The Lonely Ones By Edward W. Ludwig - https://www.gutenberg.org/cache/epub/38302/pg38302-images.html

 The line between noble dreams and madness is thin, and loneliness can push men past it....

But even more awful than the blackness was the loneliness of the six men who inhabited the silver rocket. They moved in loneliness as fish move in water. Their lives revolved in loneliness as planets revolve in space and time. They bore their loneliness like a shroud, and it was as much a part of them as sight in their eyes. Loneliness was both their brother and their god.