"We've just received word from our research team that they've uncovered some kind of hidden weapons relay upon the planet Tarsonis. They report that it's called a Psi Disrupter, and that its purpose is somehow connected with the Zerg."
The first psi disrupter was developed by the Terran Confederacy to interfere with the zerg psionic link, fragmenting the Swarm's gestalt and rendering it less effective on the battlefield. It was constructed on Tarsonis but it was not activated during the zerg invasion. The nascent Terran Dominion attempted to locate the disrupter but could not find it; it was thought lost.
Stukov's duplicity was soon discovered and a UED strike force led by Duran landed on Braxis with orders from DuGalle to not only destroy the disrupter but execute the Vice Admiral as well. The strike force succeeded in mortally wounding Stukov but before dying he revealed Duran's treacherous nature and successfully appealed to DuGalle to spare and use the disrupter. Duran then attempted to destroy the device by activating the self-destruct, but UED troops were able to foil this attempt in time despite the sudden appearance of zerg forces. A UED garrison was deployed to safeguard the now-active disrupter.
The disrupter proved its worth in the ensuing UED assault and victory on Char. The second Overmind was captured and the UED began taking control of the Swarm in the sector, creating Slave Broods. The effects of the disrupter were widespread and severely weakened Kerrigan's control over her own broods.
Kerrigan rallied the sector's factions suspicious or hostile to the UED to her and, as a first step to ousting the invaders, led them on a strike against the disrupter on Braxis. A small team led by Commander Jim Raynor first destroyed a number of large external power generators feeding the disrupter. With the disrupter offline, Kerrigan used a psi emitter provided by Emperor Arcturus Mengsk to reassert control over local zerg creatures, including a number of special zerg warriors, creating an army which was used to finally destroy the disrupter.
Despite the destruction of the disrupter and the UED force, the legacy of both endured. UED studies had discovered that concentrated doses of sigma radiation could slow zerg movement and reaction speeds by as much as 50%. Subsequent Dominion research confirmed this effect on zerg tissue, and smaller psi disrupters were developed to leverage the effect on the battlefield.
During the Second Great War, Doctor Egon Stetmann conducted research into the zerg, and came to the same conclusions as to the effect of sigma radiation on zerg tissue. It would take a lot of work and effort to safely deploy sigma radiation on the battlefield to the extent where zerg would be slowed, but he concluded that it might be worth it. Dominion research later confirmed the findings of Stetmann and the UED researchers, and the Terran Dominion deployed smaller psi disrupters onto the battlefield.
In the final missions of the Wings of Liberty campaign, psi disrupters enhance defenses when co-located at choke points and above ramps; this makes it more difficult for zerg to approach and overrun defenses unscathed. Psi disrupters are less effective against zerg flyers, especially brood lords.
Studied conducted by the United Earth Directorate have shown that concentrated does of sigma radiation can slow zerg movement and reaction speeds by as much as 50%. The psi disrupter has been developed to constantly emit sigma rays in a large area of effect, making it an essential base defense when facing a large zerg force.
All structures repair themselves to 50% life. All structure fires are automatically put out.
This all-in-one safety system automatically dispatches robotic drones to put out any fires and perform basic repairs on damaged structures. Although these drones are effective at doing basic repairs, they do not have a strong enough AI to perform the more delicate repairs needed to restore a structure past half life.
The psi disrupter was among the last terran buildings designed for Wings of Liberty, alongside the hive mind emulator and automated refinery. Most of these buildings were one-shots with no revisions but had the benefit of getting higher texture polish.
The psi disrupter may have initially been called the "sigma projector."
↑Samir Duran: "I must humbly suggest to you, Admiral, that the Disrupter be destroyed as quickly as possible. If it should fall into the hands of the Dominion we could face some very serious problems." Gerard DuGalle: "Hmm. A prudent call, Lieutenant. I am inclined to agree." Alexei Stukov: "But Admiral, this device could insure our victory over the Zerg! It is foolhardy to discard such an advantage!" Duran: "Surely, Vice Admiral, you don't doubt the tenacity of your own fleet? Your Directorate forces will devastate the Zerg without the need for such a device." Stukov: "Listen here, Lieutenant, I've had just about enough of your-" DuGalle: "This conversation is over, Alexei. Given the true nature of our mission to enslave the Overmind, we could hardly stand to have Mengsk control a device of this magnitude. This Psi Disrupter must be destroyed in order to safeguard our mission. Ensign, set your course for Tarsonis." StarCraft: Brood War. Vivendi Games. Level/area: Ruins of Tarsonis (in English). 1998.
↑Adjutant: "Admiral, our sensors have detected a fully functional Psi Disrupter on the planet's surface directly below our position. It would appear that the Vice Admiral did not destroy the Psi Disrupter on Tarsonis as was ordered." DuGalle: "What? Impossible!" Duran: "I warned you Admiral! Stukov has betrayed you! He's reconstructed the Psi Disrupter in order to sabotage your mission in this sector!" DuGalle: "I can't believe it. Yet the evidence is incontrovertible. Alexei, what have you done? Perhaps you've been right all along, Lieutenant. On my authority, enter the Psi Disrupter... and... deal with the Vice Admiral appropriately..." Duran: "Of course, Admiral." StarCraft: Brood War. Vivendi Games. Level/area: Patriot's Blood (in English). 1998.
↑Duran: "Vice Admiral Stukov, I am here under orders to terminate your command." Stukov: "Lieutenant Duran. I'm not surprised. We both know exactly what it is that you're here to terminate. Get on with it." Duran: "Say goodnight, Stukov." Stukov: "To hell with y- !" DuGalle: "Lieutenant Duran, report your situation immediately!" Stukov: "Gerard... old friend. You do indeed have a traitor in your midst... but it's not me. Duran. He has been playing us both from the start... He convinced you to destroy the Psi Disrupter... even though it was our best chance at defeating the Zerg. And then, on Aiur, ...he allowed the Zerg to overrun us even as we had the fugitives in our grasp. I came here... to activate the one hope we have of defeating them... And you killed me for it. Heh, heh... Duran is your enemy Gerard. I suspect... that he may even be infested as well... Use the Disrupter, Gerard... Finish our operation... Let my death have at least some meaning." DuGalle: "Alexei! No! What have I done? What have I done? Computer, where the hell is Lieutenant Duran?" Adjutant: "The Lieutenant no longer registers on my sensors, Admiral. He appears to have vanished." DuGalle: "No." StarCraft: Brood War. Vivendi Games. Level/area: Patriot's Blood (in English). 1998.