The Attero device was a powerful weapon created by the rogue Lantean scientist Janus as a means of ending the Lantean-Wraith war. By disrupting Wraith hyperdrive frequencies, it destroys any Wraith ship entering hyperspace within at least the range of a galaxy.
- "...if this machine is capable of actually functioning safely, it disrupts the very specific subspace frequencies the Wraith use."
"So they wouldn't be able to engage their hyperdrive."
"Well, that's the genius. They would be able to engage their hyperdrives. It's just that their particular channel of subspace would be destabilized and their ship would be ripped into a million pieces."
- ―Rodney McKay and Daniel Jackson[src]
The device was designed to disrupt the subspace frequencies associated with Wraith hyperdrive systems, causing Wraith ships to be destroyed as they passed through a hyperspace window. Since hyperdrives are unique to the species using them, Lantean vessels would still be able to travel across the galaxy and attack the stranded vessels or just let the Wraith die from starvation in the vacuum of space. Unfortunately, it had the unforeseeable side effect of causing energy to build up behind the event horizon of a Stargate's wormhole, destroying a Stargate whenever it was activated. As a result of this devastating side effect, Janus abandoned the entire project. (SGA: "First Contact")
The Attero device was first activated 10,000 years ago, when its creator Janus first tested it. He deactivated it after three days, due to "devastating and unforeseen side effects", which were later discovered to be causing Stargates to explode with the force of a dozen Nuclear warheads. (SGA: "First Contact")
In 2008 Dr. Rodney McKay and Dr. Daniel Jackson were forcibly taken to Janus' research outpost by the Vanir, where they were forced to activate the device using a control key from Janus' lab in Atlantis. This caused a duo of Wraith cruisers to be destroyed and Todd to believe that the Atlantis expedition had located and deliberately activated the device. Believing he was betrayed, Todd hijacked the Daedalus. Upon discovering the side effects of the device, McKay attempted to shut down the device, but was stunned before he was able to complete the process. While the device remained active it destroyed Atlantis' Stargate and severely damaged Stargate Operations; total destruction of the city was prevented by collapsing Atlantis' shield around the Stargate. At least one other planet ended up being affected by this: a planet that the Travelers had recently built a colony on. This was memorable as it was the first time in generations that they had lived off of their ships. The explosion of the Stargate destroyed it and two Travelers ships, one of which was their Aurora-class battleship. The resulting explosion was visible from space. Larrin dispatched a ship to Atlantis for answers and Lt. Colonel John Sheppard and Dr. Radek Zelenka boarded it to go to M6H-987 where the device was.
Meanwhile, Todd took the Daedalus to the planet as well. Along the way it was partially disabled by Ronon Dex and weapons were beyond repair so Todd set a collision course with the facility while he and his Wraith escaped in their scout ship. The Vanir were revealed to be a faction of Asgard who were using the device to get rid of the Wraith so they could leave their uninhabitable planet and move out into the galaxy without being bothered by the Wraith. They didn't use the Stargates so they didn't care about the device's side-effects. The Traveler ship arrived and two of the three Vanir spaceships engaged it to protect the device. In the meantime, McKay and Daniel broke free and managed to disable the device by removing the control crystal from the antenna, though Daniel was badly injured in the attempt. Two of the Vanir ships were destroyed by the Traveler ship and the third escaped into hyperspace. The Daedalus was prevented from crashing into the device due to the Traveler ship opening a hyperspace window in front of it and the human crew regained control. McKay and Daniel were beamed aboard the Daedalus and Sheppard on the Traveler's ship destroyed the device by blasting the complex to smithereens with the Traveler ship's weapons. (SGA: "First Contact", "The Lost Tribe")
- The term "Attero" is a Latin verb that translates as "I weaken" or "I destroy".