 Before his departure, Peter recalls a line from a film. Why does it come to mind for him?
[Transcriber's Note: This etext was produced from Planet Stories Spring 1944. He had been dead for some time now, but the dark blood was still oozing from the crushed ruin of his face, trickling down into his sodden sleeve, and falling, drop by slow drop, from his fingertips. Outside, the stars were as before: tiny, myriad points of light, infinitely far away. It was I who had changed: something inside me was dead, like the machinery, and like Peter. It was a kind of indefinable emptiness. I do not think it was what Peter called an emotion; and yet it had nothing to do with logic, either. It was just an emptiness—a void that could not be filled by eating or drinking. I did not even wish that Peter were not dead, for reason had told me that he had to die. But the void was still there, unexplainable and impossible to ignore. His dream was perfect; the Citadel was complete, every minutest detail provided for—on paper. Then there would remain only the task of blasting the great, shining ship out into the carefully-calculated orbit that would be its home. In his mind's eye he could see it, slowly wheeling, like a second satellite, about the Earth; endlessly gathering knowledge into its insatiable mechanisms. He could see, too, the level on level of laboratories and storerooms that filled its interlocking segments; the meteor deflectors, the air renewal system, the mighty engines at the stern—all the children of his brain. Out there, away from the muffling, distorting, damnable blanket of atmosphere, away from Earth's inexorable gravitational pull, would be a laboratory such as man had never seen. The ship would be filled with the sounds of busy men and women, wresting secrets from the reluctant ether. A discordant note suddenly entered his fantasy.
 He recognizes that he will be a changed, mutated man when he returns. He literally will come back "not as a boy."
 He recognizes that he will be a changed, mutated man when he returns. He literally will come back "not as a boy."  He's trying to convince himself that he and humanity will be able to come back, with the emphasis on "We'll come back."  The situation is grave. Like men who go off to war, the journey will change them. He won't be coming home as the same "boy."  He's not sure he'll be coming back, and the song is bittersweet for him.