Cryonics (Earth-7149)

Cryonics refers to the human science that preserve organisms in stasis for long periods of time. Cronics aim to allow individuals to "sleep" through extended time intervals without biologically aging and, upon awakening, to return without any ill effects. The UNSC and human civilian or non-military ships utilizes cryo chambers in their ships, where human suspension reduce the metabolism of the body to near zero, and thus eliminating any need for oxygen. Most ship personnel are suspended for 120 hours during a slipspace travel, and as a result most ships are operated by skeleton crews, executive synthetic officers, or a shipboard artificial intelligence.

Put-down cycle
Individuals enter cryo chambers to undergo suspension without any clothes, duo to the bonding between skin and clothing in low temperatures. Those who ignore this procedure will find themselves awaken with blistered skin.

The "put-down" cycle, which is the preparation for the subject to undergo stasis, takes seven minutes. The subject experiences drowsyness within the first four minutes duo to the many anesthetic gases they had to endure. Soon after, another gas reacts, forming a bronchial surfactant upon inhaling, which coates the passages of the lungs to ensure a smooth waking cycle later on.

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, like Dwayne Hicks, 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 Armed Forces.

Wake cycle
"For me, it's like dying... and then waking up again."

- - Joan Lambert 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.

Flash thawing
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.

Emergency protocol
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.