The image above this text is from the movie "Aliens". That thing shows the artist's vision of the cryostatic capsules that allow interstellar flight. There are made many visions about the systems that could make the hypothetical interstellar flight possible. When we are thinking about the possibility to use cloned crews that are dying during the mission.
We must remember the cultural aspect of that thing. For us, the cloned bodies and the transfer of the mind between those bodies is a strange idea. There is the possibility that the culture of tomorrow is making that kind of immortality possible. When the crew members would die. Computers will transfer memories to the brains of the next body. Advanced biotechnology is making that kind of thing possible.
When we are thinking about the interstellar flight with the cryogenically frozen crew that mission will not be "quite so difficult", as we might think. The idea of cryogenics is to stabilize the DNA of the crew members and deny their aging process. The cryogenic system will use liquid helium in that process and when the craft is near its target. The system starts to warm the bodies of the crew members. Returning the vital signs is a long-term process. And during cryogenic sleep, there are no chemical or other processes in the bodies of the crew.
If something unexpected will happen. The system might warm the crew members to a temperature that their nervous systems will start to work. The computer can use BCI (Brain-Computer Interface) for communicating between the crew and its systems. That thing can allow the sleeping crew members can control the computer. Without the need to wake up.
The cryogenics must not be stable. When the craft sees something unexpected it can streamline the cryogenic sleep to normal hypothermic anesthesia or hibernation. That allows the craft to react to danger. But when the problem is solved. The crew member will freeze in cryogenic conditions.
That system can also switch the memory of the crew member off. If it uses advanced biotechnology. There is the possibility that the body of the sleeping crew is injected with genetically engineered macrophages that are removing neurotransmitters that store things to long-term memory. During that time the system stores those memories on hard disks. And that means there is nothing that can store in the personal memory of the crew of the hypothetical spacecraft.
The fact is that the hypothetical spacecraft would not need very much computer power while it travels in interstellar space. The only thing that this system requires is the knowledge of how to keep its course. If the system requires more calculating- or productive thinking it can wake up a couple of crew members. Or the system can only remove the cryogenic sleep and transfer to use the normal hypothermic sleep. That allows the computers of the spacecraft can start to communicate with the nervous system of the sleeping crew.
The BCI system can be in the cryogenic chamber of the crew. But those systems would be needed only at the end of the journey when the craft needs to do more complicated missions.
