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 Cambridge.

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 it was discovered that it was hundreds of tons overweight, setting them 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, but 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.

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. During the quest Call to Arms this section of the building will be infested by synths.

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 auxillary 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 you can find the deep range transmitter and an elevator to the surface.

Notable loot

 * Discarded ArcJet worklog – In the lab control room, on a desk next to a terminal and a globe in the middle of the room.
 * 1 Stealth Boy – The first is past a locked door (novice) to the left of a collapsed stairway in the small lobby with a broken, flooded floor. Once through the door, check behind the collapsed floor/ramp to the left to find the Stealth Boy sitting on a metal shelf.
 * Tesla Science Magazine issue #1 (+5% energy weapon critical damage) – On the table with the CEO's terminal. You have to pass the same locked door as for the first Stealth Boy, but turn left instead and go up the stairs. It is in the first room you come to.
 * Overdue book – Sitting on the large table in the meeting room, which is located on the second floor in the northwestern corner of the hallway where you encounter three machine gun turrets attached to the ceiling.
 * Junk Jet – Engine Core, in the control room at the base of the rocket, on a work table beside a holotape from the creator.
 * Technician's personal log - On the table with the Junk Jet.
 * ArcJet project manager's password - In the cabinet high up just to the right of the project manager's terminal in the Engine Core section, unlocks the nearby terminal.
 * Fusion core – In the generator room behind the rocket control room.
 * Deep range transmitter – Quest item for Call to Arms, located on a synth in the upper floor control room after using the elevator in the rocket test area.
 * Fat Man – Sitting on a desk inside the north room (Marked with a '2' on the right side of the door) in the ArcJet Engine Core section. NOTE: This can either be accessed going down from the top of the stairwell, or by getting onto the railing as soon as you enter the area with the engine and jumping up to the walkway that leads to the room marked with a "2".

Appearances
ArcJet Systems appears only in Fallout 4. A ride is also named after ArcJet in the Fallout 4 add-on Nuka-World.

Behind the scenes
ArcJet may be a reference to an engine produced by Lockheed Martin by the same name.

Bugs

 * P.A.M. can give the missions to kill Coursers (Railroad) in this location but you won't have access to most areas yet due to another companion mission not being completed yet. This will leave you unable to finish the mission.
 * This can be fixed by using a Power Armor glitch. Simply face the broken door in third-person, aim your gun to push yourself into the door a little, hold the button to exit the Power Armor, then turn your back to the door. If done right, you will get out through the door. This will however start Call to Arms and cause Paladin Danse to show up but attempt to leave. The quest cannot be finished this way however.
 * In the Engine Core section, when you activate the rocket engine while the quest Call to Arms is not activated and Paladin Danse is not in the room, companions will get stuck in the observation room. Reloading an earlier save is the only way to fix them.