What is the fastest humans can travel safely in space?

If we could extend life in space, how long would it take to travel 120 trillion miles away at this safe speed?What is the fastest humans can travel safely in space?any speed is safe aslong as it is accelerated to at a steady rate the G force is what kills you not the speedWhat is the fastest humans can travel safely in space?Best to think of 'Light Years' for distances in space. Once accelerated to any given speed perception of speed would be minimal or non-existent, since there would be no local reference points. Consult the Theory of Relativity to find out the extension of time at speeds close to the sopeed of light.