After the first few minutes there was in any case not much to see. He knew that all the air cavities within Ana’s body had been filled with neutral solution, and her blood replaced with anticrystalloids. But then she went into the seamless pressure chamber. The body was held there at three degrees above freezing, while the pressure was raised slowly to five thousand atmospheres. After that was done, the temperature drop started.

“Back in the eighties and nineties, they had no idea of this technique.” The team leader was still talking to Drake, perhaps with the idea that she might make him feel more relaxed. “They used to do the freezing at atmospheric pressure. There was a formation of ice crystals within the cells as the temperature dropped, and it was a mess when the thaw was done. No return to consciousness was possible.”

She smiled reassuringly at Drake, who was not reassured at all. So they didn’t know what they were doing in the eighties and nineties. Would they claim in twenty more years that people didn’t know what they were doing now? But he had no alternative. He couldn’t wait for twenty years, or even twenty hours.

“The modern method is quite different,” she went on. “We make use of the fact that ice can exist in many different solid forms. Ice is complicated stuff, much more than most people realize. If you raise the pressure to three thousand atmospheres, then drop the temperature, water will remain liquid to about minus twenty degrees Celsius. And when it finally changes to a solid, it isn’t the familiar form of ice — what is usually called phase 1. Instead it turns to something called phase 3. Drop the temperature from there, holding the pressure constant, and at about minus twenty-five degrees it changes to another form, phase 2.