ArcJet Systems ArcJet Systems was a pre - War military and civilian aerospace contractor in the United States , specializing in communications , propulsion systems and custom - built high - tech aviation equipment . This large facility now lays abandoned in the Commonwealth . Background . In 2075 , ArcJet began working on a nuclear - powered rocket , the XMB booster engine , in hopes of convincing the United States Space Administration to award them the lucrative contract for their Mars Shot Project . Despite the risk of starting work before the contract , it paid off when the USSA gave them both the contract for the booster engine and the contract for a deep range transmitter . Both projects were completed before 2077 . However , ArcJet only received payment for the deep range transmitter project , as the rocket was delayed prior to the Great War for problems on the western front . CEO Thomas Reinhardt promised the USSA to finish both projects by July 2077 , a year before the expected launch date . Eager to deliver on its first Agency contract , CEO Reinhardt hired Dr . Rory McClellan , a private military contractor , to lead the development of the XMB booster engine . Reinhardt also ordered head of security , Sam Brent , to double the facility ' s security and install automated security systems . By December , both of their projects were on schedule , and even under budget , and the USSA was discussing the possibility of other future projects . In March 2076 , the XMB suffered a setback when at one month behind schedule , it was discovered that it was hundreds of tons overweight , setting them potentially three to six months behind schedule . Reinhardt also became increasingly paranoid about security , having turrets installed in the office areas and requiring everyone to wear special identification badges or risk being fired upon . In July , the USSA announced the Mars Shot Project to the public , resulting in an increase of popularity and media coverage at ArcJet , forcing Reinhardt to lie about their progress . In November , McClellan was able to fix the engine ' s weight issue , allowing ArcJet to finalize the project . By 2077 , ArcJet was able to complete the deep range transmitter project , allowing them to earn the proceeds from their contract . In February 2077 , ArcJet planned to hold a press event to show off the first USSA test fire of the XMB booster engine . However , before the event , a reporter somehow managed to sneak into the core engine room and was accidentally vaporized by an engine test . The press event was cancelled and Reinhardt ordered Sam Brent to cover the death up to prevent them from losing their contract . By September , the USSA warned Reinhardt that they may have to delay the Mars Shot Project due to the conflicts overseas . In October , Dr . McClellan discovered the cover up of the dead reporter and told Reinhardt he was going to inform the police . Reinhardt responded by threatening to kill McClellan and his family if he told anyone . Despite this , McClellan still planned to take the video evidence to the press . Layout . The layout of the building differs , depending on whether or not the Call to Arms quest has been started . Prior to starting the quest , the building will only consist of the main lobby and a corridor leading to a collapsed room . Once the quest has been started , the whole building will be accessible and infested by synth s . Upper floors . The upper floors of the building have suffered massive internal damage , making it a maze of collapsed floors and ceilings . This area consists of a main lobby area , offices , restrooms , data storage , and board rooms . After passing the lab control room is a lobby defended by two ceiling mounted machine gun turret s and a handful of synths . This lobby gives access to several rooms which contain a weapons workbench , an armor workbench and a chemistry station . In the room with the chemistry station , an Expert locked terminal can be used to unlock a nearby Expert locked safe . In the eastern room , some stairs are leading up to the office area . The office area is first accessed through the CEO ' s office , in which the Tesla Science Magazine issue # 1 can be found . The corridors are heavily defended by 4 ceiling mounted turrets although they can be deactivated from a terminal located in the first room on the left hand side . In the northwest corner , a collapsed floor gives access to the receptionist area where a Advanced locked safe can be found and where stairs lead down to the ArcJet engine core . ArcJet engine core . Beneath the main building is a large rocket engine test chamber . The XMB booster engine can be found suspended from the ceiling . At the bottom of the chamber is a facilities terminal inside a small control room that can be used to restore auxiliary power . The engine is still functional and can be activated by pressing the start button in this control room once power is restored . The engine will test fire and the intense flames from will turn all synths inside the chamber to piles of ash . This can only be done once and cannot be repeated . The only way to access the top section of the chamber is to ride the elevator due to collapsed stairs . At the top is a main control room and multiple synth enemies . Here one can find the deep range transmitter and an elevator to the surface . Appearances . ArcJet Systems appears only in " Fallout 4 " . The ArcJet G - Force attraction is also sponsored by ArcJet in the " Fallout 4 " add - on " Nuka - World " . Behind the scenes . The name ArcJet may be a reference to the , an engine produced by Lockheed Martin by the same name .