The Hyperspace Bypass Generator was a large wormhole generator built on Earth during the Thanagarian invasion.
The generator built on Earth was intended to be the last in a series that would create a hyperspace route allowing a Thanagarian fleet to bypass the outer defenses around the Gordanian homeworld, allowing them to attack the homeworld directly and end the war. Opening the gateway in hyperspace would have the side effect of destroying the planet Earth itself—an effect regarded by the Thanagarians with indifference.
On the pretext of building an energy shield generator to protect Earth from a Gordanian invasion, a Thanagarian force led by Hro Talak began construction of the generator in the Gobi Desert, assisted by the Justice League. When their ruse was exposed, and the Thanagarians established military occupation of Earth, they used humans as slave labor to complete the construction.
Because of its massive size, Batman determined that the only way to destroy it was to de-orbit the Watchtower and pilot it on a collision course with the generator. Batman undertook this task alone, while the rest of the League attacked the Thanagarian command ship to shut down the force field protecting the generator. The Watchtower impacted seconds before the activation sequence was completed, destroying the generator just before the hyperspace portal was opened.
Without the earth relay, the Thanagarians were unable to establish a route to the Gordanians' homeworld. Unfortunately, while their attack fleet was elsewhere in the galaxy, waiting to enter the route, Thanagar itself was left undefended, and fell to a Gordanian invasion.
- "Flashpoint" (referred to indirectly)