|Out of universe information|
Tagrean is a race of humans from the planet Tagrea. The Tagrean ancestors were taken from Earth thousands of years ago by Heru'ur. The inhabitants were under his control until its Naquadah mines ran dry around three hundred years ago, after he left the inhabitants buried all evidence he had existed and he was written out of the history books. Only a few scholars interested in their people's origins maintained a small number of relics and paraphernalia that remained from this time.
The Tagreans are technologically advanced, capable of launching missiles into their planet's orbital space. They also have monorails (possibly based on magnetic levitation principles) and flying weapons platforms. The latter may be based on the dirigible principle, or may be heavier-than-air. In that case they would however need to employ some kind of anti-gravity technology, as they are not aerodynamic and can hover but have no visible rotors. Such technology seems beyond the Tagreans' demonstrated level, but not outside the realm of possibility.
In 2003 while testing Prometheus' hyperdrive engine, the Tau'ri journeyed to Tagrea to locate a possible stargate and were forced to jettison the Naquadria core over Tagrea when it went critical. The core's overload and subsequent explosion in orbit over Tagrea caused an electromagnetic pulse that created a range of problems on the ground, rendering some Tagrean technology temporarily inoperable. The Tagrean people had no clue where the Stargate was on their planet, or that there even was one, prior to the Tau'ri's arrival. (SG1: "Memento")