The most harrowing fact that I know is that during the Apollo 11 mission, as they began to enter the moon’s orbit and headed behind it, they were no longer able to communicate with earth. This is indicated on the flight plan* by the note “Broken trajectory lines indicate loss of earth communications.” So here’s the crew, impossibly far from everything any human has ever known, for about an hour unable to hear (or most of that time even see) any sign of the only experience humanity has ever known. It’s just them sandwiched between an unfamiliar moon and the blackness of space.