The problem with hibernation is that is not remove aging.

Many scientists think that hibernation is useless in long-term space travel.  The fact is that normal hibernation or normal anesthesia cannot help people in long-term space travel at all. Hibernation can be a good way to control a person who is psychotic or injured. 

But the hibernation itself does not affect things like a lifetime. The major problem with long-term spaceflight is the aging of the people. And hibernation does not affect that thing. But hibernation is the gate to cryogenic space travel. Cryogenic space travel means that the crew will freeze to the temperature of zero kelvin. 

Why cryogenics is a promising way to make extreme long-term spaceflight? The reason, why cryogenics is better than so-called normal hibernation or narcosis is the oscillation of the DNA and other molecules' ends. This means the space traveler will not age. The idea is that when the spacecraft comes near its destiny. The system will start to warm those astronauts. 

And when they are put in the cryonic chambers, their body can equip with the resuscitation equipment that can involve a system, that can turn the heat on. A ventilator or internal blood oxygenize can help to restore vital signs. That blood oxygenize can recycle blood through the unit that will oxygenize hemoglobin. After that, this oxygenized blood will transfer back to the veins. 

The problem with cryonics is how to wake up those astronauts after frozen. If the rise of the temperature is too fast. The expansion of the ice rips those cells into bites. So the rise of temperature must be slow enough and the resuscitation equipment will start the vital signs at the right moment. If that moment is too late there is an oxygen lack in the body. The thing is that aging is the dominating problem in interstellar or extreme long space missions. 

By the way...

Phoenix-immortality 

In some visions, the astronauts will travel in interstellar flights fully awake. Those astronauts will age normally. After that, their memories will transfer to their next body. Then that system clones the astronauts' bodies. That means "Phoenix immortality". In legends, Phoenix is the bird that creates one egg before it dies. Then that mythic Phoenix will burn in fire. And the next Phoenix will come from the egg. 

In some other visions, the astronauts will travel in the form of cell cultures. When the system requires the astronaut it will make that person by using a bioprinter. That thing can be called as Frankenstein model. The idea is that bioprinters and highly advanced life support systems can make it possible to create even humans by using bioprinters.

 The thing is that many visions can make it possible to travel between stars. But the problem is that the interstellar spacecraft cannot send data back to Earth. If we can make a spacecraft that travels at the speed of light. It travels to Sirius in 8,7 years. And the message will travel back another 8,7 years. 

Time is the biggest problem in long-range spaceflights. 

The fact is that our first interplanetary flight to Mars or Venus is at the planning level. Theoretical research is on the way. But the fact is that there are many technical, social, and other problems to win before we can travel even to the closest planets. 

The journey to Jupiter will take a very long time. Pioneer 10 spacecraft reached Jupiter in one year. But that was flyby. That spacecraft must not brake when it reached the planet. 

The orbiter craft requires more flight time. The reason for that is they need to slow their speed to reach the orbital trajectory. 

The Galileo spacecraft reach Jupiter in 3 or almost 2000 days. The entire flight time to Jupiter was far longer. Galileo launched on October 18, 1989, and it arrived at Jupiter on December 8, 1995. Galileo made two gravitational assist flybys to Earth. And one to Venus to get enough energy to travel to Jupiter. 

The flight time to Jupiter is calculated from the last flyby when that craft traveled to Jupiter. And still, the travel time to Jupiter is three times longer than Pioneer 10. The reason for that was that Galileo needed the slowdown. And the manned spacecraft would need more time because their mass would be higher. 

The problems with that kind of flight are time and social relations. The flight time to Jupiter and back would be about 6-8 years. And the craft should spend little time in the orbiter. So the crew will age very much during that trip. And if we would someday make an interstellar flight or travel outside the solar system that takes even more time. 

https://owlcation.com/stem/Galileos-Fight-and-Flight-to-Jupiter

https://www.sciencealert.com/a-common-sci-fi-solution-for-long-distance-space-travel-could-be-pointless-for-humans

https://www.universetoday.com/128259/long-take-get-jupiter/#:~:text=Galileo%20actually%20took%20exactly%20three%20years%20%28about%201100,Jupiter%20and%20save%20many%20years%20of%20travel%20time.

https://en.wikipedia.org/wiki/Cryogenics

Image 1: https://www.sciencealert.com/a-common-sci-fi-solution-for-long-distance-space-travel-could-be-pointless-for-humans

Writing about interplanetary flight

https://gamesandtehories.blogspot.com/

Kimmo Huosionmaa

When we are thinking about nuclear thermal rocket propulsion and Mars-flights, we are facing the solution called "Orion". This nuclear-powered rocket could travel interplanetary routes by using small nuclear bombs for giving thrust to those devices. The idea is that neutron bombs would be fired behind that spacecraft, and that would give it extremely high speed because the radioactive particles would push spacecraft forward.

One of the ideas is to use machine-gun, what is loaded with bullets, what are made by using the highly enriched radioactive material, and they would shoot thru the electric arc, what would cause fission in that ammunition, what would give thrust to that thing. But the problem is to create the electricity for that spacecraft. Spacecraft would always need also electricity for its systems.

That's why the main engine solution for that journey was chosen NERVA (Nuclear Energy Rocket Vehicle Application), what is like a normal rocket, but it is nuclear reactor inside. The NERVA solution deletes the dead weight and the nuclear power would give also thrust for braking. In this situation, the nuclear rocket would turn to give thrust to forward, and this brake the spacecraft.  The most modern version of the spacecraft, what would be used to travel other planets is the hybrid system.

The nuclear reactor, what uses the closed-cycle cooling system would give the needed electricity for the electric systems of the spacecraft. And also at the beginning of the journey can be used the same methodology with "Orion". In the back of the Interplanetary spacecraft would be installed the plate, and the nuclear bomb would send this spacecraft in the very high speed.

And then the system would transfer to use NERVA or WARP-system, what could give extremely high speed for spacecraft. WARP is actually the particle accelerator, what is connected to the spacecraft, and what sucks ions from the space thru it. There is a theory, that this kind of device could someday break the cosmic speed limit. Traveling faster than light is basically a very simple thing. The spacecraft would accelerate to the speed of light and inside it, something would be accelerate to higher speed.

In some theories, this kind of thing would be the magnetic rail, what would accelerate some particles to the 20% of the speed of light, and it would be launched when spacecraft will travel precisely the speed of light. This thing would make by installing the particle accelerator in the spacecraft, what uses WARP, and the accelerator would shoot the atoms forward when the speed of the spacecraft would be high enough. Sometimes has been discussed the opportunity to use electromagnetic radiation for the breaking the light wall. The thing, what makes electromagnetic radiation so fascinating is that there is no thrust and that thing would not need any ions, what would give retard for the spaceship.  This kind of spacecraft is still at the theoretical level, but maybe they are someday in use and travel to other planets.

The thing, what makes this kind of electromagnetic devices more interesting, than NERVA, is that they don't need the different propellant for giving thrust, and this means that the system would be lighter. But as we know the interplanetary travel is extremely difficult. The WARP-craft would give solution for traveling in our own solar system. But that system needs very strong magnets to work properly, and that means that the only thing, what is needed is a nuclear reactor.