Cryo chamber (Earth-7149)

Cryo chambers are plastasteel pods with form-fitting gel beds which allow starship personnel to undergo cryosleep for long periods of time, commonly during slipspace jumps, which takes days, weeks, and even months to reach the designated location.

Notable models of cryo chamber include the Mark VII Personal Suspension Unit manufactured by the Weyland-Yutani Corporation for commercial freighters, and the Mark VIII Cryogenic Suspension Chamber, utilized by the UNSC on their warships.

Cryo chambers are known as "freezers" in slang, as well as "the Admiral's wife" duo to it being a "frosty bed".

Specifications
Cryo chambers are stored in dedicated areas of their respective ships, known as "cryo bays", which are monitored by the ship's Replicant executive officer or the shipboard artificial intelligence, which can awaken the crew at any moment.

Cytoprethaline is a drug used by both the UNSC and non-military personnel to prevent the membranes of the subject from being damaged duo to ice crystal formation during cryosleep. Although it is recommended that a doctor administer the drug, it is also commonly done by medics, science officers, and in the case of criminal or pirate ships, whoever is nearby. Some humans have a rare allergic reaction to cytoprethaline. Because the use of cryosleep is very frequent in common during UNSC interstellar travel, this may cause an individual from being medically discharged from service in the UNSC.

Some subjects report that they have dreamed during their cryosleep, although scientists have clarified that dreaming in cryo is physically impossible as all neurochemical processess in the brain are cessated during stasis. A common theory is that most subjects experience bursts of REM sleep during their wake cycle, and as a result they erroneously confuse that with dreaming. The wake cycle takes approximately five minutes to be completed, where the subject is controlledly warmed by an electric current, applied to stimulate the heart. The cryo chamber opens automatically with the completion of the cycle, and the interior lighting becomes bright. Many subjects only awake at the final lighting phase.

When awakened, subjects have to sit erect in their chambers, take one breath, and then cought, which may be difficult in a first try, but is of vital importance to clear the lungs of surplus surfactant. The surfactant is to be immediatly swallowed to replace lost notrients during the travel. Many UNSC personnel distate the surfactant.

Accelerated waking, better known as "flash thawing", is a dangerous method of wake cycle that garners high mortality rates. As a result, it is highly discouraged and only used in the utmost emergencial situations. Rapid infusion of stimulants and adrelina, as well as emergency coils, can bring subjects out of their cryosleep in two minutes. Because of the disorientation they suffer through the following hours, their efficiency is severely reduced.

When subjects fail to wake from cryosleep, a medical resuscitation take place, which is executed with the medical packages located at the edges of the cryo chambers. All UNSC personnel and staff aboard commercial vessels are trained to use the devices. If the subject fails to be revided, the chamber's lid is to be closed and an emergency freezing cycle is activated.

Entering cryo chambers can also be an emergency, with recorded cases of people putting others in cryo chambers to save them from succumbing to mortal wounds, such as John-117 did to Linda-058, or to save them from a Chestburster emergence, such as how Henry Marlow did to his wife, Catherine Foster. Chambers hold an individual as long as it is necessary, and as such they can be ejected before an emergency landing, saving the lives of crew members that can be recovered later. In some cases, cryo chambers preserved subjects for decades, such as with Ellen Ripley and others aboard the Narcissus and the UNSC Sulaco.