Heurkea operation
During the Galactic Civil War, the Heurkea operation unfolded on the planet of Dac. A compact Rebel squad, composed of former Senator Bail Organa, Captain Juno Eclipse, and the holodroid PROXY, executed an infiltration into the Imperial-occupied world of Dac in 1 BBY. Their aim was to augment the Rebel Alliance with the might and resources of the Mon Calamari Resistance, as the Alliance was critically short on manpower and starships necessary to genuinely challenge the Galactic Empire's dominion over the galaxy.
Beyond merely enlisting the Mon Calamari and even the Quarren species into the Alliance's ranks, Organa and his team journeyed to Dac with the specific intention of persuading Captain Gial Ackbar, an escaped slave and the leader of the Resistance, to enlist in the Alliance Fleet as a commissioned officer. Grand Moff Wilhuff Tarkin, a trusted advisor to the Galactic Emperor Palpatine and Ackbar's former master, was the official overseeing Dac's occupation.
Prelude

Not long after the disastrous mission on Cato Neimoidia, Captain Juno Eclipse provided a report to the Alliance leaders, namely ex-senators Mon Mothma and Garm Bel Iblis, as well as Senator Leia Organa, who was there to represent the interests of her adoptive father in his absence. The presumed death of Jedi General Rahm Kota was perceived as a disappointing setback. Mothma, already fearful and excessively cautious, grew even more resistant to her colleagues' ambition to openly challenge the Galactic Empire. With the war beginning unfavorably, she desired to preserve the Alliance's limited resources.
Juno Eclipse had grown tired of Mothma's static stance, much like Rahm Kota before his disappearance on Cato Neimoidia. Eclipse believed that the Alliance would never be taken seriously by the Empire if it continued to pursue the former senator's slow and ineffective approach to war. Therefore, she attempted to convince the Alliance leaders that a powerful display of rebellion would force Emperor Palpatine to consider the Alliance a real threat. Concurrently, she also emphasized the need to replace Kota with a new military leader who could inspire the soldiers to rally around the Alliance's cause. Both objectives could be accomplished with a single action on the planet Dac by recruiting the Mon Calamari Resistance and its leader, Captain Gial Ackbar. Although Ackbar pledged his support to the Alliance after being liberated from slavery, it was a weak display of allegiance without the support of his world or its valuable military resources.
However, given that Dac was under significant Imperial occupation, Mothma dismissed Eclipse's plan as too dangerous for the fledgling Alliance to endorse. Conversely, Garm Bel Iblis approved and sought to vote in favor of a mission to Dac. Due to his absence from the meeting, Bail Organa's vote defaulted to his adopted daughter, Princess Leia Organa, who declined to act before consulting with her father. Eclipse could only watch in anger and frustration as she witnessed firsthand how the Alliance leadership was stuck in division and indecision. As Mothma explained how another catastrophic setback would leave the Alliance in an even worse position and further discourage the Mon Calamari from fully committing to the Rebellion, Eclipse understood how Kota could hold the Alliance leaders in such high contempt.
When she threatened to resign her commission as captain of the Rebel flagship Salvation and leave the Alliance permanently, Commodore Yat-De Viedas threatened her with the possibility of a court-martial for working alongside General Kota without the approval of Alliance High Command. Exhausted and resigned to the situation, Eclipse accepted her fate and awaited their decision. In the meantime, she was temporarily suspended from active duty.
Recruiting Ackbar

After the meeting concluded, Juno Eclipse resolved to take matters into her own hands by pursuing her objective to bolster the Rebellion, regardless of whether the Alliance leaders approved of her actions. However, she was initially uncertain about how to proceed, considering that she was not a Force-wielding assassin who operated outside of the organizational hierarchy as Galen Marek had been. In contrast to Darth Vader's former apprentice, Eclipse thrived on knowing her place and executing all duties precisely; "thinking outside of the box" was not her forte. Therefore, she welcomed the discreet assistance of Bail Organa, who had followed her to Dac's moon. Along with PROXY, Marek's old holodroid, Organa and Eclipse successfully arrived on Dac without alerting the Imperial garrison.
Upon their arrival, the trio were greeted by Captain Ackbar. The Resistance leader agreed to Eclipse's proposal, but only if they first aided him in a plan to liberate the Mon Calamari and Quarren from the Empire's control. Consequently, they devised a plan to weaken the Imperial infrastructure that was keeping Dac suppressed. To increase the chances of a successful mission, Ackbar introduced Seggor Tels and five Quarren saboteurs. Although Tels had initially collaborated with the Galactic Empire, he assured the Rebels that the enslavement and mass murder of Dac's native population had prompted him to take up arms against the Empire by joining the Mon Calamari Resistance.
The mission's focus was to infiltrate the city of Heurkea, which was guarded by the TIE fighters of the 181st Imperial Fighter Wing. Except for full-wing debriefings, which occurred every five days, the pilots of the 181st conducted constant patrols with at least two TIEs in the air at all times. Therefore, the Rebel group aimed to make an example of Heurkea by disrupting the Imperial operation in the city. By doing so, they would also succeed in damaging the prestige of the Empire, thus achieving a symbolic victory that would encourage the peoples of Dac to launch a full-scale insurrection.

After entering Heurkea stealthily and eliminating several stormtroopers along the way, the group captured Evir Derricote, the commanding officer of the 181st. PROXY, utilizing his built-in holographic technology to impersonate Derricote, distracted the 181st pilots during a full-unit debriefing and then issued orders that would keep them occupied while the Rebels proceeded with their objective to assassinate Grand Moff Wilhuff Tarkin. As one of the Empire's most prominent figures, as well as the architect of the Imperial doctrine, Tarkin was considered a high-value target for assassination by the Empire's enemies. Simultaneously, the Quarren saboteurs discreetly planted explosives throughout the city.
When Tarkin and his stormtroopers surrounded the Rebels, the mission initially appeared to be compromised. The Grand Moff boasted about how Tels had betrayed the Mon Calamari by collaborating with the Empire once again. He also commented on his intention to reclaim his slave, Ackbar, for whom he had developed a fondness.
However, he failed to realize that it was a ruse to lure him into the open, thereby exposing himself to his would-be assassins. As the 181st TIE fighter flew over the city, the explosives were intentionally detonated to create the illusion that the 181st was attacking the Imperial-occupied city of Heurkea. The Imperials were easily deceived into believing that their own pilots were attacking them, and thus attempted to retreat to safety. In the ensuing chaos, the Rebels killed many stormtroopers, but Tarkin managed to escape with his life.
Aftermath

Despite their failure to assassinate Grand Moff Tarkin, the Rebels deemed their mission a success. The Galactic Empire's reputation had been tarnished, and the Imperials had been ridiculed—all thanks to the efforts of a small team of Rebels and Dac resistance fighters. With their primary objectives achieved, save for the elimination of Tarkin, the Rebels released Derricote so that he could provide a report of the Rebel activity on Dac to his superiors, thus spreading the word throughout the Empire's chain-of-command about the Rebellion's unwavering determination to win at all costs.
By humiliating the Empire, Juno Eclipse knew that many other beings would be inspired to rise up against Palpatine's oppressive regime. She also knew that their actions would motivate the peoples of Dac to continue resisting the Empire until their world was liberated from Imperial control. As she and her companions prepared to depart from Dac, Captain Ackbar expressed his gratitude to the Rebels by assuring them that the Mon Calamari Resistance was prepared to join the Alliance to Restore the Republic in their shared goal of overthrowing the Galactic Empire. The humiliation of Imperial forces during the Heurkea operation would ultimately lead the Mon Calamari to revolt against their oppressor and liberate their world.
When Eclipse reported the events at Heurkea to the Alliance leaders, Mon Mothma was furious with the Rebel officer's insubordination to the Alliance's chain-of-command. She even regarded Bail and Leia Organa with suspicion, believing that the two had assisted Eclipse covertly. Despite the fact that the success on Dac achieved more for the Alliance than Mothma's overly cautious approach to warfare, Mothma maintained her belief that all-out war against the Empire was a futile and reckless strategy. In her view, the Alliance would have lost Organa and Eclipse, as well as any hope of recruiting the world of Dac, if the mission had ended in failure. Garm Bel Iblis, dissatisfied with Mothma's constant complaining, denounced his fellow ex-senator and scolded her for obstructing an entire organization that wanted to fight the Empire. By opposing the will of the people, Bel Iblis likened Mothma's leadership to a tyranny, not so different from the one they were trying to fight—if Mon Mothma would just step aside instead of always being an obstacle. Mon Mothma, opposed by her own colleagues and the vast majority of the Rebel Alliance, accepted her personal defeat and realized that she could no longer impose her own style of leadership over the Rebellion and its followers. Due to the example of Dac, the rest of the Rebel leaders began to seriously consider Eclipse's views on how the Alliance should conduct its operations against the Empire. Regarding her views, Eclipse preferred Rahm Kota's aggressive tactics to Mothma's complacency, but without Kota's recklessness. She advocated decisive and smart actions, making a difference through achieving well-planned victories on a major scale, or at the very least—symbolic ones as well.