The fifth and final season of the military science fiction television series Stargate Atlantis commenced airing on the Sci Fi Channel in the United States on July 11, 2008, concluded on the same channel on January 9, 2009, and contained 20 episodes. The show itself is a spin off of its sister show, Stargate SG-1. The season upgrades previous supporting characters cast members such as Richard Woolsey (from Stargate SG-1) and Jennifer Keller. Amanda Tapping's character Samantha Carter was downgraded to recurring character in this season. The fifth and final season is about a military-science expedition team fighting against the Wraith from their base of operation, Atlantis. The Wraith primary goal is to gather a fleet to invade Atlantis and find their new "feeding ground", Earth.