Suspended Animation

Cryonics is the suspended animation of individuals by slowing their vital functions with low temperatures, for the purposes of preserving them and keeping them alive for extended periods of time.

Background
Before the Great War, companies and government agencies produced cryonic technology. The Massachusetts Surgical Journal titled an issue "Cryo-Technology: Haven or Tomb?"

Fallout 2
The United States Armed Forces experimented with cryonic technology, creating the systems and using cryonic chambers in the Sierra Army Depot. One example is the cryonic submergence of PFC Dobbs in bio med gel. A rare side-effect of cryonic stasis is Post-Cryogenic Syndrome. The condition results in the patient completely dissolving mere seconds after leaving stasis.

Fallout Tactics
Vault 0 kept pre-War geniuses in cryogenic stasis, by extracting their brains from their body and freezing them. They were then hooked up to the Calculator supercomputer, melding all of the identities of each connected brain into one. The vault also has a corresponding cryo lab to regulate these conditions.

Fallout 3
The Enclave's scientific personnel at the Raven Rock base in the Capital Wasteland have several rooms dedicated to stasis, and their prisoner restraints use the same systems. These chambers have been used to preserve yao guai, deathclaws, super mutants, feral ghouls, and human prisoners. Whether these stasis chambers are built for long-term preservation on the scale of years is unknown. Vault 87 was equipped with four stasis chambers as standard issue.

Mothership Zeta
The alien civilization aboard Mothership Zeta made cryonics a core aspect of their invasion and their research. They worked by entirely sealing the subject and the chamber from the outside, and used freezing cold air to suspend the subject. When opening, the chamber would decompress and stabilize with outside air, and force the subject to drop to the floor. Elliott Tercorien harnessed the energy to create cryo grenades and cryo mines, which cause the same effect on targets within the blast radius.

Fallout: New Vegas
Before the Great War, Mr. House and his company, as well as the Big Mountain Research Facility, are known to have produced technology within the cryogenic and cryonic field. Mr. House extensively researched extending human life and created his own cryonic chamber that allowed the user to connect their brain pattern and consciousness to an external interface.

The only instance of this technology in the Mojave Wasteland is House's cryonic preservation chamber in the Lucky 38. It is an advanced piece of technology, linking Mr. House to an external interface, from which he has access to large amounts of data from the Lucky 38's mainframe, as well as the ability to control his Securitrons. Opening the chamber, even for a second, will doom the subject to having only little more than a year left at life due to exposure to outside contaminants.

Big MT also produced hibernation chambers with similar purposes.

Fallout 4
Vault 111, located in Boston, was built to observe the effects of suspended animation on unsuspecting test subjects for 180 days, and holds multiple cryosleep pods. They are first shown to the Sole Survivor pre-War, disguised as "decontamination" pods. The Sole Survivor was preserved for exactly 210 years, with their spouse and son being taken in the year 2227, 150 years in. All the other residents of the Vault perished by 2227, due to Conrad Kellogg not reactivating their life support, with Shaun being abducted as an infant by him for the Institute. Green stasis tanks are also seen holding super mutants in the FEV Lab in the Institute's BioScience sector.

In addition, a more experimental weapon was developed by the overseer of Vault 111, who made a prototypical rig that could propel super-chilled nitrogen gas at a target, slowly freezing them as they were exposed.

Fallout 76
The Cryolator was available for use in Appalachia. Cryogenic weapon modifications and ammunition were made available upon the Settlers and Raiders resettlement in Appalachia.

Before the Great War, Vault 96 housed approximately 10,000 species in cryonic bays, such as beavers. A special bay, Cryonics Bay 86, was utilized to house an unknown organism. The chief engineer of the Vault, Hans Memling, had a PhD in Cryonic Engineering. After the Great War, the Vault studied various mutations, including implanting and splicing them into creatures, one such mutation was cryokinesis.

Additional cryogenic weapon modifications and ammunition were made available via the Brotherhood First Expeditionary Force's arrival in the region.

Appearances
Cryonic technology appears in Fallout 2, Fallout Tactics, Fallout 3, Fallout: New Vegas, Fallout 4, and Fallout 76.