Spock and McCoy in stasis chambers
Stasis chambers (also called stasis unit, stasis pod, stasis tube, or bio-pod) were a coffin-shaped device designed to preserve life if its occupant were critically-injured or terminally-ill until their conditions could be stabilized in a fully-equipped medical facility.
Specification
These stasis units suspended all cellular activity and disease processes, keeping the patient from succumbing to their illness or injury for an indefinite period of time. The device was not meant for saving a dead patient, except in a few cases. Time was required to get the ailing patient into the unit before they succumbed, presumably so that more time was available as they came out of stasis to effect proper treatment. (TOS episode: "Space Seed"; TNG episode: "Reunion"; TOS movie & novelization: Star Trek Into Darkness)
Stasis units were standard equipment on Earth's and Starfleet's DY-100, Galaxy, Defiant, Danube, and Intrepid-class starships. (DS9 episodes: "Vortex", "Change of Heart"; TOS episode: "Space Seed"; VOY episodes: "Resolutions", "One")
History
The earliest use of this technology could be traced back to the 15th century. In 1484, a Vaadwaur battalion used stasis units to survive the bombardment by the Turei and their allies. They had planned come out of stasis 5 years after the bombardment, but their controls were damaged and they stayed in stasis for 892 years. They were awakened by the USS Voyager in 2376. VOY episode: "Dragon's Teeth")
In 1937, the Briori used stasis chambers to hold their slaves. Amelia Earhart, her navigator Fred Noonan, and 4 others were left in these chambers till 2371 when they were awakened by Captain Kathryn Janeway and USS Voyager. (VOY episode: "The 37's")
In the latter half of the 20th century, Earth equipped it DY-100 ships with these units because of long voyages between planets. One of the last Augment dictators, Khan Noonien Singh had himself and his crew put into stasis chambers aboard the SS Botany Bay. They stayed in their chamber until Khan was awakened by Captain James T. Kirk of USS Enterprise. (TOS episode: "Space Seed"; TOS - Khan comic: "Issue 3")
In the 2258 of the Kelvin timeline, Khan was discovered by Starfleet's Section 31. When Khan was threatened by Marcus that his crew would die, Khan had his crew's stasis tubes built into his torpedoes to smuggle them away. When Spock was demanded to give Khan his crew, Spock had the tubes removed from the torpedoes. (TOS movie & novelization: Star Trek Into Darkness)
Bleikoff
Terminally-ill Alfred Bleikoff had been placed in a stasis chamber in the 1990s. Leonard McCoy began a procedure to revive him in the year 2266. (TOS comic: "Prophet of Peace")
Also in 2266, the brain patterns of Spock and McCoy were copied and placed into cerebots. Their bodies were placed in stasis chambers for at least several hours so as to recover from the ordeal. (TOS comic: "The Trial of Captain Kirk")
In the 2260s, Doctor Rycho used stasis chambers on Raylo to withdraw electrical energy from captive Humans in order to power his Mortard robot servants. (TOS comic: "Rescue at Raylo")
In 2353, Kohl settlement planner Viorsa and four other used their stasis units to survive the ecological disaster that befell their planet. However, the stasis units' computer system malfunctioned, creating a demented clown that lived on fear, it killed 2 of the Kohl when they tried to awaken from stasis. For 19 years, the Clown kept Viorsa and the other 2 from leaving until USS Voyager came across them. Captain Kathryn Janeway was able to trick the Clown in letting go of his hostages. (VOY episode: "The Thaw")
In the 24th century, the Cardassians used stasis units to keep unstable tests subjects in stasis. One experiment was done on the abandoned Empok Nor station. (DS9 episode: "Empok Nor")
In their time in the Delta Quadrant, the USS Voyager crew used stasis units two times; the first time was when Captain Janeway and first officer, Commander Chakotay were infected with a deadly disease and had to be kept in stasis units. The second time was when the ship had to make it through a Mutara class nebula that emitted lethal levels of subnucleonic radiation. This forced the crew to go into stasis units while The Doctor and Seven of Nine operated the ship. (VOY episodes: "Resolutions", "One")
External link
Stasis chamber article at Memory Alpha, the wiki for canon Star Trek.