Mariposa Military Base The Mariposa Military Base was a top secret United States military facility built to house Forced Evolutionary Virus research previously conducted at West Tek , located somewhere in the area of the unincorporated community in California . Background . Pre - War history . The construction of Mariposa started in October 2076 when significant progress was made in FEV research , and the government preferred to move the project to a location under military supervision In 2077 , Major Barnett ordered transfer of all FEV research to the newly - constructed Mariposa Base , despite objections from the research team . Along with the scientists , a military team commanded by Colonel Robert Spindel , which previously monitored the experiments at West Tek , was sent to Mariposa . Spindel ' s second - in - command was Captain Roger Maxson . The FEV project was moved to Mariposa , where tests on human subjects were performed . The vats were giant tanks filled with liquid FEV and as part of the research project , human subjects were dipped inside them , then examined to learn how to control and harness the process . The experiments on humans were kept secret even from Spindel and his soldiers . Wartime events . On October 10 , Maxson and his men were horrified to discover that the scientists at Mariposa were using military prisoners as test subjects in their experiments with the Forced Evolutionary Virus . Morale in the base broke down and Spindel suffered a mental breakdown , eventually committing suicide 5 days later . The men turned to Maxson ' s for leadership . After interrogating Robert Anderson , the chief scientist , and learning about the extent of their actions , Maxson executed him and the other scientists soon followed . Maxson , now in control of the entire base , declared himself to be in full desertion from the army via radio on October 20 . However , he received no response , as the rest of the army was busy fighting the Chinese threat . Three days later , the bombs were launched , and the Great War ended two hours after it started . The Mariposa Military Base survived , the soldiers within protected from the radiation and FEV flooding the wasteland . Two days later at Mariposa , a scout in power armor named Platner was sent out to get specific readings on the atmosphere . He reported no significant radiation in the area surrounding the facility . After burying the scientists in the wastes outside of Mariposa , the soldiers sealed the military base , then headed out into the desert , taking supplies and weapon schematics with them . Captain Maxson led his men and the squads families to the government bunker at Lost Hills , eventually forming the Brotherhood of Steel . The base was left sealed , however , over the years it slowly fell into disrepair . Eventually various creatures made their way inside , mutating due to FEV exposure , then proceeded to infest the surrounding area , attacking fledgling human settlements and caravans . The problem was becoming increasingly severe , to the point when Harold , a caravan master from the Hub , mounted an expedition in 2102 to locate and destroy the source of the mutants . Master ' s Army . Dr . Richard Grey was one of the explorers who was part of the expedition . Harold led the men into Mariposa , but failed to account for the automated defenses , which were still online , which promptly attacked the explorers . Taking heavy casualties , they made their way to the deepest , fourth level , the FEV vats , where a crane smashed into the two surviving explorers , Harold and Richard Grey . The former was knocked out , the latter landed in one of the virus vats , succumbing to a severe overdose . In pain and horribly mutated , Richard crawled into the control room , as his intellect grew . In a few days , he was neurolinked to the base computer , drawing upon its sizable data banks . As he created the idea of the Unity , wanderers began to enter the facility , whom Grey patiently captured and dipped , in order to create beings as perfect as him . When the first true super mutants were created , he set out to create a true mutant army , at the same time deciding to look for a permanent base of operations . In 2155 , one of his patrols located a group of vault dwellers from the LA Vault , and he made the decision to transfer himself there , occupying it . The base was entrusted to the Lieutenant , one of the greatest super mutant minds to exist . Mariposa was rebuilt and cleaned up , once again becoming the magnificent military base it was before the war . Super mutants roamed the halls , restocking the armories and medical base and soon it became the staging area for their assault on humanity , as well as the only super mutant production center . Then came the Vault Dweller in 2162 . It is unknown whether or not he infiltrated the base or blasted his way in - suffice to say , once he was through , Mariposa was little more than a caved - in , smoldering ruin . Enclave ' s excavations . In 2236 , the Enclave discovered the remnants of the Mariposa Base . Soon , assault squads combed the desert for slaves they could use to mine the military base and get to the vats . One of the squads included soldier Frank Horrigan . Enclave construction crews , as well as human slaves began excavations . In September , they uncovered the FEV and mutations began to occur in the human workers . Frank Horrigan came into contact with the virus and was sent to the Enclave labs for study . In 2237 , having obtained the FEV data , the Enclave abandoned the site after more mutations occurred , causing 2nd Generation super mutants to arise . The Enclave left a single squad behind to wipe out the super mutants , but the mutants , using armaments they had cached in the base during excavation , reduced the squad to ashes after suffering heavy casualties . By 2241 , the remains of the ruined base are inhabited by those trapped human miners who have been hideously altered by the remnants of the FEV that still contaminates the wreckage . That group formed a new community under the leadership of Melchior , whose magical talents had allowed them to hide the weapons . Structure ( " Fallout " ) . Surface . Mariposa was a reinforced military base , constructed in the middle of nowhere , in the side of a mountain . The exterior had a characteristic white lining and a massive air conditioning vent , which provided fresh air for the complex . Inside , it consisted of four levels , stretching across a mile of depth . Stronghold Level 1 . The first level of Mariposa housed the gear needed for any excursions , as well as a staging area for patrols . The main control computers for the base ' s force fields and robotic guardians were located here , allowing any infiltrator to considerably sabotage the base , just by altering the pest control setting for the robobrains , in addition to altering the force field status remotely . Apart from that , guard barracks were located on this level , for off - duty surface security teams . Stronghold Level 2 . The primary soldier living quarters , medbay and armory were located on this level . The quarters were spacious , although spartan in design , with a large stockpile of weapons just around the corner and a well equipped sickbay , stocked chock full of medical chems , surgical equipment and medical beds with integrated life support systems . Stronghold Level 3 . The third level was divided in two , one was the general access area , where the assembly room and elevator to the commander ' s office were located , the second a military prison with an elevator going directly to the vats . When Mariposa was operating under government jurisdiction , experimenting with FEV , only scientists and their security staff were allowed into the prison area and the vats - soldiers under Colonel Spindel and Roger Maxson were barred from entry . Vats . Divided in two as well , the deepest level housed the massive FEV vats , together with their control room , scientist living quarters as well as the base commander ' s office . As with the third level , access to the FEV research area was strictly limited , with only scientists being allowed to enter . A special containment squad , the super mutant Vat Team 9 , was stationed in the room near the cell block access elevator , to deal with any potential disturbances . It was composed of three soldiers . The vats control room was where the base ' s mainframe was also located , holding personnel logs ( Boyarsky , Roger Maxson , Richard Grey etc . ) as well as the self - destruction initiation subsystem . Encrypted behind a firewall , these were nonetheless accessible for a skilled hacker . Alternatively , just blowing the console up would trigger the self - destruct sequence , but the base would be set to alert status , powering up the force fields . Structure ( " Fallout 2 " ) . Surface . The layout of the base is pretty much similar to that in " Fallout " , although there are some tents ( in one of them is the Military base holodisk 5 ) outside the base , wolf packs and the entrance to the base is blocked by rubble . To get in the base the player character will need to find the metal pole and put it on the rail cart ( " Use on " ) . Next , they need to put some dynamite ( can be found in the little shack right from the entrance to the base ) on the rail cart ( one need to right click and hold on the cart , and then choose the " bag " option ; after that , simply click on the dynamite from the menu ) and push it down . Doing this will net the player character 5 , 000 XP . Stronghold Level 1 . When the player character arrives to the first level of the base , first thing they would notice are the Enclave soldiers and mutant bodies lying around . The player character can loot these , for holodisk s and a plasma pistol . The level is mostly filled with mutated rats ( which can poison the player character if they bite ) , which can be easily dispatched . However , in one of the halls , there is a super mutant , Grundel , which will attack the player character , if they try to talk to him . He is wearing spiked knuckles . In the southwest corner ( in the hall leading to the elevator ) there is a broken power generator , which can be repaired for 1 , 500 XP ( this can be easily done if one has Vic in your party ) . Doing this will also turn on the lights in the base . Stronghold Level 2 . The second level of the base is filled with super mutant s , about 15 of them , but for an experienced player character , they shouldn ' t pose a large threat . Mutants are usually wielding power fists and flamers , although few of them use laser rifles and plasma rifles . In most of the lockers , the player character can find money , stimpaks , some ammunition and in the east corner of the map , a suit of T - 51b power armor . Stronghold Level 3 . Like on the second level of the base , the third level is also inhabited by super mutants which use laser rifles , plasma rifles and flamers . Also , there are some mutated beasts ( pig rat s ) which are weak , but the player character can get poisoned if they bite them . There are super duper mutants on this level , which have greater HP than " normal " mutants . As comes to the loot , the player character should pay attention to the first room after exiting the elevator . In the room is the locker , in which the player character can find a green memory module , which can be used to expand ACE ' s medical library , thus allowing the player character to increase their Perception by 1 . Finally , in the southeastern corner of the map , there is an elevator which takes the player character to the final level of the base , the vats . Vats . The deepest level of the base houses one of the tougher enemies in " Fallout 2 " , Melchior . He is standing in the northwestern corner of the map , surrounded by goo which has remained there since the Vault Dweller destroyed the FEV vats . Melchior himself is not that tough , but his abilities are unique . From the vats ( or more precisely , the goo ) , he can and will summon deathclaws , fire geckos , floater s and mutated mole rats . They are summoned in that descending order , and if the player character is strong enough to survive several waves of them , they are rewarded with some funny lines . He can have 4 summoned allies at a time , which can be bothersome , so it is best to dispatch him first , and then his " pets . " This is quite challenging , even for experienced player character ' s with a good party , so they should be very cautious , and prepared to leave the scene of battle with 1 - 2 less companions . Melchior also guards a locker containing a PPK12 Gauss pistol . Appearances . The Mariposa Military Base appears in " Fallout " and " Fallout 2 " . It is mentioned in " Fallout 3 " by Harold in Oasis . The base is also mentioned in a terminal located in Vault 87 . It is also mentioned in the personal journals of Maxson I , which are stored in the Citadel archives . It is mentioned on a " " loading screen saying that the super mutants in the Mojave are the remnants of Mariposa , and in its add - on " Dead Money " by Dog in idle dialogue .