The IOA then announced that the city should be left under their control, which would effectively make them the most powerful group on earth. They further ordered that Atlantis should be dismantled to better study it's technology. This led to many key personal quitting.

Jack claimed that as the commander of Homeworld Security it was within his jurisdiction to seize of the city as it was military base in US waters. Ultimately no one knew if he was indeed allowed to do this but during his short time as commander, he ordered Atlantis to be repaired and its military personnel to be bolstered with new transfers. He also brought supplies on board.

The IOA then ordered that Atlantis should return to Pegasus as its presence on Earth was destabilizing as anyone who controlled the city would be more powerful than most governments.

Jack's seizing of Atlantis proved to be a ploy to which Woolsey and Carter were part of.

Jack's time as leader of Atlantis was the shortest of any official head of the city but his contributions were no less important that any of the other's before him. His unorthodox view of command and lack of attention to the rule book was what allowed the city to return.

Temporary leaders[]

  • John Sheppard
  • Carson Beckett

John Sheppard[]

John Sheppard temporarily assumed command of Atlantis after the apparent death of Doctor Elizabeth Weir up until Colonel Samantha Carter's arrival at Atlantis as Weir's replacement.

Carson Beckett[]

Though he never actually assumed command of the city, Carson Beckett, in his position of chief medical officer, had the authority to remove and even overrule the leaders orders if he deemed there to be a medical reason. The extent of to this power is not clearly defined but he was able to give directions to Elizabeth Weir, forcing her to take time off. While Beckett is no longer the chief medical officer this position is currently held by Doctor Keller.


The expedition needed a constant flux of personnel, replacement parts and other supplies. The first year, they depended of what they took with them. After that, most of it came from the Daedalus, which made regular trips from Atlantis to Earth, but even with these, it was impossible to supply Atlantis with all the necessary, so the bulk of their food had to be traded from local people, like the Athosians or the Genii. (SGA: "Death Game")


Many of the scientists on Atlantis are organised into departments, each with their own department head. Dr. Rodney McKay was head of the Science and Research Division which most likely meant he was in charge of all of the science departments. Dr. Radek Zelenka was also the head of his own department. The various science departments on Atlantis are:

(SGA: "Remnants", "Grace Under Pressure", "Suspicion")

Races encountered[]

"You have been good friends—to all the people of this galaxy."
Teyla Emmagan[src]

Since the formation of the Atlantis expedition the Tau'ri have discovered and made contact with several new races. The most notable one being the Wraith. The expedition made contact with the Wraith, disturbing their 10,000 year old hibernation cycle, almost instantly after settling in the Pegasus Galaxy. Since the Battle of Atlantis, the first Wraith conflict, the Tau'ri and the Wraith have been in war with each other. Another hostile race in the Pegasus Galaxy was the Asurans. The Asurans are a technological life-form originally created by the Ancients as a means of fighting the Wraith. They were ultimately defeated in 2007 by a united fleet of Tau'ri, Wraith and Traveler ships.

In 2008, Dr. Daniel Jackson and Dr. Rodney McKay were captured by an unknown, rogue alien race who wished for them to activate Janus' secret end-game device. The rogue aliens later turned out to be a faction of the Asgard that had broken away a millennium ago. These Asgard seem to not share the values of their Milky Way counterparts. (SGA: "First Contact", "The Lost Tribe")

They've also befriended many human civilizations as well, making allies of the Athosians and the Travelers, among others.

City life[]

The Atlantis expedition have set up numerous social activities to make residents of the city feel more at home. There is even an orientation committee to help new members get settled in. (SGA: "Remnants")

Social Activities include:

It is also implied that there is a bar on Atlantis (either officially or unofficially) where members can buy alcoholic beverages such as Beer. (SGA: "Quarantine")

Alternate realities[]

Alternate timelines[]

  • In an alternate timeline, Atlantis had no failsafe mechanism and all Zero Point Modules ran simultaneously so the city sank when it was flooded. Consequently, almost the entire Atlantis expedition was killed shortly after their arrival in the Pegasus galaxy. Dr. Elizabeth Weir, Major John Sheppard and Dr. Radek Zelenka got into a time-traveling Puddle Jumper, going back ten thousand years. After being attacked by two Wraith Darts, the Jumper crashed and Weir was the only survivor. The Ancients of the time refused to let her go back to her future since it would corrupt the timeline. Luckily, the time-machine's inventor, Janus, helped her by creating a failsafe and making sure the ZPMs ran the city one at a time to save some extra power. (SGA: "Before I Sleep")