Even if we imagine that artificial gravity has been created on a spacecraft and 100% protection of the crew from penetrating radiation has been created, a flight lasting 3 years, and this flight time to Mars on a modern spacecraft, will not be feasible.
No, the ship will automatically be able to deliver the remains of the crew to Mars orbit. On the ship, all vital supplies of air, water and food will not be used up.
At best, a few people will still be alive, but they will be insane.
This is how sensory hunger works.
The flight in interplanetary space will represent the monotonous blackness of the stellar space, filled with placers of stars by one bright star - the Sun. The rate of change of the pattern will be very slow and no dynamic movements in the surrounding space of space will occur.
The crew, at best, will consist of a dozen people. Ten people is a very small team. Even a hundred people are not enough. Already in the second month of the trip, when meeting in a narrow passage, it will be difficult to resist and not go into the ear with hateful erysipelas. Only because she again appeared before my eyes.
The author himself experienced this feeling more than once in a distant airfield in a desert area, where for 7-8 months the same faces were before his eyes. Constant dust, dirt, heat and cold and outdoor conveniences in any weather. And constant nervous tension, brightened up by flights. And it seemed that everyone was in the conditions of their home planet, and sensory hunger showed its serious fangs and not childishly.
Experiments in isolation chambers have shown that the human psyche, under conditions of limited stimuli, can paint completely unthinkable pictures with a real effect.
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Hallucinations begin within a day. If a person is prepared and with a strong psyche, then he can withstand three days in complete silence. And then he suddenly sees with horror how the dashboard melts and swells on the floor of the cabin. Nobody managed to convince him on the intercom that it was just a hallucination. The experiment had to be interrupted.
Another test subject had a television set that burned his eyes. The TV was turned off, and it became easier. But after a few hours it was turned on again, and the same thing happened. At the same time, the subject saw how a hole began to burn in the screen itself.
Some, in the noise of the exhaust fan, listened to symphonies in a perfectly clear performance.
There were those in whom the chamber space began to narrow to an unacceptable size and they panickedly demanded to stop the experiment.
It is almost impossible to suppress hallucinations on your own. Pilots flying an airplane in continuous clouds at night often have the illusion of inverted flight, or roll flight. It is even more terrible to clearly feel that the plane is falling. At the same time, before our eyes, all the readings of the devices say that nothing like this is happening. And with your mind you understand that you have to trust the instruments. Even a trained professional breaks into a cold sweat.
A person is used to believing his receptors, which in this case lie. It is impossible to convince them, just as it is impossible to convince the vestibular apparatus on a swing or carousel during motion sickness. This is called a common false triggering of the vestibular sensor in the human ear. Its principle of operation is pure mechanics. But, at the same time, it will not be possible to apply this knowledge in order to stop nausea and vomiting.
It's the same with hallucinations. Only the mechanism of their development is much more complicated and much more dangerous for the person himself. If a person is convinced that the temperature in the isolation chamber has begun to rise, he must be rescued, otherwise he will receive real burns of the entire surface of the body to a size incompatible with life. In this case, the room temperature will be within the comfortable values.
Now it's worth imagining a similar situation in space on board a ship. It will be a disaster. The crew will die in a very short time.
Modern spacecraft are not yet able to provide a person with acceptable conditions for travel in interplanetary space. We do not know not only the world around us, we have not yet comprehended ourselves. When this happens, then travel will take place on a completely different level, using technologies that have so far been described only in science fiction novels.