The most terrifying thing I can think of is described in perfect detail in David Bowie’s Space Oddity. I know it’s some sort of allegory for his own drug problems or something, but taken literally, it makes my skin crawl.
Floating helplessly through space in a fully stocked space craft is something that freaks me out more than anything. Even worse, or better depending on how you look at it, is if I got loose on a spacewalk and just started floating away from anything solid. Now that spooks me out more than anything I can think of, and it will likely never happen to me. Nonetheless, it turns my guts inside out thinking of it.
Watching 2001: A Space Oddessy and seeing Dave’s buddy go flying off into space in his orange suit is nearly more than I can handle.