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Literature / Tunnel in the Sky

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"Rod, everyone of us is beset by two things: a need to go home, and the impossibility of doing it."
Deacon Matson

Tunnel in the Sky is a 1955 juvenile Sci-Fi novel written by Robert A. Heinlein.

Rod Walker is a high school student taking an elective survival course, a requirement for anybody with ambitions in exploring other worlds. The final exam consists of being teleported to an alien world to survive there for up to a week and a half, a dangerous test but one expected to be overcome by the students. He prepares himself by following the advice of his famous survival teacher and his tough military sister, and takes only knives and light gear for the test (on the grounds that a gun would make him overconfident). Rod arrives on the planet and spends a few rough days wandering around, uncertain of what may be lurking around him, when he's jumped by another student and stripped of all his gear except for one knife concealed in a bandage.

Rod manages to survive as a savage, and assumes he missed the recall while out of his head with a fever, until he gets the jump on another student, Jack. After the hostile meeting and an awkward meal, they agree to team up together. And shortly after, Jack explains that their recall never came. Realizing that something has gone wrong, they decide they need to find other stranded students and band together to survive, possibly for the rest of their lives, on the unfamiliar world.

Provides Examples Of:

  • 24-Hour Armor: Jack wears a heavy and hot armored vest at all times after meeting Rod, one that disguises her gender. She wasn't sure that he would have teamed with her if he knew she was a girl, and as a whole, she was right. She abandons the armor once her gender is revealed and she no longer needs to hide it.
  • Accidental Discovery: Dr. Ramsbotham, inventor of the gates, was actually trying to build a time machine rather than a teleportation device. On his first successful test, he saw a jungle through the portal and, assuming he'd succeeded in reaching prehistoric times, armed himself and jumped through. He was immediately arrested for waving a firearm in a botanical garden. His research also led to Year Outside, Hour Inside devices.
  • Age-Gap Romance: Because there's such a shortage of potential husbands, Helen doesn't care how old hers is as long as she can find one. She does, marrying Rod's grizzled veteran instructor from high school.
  • Alien Sky: Rod's theory that he was on Earth All Along is dashed when he finally sees the sky on a clear night and the stars are much different than they would be from Earth.
    Framed by the ledge above him and by tree tops across the stream was a pattern of six stars, a lopsided pentagon with a star in its center. The six stars were as bright and unmistakable as the seven stars of Earth’s Big Dipper... nor did it take a degree in astrography to know that this constellation had never been seen from Terra.
  • Alliterative Name: Helen's unit is called "Walker's Werewolves".
  • All Planets Are Earth-Like: Played with.
    • Averted in that, logically, not all planets are in fact Earth-like. Early on, Rod sees a dignitary from a race of chlorine breathers arrive on Earth.
    • Discussed between Matson and Rod. Any planet used for the survival test would be Earth-like, and if it wasn't Earth-like the students would be informed about hazardous environmental conditions first. That said, "Earth-like" covers a range of conditions — the survival world will have breathable air, but might have a hostile climate, and students are expected to show up prepared accordingly.
  • Always a Child to Parent: This is Rod's experience when he returns home; despite having led a colony for years, when he finally gets back his parents expect him to move back in with them and are concerned about things like whether he will have to repeat the semester in high school and if the people with whom he spent years stranded are "desirable companionship for a young boy". This is exacerbated by the fact the his parents spent most of the time that he was gone in a Year Outside, Hour Inside device, and while they've had his situation explained to them it's hard for them to even grasp the amount of time that has passed, let alone how much he's been matured by his experiences.
  • Amazon Brigade: A literal version; Helen Walker is an assault captain in the Corps of Amazons. This trope exists because there are more women being born on an overpopulated Earth than men, so there's a shortage of available husbands, so women are taking on a lot of traditionally male roles. Helen makes it clear that she intends to leave the military and raise a large family should she find a husband.
  • Ambiguously Brown: Rod Walker, and by extension the Walker family.
  • Ammunition Backpack: Johann Braun carries a General Electric Thunderbolt as his weapon and wears its power pack as a backpack. His enormous gun doesn't save his life.
  • And the Adventure Continues: Years later, Rod becomes the leader of a new colony and leads them out to a new world.
  • Asskicking Leads to Leadership: Averted. After the colony is established for a couple of years, Rod has a confrontation with a problem citizen, Bruce, that ends in a physical altercation. Rod is badly beaten, but is surprised to learn that if anything, the incident has solidified his role as mayor — the colonists follow him because he's a good leader, not due to any physical prowess.
  • Author Appeal: As typical of a Heinlein story, the importance he places on mathematics is briefly brought up. Rod doesn't understand the hard science and math that goes into teleportation because of his age and education; he's studied tensor calculus, statistical mechanics, simple transfinites, generalized geometries of six dimensions, the practical math involved in electronics, cybernetics, robotics, and analog computers. He has yet to learn any advanced math.
  • Badass Teacher: Deacon Matson. One-eyed, reduced fingers, decorated veteran of some of the first expeditions, including an award for being the sole survivor, who thinks that students being allowed any weapon is for sissies and would test them unarmed if he could. Going unarmed does make the test safer, per Paranoia Fuel below.
  • Birth-Death Juxtaposition: Grant dies and Bob and Carmen's baby is born on the night of the stampede.
  • Blatant Lies: The Australasian government's claim that the 2 million emigrants Rod sees forced through a gate are all volunteers.
  • Call a Smeerp a "Rabbit": Most of the native animals and plants are given Terrestrial names for simple identification. For a time, recovering from a near-delirious daze, Rod convinces himself that they never left Earth and that the lion-like creatures were lions. The primary exceptions would be the "grand opera" and the "dopy joes".
  • Celibate Hero: Rod actively avoids any romance, though his own naturally obtuse attitude helps the process along quite nicely. For example, Jack shows early jealousy of Caroline, but since Rod is ignoring that sort of thing she ends up marrying Jimmy and the two are perfectly happy together. Rod also avoids becoming close to any one girl with a personal vow that the day he does is the day he steps down as leader. He's particularly careful to keep Caroline at a distance, because of her position as his right hand.
  • Coming of Age Story: Rod begins the story as a high school student; over the course of the book, he grows into a man both physically and mentally.
  • Common Tongue: Lingua Terra, described as being a simple language.
  • Compensating for Something: Why Rod's sister advises him not to take a firearm; because he'll think himself tougher than he actually is and get overconfident.
  • Cool Gate: Ramsbotham Gates saved the world from overpopulation. They allow colonization of space because the departing gate is the only equipment required for a one-way trip. Colonies must be self-sufficient until they're successful enough to warrant the cost of installing a gate.
  • Crazy-Prepared:
    • Rod averts the trope under his sister's advice: he takes only a knife, a vest pack, and rations. Even Matson questions why he didn't arrive with popular camping equipment and outdoor gadgets like other students.
    • Subverted by Matson during the final inspection. Students are expected to be prepared for any reasonable survival circumstances; in particular, not bringing cold weather gear is an automatic failure despite Matson knowing they wouldn't need it. A few students go overboard and bring pressurized space suits and Matson fails them as well, both for stupidity: the test is a test, not a Death Trap, and students wouldn't be thrown into vacuum or toxic environments without being informed.
    • And averted when one of the first kids Rod finds dead was one equipped with a whole bunch of top-of-the-line gear, including an expensive energy weapon. He was ambushed and killed by a thief because he brought that expensive weapon.
    • Caroline is an odd example; she brings a number of unlikely items that prove to be useful. Why she chose them is a headscratcher, but Rod recalls Matson saying that survival is an art, not a science, and Caroline shows up in shockingly good condition for having lived on the land for a month.
  • Dead Guy Junior: Jimmy's son is named after Grant.
  • Debate and Switch: On the first night of the test, Rod hears a man sobbing nearby and begins internally debating his responsibility to risk his own life in order to help someone else who is clearly in great distress. The issue is resolved when he hears another man start to sob, then another, and realizes that it's actually animals making the noise.
  • Democracy Is Flawed: Discussed by Grant and Rod; not that democracy in inherently flawed, but that adopting wholesale the form of government used in an agrarian democracy or an industrial republic won't work for their cooperative colony.
  • Depopulation Bomb: An offhand comment is made regarding World War III being caused by overpopulation:
    "The hydrogen, germ, and nerve gas horrors that followed were not truly political. The true meaning was more that of beggars fighting over a crust of bread."
  • Did Not Think This Through: On seeing Jack is using his Bowie knife, Rod accuses her of being the person who attacked him and stole it. Turns out that man is dead and Jack removed equipment from his body. Jack takes some convincing not to end their partnership on the spot, seeing it as a violation of trust and a sign that Rod is too stupid to think things through—she'd hardly have shown him the knife if she was the one who had stolen it, after all.
  • Disaster Democracy: The stranded students' mistake isn't establishing a democracy but making their government more complicated than primitive survival warrants. Still, as the guys who attempt to turn the thing into a Lord Of The Flies-style "do-as-you-please" Teenage Wasteland end up showcasing (by getting killed quickly), a degree of society is needed in a disaster, and thus all of the kids agree on trying to make it work.
  • Earth All Along: Subverted. When the recall never comes, Rod conjectures that the students are actually on Earth, and part of the test is figuring out that fact and making their way to safety. This is not actually the case, as proven when Jack shows him a constellation that doesn't resemble anything seen from Earth.
  • Famous, Famous, Fictional:
    • "Rod Walker knew about Dr. J. E. Ramsbothamnote , just as he knew about Einstein, Newton, and Columbus...."
    • "...Cowpertown is safe in history, along with Plymouth Rock, Botany Bay, and Dakin's Colony."
  • Fantasy Counterpart Religion: Rod and his family practice "evangelical Monism" that apparently originated in Persia at the end of the 20th century. A few details are given: Rod's father services as family priest, leading a ritual at mealtime in which a "Peace Lamp" is lit , and there's a religious text called Peace of the Flame.
  • Fiendish Fish: We never learn exactly what type of creature lives in the stream, just that being thrown or falling in is an effective death sentence.
    He did not know what it was that lived in that stream; he did know that it was hungry.
  • Foreshadowing:
    • Matson asks Rod who gave him the good survival advice and Rod explains it came from his sister in the Corps of Amazons. Matson grumbles that a woman like her would have kept him from being a cranky old bachelor. When Rod returns, Matson is now his brother-in-law.
    • Similarly, Helen states that if she found someone to marry, she "won't even count his arms and legs." Matson has his arms and legs, but is missing an eye and 3 fingers.
  • Future Food Is Artificial: Rod and his family sit down under the Peace Lamp for a yeast cutlet. With real bacon.
  • Future Society, Present Values:
    • Zigzagged. On the one hand, women make up their own (separate) military units and make up half the survival-course students in the story; on the other, sexual mores are such that a bunch of teenagers, isolated from their parents and all forms of authority, take precious time out from the business of survival to stage their own marriage ceremonies before daring to fool around. When Rod gets home, his parents' attitude is that of people who fully expect him to let them pick his friends for him. When his military sister opts to get married, she leaves the corps, though it's unknown whether she was required to (even in 1958, married women were permitted to serve in the US military, albeit in noncombat roles).
    • In a conversation with her brother, Helen makes it clear that she plans for marriage to be the end of her military career. Her goal is a farm and a flock of children. As this is also the goal of many Heinlein heroes, that should not be seen as sexist.
    • Rod is not regarded as a legal adult until he turns 21, whereas now it would be 18.
    • Weirdly zig-zagged - a bunch of 1950's students probably wouldn't be expected to attack each other during a routine (if dangerous) survival trek. But the characters in the story do expect that to happen, even before being stranded. On the final zag, several murders do take place, but seem exceedingly out of character for the characters we actually get to meet, who act like middle-class 1950's teens rather than rabid criminals.
  • Gender-Blender Name: Humanity's savior who conquered the stars was the (male) Dr. Jesse Evelyn Ramsbotham, saddled with both an Embarrassing First Name and an Embarrassing Middle Name.
  • Gender-Concealing Writing: Rod meets Jack, and doesn't realize her name is short for "Jacqueline" until Jimmy tells him she's a girl. Up until then there had been no explicit reference to Jack's gender.
  • Hammerspace: Caroline leaves for the test unarmed, barefoot, and carrying an overnight bag. A mere fifteen minutes later, Rod departs and finds her empty bag in the relay room. She arrives at the colony nearly a month after the test began, and nobody is really sure how she managed to hold onto her odd assortment of items, including her diary and a sauce pan, for so long without her bag.
  • Herbivores Are Friendly: Averted. Rod sees animals akin to antelopes and keeps his distance from them knowing that a herd with horns and hooves is dangerous.
  • Hidden Purpose Test: Subverted. When the deadline passes and the students are never recalled, Rod hypothesizes that rather than survive for a set period of time and then be picked up, the real test is to figure out that they were on Earth All Along and make their way to safety; however, one look at the Alien Sky at night tells him they are nowhere near Earth.
  • Honor Before Reason: Played with. Rod eventually learns that as the leader he needs to have a certain moral authority and thus must take impractical or even foolish actions to maintain the group.
  • Hormone-Addled Teenager: Rod, unaware that Jack is a girl, is firmly against adding girls to the team for this reason:
    "You get some pretty little darling on this team and we’ll have more grief inside than stobor, or such, can give us from outside. Quarrels and petty jealousies and maybe a couple of boys knifing each other. It will be tough enough without that trouble.”
  • Human Popsicle: A variant: Rod's terminally ill father (as well as his mother) will spend two weeks in a Ramsbotham field and return twenty years later in hopes that medical science can save him.
  • Hunting the Most Dangerous Game: Deacon Matson tells the students that they will be facing the most dangerous animal known. When a student, quoting a textbook, takes that to mean either leopards or "snow apes", Matson clarifies that he's referring to other humans.
  • I Call It "Vera": Rod follows in his sister's footsteps and names his Bowie knife. Helen's is Lady MacBeth but Rod shows a lack of creativity and names his Colonel Bowie. Jack's knife is called Bluebeard.
  • I Choose to Stay: Subverted. After they've been there a couple of years, the villagers largely agree that they are happy in their new life, and wouldn't go back even if they had the opportunity. When the opportunity actually arises, they're all gone in a couple of hours.
  • Inconvenient Itch: Upon being outed as a girl, the first thing Jack does is remove her armored vest and scratch an itch, which she claims has been bothering her ever since she teamed with Rod several days earlier and had to wear 24-Hour Armor to conceal her gender.
  • In-Series Nickname:
    • Caroline brands Grant "Hizzonor".
    • Arthur Nielsen is known as "Waxie", which he hates. Later, when he isn't such a tool, he's called by his given name.
  • It's Personal: How Rod feels about whoever jumped him. Ironically, he feels like the loss of his weapon and gear are nothing less than he deserved for failing to be properly aware of his surroundings; his anger stems from the fact that the person also took the watch his father gave him, which just amounts to theft.
  • Just a Kid: When the rescue finally comes, the adults treat the surviving students like they're still children, ignoring that they survived an alien world and formed a civilized, self-governed, and thriving colony there. On getting home, Rod finds his father expects to resume raising him, despite the fact that he's been functioning as an adult for three years and is nearly 21. This is exacerbated in Rod's case by the fact that his parents have been inside a Year Outside, Hour Inside device, so his three-year absence only felt like a couple weeks to them.
  • Kill the Poor: Essentially what the Australasian government is doing as they send out 2 million emigrants over the space of 48 hours. Although the government assures that they are volunteers, they are basically forced through with only what they can carry on their backs. Even worse, their destination planet can be assumed to be semi-habitable at best, as nobody has yet made an attempt to colonize it and Rod later states that any planet with agricultural potential is immediately colonized.
  • Killed Offscreen: Whoever attacked Rod and killed Johann Braun was presumably killed by animals, as Jack found a body that had gear from both Rod and Johann.
  • Killer Rabbit: Dopy joes are rabbit-sized carnivores with an over-sized head that are slow and clumsy. Except during the dry season when swarms of them become the planet's apex predator. An army of dopy joes chases all other animals, including the massive "lions", to the shores of a dead sea where they must feast well, given the millions of bones.
  • Land Down Under: Australia has not fared well, having been conquered by China who then built a massive inland sea in an attempt to make the whole continent more habitable; what remains of the former inhabitants have been relocated to New Zealand. Rod dismisses this "Australasia" as a slum with more people in it than all of North America.
  • Legally Dead: Quietly, when Roy and Rod are a month overdue from their scouting, Grant and Rod's close circle of friends hold a private memorial.
  • Mayor of a Ghost Town: Rod finds himself in this role after a new portal to Earth opens up and the other stranded students abandon their settlement.
  • The Missionary: Bob and Carmen plan on getting married and then becoming missionaries.
  • More Deadly Than the Male: Matson's speech on humanity's unpredictable and aggressive nature mentions that "it goes double for the female".
  • Must Have Caffeine: Matson mentions that when leading an expedition on a primitive planet, it's not the power/lights/plumbing that you miss, it's the things like coffee and tobacco.
  • Naming Your Colony World:
    • Early on, Rod watches colonists depart for a planet called New Canaan, as well as emigrants being forced to a planet called Heavenly Mountains.
    • The world they were stranded on was named Tangaroa after a Polynesian goddess, although they don't find this out until contact with Earth is reestablished, and they never got around to naming it themselves.
  • Never Tell Me the Odds!: Jimmy wants to back out of the test and offers to share the statistics of the last year's test. Rod doesn't want to hear them and leaves.
  • Noisy Nature: There's a species of animal that the colonists dub the "grand opera" due to the noise they make every night.
  • Non-Indicative Title: The titular Tunnel (and its failure) only serves to set the plot in motion, and ceases to be relevant after the first couple chapters. From a storytelling perspective, Heinlein could just as easily have made it a spaceship without having to change much else.
  • Not Afraid to Die: Rod's sister, when her mother laments that she chose a career path so dangerous, simply shrugs and points out that the death rate for the military is the same as anywhere else — one person, one death, sooner or later.
  • Overpopulation Crisis: China apparently conquered Australia and paved over the entire continent to make room for its growing population before the Portal Network was developed, now they force hordes of settlers to new, substandard worlds through the gates. And Helen apparently finds it acceptable to retire from the military and raise a large family, despite the existence of this trope meaning that there's a shortage of available husbands (because more women are being born than men).
  • Paranoia Fuel: invoked
    • The reason Helen recommends that Rod takes only a knife: a gun's power will give Rod a false sense of courage and safety, which would possibly get him killed. A knife is only so much better than being unarmed and his vulnerability will make him paranoid enough to avoid conflicts and survive. Helen knows from experience. She took a gun on her own survival test, and losing it saved her life; she ran from a native beast rather than fighting it and learned later that the creatures were virtually Immune to Bullets. Having no gun immediately makes Rod more cautious when he arrives; he elects to crawl downwind, since that would give him the best chance of seeing anything that was hunting him, rather than upwind, which would be a hunter's strategy.
    • The final word of advice given to students is to beware of "stobor". They initially assume the stobor to be the giant, lion-like creatures they occasionally encounter, but then finally identify what stobor actually are: "dopy joes", normally dim-witted and lethargic creatures who have an annual The Swarm season. However, after the rescue, Rod finds out that there never were any "stobor". It was a vague warning specifically to frighten the kids into being cautious. Nearly every life-bearing planet has some animal that turns out to be a monster of legend under the right circumstances and the best protection is being completely paranoid..
  • Portal Network: Played with. Gates are very expensive to maintain, but it makes sense to keep them open in high traffic routes; for example, Rod uses them as part of his daily commute. On the other hand, a single colony on a distant planet might have to wait years to have regular gate access, as it would need to be profitable enough to justify opening a gate.
  • Race Lift: Rod is turned into a white kid on the covers. The book does not mention his race, but Word of God would make him black.
  • Ribcage Ridge: The beach of bones on the shores of the dead sea. There are millions of bones lying there; some ancient and worn, others with gristle still clinging, but no actual carcasses.
  • Robinsonade: They were intentionally marooned as part of a high school wilderness survival course. However, due to a small technological "hiccup," they were actually marooned for much longer than expected.
  • Samus Is a Girl: Jack is really Jacqueline.
  • Sassy Black Woman: Caroline. Although apparent throughout the novel, her snarkiness really comes to the forefront when she becomes the Point Of View character as seen through her journal entries.
  • Schizo Tech: Settlers travel through portals to other planets with animal-drawn wagons. This is justified by the fact that opening a portal is expensive, so settlers on untamed worlds have to be prepared to be out of contact for long periods of time, making animals more practical than vehicles that require fuel and maintenance.
  • No Sense of Velocity: Rod and Jack notice a new star and conclude that they've just witnessed a nova. At the book's end, it's revealed a nova is what interfered with the recall. It's implied that they saw the nova that prevented them from returning home when realistically it would be many, many years before one world saw the effects of a nova, least of all both. One possible explanation is that the effect of the nova reached the space around the planet at nearlynote  the same time the light from it did, and it's flat-out stated that the portals are delicate at best, with many variables that all have to be just right. If looked at like this, the reason the cut-off happened when they saw the nova is because it altered local space.
  • Spiritual Antithesis: Tunnel in the Sky was written in response to William Golding's Lord of the Flies. Heinlein disagreed with the viewpoint that savagery and barbarianism were humanity's natural impulse in the absence of civilization. Ironically, Golding had written Flies for a similar rebuttal: having disagreed with The Coral Island, were stranded young white men are living peacefully until native savages threatened them.
  • Stranger in a Familiar Land: When Rod gets back home, his parents and family friends all seem like petty jerks that don't understand anything. He can't relate to them anymore and no longer accepts their authority. He quickly finishes college and heads out to the Outlands again.
  • Strolling on Jupiter: Strongly implied, with a reference to the "steel-limbed Jovians" who "enjoy gravity 2.5 times ours" and "poisonous air at inhuman pressure".
  • Super Breeding Program: Waxie wants to have the colony run on "scientific criteria" and start breeding a super-race.
  • Sweet Polly Oliver: Jack, her body armor disguises her feminine form and she learns that Rod has no interest in teaming up with girls, at least early on.
  • Switching P.O.V.: When Rod departs with Roy to scout for a new colony site, Caroline becomes the point of view via her diary.
  • Tap on the Head: Just a few days into his survival training, someone hits Rod from behind and he wakes up with all his gear missing. Deconstructed somewhat, as Rod concludes that his attacker meant to kill him, not knock him out.
  • Take a Third Option: More specifically, a fifth. A psychological experiment is performed on an ape, locking him in a room with four options for escape and watching to see which he employed, only for him to find a fifth way out. It serves as an allegory for the development of the Ramsbotham Gate which solves overpopulation and conquers the stars in ways nobody else could have foreseen.
  • Take That!:
    • Against the Lord of the Flies. The selfish, aggressive students are effectively the savage kids from Flies and the leader manages to get himself killed, while the others come crawling back asking to be let in. Meanwhile the cooperative ones are willing to help each other out and manage to build a functioning society.
    • During the mayoral election a number of items are chosen to serve as anonymous ballots: pebbles, twigs, and leaves. Waxie, running on his "scientific breeding" platform, needs an item to serve as his ballot. Jimmy offers a solution: the fragmented shards of a failed clay pot. Which he announces to the colony as, "I'll get chunks of it and all the crackpots are votes for Waxie."
    • Against sensationalist journalists, with the news crew at the end who decide it would be a better story to depict the students as having regressed into savagery, rather than the actual society which they created.
  • Teenage Wasteland: Type 1, the kids are stranded on an alien world because the recall to Earth never came. Those who try to make it an anarchist free-for-all (as mentioned above, aping Lord Of The Flies) get killed off fast and the ones that remain maintain democracy and organization in order to survive.
  • Terraform: It's mentioned that China, upon taking over Australia, built a vast inland sea in an attempt to turn it into arable farmland; however, Rod dismisses reports of the success of the project as mere propaganda.
  • Too Awesome to Use: Rod shoots down Jack when she suggests that they use her dart gun for hunting. Although theoretically it can be used indefinitely (as it runs off of manually-pumped compressed air and the darts can be retrieved and re-envenomed (until the venom runs out, unless they can find a suitable substitute)), Rod points out that no matter how careful they are, the day will come when the last dart will be lost — and that could be the day they really need it.
  • Training "Accident": The test was only supposed to be a week and a half maximum; after the recall fails to appear, they consider the possibility it's meant to be late and the test is secretly longer. Rod takes it further and hypothesizes that the real test is to figure out that rather than being on a distant planet, they were actually on Earth All Along and need to make their way to safety. Eventually, it becomes obvious that the recall isn't coming and they're stranded.
  • Tribal Face Paint: A highly unethical news crew arrives at the colony after contact with Earth is reestablished. Rod catches one of them spraying paint on his face as part of their "civilized kids brought to savagery" story.
  • Wagon Train to the Stars: Interstellar colonization is accomplished by means of literal wagon trains, as advanced technology can't be sustained by a survivalist colony while wooden vehicles and pack animals can.
  • We Have Become Complacent: Knowing that their current colony is not in a defensible position, Rod and Roy are sent to scout for a site that will be suitable for the long-term. An injury turns their scouting mission from weeks to months; when they return, the colony is much more established and, since no serious issues have arisen, people are willing to risk staying where they are rather than start over in a new location. Rod disagrees; a group of his close friends consider leaving the group to move to the more defensible location, but ultimately decide to remain. It comes back to bite the colony when the local wildlife goes insane due to seasonal behavior patterns.
  • We Will Spend Credits in the Future: Although Heinlein uses this trope in many of his works, it's averted here; instead, the currency is the "pluton", which seems to be roughly equivalent in value to the dollar (or at least the dollar in 1955 when the book was written). Rod runs up a (fake) debt of billions of plutons playing cribbage with Jimmy and Jack.
  • Weather-Control Machine: "Weather conditioning", as well as plumbing, heating, power, etc. are mentioned as luxuries that are absent in the new colony planets. Rod also mentions, when expounding his hypothesis that they're on Earth, that there must be cloud generators to keep the sky overcast so the students don't figure it out from seeing the stars.
  • Year Inside, Hour Outside: The same technology that allows for instantaneous interstellar travel enables people to create zones where time moves relatively faster or slower than the outside world.
  • Year Outside, Hour Inside: When Rod's father is diagnosed with an incurable disease, he and his wife go into a Ramsbotham field where two weeks to them will equate to twenty years in the real world. They will stay in the field until a cure for the disease is found, which turns out to have been discovered much sooner than the twenty years the doctors estimated it would take. Rod's parents exit the field just before he returns home from his time on the alien planet.