Atlantis' shield

From SGCommand

"Fortunately there is some sort of a forcefield holding back the w...water."

—Rodney McKay

The shield of Atlantis is the main defense for the Ancient City-ship, and is largely considered to be the most powerful shield ever created.

[edit] Functions

The shield is used to protect the city from everything trying to harm it, including weapons-fire, ocean pressure and even solar radiation and asteroids. It also is a critical part when the city takes off, lands or flies through space, since it's the shield which prevents the air from leaving the city, thus acting as a sort of outer hull.

The shield requires massive amounts of energy to be activated, which is usually only provided by a Zero Point Module. However, it has been shown that the energy of several lightning strikes provides a sufficient amount of power to activate the shield for some time. If there is no pressure on the shield it can be activated for nearly an unlimited amount of time. (ATL: "Rising", "The Storm", "The Eye")

The shield is activated by ten shield emitters, located throughout the city. (ATL: "The Return, Part 2")

The shield of Atlantis is unique in the sense that no residual energy can get past the shield (Atlantis cannot suffer so much as a scratch whilst the shield is activated unlike the shields of starships where systems are damaged and damage is sustained regardless of the shield's status). The effectiveness of the shield does not deplete under external forces, and will remain literally impenetrable as long as sufficient power exists to hold back the forces putting pressure on it. This means nothing can penetrate the shield as long as there is a constant power source (again unlike starships where power can still be active with the shields loosing integrity and needing to recharge).

[edit] Alternative uses

Over time the Atlantis Expedition has found out different ways of using the shield of Atlantis. The first different use was during the Wraith attack of Atlantis. To trick the Wraith into believing Atlantis was destroyed they were able to convert the shield into a cloak which hides the whole city, in the same manner as the cloak of a Puddle jumper can be converted into a shield. However if this is done, the cloak replaces the shield, making the city vulnerable for attacks if an enemy isn't tricked by this. (ATL: "The Siege, Part 3")

While the Asurans took over Atlantis Rodney McKay came up with the idea to convert the whole shield into a gigantic Anti-Replicator Gun. This was done by linking up the energy Control crystals of the ARGs to the shield emitters. When the shield was activated, all Asurans in the city were destroyed. For this plan to work, all shield emitters had to be changed in this way. (ATL: "The Return, Part 2")