Operation Wenna Tevuk (English: Breaking Dawn) was a Migrant Fleet joint scientific-military operation on Haestrom led by Brigadier General Tali'Zorah vas Neema and Major General Kal'Reegar vas Rayya conducted as part of Operation First Strike with the goal of investigating the rapid deterioration of Haestrom's sun, Dholen, and its potential involvement with a theoretical geth super-weapon. In late June 2185 CE, spy drones deployed by the QMFV Ciko as part of Operation Fetun in the Dholen system, relayed telemetry back to the frigate with data that puzzled its science team, who concluded that Haestrom's sun, Dholen, was aging significantly faster than it should have been, threatening premature eruption into its red giant phase tens of millions of years ahead of what it should have been, and this deterioration had led to widespread magnetic eruptions and solar instability, which had been slowly overwhelming Haestrom's atmosphere for at least 100 years, going unnoticed by previous Migrant Fleet observation teams due to its gradual nature: by 2185 CE, Haestrom's atmosphere had failed, allowing unfiltered solar radiation to assault the planet's surface, with minutes of exposure to the sun's rays causing electronic failure, and hours of exposure proving lethal to organic beings: another side effect of Dholen's extreme solar output and magnetic eruptions was that communications and sensor systems across the system were disrupted, becoming more and more ineffective the closer you got to Dholen itself, which proved beneficial to the quarians as it kept them hidden from geth patrols, allowing them closer observations of Haestrom and geth installations than would normally be safe. This news proved alarming to the science team, taking the presence of geth space stations being built in proximity to Dholen as suspicion of geth involvement in the star's gradual deterioration. Marking the information as "need-to-know", the Ciko withdrew from the Far Rim and sent a priority encrypted communique back to the Fleet, informing them of what they found and returning shortly after to present the information in person. Han'Gerrel was extremely alarmed by this, and after presenting what was found before the Admiralty Board, received permission to authorize a clandestine expedition to Haestrom to retrieve more information about the phenomenon and how it was affecting Haestrom.

Working closely with Admiral Daro'Xen, who would provide the necessary scientific personnel, Han'Gerrel agreed to provide a military escort, assigning the 2nd Force Recon Company of the 34th Marine Expeditionary Force, under the command of Kal'Reegar, considered of the Fleet's best marines to provide escort duty. Tali'Zorah, after push from Admiral Rael'Zorah to have her involved, was also assigned to the operation, largely in charge of the scientific detail's protection, but also sharing command responsibility of the military detachment. The plan was initiated on 15 August 2185 CE, the team deployed via the QMFV Hutbyk, one of two operational prototypes of a quarian stealth ship using technology inspired by that of the Alliance's IES system, to the surface of Haestrom, doing so from the dark side of the planet in order to avoid the majority of the geth forces. Once on the surface, the quarian team was able to avoid most of the geth forces and remained undetected as they reached Fort Ik'halm'la'peh, the chosen spot from which to make the necessary observations while the 2nd Force Recon established defensive positions in the surrounding area and kept an eye on geth communications. For nearly a week the operation went off without a hitch, but a slight mistake in communications protocol from one of the scientists led to a signal being intercepted by a geth observation station in orbit, and the alert was sounded. Within minutes geth troops arrived on scene and engaged the quarian forces, and Tali'Zorah sounded the exfil order. The scientists however took too long to pack up their gear, and geth reinforcements soon arrived from orbit, cutting off any chance of escape. The subsequent battle was saved only by the arrival of the Normandy Squad, but by the end most of the 2nd Force Recon had been wiped out. The scientists however were able to escape with only one casualty, and relayed what they found back to Daro'Xen. Although their data was incomplete, the larger conclusion was made that the geth were unlikely to have been involved in Haestrom's deterioration, assuaging fears of a geth super-weapon, but still leaving the larger scientific community of the Fleet baffled by Haestrom's rapid aging.

The results of the operation would ultimately save millions of quarian and geth lives centuries later. The Republic of Rannoch would establish a permanent scientific observation unit in 2196 CE known as the Dholen Observation Team, in the Dholen system to monitor the status of Dholen, and more clearly delineate and chart its exact course of collapse, allowing a clearer picture of its eventual doomsday to be painted, allowing the Republic's finest quarian and geth scientists to conduct evacuations at the necessary time: however, ontop of this, the unit was assigned the duty of hopefully finding a way to stop, or at least stabilize, Dholen's aging for a while longer or return it to its natural rate of decline. Through these efforts the culprit of dark matter affecting the interior of the star was discovered, and while the team was not able to stop it, subsequent efforts by 2389 CE were finally able to stabilize the star's aging, extending it by several million years.