How would a cryofreeze work in order to keep the pilot alive long enough to survive an automated travel to some destination?
The objective of cryofreezing is to slow or stop the body’s metabolism. Essentially, put you to sleep for a very long time without aging and thaw you out when you get to where you’re going.
While it sounds whacky it’s actually closer to reality than it sounds. Slowing of the metabolic rate happens naturally in many animals during hibernation, and there is some speculation that it may be possible to induce hibernation in humans.
However hibernation will only get you so far, it only slows, not stops the metabolism, and it hasn’t yet been attempted for more than a few days at a time.
In principle entering cryofreeze (or cryostasis is another technical term) is easy, find a massive freezer, anesthetise the patient, and sling them in. The problems come when we try to thaw them out. Currently the biggest problem is that as the water in the body freezes it forms crystals that puncture cell membranes. Think: full body freezer burn. While there are potential solutions, mostly involving completely replacing the water with an antifreeze solution, they are still very much works in progress.
Another problem is bacteria; with the human immune system offline there’s nothing to stop bacteria from slowly munching through whatever they please. So on entering long term cryofreeze you’d need to be completely sterilised (both inside and out). Here is a good paper on low temperature bacteria.
So there are many unsolved problems before we can bring someone back from the freezer, and it’ll probably take another few decades before cryofreeze or induced hibernation can be seriously considered for use in crewed missions.