The deep dark. The edge of sanity. Emptiness and pure black with nothing for your mind to grasp hold of. Not even a pinpoint of light from a distant star to any other celestial body of any type. Just blackness and empty space. The void. Hour after hour, day after day, week after week. Black empty space. This is traveling in space, not through it. Subtle difference you may think but finally we discovered the the real enemy in space. Time
Time is the enemy. We have always know this, but nowhere is this more acute than when traveling in deep space. Distances are so far beyond comprehension that we measure distance in time. The distance light travels in a year becomes the equivalent of the mile, or Kilometre. We measure our velocity as parts of the Speed of light or C. We see far off distant bodies in space and determine how far they are in light years. Parsecs is another, approximately 3.26 lightyears if you are measuring outside the Earth’s solar system and want to get all technical. But none of this matters if you are using space to travel in it.