Sentinel Site

The Sentinel site, known as Sentinel Site Prescott before the Great War, is a location found in the Glowing Sea in Fallout 4.

Background
The Sentinel site was a pre-War military facility that was working to make the air-dropped 'Mk. 28' nuclear bombs compatible with a newer ICBM delivery system. The facility was discovered by the Children of Atom after the Great War, who were able to activate the launch sequence before being massacred by the feral ghoul inhabitants. Although no missile was present on the launch pad, all internal blast doors in the facility were closed and locked, requiring the Sole Survivor to deactivate the sequence in order to gain full access to the facility.

Captain Dunleavy of the 132nd Engineering Corps was stationed at the facility when the bombs fell, in which his holotape reveals that many of the military personnel stationed at the site that day were nervous because communications were down and multiple launches were being detected, but no one knew if it was a drill or the real thing.

Given the strong military presence at the facility and its tactical purpose, as well as its proximity to the Crater of Atom, it is possible that during the Great War, the Chinese may have been aiming for it.

Layout
The exterior of the structure is a concrete pyramid, with a large blast door entrance on the North side.

As the Sole Survivor enters the facility, they will find themselves in a rather tall room that looks like a missile silo with some catwalks going through it. In the first control room when you go left after first entering the site, go in, and down the stairs to the right is a Sentinel site blast door override holotape on the teal control panels, it will open the blast doors in the facility. At the bottom of the facility there are three unused nuclear warheads in metal crates and a fourth on a forklift. They will not detonate from gunfire or explosions, but be prepared for a horde of feral ghouls hiding in a tunnel nearby. At the end of the tunnel there is a lift that will take the Sole Survivor to a second exit; not marked on the map. When the lift is called, a leveled glowing one will appear guarding a crate with minor loot.

Notable loot

 * Astoundingly Awesome Tales #10 - found in the first control room when walking left from entering the site (lower half of room to right of the bottom of stairs on the teal control panels).
 * Sentinel site blast door override - found in the same room as the Astoundingly Awesome Tales on a different desk.
 * Three Vault-Tec lunchboxes can be found here:
 * One in the lower tunnels, inside a hidden tiny room accessible via a hole in the left wall of a large room you pass through.
 * One in the flooded room in the lower levels, behind the nuke on the right hand side (immediately before ending elevator).
 * One under a bunk in a barrack room on the lower levels.
 * Captain Dunleavy's holotape - on a desk in the console room with Brother Henri and Atom's Wrath, near the large stockpile of nukes (the room is only available after the relevant quest has started).
 * A mini nuke, found at the end of the lower levels in the room with the Mk. 28 nuclear bombs in a knocked over crate, right next to the objective to place the signal pulser.
 * Henri's terminal password - Carried by Brother Henri, gives access to his terminal.
 * Henri's instructions - a note carried by Brother Henri.

Related quests

 * Liberty Reprimed

Appearances
The Sentinel site only appears in Fallout 4.

Behind the scenes

 * The exterior design of the Sentinel site mimics that of the real world Stanley R. Mickelsen Safeguard Complex the anti-ballistic missile radar and missile installation pyramid near Grand Forks, North Dakota. The facility was built as part of the Safeguard anti-ballistic missile program, itself a scaled-back version of a previous program dubbed Sentinel.
 * The original Sentinel Program was designed to place nuclear-tipped interceptor missiles in the suburbs around major cities, protecting them from incoming ballistic inbound threats. The project was scrapped due to public backlash, but one site was partially constructed at Sharper's Pond, located near Andover, Mass.
 * In real world, the Mk-28 nuclear bomb (also known as B28) was the longest-serving US tactical nuclear weapon, commissioned in 1958 and retired only in 1991. Some versions of this weapon were actually used as missile warheads, however not on ICBMs.