Life support is system found on spaceships that allows for breathable air to be purified and circulated across the ship.
In 2006, the Daedalus was used in an effort to evacuate the Taranians from their planet pending the explosion of a super volcano. However, despite the large size of the Daedalus, four trips were required to ferry the population between Taranis and Lantea given the limits of the ship's life support system. (SGA: "Inferno") Later that year, during a battle with two Wraith Hive ships, the Daedalus sustained weapons damage that took out life support and left the back-up systems unresponsive, necessitating the evacuation of the Daedalus' crew until the system could be repaired. (SGA: "No Man's Land")