Is there a max speed a space ship can go to keep an human alive?

There is no maximum speed for a human body. There is a maximum acceleration rate but that differences from person to person but it is generally accepted that you will pass out around 8 or 9 Gs.

There is a theoretical max speed for a space ship through, which is the speed of light. Nothing can go faster than that according to Einstein.

Speed is not the limiting factor but acceleration. More than about 9gs or 9 times the acceleration experienced on earth, even for a few moments will cause you to black out since you can't keep the blood flow to your brain in that environment. A space vehicle could accelerate over many years though and the top speed would not matter to the people inside. Stopping (accelerating in the opposite direction) would be the same, so there is a limit to how fast you can stop too.

Speed is irrelevant, as you are always at a speed relative to something (for example, Earth moves at 29 km per second around the sun, while the sun moves at about 150 km per second around the center of the galaxy). Acceleration is the problem.

You don't need much acceleration for killing a human, 3g for one hour would already be enough to kill but the strongest astronauts by cardiac arrest (The weight of the blood in your body also increases, making it more and more difficult for your heart to pump it). The time of the acceleration is important. You can for example also easily survive 30g vibrations, like you experience when a fast freight train passes close to you. The accelerations are too short for causing damage.

We do know that humans can survive up to 46g for short times, Colonel John Stapp reached this during his rocket sled experiments. Before Stapp, it was claimed that humans will die at 18G. His experiments also helped in the development of the seatbelt.

You can't travel at the speed of light. It's not an engineering or technology problem. Travel at c violates the fundamental principles of physics. Regardless, it is physically possible to travel at nearly c relative to other bodies. At such speeds, there is absolutely nothing different going on than at rest. That is the entire point of Relativity: that anyone traveling at constant speed can justifiably consider himself at rest. Speed itself does absolutely nothing to your body, to the spaceship, nor do anything whatsoever to change the outcomes of any experiment within it from the outcomes you would discover at rest relative to other bodies. You experience time and age by exactly the amount that is read out on your watch, which operates precisely the way it does anywhere else. You would have to shield the spaceship pretty well though, for the incredible energies with which the atoms of diffuse hydrogen gas and visible light blueshifted into the hard gamma ray would be hitting it would tear it apart.

It depends on the ship. The Apollo missions used very flimsy protection to the point where a pea sized rock could have killed the whole crew. Part of SDI was to shoot pea sized rounds at ICBMs.

Not only are rocks and dust a major hazard, but eventually at a certain speed, solar winds could be dangerous much like the space shuttle that blew up from friction in reentry.

No. A human or any living being can travel at any speed. It's all about relativity.

The problem is with acceleration an deceleration.

So if you want to get near the speed of light it would take bloody much to accelerate to that level and if you decide to stop to a near coffee shop, you would need to wait as much to decelerate .

Except at speeds approaching the speed of light (which mankind will probably never achieve), all that matters to sustaining human life is how quickly you accelerate. If you speed up, slow down or turn too quickly, you can die. But if you're traveling at a constant velocity, you'll hardly notice you're moving at all. In fact, if you have no way of looking outside the spacecraft, you won't know that you're moving at all.

The speed at which a spaceship travels doesn't directly affect the astronaut in it. So the limit would be close to the speed of light.

In fact our "Spaceship Earth" travels at a speed of several thousand miles an hour trough our galaxy without it affecting us.

Just under the speed of light.

Peace.

three thousand million miles per hour