流浪中的都市太空船 (1963)

Orphans of the Sky is a science fiction novel by American writer Robert A. Heinlein (1907–1988), consisting of two parts: the novella "Universe" (originally published in Astounding Science Fiction, May 1941) and its sequel, "Common Sense" (Astounding Science Fiction, October 1941). "Universe" was republished alone in 1951 as a 10¢ Dell paperback book. The two novellas were first published together in book form in 1963. The work presents one of the earliest fictional depictions of a generation ship—an interstellar "ark" travelling at sub-light speeds and requiring many generations to reach a "nearby" star—in this case Proxima Centauri.

"Universe" was selected in 1973 by the Science Fiction Writers of America for inclusion in The Science Fiction Hall of Fame, Volume Two, which collected the most important works published prior to SFWA's founding in 1965.

Plot summary

Part I—Universe

A brief prologue states that after launching in the year 2119, the Proxima Centauri Expedition, the first attempt at interstellar travel, was lost and its fate remains unknown.

Hugh Hoyland is a young man of insatiable curiosity and energy. His society ("the Crew") inhabit and maintain their home ("the Ship") as a semi-feudal community consisting of two classes. The first are the "Scientists" (really, priests) who maintain both technical and spiritual traditions. The second are the illiterate "peasants" who farm animals and raise crops by hydroponic means. Hugh is selected as an apprentice Scientist. The Scientists ritualistically feed trash (including people) into a mass-to-energy "Converter" to generate power, but remain largely ignorant of its functions. So far as anyone knows, the Ship is the entire universe. The Scientists have access to some ancient texts, produced by their ancestors, which refer to the Ship "moving" and being on a voyage, or "Trip", to a destination known cryptically as "Far Centaurus". But these concepts are interpreted as religious metaphors and literal belief in them is considered heresy. The Crew are ruled by a "Captain", the current one being an obese, nasty incompetent. Crew members occupy the "lower (heavy-weight) decks" and seldom venture to the "upper (low-weight) decks", which are the domain of the barbarous, cannibalistic "muties" (the name is short for "mutants" or "mutineers", no one seems to know which). Several decks in between are uninhabited and considered neutral ground. If any muties (sometimes identifiable by monstrous deformities) are born among the Crew, they are killed at birth.

One day, on a hunt for muties, Hugh is captured by them. He barely avoids getting eaten by the microcephalic dwarf Bobo and instead becomes the slave of Joe-Jim Gregory, the two-headed leader of a powerful mutie gang. Joe and Jim have separate identities, but both are highly intelligent and have come to a crude understanding of the Ship's true nature. They take Hugh up to "no-weight" (the axis and core of the Ship) and into the Ship's "Control Room" (a kind of stellarium where a realistic simulation of the outside celestial sphere is projected). Hugh is initially overwhelmed but recovers and later studies ancient texts that were not available to the Crew. After much deliberation he comes to a fuller understanding of the true nature of the Ship than anyone else. It emerges that, after many centuries, the Ship—which is in reality a gigantic, cylindrical starship called the Vanguard—is still cruising without guidance through interstellar space after a mutiny killed most of the officers. The descendants of the survivors then lapsed into a state of superstitious ignorance, having forgotten the purpose and nature of their existence.

Now convinced of the Ship's true purpose, Hugh persuades Joe-Jim to complete the mission of colonization since he notices that there is a nearby star that Joe-Jim has observed growing larger over the years. Intent on the mission, he returns to the lower levels of the Ship to convince others to help him, but is arrested by his former boss, the Chief Engineer Bill Ertz, and sentenced to death. He is viewed as either insane or a previously unrecognized mutant; he was a borderline case at birth, with a head viewed as too large.

Hugh persuades an old friend, Alan Mahoney, to enlist Joe-Jim's gang in rescuing him. He then shows the captured Bill and Alan the long-abandoned Control Room and its view of the stars.

Part II—Common Sense

Now convinced that the "universe" is much more than just the Ship, Bill enlists the Captain's aide, Commander Phineas Narby, in Hugh's crusade.

Inspired by one of Joe-Jim's favorite books, The Three Musketeers, the friends undergo a "blood brothers" ritual and adopt a "One for All, All for One" ethos. Joe-Jim visits the local knifemaker, a hideous four-armed old woman called "Mother of Blades", and bullies her into manufacturing swords which were previously unknown weapons. (Throwing knives were always the weapons of choice.) When a general assembly of the Crew gets ugly, the blood brothers overthrow the Captain, install Narby in his place, and embark upon a campaign to subdue the many other mutie gangs and bring the entire Ship under their control. This process is quite bloody and takes many months.

Joe-Jim, Hugh and Bobo manage to force their way into abandoned compartments forward of the Control Room that have never been entered in living memory. These "rooms" turn out to be the last one of several auxiliary "boats" intended by the Ship's designers to transport colonists to their new home planet. (The other boats were commandeered by the mutineers long ago.) In this boat, Hugh finds and reads the final entries in the log of the Starship Vanguard (June–October 2172) as the last holdouts among the officers made their last stand against the mutineers, an uprising that was led by the Ship's Metalsmith Roy Huff.