Amanda Tapping was part of the Stargate SG-1 main cast for all of the show's ten seasons. She did not appear in season 6's " Disclosure " or season 7's " Inauguration " except in clips from previous episodes and was completely absent from season 8's " Prometheus Unbound " and the season nine episodes " Avalon (Part 2) ", " Origin ", " The Ties That Bind " and " The Powers That Be " due to Tapping's maternity leave (she appeared briefly in " Avalon (Part 1) " to explain her absence); and season ten's " Bad Guys ".