The power station. Note how the ridges situated around it provide the perfect cover for an attacker and put defenders at a severe disadvantage
Operation Sunburst was a decisive strike on the Mojave Chapter of the Brotherhood of Steel by the New California Republic (NCR) over the control of the pre-War, Poseidon Energy solar plant Helios One during the Brotherhood War in 2276.
The occupation of Helios One was a decision made by Elder Elijah, who intended to unlock the secrets of the power plant. The Mojave chapter operated freely amid the Vegas wastes for several years, carrying out many reclamation missions without serious opposition. The balance of power shifted in 2273, when a large contingent of NCR troops entered the region and occupied Hoover Dam. Conflict was inevitable.
In 2274, the NCR had officially set up a base at McCarran International Airport and moved into the Mojave in force. The Elder's obsession with Helios One and the need to defend against NCR forces deploying into the Mojave resulted in the Brotherhood ignoring the expansion of the Van Graff family into the Mojave, despite them distributing pre-War energy weapons. The Elder's orders were clear. Two years of guerilla warfare against the NCR followed, ultimately leading to the confrontation at Helios One in 2276.
The power plant was not defensible, leaving Brotherhood forces exposed to attack from all sides, save for a small canyon leading to Hidden Valley. Despite recommendations for fighting a retreating action, Elder Elijah ordered his troops to dig in and protect the facility as he attempted to unlock the Archimedes orbital weapon system. The Brotherhood forces dug in, but their positions were exposed, vulnerable, and impossible to defend properly.
The Elder's decision to remain at the facility doomed the chapter. NCR troopers attacked the Brotherhood from every direction in waves, allowing fresh troops to sustain the attack while those who were repulsed pulled back to rally and regroup. Outnumbered fifteen to twenty times, the Brotherhood defenders were eventually exhausted and their defensive lines began to fragment. When the collapse became imminent, Elder Elijah disappeared. Head Paladin Nolan McNamara assumed command of the Brotherhood remnants and led a counter-offensive west into the McCullough mountains. Disappearing into the mountains, he managed to save what remained of the chapter. Over a half of its number was dead or left behind.
Elder Elijah abandoned troops under his command and disappeared into the wastes. McNamara wasted no time in gathering the survivors and retreating to Hidden Valley from Helios One, but not until reactivating the security measures inside the solar collection tower to prevent NCR from picking up on Elijah's research.
With their leader gone, McNamara assumed command in accordance with the Brotherhood's chain of command protocols. Abandoning the facility, the surviving Brotherhood members retreated into the canyons west, towards Hidden Valley. Instead of pursuing, NCR forces regrouped and secured the power plant; when they finally set out to locate and destroy remaining Brotherhood forces, they were nowhere to be found.
The Brotherhood, hidden within their sole remaining stronghold in the Mojave, declared a full lockdown. Activity outside the bunker was drastically restricted: only supply runs, occasional reconnaissance missions and night patrols were allowed to leave the underground installation and even then, they were strictly forbidden to engage NCR patrols. Though the Brotherhood's ascetic lifestyle has prepared its members for a sequestered existence better than most, the passivity of the current situation has proved highly stressful - especially as the order was extended in response to the NCR increasing its presence in the Mojave five times, while the Brotherhood failed to recover its strength. The lockdown order has remained in effect for five years, until 2281, when the conflict in the Mojave forced the Brotherhood to be either destroyed or become active once again. 
Although the bulk of the fighting force was almost immediately redeployed to secure Hoover Dam in preparation for the coming confrontation with the Legion, the NCR established a garrison in Helios One. Due to a stroke of bad luck, an incompetent con artist was hired to act as the facility's principal engineer. He was unable to bring the facility to even moderate operational status, leaving it stuck at 1% efficiency. Ignacio Rivas was posted by the Followers of the Apocalypse to research the facility independently and ensure that the ignoramus hired by the NCR would not figure out a way to unlock the facility's dark secrets. As he puts it, "Some things are best left buried with the Old World."
Operation: Sunburst is mentioned only in Fallout: New Vegas.
- Hidden Valley bunker terminals; Terminal, Journal Entry 01: "It's been a hard day. I think I lost more than twice as many as I saved. At a guess, I'd say we've lost a little over half our number, and all for some broken down solar energy station that barely works. I think if Elder Elijah hadn't gone missing I might have refused to treat him. Would have served the prick right.
Edit: God, I haven't looked over these in a while. I remember writing this like it was yesterday. Who would have imagined I'd spend the next few years of my life trapped underground?"
Note: Schuler has kept a once-a-week log since the end of Operation Sunburst. With the number of logs made, it can be figured out that the log has been going on for five years and the last log is on the anniversary of the battle.
- Fallout: New Vegas Official Game Guide Collector's Edition p.43: "Brotherhood of Steel"
"The Brotherhood of Steel is a militant organization devoted to the preservation of pre-war technology and human knowledge. Their professed mission is to preserve pre-war technology and human knowledge for the benefit of future generations. In practice, its definition of technology is strangely selective, ignoring basic but potentially useful technologies (genetic modification of crops and civil engineering, for example) in favor of combat technology such as energy weapons and power armor: and even now, nearly two centuries after the Great War, the Brotherhood zealously restricts the use and knowledge of such technologies to its own membership.
The Mojave Brotherhood operated freely amid the Vegas wastes for several years, carrying out many reclamation missions without serious opposition. The balance of power shifted in 2251, when a large contingent of NCR troops entered the region and occupied Hoover Dam. Conflict was inevitable. Nearly two years of guerilla skirmishes culminated in a pitched battle at HELIOS One, a solar energy plant the Brotherhood had been refurbishing for several months with the goals of bringing it back online and activating its hidden offensive capabilities (the ARCHIMEDES II death ray). The battle for HELIOS One (Operation: Sunburst) proved a disaster for the Mojave Brotherhood. More than half its Paladins and Knights were killed. The chapter's leader, Elder Elijah, disappeared without a trace. The Brotherhood was driven from the facility, which suffered extensive damage. Survivors retreated to Hidden Valley.
Since that defeat, the chapter's leader, Elder McNamara, has restricted activity outside the bunker to occasional reconnaissance missions and high-value raids. All operations take place at night, and engagement of NCR forces is strictly forbidden. Though the Brotherhood's ascetic lifestyle has prepared its members for a sequestered existence better than most, the passivity of their current situation has proved highly stressful."
(Fallout: New Vegas Official Game Guide faction profiles) Note: The date of the NCR occupying Hoover Dam is wrong, as the first NCR Rangers scouted Hover Dam in 2273, with the deployment following in 2274; article dates have been corrected to match.
- The Courier: "Why do you hate the Brotherhood so much?"
Robert House: "Because they're ridiculous! Because they galavant around the Mojave pretending to be Knights of Yore. Or did, until the NCR showed them that ideological purity and shiny power armor don't count for much when you're outnumbered 15:1. The world has no use for emotionally unstable techno-fetishists. Just wipe them out, will you?"
(Robert House's dialogue)
- The Courier: "Why was the Brotherhood of Steel here?"
Haggerty: "Damned if I know. Put up a hell of a fight, though. We had them outnumbered, I don't know, twenty to one, maybe. They held out as long as they could. Lost most of their force before they retreated. Gave us a little parting gift, too. They had some of the plant running, but they shut it all down. Enabled an old security system, too, to keep us away from the controls. Jerkoffs."
- The First Battle of Hoover Dam cost the NCR 107 Rangers and troopers, which is considered heavy casualties. Operation Sunburst is repeatedly referred to as a decisive, crushing defeat for the Brotherhood of Steel and no reference is made to casualties, indicating they must be lower in absolute numbers than the losses at the Dam. Furthermore, the fighting force retained combat potential, which allowed it to almost immediately redeploy to Hoover Dam, according to Lt. Haggerty. Finally, the total number of deaths in the Mojave is pegged at 400 civilian and military between 2273 and 2277, with over a hundred of these in 2277 and the Battle for the Dam alone.
- The Courier: "Mr. House won't be a problem. He's been disconnected from his system."
Cassandra Moore: "But he's still alive? I'll have to remember to send someone to follow up on that later. Anyway, at least he's out of the picture for the time being. You might be happy to know that your efforts haven't gone unnoticed, either. The brass have been throwing around the idea of having the president visit the dam for a while now. To rally the troops and boost morale and such. With our recent achievements, they finally feel secure enough to stage the damn thing. But while it's being planned, I have one last mission for you. Several years ago, we managed to wrest the HELIOS One solar power station from the Brotherhood of Steel chapter local to this area. It was a crushing victory, but no one's heard a peep from the Brotherhood since. Most people assume the Brotherhood is scattered and not a threat. Recently we've had scouts go missing in an area west of HELIOS, and I'm concerned that the Brotherhood is involved. I want you to find them, and once you do, finish them for good. Any questions?"
(Cassandra Moore's dialogue)
- Nolan McNamara: "Veronica. I hope-"
Veronica Santangelo: "I brought you a present. We unlocked the secret of HELIOS One."
Nolan McNamara: "What? Wonderful news!"
Veronica Santangelo: "No. It's not. ARCHIMEDES II is an orbital laser. Effective only outdoors in a limited radius and requiring a long recharge."
Nolan McNamara: "In the hands of the enemy-"
Veronica Santangelo: "They'd be marginally more effective. We lost most of the chapter defending glorified artillery."
(Veronica Santangelo's and Nolan McNamara's dialogue) Note: This conversation continues.
- The Courier: "Yes, what is the task?"
Edgar Hardin: "Back when we were stationed at HELIOS, our scouts reported that a group was establishing itself in the area as a distributor of Pre-War weapons. Our Elder at the time, Elijah, was too concerned with getting HELIOS running and fending off the NCR, so he ordered us to leave them alone. It's time that we correct that oversight, and show this region that the Brotherhood is still a force to be reckoned with. I want you to visit these weapons dealers, this Van Graff family, and make an example of them. Leave no one alive. When the job is done, report back and I'll arrange for a team to clean up the site and retrieve the weapons."
(Edgar Hardin's dialogue)
- The Courier: "Tell me about your last Elder."
Edgar Hardin: "Elijah was a strange one. His even becoming Elder was highly questionable, seeing as how he was a Scribe. Typically, only Paladins are eligible. But an exception was made in his case, on account of him being a genius. Unfortunately, whatever scientific acumen he had didn't extend to tactics. Trying to defend HELIOS was a blunder of the worst kind, and many brothers lost their lives because of it. Many of the senior paladins, myself included, advised him to fight a retreating action, but he refused to budge. Said he almost "had it working". We never did find out exactly what he was talking about. When the perimeter was finally overrun, the Elder had simply vanished."
(Edgar Hardin's dialogue)
- The Courier: "Tell me about what happened at HELIOS."
Ramos: "I'm sure someone's told you all this before. Several years back, we were running our chapter out the HELIOS One solar power station. Our Elder at the time, Elijah, had some kind of obsession with the place. Which is the only reason we stayed as long as we did. That place was hardly defensible, and we knew the NCR was moving in on us, but the Elder refused to budge, insisting that he just needed "more time". We never found out what he needed the time for. Wave upon wave of NCR troopers hit us from all directions. We held out for a time, but we were grossly outnumbered, and they had more men than we had ammo. Eventually our positions collapsed. Elder Elijah was nowhere to be found, so McNamara took charge and led what remained of us on a counter-offensive west. We lost a lot of men and women, but we broke through and made it here. Make no mistake, McNamara saved this chapter that day."
- The Courier: "I thought the Brotherhood were all wiped out at HELIOS One. How could they have survived?"
Cassandra Moore: "After the battle, we consolidated our hold on the plant before pursuing our enemies. It was a mistake, to be sure, but there wasn't really any place for them to go. When we finally gave chase, however, they had simply vanished. Some of our people think they had some means of conveyance, like the vertibirds the Enclave used, and hightailed it out of here. I think that they found someplace to hide close to HELIOS, and never went that far at all. Any other questions?"
(Cassandra Moore's dialogue)
- The Courier: "Tell me about the lockdown."
Nolan McNamara: "It's a protective measure that was enacted after our defeat at HELIOS. The NCR was hot on our heels, and we wouldn't have survived another encounter. It was decided that we would stay quiet for a time, heal the wounded, and try to come up with a new strategy. However, after we had fully recuperated, our first scouting measures showed that the NCR's presence in this region had only increased in our absence. There are now more than five times the number of NCR troops in the area as when we fought them, and we have half the number we did at HELIOS. And so the lockdown has been extended. To go outside would be the death of us all."
(Nolan McNamara's dialogue)
- The Courier: "Shouldn't there be more people than this defending a power plant?"
Haggerty: "There should. But we're not getting much power out of it so none of our enemies have a big interest in it either. Not like Hoover Dam, anyway. We had a real fighting force here just long enough to take it from the Brotherhood of Steel. Then they got sent east to the dam like everybody else. Caesar's Legion sends skirmishers every so often. Prodding for weaknesses, mostly. The reality is, if they really wanted it, we'd all be dead."
- The Courier: "I just do what's necessary to keep the peace."
Ignacio Rivas: "That's reassuring, although many who've made that claim to the Followers of the Apocalypse over the years have had less than pure intentions. But if it's really as you say, then take my advice. This installation carries with it dangers that no one here has realized. Take care what you do here, and who you listen to. Some things are best left buried with the old world."
(Ignacio Rivas' dialogue)