Space Sector

"They were prefects in the old days, all part of the same province, which in turn had been part of a sector, which in turn had been part of a quadrant, which in turn had been part of the all-embracing Galactic Empire."

— Foundation (1951), "The Mayors"

Various science fiction writers and franchises have used the word "sector" to mean a defined region of outer space or a specific collection of stars and their planets, with either a proper name ("the Sirius Sector") or with a numerical or alphanumerical designation ("Sector 001" or "Sector ZZ9 Plural Z Alpha"). This is invariably in the context of interstellar civilizations, since it makes little sense to divide up the Solar System into "sectors": Any interplanetary traveler must take into account that rather than being located in a specific region of space, the various planets are all constantly moving around at astronomical speeds. Such interstellar sectors are often political subdivisions of larger empires or federations, but may also simply be convenient groupings of politically independent star systems or planets that happen to be near each other in space. Science fiction authors are also fond of the word "quadrant", using it alongside "sector" in various fictional universes. (The word quadrant really implies there are exactly four of them, but this has often been ignored.) Individual science fiction planets are sometimes also divided into sub-planetary "sectors", in some cases co-existing in the same fictional universe with interstellar "sectors".

In real life, "sector" is simply a word for a division or portion of a larger something. The way astronomers use Constellations is a little like science fiction sectors, although in this case, the "sectors" are oddly-shaped geocentric wedges extending outward to infinity, so that Proxima Centauri (the nearest star to the Sun, a bit over four light-years away), the globular cluster Omega Centauri (thousands of light-years away), and distant galaxies in the constellation Centaurus (millions or billions of light-years away) are all in the same "sector" of space from the point-of-view of the denizens of planet Earth.

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Examples:

Comic Books

• Green Lantern: Members of the Green Lantern corps are assigned to guard one of 3600 sectors of space (in fact, explicitly referred to as "Space Sectors"), each of which is given a number (Space Sector 2814).

Comic Strips

• The Far Side: One comic features the "quadrant" variation of the trope; aliens (in what looks to have been a classic Flying Saucer) have crash landed on Earth (which they misidentify as "Bob's Shoeworld"). In their distress call the aliens say the planet they're stranded on is in "quadrant 57 of the Milky Way".

Films — Animation

• Toy Story: Buzz Lightyear initially insists that he was stationed in the Gamma quadrant of Sector 4, and was en route to Sector 12.

Films — Live-Action

• Galaxy Quest: The film has "the 23rd Quadrant of the Gamma Sector", which makes even less sense than the way Star Trek: TOS uses "quadrant", but of course pretty much everything in the movie is played for laughs.
• Star Wars: The Galaxy is typically described as being divided into sectors, each containing a large number of inhabited systems, sometimes further divided into subsectors and grouped into oversectors. During the Republic's time, sectors were each represented by a Senator; in the Empire, each was instead overseen by a Moff, with oversectors run by Grand Moffs. Their precise size and scope varies when it's discussed in detail at all, although Legends material describes the Republic as having consisted of 1024 total sectors.

Literature

• Ashes of Empire: In Eric Thomson's Military Science Fiction series the now-disintegrating Empire is divided into sectors (the Coalsack Sector, Rim Sector, Shield Sector, and so on) governed by viceroys (who are now rapidly becoming warlords), with star systems ruled by governors general.
• Battle for the Stars: In this novella (later expanded to novel length) by Edmond Hamilton (writing as Alexander Blade), the five sectors of Earth's former interstellar empire—the Orion Sector, Cepheus Sector, Leo Sector, Perseus Sector, and Lyra Sector—are now interstellar empires in their own right, jockeying for power among themselves while barely paying lip-service allegiance to the central government on Earth, but still called "Sectors" and still ruled by "Sector governors".
• In the short story "Beyond the Aquila Rift" by Alastair Reynolds, known space ("the Local Bubble") is divided into seventy-odd "navigational sectors", including the Schedar sector.
• In Jack Vance's pentalogy The Demon Princes one character notes that "Ophiuchus isn't a star. It's a sector". There's also a reference to the Aquarius Sector.
• Dragon Pearl: Yoon Ha Lee's Science Fantasy novel includes the Ghost Sector, where the Fourth Colony is located.
• Dragonriders of Pern: The setting of Anne McCaffrey's series, the planet Pern, is "third planet of the sun Rukbat in the Sagittarian Sector".
• In Janet Edwards' Earth Girl series the hundreds of human-colonized star systems are divided into sectors named after Greek letters, from Alpha sector in the center (containing Earth itself at the center of the sector) to Epsilon sector and Kappa sector on the frontier.
• The Empire Novels of Isaac Asimov (a loosely-connected group of three books that are distant Prequels to his Foundation Series):
  • The Currents Of Space: The "ancient worlds of the Centaurian Sector" are mentioned (although—rather inconsistently—Earth is placed in the Sirius Sector).
  • Pebble in the Sky: Earth (the setting of the novel) is described as being in the Sirius Sector (or the Sirian Sector). The Rigel Sector is also mentioned.
  • The Stars, Like Dust: The main setting of the novel are the Nebular Kingdoms, which are also referred to as the Nebular Sector. Earth is also described as being in the Sirian Sector in this book as well.
• The Trope Codifier is Asimov's Foundation Series, in which a sector is a spatial region that is one level of the elaborate administrative hierarchy of the Galactic Empire, including "prefects" (oddly enough not "prefectures"), provinces, sectors, and quadrants, with sectors ("the Arcturus Sector", "the Normannic Sector", "the Sirius Sector") being probably the most often mentioned of these. (Later in the series the term "sector" is also used for local sub-planetary subdivisions of the City Planet of Trantor.)
• Julian May's Galactic Milieu series includes numbered sectors; thus, the planet Assawompset is Planet 4 of the star Landa (Star 14-893-042) in Sector 14.
• In The Glory Game by Keith Laumer the warlike alien species known as the Hukk "have their collective eye on Terran holdings in the Sirenian Sector".
• The Hitchhiker's Guide to the Galaxy Trilogy: In Douglas Adams' comic science fiction series, the sector of the Galaxy containing Earth is "Sector ZZ9 Plural Z Alpha"; like much else in the franchise, likely an Affectionate Parody of a widely-used science fiction trope.
• Honor Harrington: Various galactic powers in David Weber's Military Science Fiction series use "sectors", from the several sectors of the Silesian Confederacy (which are not only spatial regions but also explicitly have political institutions including "Sector Governors") to the sectors established by the Solarian League as protectorates on its frontier areas.
• Humanx Commonwealth: Alan Dean Foster's space opera setting includes mentions of places in space like "the Bryan Sector" and "the Vandy sector".
• In Fury Born: In David Weber's novel the Terran Empire is divided into Crown Sectors (such as the Franconia Sector or the Melville Sector), collections of systems ("ninety-three systems under imperial claim—twenty-six with habitable planets") with a Governor General and a planet as the sector capital.
• The novella Last Call for Sector 9G by Leigh Brackett is about the struggle to control the two planets of star system KL421 (one inhabited by a humanoid race, the other by a non-humanoid race), and therefore by extension to control the entire region of space (Sub-sector 9G of Sector 80 of Quadrant 7) in which star system KL421 is the only system with any inhabited planets.
• In the Liaden Universe by Sharon Lee and Steve Miller, the planet Surebleak (an important setting in the series) is in the Daiellen Sector, while other locations mentioned in the series include the Clanave Sector, Faerie Sector, Kinsa Sector, and Tipra Sector.
• Lucifer's Star: In this series by C.T. Phipps and Michael Suttkus, the Spiral (the part of the Milky Way Galaxy settled by humans) is divided into thirteen Sectors, referred to by number (e.g., Sector 7).
• Mageworlds: The setting of this Space Opera series by Debra Doyle and James D. Macdonald includes the Infabede Sector; the Latam, Ontimi, and Arcari sectors are also mentioned.
• A Memory Called Empire: In this novel by Arkady Martine space both within and beyond the Teixcalaanli Galactic Superpower is divided into named sectors. Each sector is large enough to contain many star systems, potentially accessible through the jumpgate Portal Network. In particular, the protagonist is from a Space Station colony in the Bardzravand Sector, which is struggling to maintain its independence from Teixcalaan.
• The Mote in God's Eye: The action of Larry Niven and Jerry Pournelle's novel and its sequels takes place in the Trans-Coalsack Sector, an administrative division of the Second Empire of Man.
• Prince Roger: In this collaboration between David Weber and John Ringo, the Empire of Man (the monarchy of which the protagonist of the series is a prince) includes the Sagittarius Sector (which includes the planet to which Prince Roger and company were originally headed), Baldur Sector (the location of Marduk, the Death World which they wind up stranded on), and Handelmann Sector (a neighboring sector to Sagittarius Sector).
• In the Paradox Trilogy by Rachel Bach, the Falcon Sector (which includes the planet Falcon 34) is an undeveloped area, with not even half of its worlds terraformed yet.
• The Rim Worlds series: A. Bertram Chandler's stories of Commodore John Grimes frequently mention the "Shakespearean Sector".
• Sector General: The eponymous hospital space station of James White's medical science fiction series (in full, Sector Twelve General Hospital) is naturally enough located in Galactic Sector Twelve.
• The Skolian Saga: Locations in this series by Catherine Asaro include Onyx Sector (divided between the rival empires of the Eubian Concord and the Skolian Empire, along with the smaller interstellar power known as the Allied Worlds), Sphinx Sector (deep inside Eubian space), and the Platinum Sectors (disputed between the Skolians and the Eubians, and—not surprisingly—a major source of platinum ore).
• The Starchild Trilogy: The series by Frederik Pohl and Jack Williamson features such locations as "Planet 5, Star 4894, Sector B-311-C, Galaxy 1" or "Planet 3, Star 7718, Sector Z-989-Q, Galaxy 5" (the latter also known as "Earth").
• In Mike Resnick's Starship series the Republic (which in spite of its name is perhaps as much The Empire as it is The Federation) is divided into named sectors (the McAllister Sector, the Matheson Sector, the Terrazane Sector) which are collections of star systems complete with "capital worlds".
• Technic History: Poul Anderson's stories of the Terran Empire feature such locations as the strategically important Sector Alpha Crucis.
• The Vorkosigan Saga: Lois McMaster Bujold's science fiction series repeatedly mentions numbered sectors ("Sector II", "Sector V"). It's not clear if these are generally-used spatial divisions, or specific to the Barrayaran Imperial Service (though the Barrayaran Empire explicitly does not rule these various sectors). The planet Komarr is also divided into sub-planetary sectors as its major administrative subdivisions.

Live-Action TV

• Babylon 5: Known space is divided into sectors, which are numbered but in many cases also have names. Earth is located in Sector 100, or Earth Sector; the eponymous Space Station Babylon 5 is located in Sector 919, also known as the Euphrates Sector. Sectors in turn may contain multiple "quadrants". (Babylon 5 is itself divided into sectors named after colors, which are functional areas of the station: "Green Sector" is the diplomatic area of the station, while "Red Sector" is the commercial area, and so on.)
• Star Trek: The original series often used "quadrant" instead of "sector" (with references to the Enterprise being "the only ship in the quadrant") but by the Next Generation era named sectors ("the Archanis Sector") or numbered sectors ("Sector 001") are firmly established as regions of space. Other parts of the franchise also refer to "sector blocks", large groupings of a hundred sectors. "Quadrants" are also still used, but now more logically refer to one of four divisions of the entire galaxy.

Tabletop Games

• GURPS Space Atlas: The different volumes of this series of supplements for GURPS Third Edition cover several sectors of space (the Old Frontiers Sector in the original Space Atlas; the Corporate Worlds Sector in Space Atlas 2; the Phoenix and Saga Sectors in Space Atlas 4) while other tools allow for the creation of whole new sectors.
• Scum and Villainy: The game is set in the Procyon Sector of the Galactic Hegemony. In the setting, Hegemonic space is parceled into sectors of various size and given out to scions of the six nobility clans to govern. Given how Procyon only consists of four star systems mostly engaged in basic mining operations on the outskirts of the Hegemony, it is as backwater and frontier-sy as it gets.
• Traveller: The game's setting includes an interstellar empire divided into domains (or archduchies), each of which is divided into several sectors (or duchies), which are in turn divided into subsectors (or counties).
• Warhammer 40,000: The Imperium of Man has a military-administrative hierarchy in which the galaxy is divided into five segmentae, which are then divided into sectors (e.g., the "Gothic Sector"), with sectors in turn containing both "inter-sectors" of unexplored or uninhabited systems, and organized sub-sectors of one or more inhabited star systems.

Video Games

• Elite Dangerous: The galaxy is divided up into cubic 1280 lightyear sectors, each assigned a systemic name that is carried over to the systems within it. Additionally, it is also divided up into 42 galactic regions with more evocative names, such as the Inner Orion Spur (where Earth is), Odin's Hold, and The Abyss.
• FTL: Faster Than Light: Gameplay features the player traveling between jump beacons which are grouped into "sectors" of space (starting with Sector 1). Each of these sectors has an "exit" beacon that connects a given sector with one or two other sectors.
• Halo: The UNSC divides their roughly 100 light year bubble of space into an unknown number of sectors. The star systems therein don't actually have to be close together in real space; rather sectors are determined by how long it takes to to traverse them in slipspace. The Covenant equivalent seems to be "sub-domain."
• Helldivers II: The Federation divides the space around Super Earth into named sectors (the Akira Sector, the Severin Sector, and so forth) each containing multiple planets.
• The Last Starship: The game is separated into sectors. As you jump between planets the void starts enveloping planets limiting your options before you're forced to travel to the next sector.
• Mass Effect: "Sector" is used to denominate all the solar systems that are in FTL range of a single Mass Relay, often 3 to 5 inhabited systems. There are at least a few hundred of them within Citadel Space (one of the relays is labeled 314). Used interchangeably with "cluster."
• Metroid Fusion: The B.S.L. station has six sectors designated in numerical order then by their biome (such as Sector 1 SRX simulating the environment of the planet SR388 or Sector 4 AQA hosting aquatic creatures).
• Space Quest: Several games use different definitions for space sectors, ranging from Sector EG in Space Quest 1, to Sector 82 on a grid in Space Quest 3.
• Space Rangers: The map is divided into sectors, which contain systems. This mostly matters for the purpose of purchasing maps.
• StarCraft: Set in the "Koprulu Sector" of space, tens of thousands of light-years distant from Earth. Unusually, we don't actually see any others. We only know of one other, the Dinares Sector, because of a single line in the first game's manual mentioning that it was consumed in the past by the Zerg.
• Star Fox 64: The game's setting includes "Sector X", "Sector Y", and "Sector Z" (all with names based on the shapes of nebulae which are located in those respective areas).
• Starsector: The game's setting is the Persean Sector, an area which was being colonized by the Domain of Man before the catastrophic collapse of that empire's network of interstellar gates left the sector isolated.
• Stellaris: Gameplay includes the creation of Sectors as autonomous (partly computer-controlled) regions of your interstellar empire.
• Wing Commander: Both the Terran Confederation and the opposing Kilrathi Empire are divided into sectors, at least some of which are further subdivided into quadrants.

Real Life

• There are of course no actual "space sectors" (at least not yet). "Sector" has occasionally been used to signify various real-world administrative divisions or permanent geographic areas. According to the Other Wiki several African countries and the city of Bucharest, Romania, use "sector" as the term for an administrative division. During the Cold War the word also featured prominently on the now-iconic multilingual "YOU ARE LEAVING THE AMERICAN SECTOR" signs displayed at such places as Checkpoint Charlie.

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