Of course, the premise of cryonics also makes it essentially untestable. Nobody has ever tried to bring a human back to life after preservation. While researchers working on ‘suspended animation’ are finding that they can cool a living being down to appear apparently dead before reviving them, freezing a body for decades is a different matter. More points to studies in which scientists have examined the preservation of cells and tissues and even worms, but scaling that up to a full human body isn’t a trivial proposition. But whether the science is there or not, people are being frozen in liquid nitrogen with the hope of seeing some distant tomorrow.

The Alcor operating room, ready to receive a patient (Alcor Life Extension Foundation)

Alcor’s members come from all over the world. Ideally, More says, the company will have an idea of when their members are going to die. Alcor maintains a watch list of members in failing health, and when it seems as though the time has come they send what they call a “standby team” to do just that—stand by the person’s bed until they die. “It could be hours, days, we’ve gone as long as three weeks on standby,” More says.

Once the person in question is declared legally dead, the process of preserving them can begin, and it’s an intense one. First, the standby team transfers the patient from the hospital bed into an ice bed and covers them with an icy slurry. Then Alcor uses a “heart-lung resuscitator” to get the blood moving through the body again. They then administer 16 different medications meant to protect the cells from deteriorating after death. As they note on their website, “Because cryonics patients are legally deceased, Alcor can use methods that are not yet approved for conventional medical use.” Once the patient is iced up and medicated, they move them to a place for surgery.

The next step includes draining as much blood and bodily fluids as possible from the person, replacing them with a solution that won’t form ice crystals—essentially the same kind of antifreeze solution used in organ preservation during transplants. Then a surgeon opens up the chest to get access to the major blood vessels, attaching them to a system that essentially flushes out the remaining blood and swaps it with medical grade antifreeze. Since the patient will be in a deep freeze, much of the preparatory work involves trying to ensure that ice crystals don’t form inside the cells of the body.

Surgeons prepare a body to prevent ice formation in tissue. (Alcor Life Extension Foundation)

Once the patient’s veins are full of this antifreeze, Alcor can begin to cool them down by about 33 degrees Fahrenheit every hour, eventually bringing the body down to -320 degrees Fahrenheit after about two weeks. Eventually the body finds its final home for the foreseeable future: upside down in a freezer, often alongside three others.

Groups of four are kept in refrigerators cooled by liquid nitrogen. (Courtesy of Alcor Life Extension Foundation)

This is the ideal scenario. But it doesn’t always go this way—if a patient hasn’t told Alcor they were sick, or if they die suddenly, the process can be delayed for hours or days. In one of their most recent cases, an Alcor member committed suicide, and Alcor staff had to negotiate with police and the coroner to get access to the body. The longer the wait between death and preservation, the more cells will decay, and the harder it will be to resurrect and cure the patient, More says.