Orphans of the Sky

Orphans of the Sky is a science fiction novel by American writer Robert A. Heinlein, consisting of two parts: "Universe" (Astounding Science Fiction, May 1941) and its sequel, "Common Sense" (Astounding Science Fiction, October 1941). The two novellas were first published together in book form in 1963. "Universe" was also published separately in 1951 as a 10¢ Dell paperback. The work presents one of the earliest fictional depictions of a generation ship.