A mothership uses the finest alien technology and possesses both offensive and defensive capabilities. It is protected by shield technology and its main weapon is a powerful raygun cannon named the death ray (this device, when used on Earth, resembles the power of a nuclear warhead), which connects to the lower section and can be used for both orbital strikes on a planet and combat against other space vehicles.
Passages between the various sections can be made faster with teleportation matrices installed in key points of the ship, which can be turned off in case of internal problems by the captain of the ship. It also possesses a large number of healing archways placed in all sections, that will heal and remove all radiation of anyone who walks through them.
A mothership also contains various laboratories for experimentation on living beings and technology such as biological research, experimentation labs, and research labs. There are also a vast number of storage facilities in which items retrieved from a planet below are stockpiled, and abducted species are kept alive or are frozen for preservation, used for experimentation or targets for weapons. Many of the subjects (Living specimens) are mutilated in the process of the Zetan's "Research".
Aside from living quarters for the crew and the bridge, the remainder of the vessel is dedicated to the ship's basic functions. The engineering core in the lower part of the ship provides access to most of the maintenance sections like the maintenance level, engine room, or waste disposal. In the robot assembly, the various alien drones are produced and repaired. Death ray control and death ray hub are dedicated to controlling the mothership's main weapon. A mothership also features its own hangar in which other smaller alien ships can be stored and maintained.
According to the description of the amplified alien blaster in Fallout Shelter, a weapon of its power is usually reserved for a Zetan cruiser. This refers to Fallout 3 and Fallout 4, where the aliens are identified as Zetans.
After This Galaxy Ain't Big Enough..., only Bridge, engineering core, steamworks and holding cells can be entered. The other doors will be marked as "inaccessible".
It seems that the alien captain of the ship or some other ranking alien can broadcast itself throughout the ship as a hologram.
Companions will not follow the Lone Wanderer onto the ship even after beating the last quest. However, contrary to the previous add-ons, followers will wait next to the homing beacon upon boarding, with the exception being Dogmeat, as he returns to Vault 101.
Many of the chairs on the ship throw off a spray of blood when struck with a melee weapon. Unlike the aliens, the chairs bleed red.
When wearing the spacesuit, the left sleeve has been replaced by the Lone Wanderer's Pip-Boy, with its trademark fingertip-less glove. This glove remains fingerless when the depressurization chamber is depressurized, even though this would cause considerable pain and swelling in real life.
Taking the spacesuit off during the spacewalk results in the Lone Wanderer's head exploding.
If Initiate Pek was saved at Falls Church, Paladin Hoss, the unnamed paladin, and Pek may randomly appear somewhere on the ship. They will not aid the Lone Wanderer but try and reach the bridge to get back to Earth.
On one of the captive recordings (subtitles are needed to see what it says, as only the alien audio plays) one of the captives, who is a high ranking military officer, can be heard talking about how he has the codes for a part of the U.S.'s ICBM arsenal hinting that the aliens launched the United States' missiles at China. However, it's equally likely that the officer was merely offering the most sensitive information at his disposal believing it's what the aliens wanted, as the ability to clearly communicate specific questions to humans seems to elude the Aliens in many recordings.