Discenna is an Ancient city-ship.


Millions of years ago, Discenna, which means ''To Learn'' in Ancient, existed on Dakara before the Ancients abandoned the Milky Way Galaxy for the Pegasus Galaxy due to the Ancient contagion. Like Atlantis, Discenna departed its home planet for the Pegasus Galaxy. Before the city-ship left, the inhabitants had been working on a cure for the Ancient contagion, an organism later came to be known as Fenrir that had a hive mind similar to the Replicators, but organic in nature. After departure, the inhabitants continued to work on Fenrir, but eventually suffered a containment breach. Infected with Fenrir, the inhabitants of Discenna dropped out of hyperspace in the void between the two galaxies and disabled the Stardrive so the organism could not use it to escape. The city's inhabitants were presumably eventually consumed by Fenrir, but not before they left a warning message in the form of a hologram and programed the city to vent its atmosphere if anyone arrived to stop them from leaving after the organism infects them.

Discenna was left floating in the void between galaxies for eons, eventually having an asteroid build up around it and be powered by a single ZPM that was hanging on to life. In 2007, Discenna was rediscovered by a Wraith hive ship that was stranded in the void and Fenrir infected the ship. Discenna was discovered soon after by the Tau'ri after the Daedalus destroyed the hive ship and the crew became infected by Fenrir. Learning that Discenna was the source of the infection, Doctor Rodney McKay, Lt. Colonel John Sheppard and Asgard engineer Hermiod beamed into the city and accessed its database. Shortly after arrival, the warning hologram played and the city began to vent its atmosphere. Just in time, Hermiod was able to beam them back to the Daedalus where Hermiod was able to use the information downloaded from Discenna to determine the true nature of Fenrir and come up with a solution. Following this, Discenna was left abandoned in the void once more. At least a ZPM powered the city, but Shepard and McKay didn't attempt to take it. (SGA: "Hermiod's Last Mission")