Traveller

"This is Free Trader Beowulf, calling anyone... Mayday, Mayday... We are under attack... Main drive is gone... Turret number one not responding... Mayday... Losing cabin pressure fast calling anyone... Please help... This is Free Trader Beowulf ..."

"...mayday..."

Traveller was first published by Game Designers' Workshop (GDW) in 1977. Thirty-plus years later, it still has a rabid pack of followers, despite the fact that GDW closed down in 1996. The publishing license has passed through a number of hands since then.

System:

Traveller was one of the earliest published role-playing-game systems, and probably the first to divorce the concept of skills from that of occupation or class. Characters did not enter the campaign young and untrained; rather, they had careers during which character development occurred. This was generally perceived as giving the game a more "three-dimensional" feel. While there were some assumptions about the campaign world, an interstellar setting called "the Spinward Marches", little actual information was initially provided, leaving the campaign world to the Referee's fertile imagination. The system wasn't static, though; the release of supplements and of subsequent editions of the system, brought more detailed character generation, task systems, rules for skill improvement, and additional skills and rules for them. But Traveller isn't a role-playing system, because you can play GURPS Traveller, which is a different system entirely.

Setting:

Traveller eventually came to describe an interstellar community of sorts, focused on a "Third Imperium", of which the original Spinward Marches was merely a small frontier area. Published and well-regarded science fiction was a major source of inspiration for aliens and their societies, and for various aspects of technology. A broad history was mapped out, and cultural differences were developed and illustrated. This led to a background in many ways richer than that of previous role-playing settings, yet without significantly limiting the referee. Again, the setting wasn't static; every release of Traveller or Traveller supplements brought new information to light. But Traveller isn't a role-playing setting, though, because you can play Traveller in a setting that is unrecognizable in comparison to what's in published material.

Story:

As with any RPG, Traveller can be an opportunity to develop characters, their likes, dislikes, habits, idiosyncrasies, motivations, and so on. The events of any particular session can be part of a grand story arc throughout the campaign, or not, if the players and referee choose not to play that way. The Traveller Supplements, over time, described a very-large-stroke history of the "Third Imperium", but the real story was in the gameplay and gamemaster's hands.

Editions:

There have been many.
 * Classic Traveller (1977-86): The original. Then just called Traveller but since acquired the "Classic" qualifier to distinguish it from the later editions. It has also been called "the Little Black Books" because of the printing format and minimalist covers used.
 * MegaTraveller (1987-92): An update to the original rule system, complete with a controversial Metaplot shift involving the collapse of the Imperium.
 * Traveller: The New Era (1993-95): A post-apocalyptic take on the original setting, with options for almost-original flavour and an entirely new system. Some retcons as well, mostly dealing with how tech worked in the Third Imperium.
 * The timeline has been continued with Traveller 1248, a series of systemless sourcebooks by Comstar Games, now out of print since Comstar lost the licence.
 * Marc Miller's Traveller aka Traveller 4 (1996-98): The first edition of the game after GDW folded. Set in "Mileau 0" - the beginning of the Third Imperium. Mr. Miller has said it was something of a "rushed" product. "Pocket Empires", however, is still quite highly regarded by players interested in the economics of the setting, which as trading is often a major part of the game isn't as esoteric a concern as it may seem.
 * GURPS Traveller (1998-present): Exactly What It Says on the Tin, complete with a timeline reboot in an ultimately unsuccessful attempt to unbreak the base. The most recent book, Interstellar Wars, presents the initial contact between Earth and the First Imperium from the Backstory for the first time.
 * Traveller 20 (2002-present): The inevitable d20 version.
 * Traveller Hero (2007-present): Again, Exactly What It Says on the Tin.
 * Traveller 5
 * Mongoose Traveller (2008-present): An updated version of Classic Traveller by, well, Mongoose Publishing. Mongoose has also adapted several of their licensed properties to use the Traveller rule set. A Traveller version of Babylon 5 was released in 2009 to mixed reviews, along with Judge Dredd in the same year. Later adaptations have included Hammers Slammers and Strontium Dog. Again, Mongoose Traveller is not the official name: it's sold simply as Traveller.

Marc Miller is currently funding a Traveller 5th Edition via Kickstarter.

Provides examples of:

 * Absolute Xenophobe: the K'kree, toward any creature anywhere that can be classified as a carnivore.
 * Adventure-Friendly World: One of the best in RPGs. The limitations of the jump drive mean that the Imperium is very hands-off, leaving plenty of room for odd societies to interact with, local wars to fight, lost civilizations to explore, pirates, and just about anything else the Referee can think of.
 * Apparently Human Merfolk: The Nexines, an offshoot of humaniti that were genetically engineered for underwater mining.
 * A Real Man Is a Killer: Aslan think all males have to be interested in little besides fighting or else they're not truly men. This is taken to extremes by Aslan. Anyone not working in the occupation associated with their gender according to Aslan is referred to as being in the opposite gender.
 * After the End: The New Era and The Long Night
 * AI Is a Crapshoot: Virus, very much so. Technically, this trope isn't quite played straight, though it was the clear reference point for the authors. Virus isn't A.I. in the conventional sense of the word; it's more like an extremely opportunistic, intelligent parasite. That just makes it this trope dialed Up to Eleven when any transistor can become intelligent and malicious. Of course, Virus is doing exactly what it was designed to, so it may be more of a case of Gone Horribly Right.
 * Air Vent Passageway: An entire paragraph of FASA's Classic supplement Action Aboard: Adventures on the King Richard is devoted to the use of air vents to move around the ship.
 * Aliens Speaking English: An evolved form of English is a popular language. Justified by the wide spreading of Solomani culture.
 * All Planets Are Earthlike: Strongly averted. Most of them are actually quite a bit less hospitable than Earth.
 * Alternate Continuity: GURPS Traveller
 * Alternate Character Interpretation: Nearly everything in Traveller can have an alternate interpretation - by design. The Imperium itself can be viewed as a peaceful and benevelant federation that lets its worlds largely govern themselves or as an oppressive, tyrannical empire that cares only about the taxes it receives, or anywhere in between. The Zhodani are also especially open to this.
 * Alternative Number System: The various alien species use different bases. The Aslan use Base 8, the Hivers use Base 16, and the Droyne use Base 6. Most of the various Human Aliens, as well as the Vargr, use Base 10.
 * Anachronic Order: Later editions of the game are all set earlier than The New Era, and most of them are set earlier than MegaTraveller. Some of them much, much earlier.
 * Ancient Artifact: The Ancients, the Pre-maghiz Darrians, the first two Imperiums before the Long Night. All sorts of sources of Ancient Artifacts are available. The Darrians have a whole fleet of starships that had been discovered at a hidden cache.
 * And Man Grew Proud: The Darrians got a little too carried away with their scientific ability. The result was the destruction of their society and the death of nearly everyone on their homeworld.
 * Animal Wrongs Group: The K'kree are a Planet of Hats of these, prepared to wage wars of extermination on people for eating meat.
 * Ape Shall Never Kill Ape: The K'kree would like to believe that K'kree are incapable of ever eating meat. The Hivers used this belief and their skills in manipulation to win their war, and to keep the peace between the two ever since.
 * Apocalypse How:
 * Both the Long Night and the Rebellion resulted in light Class X-3s, with the fall of interstellar civilization in each case.
 * The Ancients also apparently had a Class X-3, warring themselves into extinction hundreds of thousands of years before any other race had the jump drive.
 * The Darrians caused their own Class 3 on Darrian.
 * Arc Number: 6 turns up quite a lot in Traveller - jump drives go up to 6, maneuver drives go up to 6, there are 6 major races, and let's not even get started on the Droyne.
 * Artificial Gravity: Ubiquitous throughout the setting.
 * Artificial Limbs: A failed survival roll during character creation in the later editions of the game might give you one of these instead of outright killing you.
 * Ascended to Carnivorism: In the supplement Aliens of the Rim: Hivers and Ithklur. During a military campaign between the herbivorous K'Kree and the Ithklur, the fighting became so bitter that each side started performing atrocities on the other, including the K'Kree eating dead Ithklur bodies.
 * Asskicking Equals Authority: The essence of Vargr political philosophy.
 * Asteroid Miners: The typical example is the classic grubby back-of-beyond Asteroid Thicket. Glisten however is an urbane and civilized place.
 * Auto Doc: The Auto Doc Independent Medical Treatment Center in the Classic supplement Merchants and Merchandise by Paranoia Press.
 * Back From the Dead: Emperor Strephon tried to prove that he really hadn't been assassinated, but it was too late.
 * Backstory: Most sourcebooks are for developing this. They can make very good reading on their own without actually playing for those who actually like devouring data, fictional or otherwise. The Backstory provides very "realistic" detail.
 * Backup Twin: Lucan was this to Varian, at least as far as the Imperial succession was concerned.
 * Badass Army: most notably the Imperial Marines.
 * Badass Bookworm: The IISS is not only known for its success in exploration, spycraft, and daring-do (and sometimes daring don't), but for being at the pinnacle of scientific achievement. Furthermore many scouts take package courses (offered as a job perk) along boring voyages to educate themselves and graduate as great poets or scholars after their studies.
 * Badass Bureaucrat : The Bwaps' Hat.
 * Badass Mustache: Archduke Norris.
 * Bad Dreams: The Emperor Strephon suffered from these after his family and his double were killed and the Imperium he had sworn to protect descended into Civil War because they thought he had been assassinated.
 * Barbarian Tribe: The Aslan are a partial example. They have the social and political structure of a tribal society but are technologically advanced.
 * The Battlestar: Several examples, most notably the Tigress battleship which can only be described as a mini-Death Star. The Azhanti High Lightning is the other iconic example.
 * Beam Spam: The larger capital ships tend to mount hundreds and hundreds of laser turrets that let them do this, though they are mostly intended to shoot down enemy missiles.
 * Beleaguered Bureaucrat: In GURPS Traveller: Interstellar Wars, the Vilani Imperium was deliberately organized to make the Emperor this. The idea was that there would be less volatility if everything was slowed down.
 * Big Badass Wolf: The Vargr
 * BFG:
 * The FGMP-15 (Fusion Gun, Man Portable). It includes a gravitic compensator so you could theoretically carry and fire it unarmored. If you survive the radiation it releases all over the place when fired, that is.
 * The earlier PGMP (Plasma Gun) all but requires Powered Armor to be fired by a human without high-level augmentation.
 * Brainwashed: There is some question whether the Zhodani proles are this, or whether they are genuinely happy.
 * Cadre of Foreign Bodyguards: One of the mercenary tickets (scenarios) in Mercenary is to act as bodyguards to the leaders of the planet Jokotre while they make a pilgrimage to the shrines in the holy lands.
 * Casual Interstellar Travel: It's practically the name of the game.
 * Less casual than many; it takes two years or more to get from one end of the Imperium to another with a fast ship.
 * Catfolk: The Aslan are race of lionlike creatures. Their name is also a Shout-Out to The Chronicles of Narnia.
 * City of Spies: The Federation of Arden
 * The Clan: Universal among Aslan and common among other races notably humans.
 * Cloak and Dagger: Political intrigue is constantly going on.
 * Colony Drop: Whether or not your average player group can use their ship to drop hyper-accelerated rocks on planets that annoy them is a common subject of discussion among fans. The Third Imperium has its own term for this trope: "Deadfall Ordance". That alone says something.
 * Combat Pragmatist: Darrians and Vilani. Subverted in the Vilani case. They knew how to be ruthless but not how to fight.
 * Comes Great Insanity: This was apparently Lucan's problem. He may not have been that stable before he became Emperor, but nobody cared when he was fourth in line.
 * Communications Officer: One of the crew specialties in GURPS Traveller: Starships.
 * Contagious AI: Virus again.
 * Cool but Inefficient: Averted: assorted slugthrowers are still in use even at tech level 15.
 * Cool Starship: Just pick your favorite.
 * Corrupt Corporate Executive: These show up quite often in the printed adventures.
 * Courier: The IISS
 * Cultural Posturing: A large part of the cause of the Interstellar Wars seems to have been a disagreement over whether Earth was the center of the universe or just an Insignificant Little Blue Planet.
 * Crew of One: The Type-S scoutship can be operated by one scout. So can the X-boat. Bigger ships need more crew, with many Imperial warships carrying spare frozen crew members to thaw out when necessary.
 * Crystal Spires and Togas: The Vilani Imperium. The ruling caste of the Third Imperium as well.
 * Darker and Edgier: In some ways what The New Era tried to be. It was produced in the '90s, after all.
 * Days of Future Past: Traveller is often compared to the Age of Sail.
 * Dead Man's Hand: Journal of the Travellers' Aid Society magazine #14 adventure "Aces & Eights". A set of playing cards (two aces, two eights and the joker), will, when put in an X-ray machine, create a map to the location of a 20 million credit treasure. The money was the payroll of the 1188th "Aces and Eights" Lift Infantry Brigade. The man with the cards is killed by the bad guys and the cards stolen, and the PCs must retrieve them.
 * Death by Origin Story: Early versions of the character generation system frequently killed player characters before play began.
 * Death From Above: The Imperial Marines like to drop their troops in pods from orbit.
 * Deflector Shields: The black globe generator, and nuclear dampers, to a limited extent. Otherwise, perhaps surprisingly, absent.
 * Deliberate Values Dissonance: Ranging the spectrum from the merely curious to the absolutely shocking. Yes, it is perfectly possible to roleplay Scary Dogmatic Aliens.
 * Derelict Graveyard : There are lots of these in the Spinward Marches left over from wars through the centuries. The planet Entrope is notable for this.
 * These are often under heavy guard because illegal weapons can be found there.
 * Despair Event Horizon: Emperor Strephon crossed over after he realized giving up his claim to the throne wouldn't save his followers. Several other claiments to the throne also gave up when they saw how the Rebellion was destroying the Imperium.
 * Determined Homesteader: And any variation thereof. In undeveloped places you will find several examples of these. Once or twice they will end up as sample characters or characters in sidestories. This is the Sword Worlder's second hat to accompany Proud Warrior Race.
 * Did Not Do the Research: In-universe example; the logo of the IISS is supposed to represent the Pony Express. Except they mistranslated 'Pony' into 'Poni', an eight-legged dinosauroid from another planet. So, yes, the logo is a person riding a dinosaur like a horse.
 * Verging on a Critical Research Failure, out of universe, an early supplement included game stats for various science fiction personalities, including Luke Skywalker and Darth Vader ... described as the creations of one Gene Lucas!
 * Discontinuity Nod: Prince Varian's dream of the Final War and the virus, among many others in GURPS Traveller.
 * Downer Ending: Players of Interstellar Wars who know the background will know that the Terrans eventually win, but four hundred years later galactic civilization collapses completely anyway.
 * Drop Pod: The Kinunir, an early adventure, uses these for the marines.
 * Duel to the Death: There are a number of ways to do this. Aslan prefer dueling with claws. When a human duels Aslan-fashion, he wears an artificial claw (called an Ayloi) on his hand.
 * Dying Race: The Droyne,
 * Earth Is the Center of the Universe: Averted. Earth is in fact on the extreme rimward edge of the Imperium. It is the center of the Solomani sphere, however.
 * Elaborate Underground Base: The Zhodani had one of these during the Fifth Frontier War
 * Eldritch Abomination : Grandfather. Some alien races come close to this as well.
 * The Empire: The Solomani Confederation and Zhodani Consulate have elements of this, and Lucan's Imperium fits the trope to a T.
 * Energy Absorption: The Black Globe.
 * The Epic : The sample campaign 100 parsecs which is about The Migration of a band of Sword Worlders to the far reaches of space. Also the original journey of exiled soldiers through Aslan territory to found the Sword Worlds.
 * The Extremist Was Right: Emperor Cleon created the Imperium by a labyrinthine arrangement of evil and manipulative schemes. And it produced peace, civilization, and prosperity for thousands of years. He read the Evil Overlord List no doubt. That explains it.
 * Fantastic Caste System:
 * The Imperial Nobility acts as a glue to keep the Imperium together. In effect rather than being an ethnic empire (I.E. the Roman empire, etc), it is a caste-based empire and the nobility is the central cadre.
 * Not only that, a state the size of the Imperium could not possibly find high command by merit alone as everyone would die before getting to high enough position, hence there has to be a caste system.
 * The Zhodani are more grotesque. It is a caste of psionics which means that among the rights of the ruling caste is access into the minds of the commoners. The rulers of course are allowed privacy; after all, one must have limits.
 * As for the aliens, Droyne have several physically different castes and the K'kree divide themselves into servants, merchants, and nobles.
 * Fantastic Racism:
 * Between humans and aliens, different human subspecies, and in some cases natives of different planets.
 * Heck, sometimes natives within different planets too.
 * The K'kree are the worst in this regard. They think all carnivore races are a plague to be extinguished or at least brutally reeducated into vegetarianism.
 * The Sword Worlders think every Darian is an Insufferable Genius and Darians think Sword Worlders are a Barbarian Tribe. A cynic might say both are right.
 * Some Vilani and Solomani still hate each other thousands of years after the Intersteller Wars. This is not universal however.
 * Every race that claims to have invented jump drive separately is a major race. The rest are minor races. There is a curious dispute over that with regard to Aslan whom some Solomani claimed to have "stolen" (whatever that means) jump drive from them.
 * Fantastic Rank System: The Vilani have one. See the trope page for details.
 * Fantastic Recruitment Drive: The Zhodani Consulate extensively uses psionic abilities in its government and military. They test children for psionic aptitude and train those with a significant level of power.
 * Fantasy World Map: Worlds have maps, of course, but the scale of the setting can only be appreciated by viewing the online Traveller Galactic Map. Check out the Zhodani Core Expedition sectors; they've gotten all the way to the edge of the uninhabitable regions of the Core!
 * Faster-Than-Light Travel: Of course, though it is considerably slower than many other forms (see Feudal Future below).
 * The Federation:
 * The Third Imperium, despite its name and feudal structure, is as written closer to this than to The Empire. Some of its successor states, such as the Regency and the Reformation Coalition in the New Era, also fit here. Others don't.
 * The Terran Confederation from the volume Interstellar Wars would probably be The Federation too, despite it's expansionist tendencies.
 * Feudal Future: In the setting, FTL communication is only by ships using Jump Drive, which takes a week to reach a destination ranging from one to six parsecs away. With the Imperium being hundreds of parsecs across, it would literally take months or even up to a year or more for information to travel from one end to another, or from the capitol to the fringes. This necessitates a decentralized government, with a large amount of autonomy granted to the local powers. A feudal system is what you would end up with no matter what you chose to call the Imperium's lords. As a side note, the Aslan are a Tribal Future.
 * Fire of Comfort: The Hearthfire is a sacred symbol to Sword Worlders. Soldiers and police "guard the hearthfires" and goodwifes "tend the hearthfires".
 * First Contact: The Imperial Interstellar Scout Service has done this so many times that it has standard proceedures for it.
 * Fixed Forward-Facing Weapon: most starship weapons did incremental damage and could wear down an opponent over time. Spinal mount weapons (either a particle accelerator or a meson gun) ran the length of the ship and could blow opposing ships to atoms with a single shot.
 * Floating Continent: The Imperial Palace.
 * For Science! : The Darrians' hat.
 * Forever War: The Intersteller Wars which went on for two hundred years before the Terrans conquered the Vilani. The frontier wars between the Imperium and the Zho which are still going on (in the GURPS version).
 * Framing Device: the Backstory to Traveller acts as this. Traveller can easily be used as Fan-fic as well as RPGs and manages remarkable development while retaining flexibility.
 * Four-Star Badass: Admiral Manuel Albadawi, leader of the Terran fleet in the decisive part of the conquest of the First Imperium. Lucky dice rolls can give players a retired general or admiral as a character, too.
 * The Future: Bordering on A Long Time Ago in a Galaxy Far Far Away, except for Earth still being in the picture.
 * Galactic Conqueror : Cleon is a combination of this and Well-Intentioned Extremist. He is the closest example of the classic model. Albadawi is this in the sense that he is in fact conquering. He is however doing that as a servant of the Terran Confederation rather than on his own, and it is just a function of his being a Four-Star Badass.
 * Generational Saga: One of the sample campaigns in the volume Interstellar Wars is a generational saga called Legacy of War. The characters are not given and creating them is left to the GM and players.
 * Generican Empire: The Third Imperium.
 * Ghost Ship: The Annic Nova, among others.
 * Global Currency: The Imperial credit in Classic Traveller. This ended in MegaTraveller after the Empire collapsed. TNE, set after the fall of the Empire, explicitly claims that the Imperial Credit is still the principle currency. The explanation: well, there sure are a lot of 'em lying about. Averted as well as played straight. The Imperium is strong enough to justify having a large influence on currency. But other worlds often mint their own.
 * Glory Seeker : The Azhanti are a Proud Warrior Race that are rewarded by God according to the challenges they seek out and overcome. Naturally there are other Glory Seeker s but these have a religion centered on seeking glory.
 * God Guise: In Classic Traveller Double Adventure 6 Divine Intervention and MegaTraveller supplement Vilani and Vargr: The Coreward Races.
 * Good Guy Bar: Brubeck's, a high prestiege bar that advertises itself as a nostalgic throwback to the Cheers style bar. There are also the Altikrigarnir soldier's clubs where veterans of both the Sword Worlds and of Aslan clans in Darrian service visit in between wars, presumably to congratulate each other about what brave warriors they both are.
 * Good Is Not Nice: The Imperium is generally viewed favorably, but this is a government that grew largely through conquest and isn't afraid to put down rebellions hard.
 * Government Agency of Fiction: The IISS. It is an exploration and intelligence arm of the Third Imperium. Loosely similar to a combination of NASA and the Indian Political Service. Other analogies can be thought of.
 * The Great Repair
 * Grey and Grey Morality: A major theme of the game is that there are very few clear-cut "good guys" and "bad guys", just people who may do good and bad things.
 * Gunboat Diplomacy: One of the ways the Imperium expanded.
 * Half-Human Hybrid: Averted, but the different sub-species of humans can interbreed, with the inhabitants of the Third Imperium being largely a mixture of Vilani (humans from Vland) and Solomani (humans from Earth).
 * Hegemonic Empire: The Third Imperium is more a straightforward Empire(albeit a semi-benevolent one), but still has elements of this including taking time to flatter substates for ideological and policy reasons.
 * The Sylean Federation went from that into the Third Imperium under Emperor Cleon I, by utilizing the methods of a Hegemonic Empire.
 * Heroic Dolphins: In one sourcebook, a story is told of some uplifted sapient dolphins who helped bring to light a scandal involving the secret enslavement of an intelligent species by a megacorporation.
 * Hero of Another Story: A typical NPC has a good chance of being this.
 * Hidden Depths: Traveller itself. This is easily underestimated because RPGs are a pop-art. However the detail of this setting is even more than that of Dune and the flexibility is greater.
 * Hired Guns: This is a popular background for games. There are a large number of Private Military Contractors available for hire.
 * Honor Before Reason: The Aslan Fteirle code.
 * The Horde: Vargr. "uplifted" wolves who act like, well, wolves.
 * Human Aliens: Many varieties, all of which are descended from humans transplanted from Earth by the Ancients, apart from the Solomani who are descended from the humans left on Earth, i.e. us.
 * Humans Are Bastards: One item of jewelry called Denuli gems is exceedingly rare and harvesting them is banned in the Imperium. The reason? It turns out that they are the eggs of low-tech sophant aliens.
 * Humans Are Leaders: All three Imperiums were/are ruled by humans.
 * Humans Are Cthulhu: Vargr view humans this way especially Zhodani(which are regarded that way by other humans). Humans can build large abstract societies which attract Undying Loyalty from their members, whereas Vargr have trouble giving loyalty to anything but a Magnetic Hero. As a result humans sometimes appear to Vargr the way a Hive Mind appears to humans.
 * Humans Are Special: Most of the known 'verse is dominated by the three races of humans.
 * Humans Are Warriors:
 * The Solomani have long had a far greater martial reputation than the other two major human races and the Third Imperium's military traditions are largely Solomani. To the extent that 57th-century Imperial Marines aren't that different in culture and ethos from the 20th-century US Marine Corps and Royal Marines, especially in TNE.
 * The Solomani are really the top predators of the Traveller universe. The Vilani and Zho are less warlike and their collectivism is crippling. Vargr are on the other extreme too chaotic, and Aslan too clannish. Vargr make good pirates but bad soldiers and while Aslan have a lot of individually skilled warriors they are limited in their capacity to systemitize warfare.
 * This is speaking of Solomani military tradition rather than the Solomani as a race. The Solomani and Vilani are by the time of the Third Imperium so interbred that the difference is more of identity rather than race. Neither of these marry Zhodani very often as the Psi thing leaves them out on their own, effectively alien and more alien to other humans than Aslan or Vargr.
 * All that said, non-terran humans usually are no wusses themselves, even if not at the Terran level; and a number are Proud Warrior Race s. In Traveller you really do not want to get on humaniti's bad side.
 * Human Popsicle: Low berths: a low-cost way to see the galaxy, but not without danger. The crews and passengers of passenger ships sometimes play "the low lottery" - a Cr 10 bet on how many low berth passengers will survive the trip. If the winner doesn't survive the Captain of the ship gets the money.
 * Hyperspace Is a Scary Place: Ships can go into jumpspace and not come out. Or come out at a random destination; or hundreds of years later, with only a week passing aboard ship, or vice versa. Naturally enough, spacers have all kinds of superstitions regarding jumpspace.
 * In most editions, close exposure to jumpspace (usually resulting from battle damage to the hull and the grid that forms the "jump bubble" of normal space around the ship) and its... different laws of physics can cause insanity and other bad effects in sophonts.
 * Hyperspace Lanes: Jump routes are limited mainly by the presence of fuel stops. As most ships can only jump one parsec at a time that means that most traffic follows places where the stars are one parsec apart. A ship equiped for the purpose can obtain fuel at a gas giant without landing in port. It is still necessary to be in-system.
 * In the Future, Humans Will Be One Race: Both played straight and averted. The Imperium is largely a mixture of two human races that are now largely the same race, but other human races maintain their own empires on its borders.
 * There are also small Solomani ethnic splinter cultures like the Sword Worlders, who are very Germanic.
 * In the Future We Still Have Roombas: The maintenance robots in "Research Station Gamma".
 * Intrepid Merchant: Free Traders. Who are constantly in a desperate struggle to survive by their wits, on the frontier. A Free Trader centered game is one of the most popular because of its flexibility and the ease with which a small number of characters can fit in. It can have recognizable similarities to Firefly in some ways, but it is set in an even more complex universe.
 * While the Space Trucker variety described above is a favorite possibility, there are several types of Intrepid Merchant s that can be imagined.
 * It Got Worse: The transition between MegaTraveller and The New Era reveals that the Rebellion was only the beginning. The Hard Times supplement for MegaTraveller relesed late in the line included rules for reducing the population and technology ratings of worlds in the war zones of the Rebellion.
 * It Makes Sense in Context : The Vilani prejudice against technical advance was the result of a deliberate decision made long ago. When one realizes that they already had an Empire of thousands of worlds and enough technology to give men the power of Olympians, one can understand. After all, they had plenty of wealth and power, there might actually be some things that Man Was Not Meant to Know and their biggest threat was instability as they had already eliminated all outside threats. This actually worked for awhile. Unfortunately the Vilani ran into folk from an Insignificant Little Blue Planet who saw no need to play by their rules...
 * Jabba Table Manners: The Hivers eat rather messily, and they tend to enjoy what humans would regard as extremely fragrent food.
 * Killer Game Master: One of the few games where your character can die before you even get out of character creation. More recent editions, understandably, make it optional (Mongoose Traveller calls it "Iron Man" rules).
 * Kinetic Weapons Are Just Better: Many of the weapons used aren't that much different from ours. It is pointed out that a supersonic lead slug kills you just as dead at tech level 15 as at tech level 7. Space combat is the exception, as conventional projectiles are trivially easy to dodge at the distances and speeds involved.
 * A Light in the Distance: Twilight's Peak. While traveling on the world of Fulacin, the adventurers can find an octagonal structure with a light in the window. If they encounter it at night, the light will lead them to the building.
 * The Laws and Customs of War: The Imperial Rules of War, which are an unwritten guideline as to how Imperial vassals will settle difficulties between them. Basically they boil down to, "Have fun boys, but don't make to much of a mess because The Emperor has means to punish you."
 * The Imperium acts as Combat Referee between its substates. There are a number of guidelines to when an imperial intervention will be launched. War crimes, or the use of WM Ds on the ground(in space it is different), being too obviously the aggressor, trying to grab too much power or to disturb too great an area and so on are likely to attract an Imperial intervention. The general rule though is "be unnoticeable and you won't be noticed".
 * Client planets are pretty much allowed free play so long as a war doesn't go on too long or cause too much death and destruction. There are a few hard and fast rules, however, which all local warmongers should bear in mind: Do not harm Imperial officials, soldiers or nobles; don't throw around nukes and other WMDs (the Imperium reserves that privilege to themselves); and don't ever interfere with trade.
 * Lost Colony: The Island subsectors in the great Rift were these before a misjump by an Imperial cruiser brought them jump technology.
 * Lost Technology: Loads. Apart from artifacts of the Ancients there are any number of other lost races who left strange artifacts. The Darrians they still have some of theirs from their first interstellar civilization.
 * Lured Into a Trap: In the supplement The Traveller Adventure, adventure "Kidnapped on Aramanx". The villains who kidnapped Lisa Fireaux demand that Gvoudzon deliver the ransom so they can kidnap him as well.
 * Macross Missile Massacre: The Terrans employed missile boats during the Interstellar Wars that were basically mobile missile launch platforms. Most Vilani warships in the same conflict used missiles as their main armament.
 * Made of Iron: TNE gave player characters a ridiculously high number of Hit Points relative to the damage of even the heavier weapons in the setting. When you can survive a direct hit from an FGMP, it's time for House Rules.
 * Made a Slave: Forbidden in the Imperium but sometimes done underground. It is not said what slaves can do that machines can't(other than the obvious inference of course). In the Sword Worlds capital crimes are sometimes punished with enslavement.
 * The Manchurian Candidate: Zhodani intelligence does this from time to time with their expertise at Mind Manipulation.
 * Manipulative Bastard: This is the Hivers' hat, to the extent that "manipulator" is the most exalted title in their society and conspiracy theories about their activities reach the level of in-universe Memetic Mutation.
 * Mega Corp: Commerce in the Imperium is dominated by these. They are probably best used as opposition, but the players can have a Dune-like experience trying to run one
 * Merchant City: most starports
 * The Metric System Is Here to Stay: Most of the editions except the GURPS version use the Metric system.
 * Metaplot: The Fifth Frontier War for Classic Traveller, the ongoing Rebellion for MegaTraveller, and the "Empress Wave" for The New Era (though it never got very far). Later editions don't have much of a metaplot, really.
 * The Migration: Most notably Ihaiti(or landless Aslan). Land is a biological obsession to Aslan males, and being landless makes for loss of status. Thus Ihaiti fleets are always travelling and have a reputation for not worrying about who is in the way. Often though they make a peaceful arrangement with a planet's inhabitants. Many planets have room to spare, and some are eager to have a Proud Warrior Race as allies to keep away their neighbors.
 * Military Science Fiction: One option, though often held to be difficult to arrange for an RPG, given the strict hierarchies of a military system. Private Military Contractor s campaigns are more popular than campaigns centered on regular armed forces, though these remain an option.
 * Mind Manipulation: the Zhodani embrace this art, the Imperials outlaw it. Given the considerable advantages it gives in competition for power arguably a ruling class must either do one or the other.
 * Minored in Asskicking: The Darrians are a Proud Scholar Race that has scientists, scholars, or artists as its heroes instead of warriors. They are also some of the toughest in the Spinward Marches.
 * Mohs Scale of Sci Fi Hardness: Minovsky Physics level.
 * More Than Mind Control: On the other hand, the Zhodani might be doing this as well.
 * Multicultural Alien Planet: The Aslan are divided into many different clans with their own parochial customs. The Vargr have no rhyme or reason to their organization, being Chaotic Neutral.
 * A Nazi by Any Other Name: The Solomani Confederation, with its doctrine that humans are better than aliens and Solomani are better than the other humans, is usually portrayed this way. An Author's Saving Throw in the GURPS Traveller supplement Rim of Fire retconned this into ethnic nationalism, not racism. The old portrayal of the Confederation also owed a lot to Red Scare; it was easy to tell when it was written.
 * Neural Implanting : A possibility with the Wafer Jack augmentation though not much is made of it.
 * Notice This: In the video game adaptation.
 * Not-So-Safe Harbor: In Imperial territory, most starports are a section on the planet administered directly by the Imperial government, and not subject to the laws of the surrounding nation. Just outside the boundary fence on most worlds is a "startown", often an ill-kept area in which The City Narrows.
 * Not Worth Killing: In Interstellar Wars the Vilani don't bother making a real effort to subjugate the Terrans because they are "just another barbarian tribe". By the time they learn differently, it is the Vilani who are being subjugated.
 * Precursors: The Ancients, and vague references of dubious canonicity to even earlier civilisations.
 * New Technology Is Evil: This was the general attitude of the Vilani Imperium after they decided they had expanded enough, thank you very much.
 * Numbered Homeworld: Some of the worlds in the Imperium have just a six-digit number as a name. All of the worlds in the Imperium can also be designated by which hexagon they occupy on their sector map.
 * Officer and a Gentleman: You can do better in the Imperial Navy if you have a higher Social Status characteristic.
 * Omnicidal Maniac: The Virus. Of course, that's what it was designed to do.
 * One-Gender Race: The Hivers are all the same gender.
 * One Federation Limit: Averted. The Third Imperium is the main Federation but there are other, states that play that role. For instance the Sword Worlds Confederation is The Federation in the GURPS Traveller volume Sword Worlds and The Terran Confederation was definitely a Federation long before The Imperium. Even the states that most resemble Empires have "Federation-like" aspects to them.
 * Order Versus Chaos:
 * The original Interstellar Wars, between the Vilani who were careful, venerable, but something of control freaks and the Solomani(Terrans) who were Innovative, Freedom-Loving but rather reckless. The Solomani won but couldn't figure out how to run the empire they just conquered. This brought about The Long Night which lasted until the rise of the Third Imperium.
 * The Zhodani are the most extreme example of order. Their regime is ruled over by a caste of psis who are allowed to look into their subjects minds and sometimes control them. Mere discontent is a crime and is easily found out.
 * Zhos are used to it, and think being read by a mind reader is no more embarrassing than being examined by a doctor. But non-Zhos think it to be a Fate Worse Than Death.
 * Vargr by contrast are the epitome of chaos. They live in ill-organized groups that are led by the one with the most "charisma". They also consider piracy a respectable profession.
 * Our Dwarves Are Different: The Geonee, a minor human race from a high-gravity world that makes them stocky who once had an ancient empire conquered by the Vilani are rather Dwarf-like.
 * Our Elves Are Different: The Darrians, a minor human race who once had greater technological prowess than the Imperium before they accidently blew up their star are pretty much elves - In Space! Right down to their elvish-sounding language, affinity for trees and the arts, and pointed ears.
 * Our Orcs Are Different: The Ikhlur, a Proud Warrior Race that serves in a "gurkha-like" role for the Hivers. They are reptilian and are formidable soldiers. They fit the later adaptation more than the Tolkienite Always Chaotic Evil Mooks. They are all BoisterousBruisers and think War Is Glorious, but are also often good natured. Though they delight in violence it is in the Blood Knight sense rather than the For the Evulz sense. In fact not only do they delight in violence they think it hones their inteligence so that school classrooms are marked by roughhousing as a natural part of a lesson.
 * Outgrown Such Silly Superstitions: Averted. Religion is still a part of Traveller life and there is room enough for anything the GM and Players desire; even their own Real Life religion if it pleases them. The Backstory does not go to much effort designing religions(deliberately so, apparently, to avoid causing tension between the players) for the game but one or two plausible ones are made such as the K'kree beliefs or the Aslan Fteir code of honor or the Shugalii chef-priests(they actually seem more like Rabbis than priests) of the Vilani. Actually the best comparison to Shugalii might be Kosher-butchers.
 * The volume Humaniti does a good job in describing in-verse religions.
 * The Maar Zon faith of Sylea seems to be a form of Deism but is less abstract than the Terran Deism of the eighteenth century. It has customs that seem similar to some Terran religions. The Vilani seem to be Agnostics but have a code of honor that vaguely resembles Confucianism . Bwaps are nature worshipers of a sort that emphasize nature as representing order. Many Sword Worlders are Aesirists which is a form of Nordic-style Neopaganism.
 * One of the more interesting aspects of the Maar Zon is the idea that ideas are free. This is said to have come from days when the Vilani Imperium(who once oppressed the Syleans) would use inordinate and draconian intellectual property laws to ensure that technology could not be used outside the will of the ruling class. Under this theory, it was originally a Take That to the Vilani. As the Maar Zon is dated from before the arrival of the Vilani, actual adherants of the Maar Zon faith think this idea has Unfortunate Implications.
 * Planet of Hats: Played with. The Aslan are warriors, the Vargr are Space pirates, the Hivers are Manipulators and so on. However there is usually enough complexity available for it not to be to hatty.
 * Planetary Romance : A number of the planets would make good settings for this. An entire epic can often be made on a single world.
 * Planetville : Zig-zagged. Travellers tend to visit only the Starport but there is often a whole civilization on that planet. Many systems remain unsettled because with jump drive it can often take no longer to get to the neighboring star system than to the outer planets, leaving the outer worlds barren(and a good place for adventures). Then too, some planets just have one small settlement on them and are therefore literally a planetville.
 * Powered Armour: Battledress.
 * Precursors: The Ancients  who transplanted humans all across the galaxy.
 * Privateer
 * Proud Warrior Race: The Aslan. Also the Sword Worlds, a cluster of Solomani cultures that claim Scandinavian-Teutonic heritage. There are a number of minor Proud Warrior Race s as well. The planet of Lanth, as described in the volume Spinward Marches seems to be a fortress world on the Imperial border and can be justifiably pictured as a Proud Warrior Race, especially as the Imperium's strategic interests, would allow the culture to specialize.
 * Proud Scholar Race : The Darrians. They are in a Forever War with Sword Worlders who are a Proud Warrior Race.
 * Psychic Block Defense: Anti-psi technology.
 * Planetville: Zig Zagged. While many planets have only one city of interest to starfarers they often have a highly developed civilizations and complex local politics that has only tangential relation with interstellar goings-on. Except at those times when it's a Planet of Hats. All more or less peacefully coexist, as based upon the needs of the tabletop game. Some planets are so sparsely settled that they actually do have no more than a single settlement or outpost on them. In this case the trope would be justified as the rest of the planet is wilderness.
 * Psychic Powers: The Zhodani's hat.
 * Puppet State: Many states are like this in the setting.
 * These vary. The Darrians are simply allies that happen to be unequal in strength to the Imperium. The Border Worlds Authority is a group of conquered Sword Worlds that barely pretend that they are not a Puppet State of the more degrading sort(they were a rather clumsy policy whose main justification was to keep Swordies from causing trouble without using Imperial troops. No one was really fooled). The member substates of the Imperium are theoretically all there with their own consent, though a number of them of course require rather rigorous persuasion. Imperial member substates have often been in the Imperium so long that they are pretty much integrated into the system and they are distinct from Client states. Some planets are directly ruled by the Imperium.
 * Actually, having Puppet States is central to Imperial ideology. It's constitution gives it power primarily over "The space between the stars", meaning that it provides defense needs and central authority to otherwise autonomous states. In practice it is far more complex.
 * Quicksand Sucks: Appears in the Classic adventures Twilight's Peak and Double Adventure Marooned/Marooned Alone.
 * Rancher: The ideal Aslan noble family owns a ranch. As Aslan are a Proud Warrior Race the male is supposed to hold it by virtue of his status as a Real Man.
 * Random Number God: In most editions, whether you are playing a naive youngster who washed out of flight school or a grizzled veteran depends largely on how your dice rolled.
 * Right Hand Versus Left Hand: Because of the limited speed of interstellar travel, entire frontier wars can be fought and ended before orders arrive from the Imperial core.
 * Royal Decree: An Imperial Warrant. Issued in important circumstances to a holder who has the power to override precedent according to the framework written out by the Emperor. Archduke Norris used one to reorganize the Imperial forces and retake the initiative during the Fifth Frontier War.
 * Sacred Hospitality
 * Vilani consider it rude to force a guest to sleep at a hotel. Rather the local VIP picks someone to billet a visitor. They are responsible for ensuring that the guest is well kept.
 * Aslan, as one would expect of a Proud Warrior Race have a lot of rituals to do with this. In one sidestory there is told a tale of a wounded Aslan warrior who was being tended by a rival clan according to The Laws and Customs of War. When this Aslan's clan made a raid he was obligated to help defend, and in doing so slew his own brother in a display of honor before kinship. After this the two clans made peace and this deed was remembered ever after.
 * Salvage Pirates : The Frontier Wars were all fought on roughly the same area with little change in political geography. There are thus planets which have hundreds of years of wrecked ships in them. Finding weapons there to arm the escort for the colonial convoy in the campaign 100 parsecs is one of the options.
 * Sapient Cetaceans: Issue 6 of the Journal of the Travellers' Aid Society had an article on dolphins genetically engineered to have higher intelligence, up to 13 (with the human average being 7). Some of them can learn human languages.
 * Sapient Ship: Classic adventure The Kinunir. The Kinunir's AI security system goes berserk and kills the entire crew of the ship. The PCs must deal with it in order to bring the Kinunir home.
 * Scary Dogmatic Aliens: The K'kree insist that everyone become vegetarians or die. This is also another way to view the Zhodani.
 * Science Fiction: One of the first RPGs to have a science fiction setting.
 * Sci-Fi Writers Have No Sense of Scale: Completely and utterly averted, see the link in Fantasy World Map above.
 * Schizo-Tech: Different planets often have wildly different technology levels. This is really for the purpose of allowing game flexibility and is therefore a concession to the Rule of Cool. However it is Justified by assuming political, social, and economic fluctuations over thousands of years that caused variability over large amounts of space.
 * Scrapbook Story : The Sourcebook s have a number of short side stories, some presented in this form.
 * Screw the Rules, I Make Them: The Emperor sometimes issues an Imperial Warrant to people specifically chosen as troubleshooters that allows him to overrule standard procedure in areas specified by the warrant. Typically this will be used for special missions like overseeing a Peace Conference or what not.
 * Shout-Out : The Intersteller Wars were a rewrite of the old board wargame Imperium and the Sword Worlds are an obvious shout-out to Piper's Space Viking.
 * The name of some emperors (Cleon) is also a shout out to Isaac Asimov's Foundation.
 * Shown Their Work: Taken Beyond the Impossible in such a manner as to practically undermine the whole point. There are books explaining the underpinnings of design that occasionally break into the underlying physics of, say, a gun, and the math to translate that into game terms. This is a game that even researches its Applied Phlebotinum, or at least treats it as if it can be. Alas... it constantly goes too far. In the gun example, vast calculations produce virtually the same results for any handgun. Pages detain the minutiae of planet climate, except to prove only Earth-like worlds around Sun-like stars are good for anything. Combat is very harsh...but only if you take into account all of the rules, of which there are many, and many are strange.
 * Space Amish: This is a fairly common explantion for all the low-tech worlds with working spaceports.
 * Another reasonably common explanation is simply that the starport was built by the Imperium and the two cultures ignore each other.
 * On the planet of Prometheus there are some literal Amish.
 * The Imperium itself and several other intersteller states have a prejudice against psionics, robotics, and cybernetics and limit them to specific circumstances. This makes the Imperium itself a mild form of Space Amish in the future. It also justifies a few aspects such as We Will Use Manual Labor in the Future, and having Badass Army s, instead of clouds of nanites or hordes of robots and in general gives it a more heroic and personal feel. Taboo technology, can of course still be found in a lost city, or a secret Imperial research station, or whatever.
 * Space Fighter: though it depends on which version of the game, as well as a Fanon issue.
 * Space Marine: The Imperial Marines. As well as the earlier Terran Confederation Marines. Curiously hardly anyone else seems to field Space Marine s although similar units with different titles are common.
 * Space Navy: several, quite naturally enough. The Third Imperium has one of the biggest.
 * Space Pirates: The realism of such is a cult-controversy among Traveller fans, rather akin to the "do Balrogs have wings." However Vargr Corsairs (which are somewhat different) as well as pirates from other races often appear. As well as more respectable privateers. The issue is so controversial that Mongoose Traveller's notes on piracy feature a "Flame War Warning" sidebar.
 * Space Police: Imperial Customs in the Imperium, Confederation Patrol in the Sword Worlds Confederation. These often deal with Space Pirates. Some sub-departments of the IISS as well, notably the S3 which are kind of "space SWAT-teams".
 * Space Battle: Tons. The Intersteller Wars and the Fifth Frontier War are the two most detailed in the canon, though the Rebellion/Final War was technically even bigger.
 * Space Cossacks: Several variations of these.
 * Space Is an Ocean: Several versions of the game compare the Imperium to the Age of Sail.
 * Space Opera : The standard scope of the game, although the game your Referee runs doesn't have to be Space Opera. There's a definite Hard SF feel to the technical limitations of the weapons, the tight parameters for ship design, etc. The character creation system encourages characters with human-scale abilities and limitations, not even Heinlein-style Competent Men, let alone larger-than-life heroes. Contrast this with, for example, d20 Star Wars, in which you can't not play space opera.
 * Space Western: Not only are there quests, epic voyages, and space battles, and all the stuff of grand style Space Opera, there is grubby frontier mayhem, pioneering and that sort of thing.
 * Splat: Lots of expansion materials, especially for the Mongoose edition. There are the Alien Modules, and a whole line is pretty much devoted to fleshing out the 'core' careers by adding new careers and branches/facets of those careers, and providing more information on various parts of the 'verse. There are also a number of supplements with vehicles, ships, more equipment, and so on.
 * Spheroid Dropship: The Broadsword class mercenary cruiser. Oddly, though its description says it can't land on planets with atmospheres, one does exactly that in Adventure 7 Broadsword.
 * Spoiler Title: Guess what the players find out during the adventure Secret of the Ancients?
 * Staged Populist Uprising:
 * In the supplement 76 Patrons. Two of the missions involve a rebel uprising in the country of Anisinta on the planet Porozlo. The PC are hired by a group of business executives to either create a rebel force to overthrow the government or take over an existing rebel group for the same purpose. The executives intend to profit by making the government more friendly to business.
 * In the 3rd Imperium's Spinward Marches, the Ine Givar rebels are under the control of and supplied by the Imperium's enemy, the Zhodani Consulate.
 * Adventure 7 Broadsword. On the planet Garda-Vilis the Tanoose Freedom League was originally a home-grown rebellion against off-world control by the planet Vilis, but eventually came under the control of the Ine Givar rebels and switched to an anti-Imperial stance.
 * Standard Sci Fi History: Once in their glory days the Vilani ruled over a vast domain for thousands of years. When they fell into complacency a Barbarian Tribe from an Insignificant Little Blue Planet seized the worlds of the Vilani in a series of conquests. However these too fell from their glory and darkness fell on the universe. Then under the reign of Cleon Zhunastu the Third Imperium was founded to explore and colonize and rise to claim the legacy of the two great empires before it. The Imperium stands to this day shining the light of civilization across the stars. But at the borders chaos reigns. Rival Empires plot and scheme, warlords clash, pirates plunder and alien races seek their dominion. It is not a safe universe.
 * Standard Royal Court : The Imperial court and the court of every sector and subsector capitol. Generally gives an air of Ermine Cape Effect but there a trace of Deadly Decadent Court as well.
 * Star-Killing: No known race in the "present day" of the setting can do this except the Darrians who have an unusual level of technology.
 * Starfish Aliens: Although some of the races are Rubber Forehead Aliens or People in Rubber Suits, or even Human Aliens, several others, especially some of the more obscure minor races, are rather strange. The Hivers even look like starfish.
 * Stat Death: Damage in most editions is done directly to your physical statistics (Strength, Dexterity, and Endurance); you're helpless if two reach zero and die when all three run out.
 * State Sec: SolSec, among the Solomani, and the Zhodani Thought Police.
 * Stay in the Kitchen: K'ree are the most extreme and simplistic example. Some Proud Warrior Race s have a more complex and ambiguous take on this.
 * Stealth in Space: The black globe generator, and ECCMs.
 * Subspace Ansible: Averted. One of the fundamental features of the Traveller verse is the lack of these.
 * Suspended Animation: Low berths.
 * Sweet Polly Oliver : Both Aslan and Sword Worlders have elaborate rules for this. On such occasions when a Sword Worlder desires a masculine vocation she is expected to dress and act like a male(in the cultural sense, not the biological presumably) while engaged in it. This is allowed when home obligations do not interfere, notably in a wealthy female who can hire servants. Such females are called "nontraditional" in canon, which is a misnomer as it actually is a tradition, just rarely enacted one. In the case of Aslan females sometimes become this when there are no male heirs; if they do they are obligated to vow celibacy and perform male duties and are addressed as males rather than females. In both of these cases it is a traditional arrangement to allow for a rare circumstance rather than a disguise.
 * Sword Fight: While the modern Marine sword drill consists of little more than a salute, the Imperial Marines in Traveller are trained to use their cutlasses in combat. Often this is more for sport (and sometimes dueling) than combat; there are however low-tech worlds in the Traveller Universe. As well, sometimes boarding parties find it inadvisable to start slinging bullets and grenades and laser beams around in close proximity to the reactors in the engine room and appreciate having additional tactical options.
 * Technology Levels: Trope Maker, at least for the medium. TLs may look implausible if taken literally. The Sourcebooks imply that exactly the same technology evolves in planets that sometimes have different conditions and no connection. However, using TLs as a base a clever GM can construct something more believable. MegaTraveller's "World Builder's Handbook" introduced the idea that a world may have different TLs for different areas of science and engineering, and a similar system was adopted by GURPS Traveller's "First In" sourcebook.
 * Technology Porn: Gobs of space tech porn including a system for designing your own Cool Starship. Many find that their favorite part.
 * Teleport Interdiction: In the classic adventure Broadsword, a unit of Zhodani Commandos tries to teleport aboard the title ship in order to capture it. The crew must prevent this by filling unoccupied parts of the ship with solid material so the Zhodani can't use them as a teleport location.
 * Time Travel: almost averted. Potential for it exists, but few arrangements are made for it in canon. Those who wish to deal with it can cross-reference Gurps: Time Travel and Infinite Worlds. Zhodani are said to have a secret Ancient Artifact that sees the future but little is made of that.
 * Translator Microbes: Justified, being just a computer program that collects languages. Newly discovered languages have to be decoded the hard way; in the case of the IISS, by listening to transmissions or by putting a robotic bug on the planet to pick up conversation in preparation for First Contact.
 * Truce Zone: The Federation of Arden.
 * Truth Serum: Truth drug. The recipient answers questions truthfully for two minutes, then falls unconscious for an hour and takes moderate damage.
 * 2-D Space: All of the maps of the Imperium and its sectors are flat. Some fans suggest that this is because the maps are jumpspace maps.
 * Twin Telepathy: The Clotho are a minor alien race that has this. They are born in brother-sister pairs and when they mate one pair is bonded with another pair instead of one individual.
 * Uncanceled: GURPS Traveller, T4, and other latter-day incarnations.
 * Unexpected Inheritance
 * United Space of America: the Terran Confederation. Justified in that the Terran Confederation is only a few generations into the future, close enough time for the culture not to have changed unrecognizably. For this reason the Intersteller Wars era is a good entry level period for players as it does not require roleplaying a strange culture(a fun exercise of course, but one for which some might prefer to wait until they've practiced a bit more).
 * If you consider roughly 150 years from now to be only a few generations that is. But the justification does work well enough for the purpose and is somewhat more believable than 3000 years from now having the same culture as the players.
 * Unobtainium: Lanthanum, which really exists and really is rare, but as far as we know doesn't facilitate Faster-Than-Light Travel - its most common use is in making flints for cigarette lighters. It is speculated that the role of lanthanum in the mechanism of jump drive is connected with the fact that it reacts reversibly with hydrogen, which is used as fuel for the drive. There are enough kinds of Unobtainium knocking around in the Traveller universe to warrant a Lampshade Hanging in Mongoose Traveller, where "unobtainium" is listed as a trade good.
 * Used Future: Players can get a good discount on their starship by taking one that is several decades old. The Darrians in the 1100s still use a few of their high-tech starships left over from before they blew their star up - about three-hundred years old.
 * For that matter, one can still find some grubby old Siigiizuni class(predecessor to the ubiquitous Beowulf s) hanging around some places. These ships were from about the beginning of the Vilani Imperium, but the specs remain on record.
 * Unreliable Narrator: Sort of. Canon can be changed according to the will of the players naturally enough and many distinguish between canon and their traveller universe.
 * Some of the side-stories contain narratives by people who are obviously unreliable(for instance because they are criminals or because they are ideological extremists).
 * The Verse: One of the first really memorable science fiction RPG settings.
 * Vestigial Empire: obviously all empires become this sooner or later. But a well described one was the Vilani Imperium had been this for thousands of years, its organization ran effectively on autopilot and survived because it hadn't had a competitor in ages. When they met the Terrans they were in for a big surprise. Not least because Terrans were only recently united and still remembered how to fight.
 * Wagon Train to the Stars: exploration expeditions are a large part and the Imperial Interstellar Scout Service which is an Imperial government exploration and intelligence organization, does this as one of its main duties.
 * Walking the Earth: What most player groups do, only the Adventure Towns are planets.
 * The War of Earthly Aggression:
 * Played with. Toward the end of the Intersteller Wars, the constitution of the Terran Confederation became obsolete because Planet Terra had conquered and assimilated so many worlds that Planet Terra could no longer be considered the center of the confederation. When no one could solve the problem, a naval coup took place instituting the Second Imperium.
 * The Long Night could be an aversion. There is no mention of a mass rebellion per se; the Second Imperium just disintegrated.
 * War for Fun and Profit: What mercenary player groups do.
 * War Is Glorious: Aslan think so.
 * The Aslan are a Zig Zag. They are certainly a Proud Warrior Race. But they have an elaborate code to minimize violence and even when war occurs it will likely be through such means as Combat by Champion. Aslan are warriors but they are not stupid.
 * Azhanti are a human Proud Warrior Race who have a religion that demands seeking challenges. As war is one of the most popular methods of doing this they in essence consider war a path to heaven.
 * War Is Hell: Several units of Imperial Marines were actually disbanded for atrocities committed during the Imperial civil wars.
 * The beginning of the volume Sword Worlds shows a scene where a Sword Worlder soldier returning to find his house blown to bits, and his wife desperately trying to rebuild it. Then in a Crowning Moment of Heartwarming they greet each other and,as the book puts it "Spend the night celebrating being together after all they had been through".
 * Some star systems in the Spinward Marches are choked with wrecks left from hundreds of years of war after war. This is a good place for the adventures of teams of Salvage Pirates
 * The Sword Worlds in general pretty much had a broken jaw from the Fifth Frontier War. Some districts were nearly depopulated of young males. But the whole Spinward Marches is still recovering as of Emperor Strephon's time and damage is splattered all about.
 * Wave Motion Gun: Spinal mounts on most capital ships.
 * We Don't Need Roads: Triphibians starting at Tech Level 8 in MegaTraveller.
 * We Will Use Manual Labor in the Future
 * We Will Wear Armor in the Future: Due to the general lethality of combat armour is all but required to survive more than a couple shots. Besides Battle Dress available armours range from practically useless leather (jack) to full combat armour that requires a laser or gauss rifle to really penetrate, there's also reflec that only defends against lasers and can be added to other types of armour. However most armour tend to be a higher tech level and much more expensive than the weapons that can pierce it.
 * What Kept You?: In Classic Traveller Book 0.
 * Wine Is Classy : The Emperor drinks a Hungarian vintage brought all the way from Planet Terra.
 * Winged Humanoid: The Droyne, among others.
 * The Woman Wearing the Queenly Mask: Empress Arbellatra
 * Wooden Ships and Iron Men: Traveller is often compared to the Age of Sail.
 * The main resemblance is the long voyages. On a strictly tactical level it is different.
 * Women's Mysteries : The Kenningsboken, a mysterious book containing rhymes dealing with such subjects as child care and home management is popular among Sword Worlder women and only occasionally read by men. Rumor has it that it is in fact a psionic exercise tool.
 * Wretched Hive: The planet Granicus is a notorious pirate haven ruled by three competing organized crime groups.
 * Your Terrorists Are Our Freedom Fighters: Once or twice there are anomalies in the description of various cultures that are most easily Handwaved by simply saying "Yeah, well that's THEIR version". In the volume Milieu 0 of Marc Miller's Traveller it actually invites this by giving arguments from both sides about the morality of building the Imperium, as if it was a Real Life political controversy. This sort of thing actually manages to help reinforce Willing Suspension of Disbelief. When writing a Backstory Traveller is Just That Good.
 * You Will Be Assimilated: the Marc Miller's Traveller volume Milieu 0 gives traces of the IISS's Big Book of War that tells how to do this to hapless planets during the founding of the Imperium. It gives an idea what a Magnificent Bastard Cleon was.
 * You Will Be Assimilated: the Marc Miller's Traveller volume Milieu 0 gives traces of the IISS's Big Book of War that tells how to do this to hapless planets during the founding of the Imperium. It gives an idea what a Magnificent Bastard Cleon was.