The Ha'tak-class mothership is the premier capital ship used by the Goa'uld, Jaffa, SGC, and Tok'ra. Throughout the years of the SGC's existance, the Ha'tak has undergone numerous upgrades due to Apophis, Anubis, Ba'al, and even Loki.
Apophis was the first to upgrade his ships with improved hyperdrives, shields, ands weapons. Anubis later appeared with ships that had improved sensors, weapons, and shields. Ba'al later combined the improvements of both Apophis and Anubis. Loki later allied himself with Anubis further upgrading his Ha'taks. After the Battle of Antarctica, Thoth defected to Ba'al and worked with Nerus to further enhance the abilities of Ba'al's fleet.