As far as most writers are concerned, space is flat, like a great big tabletop. A few who have actually seen an airplane fly allow that space may have a third dimension as large as five or ten miles high, but not much more than that. There's just enough up-and-down to allow for dogfights between fightercraft and clever one-time-only attacks from above during battles between space warships. Otherwise, vessels approach each other as if they were floating on the sea and attempt broadside or bow-to-bow shots almost exclusively.
Maneuvering is also shackled to the horizontal plane most of the time. Very rarely will shows and writers take advantage of the lack of "up/down" in real space by having ships attack each other at odd angles or vectors, which would offer something visually and tactically fresh. Even outside of battle, when two ships approach each other, no matter where they come from, they will always be oriented the same way; you never see a ship flying "upside down". (On rare occasions, an exception will be made for derelicts. Then again, upside-down derelicts can be found in the ocean, too.)
Perhaps as a corollary to the above, two (or more) starships, when involved in a standoff situation, will inevitably position themselves literally nose to nose in classic stare-down posture. This can be justified depending on the ships' weapons placements, but as often as not it's just a metaphor for the situation. The flip side of this is that when two friendly ships are together they will always be traveling side by side — that is, "shoulder to shoulder" — not unlike escorts, even when they're not escorting. Abandoned/damaged ships may list visibly to one side as if sinking. The near-total separation spaceships have between yaw, pitch, and roll, and the path their inertia is carrying them on, is very rarely observed — "fighters" will nearly always be pointing in the precise direction they are moving in (and bank when turning), as atmospheric planes are forced to.
Needless to say, nobody will ever think of bypassing a planar asteroid belt or similarly hazardous feature by simply going above or below it. It's also possible to wall off part of the universe by placing a barrier that spans the full ten-mile height from top to bottom.
By extension, and by analogy to earth-bound geography, every major location in space is at a fixed position. A planet may turn on its axis (if you're lucky), but its place relative to its sun and other planetary neighbors never changes. Think of a model solar system made of balls on a table. All distances and travel times are static; all positions are permanent and unchanging. Orbits simply don't happen — if two planets are X units apart on the left side of their sun, they'll always be X units apart and on the left side of the sun.
It isn't always a result of hack writing, though. Sometimes writers do this as intentional Acceptable Break from Reality; two-dimensional strategies are simply easier to show and explain, and much easier for most viewers to grasp (since that's how we're used to thinking). This is especially common in older video games, or ones where three dimensions would needlessly complicate the interface. Furthermore, not only are we used to thinking in two dimensions, but there is no concrete precedent for 3D combat yet; ground and naval combat is two-dimensional, dogfighting isn't done with fleets and is limited by the atmosphere and ground, and submarine combat has important depth restrictions and maneuvering concerns (and has also almost never actually happened).
For pre-CGI film and live-action television, using motion control photography, it's also a technical limitation. You have to mount the spaceship somewhere.
Note that having one character (generally the main character or a strategic genius) think in 3D is not an aversion of this trope — 3D thinking would logically be an absolutely basic requirement for any sort of military training in space; playing it up as a surprising stroke of strategic genius is just approaching this trope from another angle by applying it to everyone except the main character (or whoever the writer wants to make look awesome), akin to trying to show someone as a military 'genius' on Earth for realizing that their army can move from side to side, not merely forward and back. Particularly wall-banging examples will have a character use 3D once, and never again.
Note further that treating the third dimension, or motion in the third dimension, as qualitatively different isn't an aversion either. It's a wallbanger.
Note that all of the negative connotations above applies mainly to a television series, movies, sequential art, and books... put 2-D Space in a video game and thanks to the Rule of Fun it becomes one of the Acceptable Breaks from Reality.
See also Space Is an Ocean, Acrophobic Bird, One-Dimensional Thinking, Sci-Fi Writers Have No Sense of Scale, and Old-School Dogfight.
open/close all folders
Lampshaded in an Esurance Star Trek parody. When an alien ship hits the Enterprise, the Kirk stand-in quips that they're in space and he could have just gone around.
Anime & Manga
Both justified and averted in Mobile Suit Gundam and its kin, which primarily take place in the "Earth Sphere", the immediate neighborhood of Earth consisting of the moon and the five Lagrange Points. Lagrange Points are points of zero net gravity relative to any large two-body system, and are often used as the location for colonies. These five points all fall within the plane of rotation of the Moon around the Earth, which provides a natural 2D "landscape" for space. Any movement off this plane would be wasteful, all meaningful paths between important points would fall within the plane. This being said, many battles in space do involve movement perpendicular to this plane, for tactical reasons.
The problem does however crop up in terms of ship and mecha design. A recent example would be the giant mobile armor Alvatore from Mobile Suit Gundam 00: it has 27beam guns, of which zero are capable of firing downward. That glaring design flaw was not exploited by the heroes when they fought it. This is not a particularly uncommon occurrence; even when spaceships and mobile armors (it's not usually an issue with the humanoid mobile suits, since their hand-carried weapons are pretty easy to aim in any direction) do have bottom-mounted weapons, they're almost always much less numerous and less powerful than those mounted on the top and sides. Given that "up" and "down" are completely arbitrary distinctions in space, this is clearly a dumb way to design a warship, yet it rarely if ever presents a problem.
Towards the end of Gundam 00's first season, Lockon initially attacks the enemy ships from "above" then for no clear reason moves and attacks them head on. As in the direction that ALL their guns seem to be facing.
A more glaring issue is with the design of the mecha themselves. Their defenses and offenses are based entirely upon 2D combat, with absolutely no defenses from below or above (or heck, behind even). Why not just attack from the legs, which are just needlessly large landing platforms in the first place? Amazingly this issue never seems to come up in tactics or strategy.
For good reason: as opposed to conventional vehicles, which remain stationary, mobile suits are constantly moving and can shift their direction in little over a second or two. In actuality attacks have been made against mobile suit "blind spots", such as the back or underneath; for example, the first series had Amuro attempt to attack Char from behind in one of their later fights, only for Char (being a Newtype, he detected the attack) to raise his Gelgoog's twin beam sword overhead to defend. As well, Gundam 00 had Ali al-Saachez constantly attacking the open areas of his targets, such as the back, sides and yes, above and below, and the only time he managed to fully exploit an opening was against the first Lockon, who was blind in his right eye and therefore open to attack from that angle. And contrary to the above claim (and the Zeon engineer it originated from), the legs of a mobile suit tend to hold additional thrusters and apogee motors (smaller thrusters used for directional control)note Not to mention the fact they can be used offensively, as Char, Athrun and Tieria have all demonstrated, so they're functionally more than just landing platforms.
It is an even more glaring issue with the ships, which seem to factor one direction of the 3rd dimension (directly above), where an attack in the opposite direction (directly underneath) would be nearly unstoppable... much like a naval ship.
Strangely enough, such attacks have occurred in Gundam by way of the mobile suit, but for some reason none of the various series have ever come out with a ship with all around AA defenses. One would think Aegis ships (as in ships geared primarily for AA warfare) would be a common sight in the Gundam franchise (with or without Minovsky particle interference), but alas...
In Crest of the Stars and its sequel Banner of the Stars, hyperspace is two-dimensional, with important strategic and tactical consequences.
In Uchuu Senkan Yamato, Captain Okita (Captain Avatar in the English dub) shocks the bridge crew by commanding the helmsman to maneuver safely through a cluster of space mines by tilting the ship five degrees, a concept which shouldn't surprise anyone trained to fly in three-dimensional space.
This trope was played with many many times in the series and movies, as Space Is an Ocean ruled almost every moment. You get the usual 2-D Space issues: horizontal-only blockades, a spaceship which was retooled from a naval vessel so that it still has an underside bereft of weaponry or defense, and gravity that holds people to the tops of ships (Just the tops..). The Cosmo Fighters were dogfighting planes, and you had plenty of 3-D combat there.
Averted once in the third series when the Yamato orients itself with the Z-axis (in comparison to the enemy fleet surrounding it on the X-Y plane), rotating along the Z-axis to allow the guns which are only on the topside to sweep around in all directions. You'd think after awhile it would have just been easier to put guns on the underside as well.
Tytania plays this straight for the most part. Some of the tactical formations shown on the command screens were 3 dimensional. Alas, most of the actual fleet battle scenes consisted of opposing walls of ships shooting in straight lines at each other, shared horizon et al.
Macross/Robotech was pretty guilty of this as well; ships would usually travel more or less on the same plane, wth only the occasional "stack" of ships; even then, ships would allways be orientated in the same direction. Robotech: Shadow Chronicles avoided this to a degree.
Last Exile both plays this trope straight and averts it in the first episode. At first, the airship fleets attack each other on a 2-D plane, according to the regulations of warfare (oxymoron much?), but soon after their "chivalrous" exchange of fire, a mysterious fleet appears from above them and proceeds to "blow shit up" as the colloquial goes.
Beautifully lampshaded and subverted in the manga version of Captain Harlock: in one of the first encounters with the Mazone fleet Harlock gives orders to rotate the Arcadia 180° to face the flotilla of Mazone attack ships that were chasing him, resulting in the Arcadia being upside-down while Harlock remarks that such a thing wouldn't be possible if they were on the sea.
"You think you know everything there is to know about battle? You know Orc droppings! Underwater combat is three dimensional. Those thrice-damned Vodalians don't attack in ranks; they attack in schools."
In one issue of Knights Of The Old Republic the Republic Navy prepares to prevent an invasion of Coruscant by forming a ring of ships above the planets equator◊. This is supposed to keep any ships from reaching the planet. A possible justification would be that the equator holds significance for launch, landing, and orbit physics — real world launch sites like Cape Canaveral are located as close to equatorial regions as possible, and any space elevators or space fountains would also be located along the equator. Protecting this line would then be protecting these critical areas.
This and Acrophobic Bird is common situation in comic books, seeing as how many characters can fly.
Averted in Annihilation Conquest, where a barrier encases Kree space. It's entirely three-dimensional and is basically a giant sphere trapping everyone.
Spoofed in a Star Trekparody where the Enterprise crew, Klingons, Romulans and Ferengi all start arguing about whose ship is the right way up.
Lampshaded in Star Trek II: The Wrath of Khan, where the page quote comes from, though not as much as it appears at first glance. Kirk and his Enterprise, battling Khan in a sensor-jamming nebula, manage to duck under Khan's Reliant and then rise to deliver the fatal shots. However, while in normal, empty space sensors would have rendered this specific trick ineffective, for all the implications that his "two-dimensional thinking" was a critical flaw in Khan's strategic prowess, this is one of perhaps two times in the franchise's entire history that anyone tries anything like this, so it's ultimately a reinforcement of the trope.
This is completely avoided in Star Trek VI: The Undiscovered Country. When the IKS Kronos One is attacked by Chang's ship, the shots come from "below" it in a vertical sense and a short ways off in the lateral, which is where the Enterprise was at the time. Later, Chang's Bird-of-Prey seems to move all over the place in shooting the Enterprise and Excelsior, including one torpedo shot after the Enterprise's deflector shields collapsed, blasting upward through the saucer segment of the hull from directly below in an alarming display of destructive power.
The latest Star Trek by J.J. Abrams doesn't make a major point of it but manages some aversion, at least for its franchise, such as a few other shots showing the Enterprise and Narada at odd angles instead of the typical nose-to-nose face-off orientation.
An atmospheric example comes from Top Gun, and indeed most movies involving modern close-range air combat. Here, fighters will never use the vertical dimension, despite the fact that very significant advantages can be gained from doing so. In fact, the Top Gun course was established to teach exactly these tactics when US F-4 Phantom fighters were being shot down by Vietnamese MiG-17s, which were slower but more maneuverable in the level plane...
Averted in The Empire Strikes Back, with the Millennium Falcon pulling off 3D manouevers all the time during the Hoth chase, and Star Destroyers are often seen at odd angles relative to one another. Also an example of Visual Effects of Awesome, as the Falcon did all this while filmed with motion control photography, which (as noted above) makes 3-D space difficult to shoot.
In versions of the movie prior to the 2004 DVDs, the Rebels hide what remains of their fleet "above" the edge of the galaxy. See The Milky Way Is the Only Way for more detail.
Averted carefully in Return of the Jedi, where the Rebel fleet is "trapped" while facing the Death Star and the Imperial Fleet. The Rebels are fully capable of leaving — Admiral Ackbar even declares that they need to retreat, but Lando convinces him to stay because their objective was to destroy the Death Star while it was unfinished and vulnerable; if it was finished the Rebels would have no hope of destroying it.
In The Phantom Menace the Trade Federation blockade Naboo with a fleet of ships arranged in a ring around the planet. Instead of just flying around them, the main characters try to fly through them and barely survive.
Although it's not obvious at first, averted to some extent in Revenge of the Sith. It's evident that the vessels are all over the place in terms of dimensions, and following the path of the Jedi fighters it's clear they're flipping through various vectors quite neatly.
This was reinforced by the 2003 Clone Wars series. When CIS ships exited hyperspace around Coruscant, they came in at odd angles, turning their cruisers into battering rams, smashing into the disorganized Republic destroyers.
In the film adaptation of Harry Potter and the Chamber of Secrets, Ron and Harry drive their Flying Car just above some train tracks in order to guide their way to school. When they hear the whistle of the Hogwarts Express, they think they must be following it. After they realize that the train is directly behind them, they scream for a full ten seconds before driver Ron considers moving sideways instead of forward (and does so with such force that they barrel-roll repeatedly).
Notably averted in Alien Cargo, wherein a spaceship has drifted off to a location far above our solar system's ecliptic plane.
This is especially apparent when anyone wants to invade Coruscant (at the centre of the galaxy); be it General Grievous, the Rebels, Thrawn or the Yuuzhan Vong, no-one ever considers the possibility of approaching it from above or below the galactic plane.
Whenever a Star Destroyer shows up, there's about a fifty-fifty chance someone will point out that it has most of its guns along its sides, and tries to exploit this with an attack to the top or rear. One notable instance is the Battle of Thyferra: ISD Freedom comes in above and perpendicular to the (much larger) SSD Lusankya, allowing Freedom to bring its whole starboard gun deck to bear.
The X Wing Series also frequently has large ships being attacked from only one side spin as their shields on that side take a beating, letting them bring an undamaged and fully shielded flank to bear. Reinforcements and snubfighters will often then try and get at the damaged side, but they have to contend with the damaged ships' own reinforcements and snubfighters. And that same series also has Rogue Squadron sneaking into a planet's atmosphere from one of the poles, where it's sparsely populated.
The New Rebellion has General Antilles on the bridge of his fleet's flagship, looking out through the viewport and thinking he likes the design of this ship. It reminds him of being a fighter pilot, with only a thin barrier between him and the vastness of space.
It also gave him great perspective, allowing him to remember that in space battles, as opposed to ground battles, the attacks could come from any position: above, below, behind, or sideways. So many commanders forgot that after years out of a fighter pilot's chair.
Averted, and lampshaded, by the very first modern EU book, Heir to the Empire; Thrawn's Establishing Character Moment has him ordering his ship to to rotate flat to an invader's vector, pointing the superstructure — the tower bit that sticks up out of the wedge of the Star Destroyer — at them, and then launching TIE fighters in an unstructured attack profile. The Elomin trying to fight him simply cannot handle that, because they are constrained in how they think about space combat.
Lampshaded, as it's implied that Ender's ability to think in three dimensions (which he sees as common sense) sets him apart from 99.9% of the human race, complete with rival schoolmates who don't get how he does it. It's less ability to think in three dimensions — other commanders were quite capable of using three-dimensional attacks, formations, and flanks — as it is his ability to rearrange those dimensions however he wants, since they're all arbitrary in zero G. Remember, the enemy's gate is "down".
Ender's line of thinking: most people, when stepping out of the airlock (which has gravity) to the battle room (which doesn't) most people use the same "up" and "down" for both rooms. This creates an immediate problem: No Peripheral Vision. By assigning "down" to "the enemy's gate" Ender could effectively outflank the enemy from four directions instead of two (and it came with the added benefit of being able to use his feet to shield his head from enemy lasers).
Taken even further in Ender's Shadow. Bean is smarter and much less trusting than Ender, and rarely assumes that something is true just because it was taught to him. This is best demonstrated in the scene where Bean comes to the conclusion that none of the solar system defenses are practical, because the Buggers could just hop over them. He realizes that the only defensive strategy that makes any sense is a preemptive attack against the enemy's planet. He decides that Earth's attacking force must have been sent decades ago, and would be arriving within the next few years.
Averted at least sometimes by the Buggers. The first "mission" Ender faces features a fake command ship in the center of a spherical entrapment formation.
The Lost Fleet, divided space between above the planets' orbit and below, so that they have some semblance of up and down. It's mentioned that ships almost always pull "up" instead of diving "down", even though in space there's no difference.
The Prince Roger series makes the human tendency to do this a plot point when an Admiral notes that an opposing Admiral is from a watery planet, and thus likely to go 'down' rather than up like most other humans would.
Averted and played straight in Isaac Asimov's Foundation series in Foundation and Empire. One of the astounding victories that contributed to Bel Riose's arise to fame was attacking an enemy fleet from below the planetary plane in the solar system. As the rest of the naval brass felt that was very unsporting, it is implied that they didn't learn anything from it. Asimov also points out that "below" the planetary plane is an arbitrary designation; more something everyone agrees upon than an actual up-down correlation.
Alluded to in David Brin's Uplift series. Most space-faring species (humans included) are descended from terrestrial creatures and 2-dimensional thinking dominates their naturally evolved spatial reasoning capabilities, making most of them mediocre space pilots. Dolphins on the other hand, having descended from an aquatic species, had evolved superior 3-dimensional spatial reasoning, making them superior space ship pilots.
Mentioned in Only You Can Save Mankind, Johnny realizes when he sees Kirsty fly just how badly everyone else flew — they moved like they were playing a computer game, while Kirsty's ship pirouetted.
In The Final Reflection by John M. Ford, Krenn notices that a group of Romulan ships his ship is fighting move in a plane, then recognises the patterns in their movements and infers that their commander is visualising the battle as if it were a game of latrunculo, the Romulan equivalent of chess.
Averted and played straight in the Lensman series by E. E. “Doc” Smith. On the one hand, space fleets move in three dimensional formations, such as cones and cylinders, and englobement is a common tactic. On the other hand, in "Second Stage Lensen", the Patrol defends Earth by turning the asteroid belt into a huge solar array, focusing sunlight on the invading fleet — a defense that could have been averted if the Boskonian fleet was not in the plane of the solar system (in fairness, though, Boskone did not know the weapon existed).
Played with in Myth-ing Persons, when levitating Skeeve chases winged Vic through the air above the city rooftops. Vic's wings aren't that strong and he mostly circles and banks two-dimensionally like an Acrophobic Bird, whereas Skeeve has freedom to move in all three dimensions and jinks side to side and up and down, trying to catch Vic off guard and intercept him.
Semi-averted in When Worlds Collide; the incoming planets approach the solar system from below the ecliptic. However, when one settles into a new orbit around the Sun, it seems to be in more-or-less the same plane as the rest of the planets.
Averted in Honor Harrington. In keeping with the Age of SailIN SPACE! motif of the series, ships line up to present broadsides, but this is explained as being due to the "Impeller wedges" formed by the propulsion system being impenetrable, because they're just massive lumps of gravity. Although since space is 3-D, they line up vertically as well as horizontally: a "wall of battle" rather than a "line of battle" (and in turn, heavy capital ships are called "ships of the wall" instead of "ships of the line").
Deliberately done by Earth defense forces in Vladimir Vasilyev's No One but Us, when the Shat Tsur armada is about to attack Earth. In order to prevent the enemy from coming in at any vector, extremely powerful "nonlinear" generators are activated that create a No Warping Zone around the Solar System except for a very narrow vector on the ecliptic (they could have fully isolated themselves but that would just put Earth under siege, cutting it off from the war). Even then, the Shat Tsurs jump in along the vector at the edge of the system only to immediately jump at another vector within the bubble.
The "barrier at the edge of the galaxy" in the second pilot of Star Trek: The Original Series, "Where No Man Has Gone Before", looked to be no more than dozen miles or so tall — but a starship capable of travelling light years in a day couldn't go over it — or, for that matter, straight up, which relative to the plane of the ecliptic is one of the two fastest ways to get out of any galaxy. (The other being, of course, straight down.)
On the other hand, at least the Tholian Web appeared to be spherical.
The gravity onboard starships is artificial, therefore "down" to the crew is wherever the floor is. This should make the series' signature crew lurch from hull impacts impossible. The reason the crew don't turn to chunky salsa every time the ship accelerates is that there's an "inertial damping field". The reason they lurch when hit is that the dampers take a second to kick in. (ST:TNG Tech Manual).
Star Trek: The Next Generation was extremely fond of the "starship standoff" posture, to the point of being nose-to-nose with hostile vessels. On the other hand, the Grand Finale stupendously averted this trope: "Admiral" Riker's customised Enterprise-D not only destroys three Klingon warships in the space of about five seconds, but then flies straight through the resulting debris straight along the Z-axis. (a.k.a. the vertical one in 3-D space).
It was also averted in the episode "Time Squared" where the Enterprise was stuck in a vortex/entity that was pulling them downwards, and the only way to escape it was not to fly straight down into it.
In the TNG episode "Redemption II", Picard blockades the entire Romulan-Klingon border with twenty-three ships. It's not intended to be a true blockade (the travel distances would be much too slow to intercept anything); rather, it is intended to expose any cloaked Romulan ships going into Klingon space. However, the way it is supposed to accomplish this is by sending "active tachyon beams" between ships such that it would be possible to detect the ships if they "cross one of those beams". So... considering the vast distances involved, what is the likelihood that any ship in a clandestine operation is going to cross any of these beams in a three-dimensional space, even if you set them up as a web?
One rather entertaining TNG episode plays with this by having a hostile alien thingamajig that is only visible from a direction perpendicular to the standard Starfleet viewscreen orientation, which gives the Enterprise science crew a lot of trouble trying to figure out what is draining their power.
The entire concept of the Neutral Zone is depicted as being a linear area not unlike the Korean DMZ. No explanation is given as to how far vertically the zone extends.
Another reason "Genesis" is considered a particularly bad episode (in addition to the Evolutionary Levels crap) is the fact that, when the Captain's shuttle returns, they can tell something's wrong... because the Enterprise isn't straight on. Think about that a moment.
Interestingly subverted with the Borg cubes which, in spite of having a definitively "up" face, tend to disregard everything about the positions of enemy ships, including facing and "height".
Star Trek: Voyager has an episode where the Voyager gets trapped in some kind of space anomaly. When asked to try to fly out of the anomaly, the helmsman states he can't, because the anomaly surrounds the ship "like a ring".
The vast Astrometrics display was at least an attempt to bring some three-dimensionality to space; certainly an improvement on the flat-display star charts.
In Star Trek: Deep Space Nine there was an interesting case of that "tilted derelict" principle. A derelict space station, Empok Nor, was constantly being shown as tilted. Of course, this was for the benefit of the viewer, so that a viewer can tell it apart from its sister space station, Terok Nor (a.k.a. the Deep Space Nine), since they actually look the same.
Another episode concerned a Klingon plot to place mines around the Bajoran system. Near the end of the episode the minefield is detonated, and they are shown to have been placed in a shallow ring around the system. Neither the Klingons nor the DS9 crew seem to realize that it would've been easy enough just to fly over or under the mines.
The image at the top of this page is from the Star Trek: Enterprise episode "Exile". The spheres only shoot out "gravometric waves" (not to be confused with boring old gravity) in lines, and since space is two-dimensional, the lines intersect, misshaping reality.
One should note that several of the gravometric lines are shown to overlap each other, indicating that the chart is only displaying space from an "overhead" perspective (as if one were looking "down" or "up" into the Milky Way) as opposed to space itself being 2-D.
Babylon 5 is pretty good that way, at least in the early seasons. From about the middle of the third season ("Severed Dreams" and on), space battles became rather more 2-D than they had been. Still, there's at least one example of a Narn ship being bushwacked by a Shadow ship from directly below; the attacker even flies right through the space where the Narn was before it got blown to pieces. There are also multiple shots of Starfuries (the human fightercraft) spinning around their centers of gravity to get a shot, without changing the speed or direction of their travel.
Firefly. Lampshaded hilariously in one episode when Wash tries to lose a pursuing spaceship by flying into a narrow canyon. After some fancy maneuvering and bragging on Wash's part, a pan out reveals their pursuer simply flying over the canyon.
The entire Milky Way galaxy in had a ring of mines around it to deter a certain group of aliens from ever invading. A ring. Around a galaxy.
Also, when Travis spots the Liberator he says "I knew he'd have to return to this galaxy!" Space isn't only flat, it's tiny. See also Babylon 5 where the width of a numbered "sector" sometimes seems to be a light-second, sometimes several light-years.
In another episode, Avon forces the crew to cross an unidentified material in space. At no point do they suggest going under or above it which ultimately leads to the destruction of the Liberator.
An episode of Lost In Space once had the Jupiter II in great danger because a navigation error put the ship on a direct course to Earth — with the sun in the way. And apparently the sun was too large an object for an interstellar craft to go around. 1-D Space?
While this spinoff tends to ignore orbital mechanics and such (in one case having a spaceship make a hyperspace jump from a planet's surface into space, where it miraculously begins orbiting), in the season four opener Atlantis, traveling through space, hits an asteroid field, but is saved by skimming only the top edge (giving the chance for an Asteroids-like shooting sequence).
While allied fleets typically face the same direction, battles may include any number of complicated spatial maneuvers. The space battle in the episode "The Lost Tribe" also features brief scenes of a Traveler and an Asgard ship, battling in vertical position around another.
In the episode "The Last Man", Micheal's Hive attacks two warring Wraith ships from above, which were already damaged. Needless to say he kicks their ass in seconds.
Applies in the spin-off game Battlefleet Gothic which, naturally, is fought across a flat table top. In the designer's notes, the game's author acknowledges that space is 3D, but it would be logistically difficult to actually make a game that worked that way and also, because there's no gravity in space, making things 3D would just amount to being a range-modifier. Instead, the movement of the ships (much like their size compared to celestial phenomena) is assumed to be an abstraction for the sake of playability.
The 2-D space problem also pops up in the background material about the Tyranids. The Imperium, accustomed to strategic planning across a flat-ish galaxy, is perplexed when Tyranid swarms start popping up deep "behind" their defensive lines, rather than approaching from the edge of the galaxy like the others. Then it dawns on them that this new Hive Fleet is making a flanking action of sorts and attacking "upward" from "beneath" the galaxy. To be fair, the humans haven't had to deal with extra-galactic threats until this point. Nightmare-inducing image.
All space charts in the BattleTech game are two-dimensional, even the maps of the Inner Sphere.
Some of the authors prove that they did the research when writing battle scenes between aircraft or starships; one captain explicitly says that the 'threat zone' of an enemy warship is best thought of as a sphere constantly moving in three dimensions. He goes on to demonstrate just how this works: his warship is oriented perpendicular and rotated 90 degrees off on its long axis above an enemy warship. This lets him order a staggered broadside as they pass 'above' their enemy, which has each battery on one side of their ship striking the exact same targeted area as it passes to 'break the spine' of the enemy ship.
The Star Trek-based Star Fleet Battles tabletop game also has 2-D Space. The designers always felt the quote above was a dig at their game. However, attempts to add 3D maneuvering when they were first designing the game greatly increased complexity for little improvement in gameplay. Star Fleet Battles also has a core rulebook that's, no kidding, 428 pages of double column, 9 point Helvetica type as of this writing — and even then, there are new supplements adding to it every year. Trying to make SFB 3-D would probably make someone's head explode.
In the boardgame Battlefleet Mars they went to some effort to develop a system of representing three-dimensional movement for the ships... showing why Tropes Are Not Bad, since it was a wasted effort. There was simply no tactical advantage to maneuvering in more than two dimensions. Plus, it had the players doing the Pythagorean Theorem, by hand, every time they wanted to take a shot, or plot a maneuver. They also had to track movement (with counters) on two maps, one for the vertical, one for the horizontal; keeping track of the two data sets meant a lot of fiddle factor, for no real boost in playability.
In Spelljammer, a Space Opera Meets Fantasy AD&D setting, ships carried their own "gravity plane" with them. However, if docking or otherwise directly interacting with a bigger ship, the bigger ship's gravity would override the smaller one's. Space etiquette thus required that ships intending peaceful interaction line themselves up so all the gravity planes were on the same 2D plane. (The way gravity worked in Spelljammer, you could bring your ship in on another ship's gravity plane, but flipped "upside down". This was the easiest way of identifying your captain as a smartass.)
In a rather egregious example, the Star Wars Roleplaying Game Revised Core Rulebook makes an obvious and ultimately pointless lunge for this trope in the actual rules: "Sometimes a pilot needs to reverse course but maintain relative gravity — that is, keep "down" on the ship the same as "down" in the prevailing gravity — to avoid straining the ship's inertial compensators." Because we all know that our own modern spacecraft can't maintain an orientation other then floor-towards-Earth when in close proximity to our planet's gravity well. Because of the inertial compensators.
Ironically, the old West End Games RPG version of Star Wars handled it better: it explained battles are generally fought in two dimensions because that's as much as most starship captains can psychologically cope with. Apparently it would be too psychologically disturbing to have a Star Destroyer hanging upside-down above your vessel blasting the hell out of it. The RPG goes on to muse that a species psychologically comfortable with, and able to grasp, the intricacies of three-dimensional starship combat, would certainly stomp pretty much every other starfaring species in the galaxy. (Which doesn't explain why the Mon Calamari, an aquatic species, choose to fight in two dimensions as well.)
Fantasy Flight Games' X-Wing miniatures game uses 2D combat, but that's because the game is played on a 2D tabletop and the creators found that rules for three dimensions added unnecessary complexity that were not well received in playtesting.
Justified in Traveller. The 2D maps are feigned to be a simplistic projection of 3D space for normal usage. Which falls apart when considering all ordinary 3D-space navigation ever portrayed in the game (the tactical space combat rules, STL colony ships, radio communication between systems, misjumping, the Sword World exodus, the Darrian Maghiz, et al.) only work if every point in the universe is on a 2D plane.
In Jovian Chronicles the space combat rules allowed for vertical movement and distance between units; however, those rules were "optional" and could be disregarded to speed gameplay. The artwork and fiction would frequently show ships and craft moving on different planes to each other.
Likewise, every 2D space shooter, from Darius to R-Type to Gradius to Ikaruga, uses this trope. Heck, it's right there in the name of the genre.
Flatspace and Flatspace 2 are just what it says on the tin.
Flotilla, a sort-of-turn-based, sort-of-real-time (it's difficult to explain) space fighting game averts this. Every turn you decide the position in three-dimensional space and the yaw, pitch and roll of every single ship in your fleet. In fact the game enforces three-dimensional thinking because all the ships take absolutely no damage from most of the attacks if hit at the front or top, but take a lot of damage if hit at the bottom or back. Keep in mind that having five ships in your flotilla is a lot in this game. While the actual fighting is three-dimensional, the map where you decide to go in-between fights is entirely two-dimensional.
Star Trek Encounters depicts space as having three discrete "levels": a ship can fly normally, ascend to the "high" position, or descend to the "low" position. Only very large objects such as planets can occupy more than one level at the same time.
The original 1980's Star Trek arcade game takes place in space, which is completely 2D.
On the other hand, Star Trek: Bridge Commander actually forces the player to turn and tilt the ship to get the best firing/shielded angle to the target.
One of the biggest complaints about Starfleet Command was its 2-D space, by being a port of Star Fleet Battles, as seen in Tabletop Games.
In Star Trek Armada, the player is limited in how high above/below the plane they could get, and 3D maneuvering offered little benefit beyond going to the bottom of the plane to minimize the ship's size on the other player's screen.
In Freelancer, everything, that is, everything, lies in the same two-dimensional plane: planets, bases, trade lanes, jump holes, et cetera, et cetera, et cetera. The player, however, can move along the vertical axis, allowing for some really intense space battles. Since gameplay would certainly be harder if the game followed the actual three-dimensional structure of the space, this is part of the many Acceptable Breaks from Reality that can be seen on video games.
Due to the fact that planets tend to be almost exactly in a horizontal plane around their local star, that's not so bad — if the planets are on that plane, the lanes joining them would be as well, and since the axis of rotation also tends to be perpendicular to that same plane, geostationary satellites would be on it- so any stations orbiting the planet could well be in the same plane to make it easier to set up ground-based logistics. Granted, the jump holes and the stations not associated with any particular planet have no reason to be in that plane (except, perhaps, ease of mapping...). Granted, it is possible to place everything over and under the same plane. In many mods new objects, space stations, jumpholes etc. ARE over and under the classical 2D plane, making it sometimes much harder to find. Of course, the in-game map is also in 2D.
Space is very 3D in the Microsoft-turned-Open Source game Allegiance; rolling the ship to present the narrowest profile (and most weapons) is critical, enemies will fly at you from any direction, asteroids, stations, alephs, and valuable items may be vastly above or below you. The tutorial specifically advises dropping scanner probes above and below the plane of the ecliptic, since pilots are less likely to look for them there. However, it is not a perfect aversion, as the "sectors" in which combat takes place are not entirely spherical, but somewhat squashed — there is less "up and down" room than "side to side" or "back and forth," and sometimes this becomes important in gameplay (such as when trying to hide in a stealthy ship). Also, there is still a well-defined "plane" lying across the middle of the sector, and while some asteroids will be found far above and below, most of them will be scattered relatively close to it. In the end, however, the game is still remarkable for averting, if imperfectly, this and many other Space Is an Ocean and Space Is Air tropes while remaining very fun to play.
In the Galaxy Angel gameverse, you can't plan your attacks in three dimensions, but at least when they're executed they work that way.
Played with in Homeworld: The environment is three-dimensional, but everything orients along an invisible horizontal plane and capital ships tilt to move "up" or "down", like submarines. This has less to do with technical limitations, and more with looking cool. Inherently played straight in some: some warship models have more guns on the top side than on the bottom side (cf. destroyers, both Hiigaran and Vaygr). Subverted in more ways when the warships have cannons on top, bottom, and sides, or the weapons turn out to be missile launchers, in which the homing ability renders the issue of direction (almost) moot.
Several modders took this to heart and played with it in the most interesting ways. Some notable, famous mods have some types of frigates ditch the 2-D adherence and circle the target at a spherical, instead of a ring trajectory. This gives a very interesting battle as when the other, more stationary battleships are pounding away head-to-head, some annoying frigates are either taking potshots from up, down, or behind, or a hard-to-catch mezzer is running around in spheres, effectively Min-Maxing his fleet.
Multi-beam Frigates in Cataclysm did this in the un-modded game, and also didn't bother with the orientation convention.
Ships move and attack three-dimensionally in space MMORPG EVE Online, but stationary ships pitch parallel to the ecliptic plane for no explained reason. Also rather subtly averted in EVE by the layout of the planetary systems, which often have planets arcing above the ecliptic or stargates located far below the system proper. Also, there's always a sense of where "up" and "down" are, because the camera can't vertically rotate past top and bottom positions. There is also a tactical view, which superimposes a set of horizontal circles around your ship, no matter what direction your ship is facing.
As noted in the comments (and illustrated in the pictures) for this article major EVE spacebattles look like big tangled balls of light, with attacks coming and going in all directions.
The Elite remake Oolite both averts this (you can maneuver three-dimensionally, and pretty much have to in order to do much of anything) and takes it to an extreme: the large-scale structure of space is one-dimensional, with everything of interest lying roughly on a line connecting a solar system's jumpgate with its space station (asteroid fields, stars, moons, and some space stations excepted). Justified in that most of the objects of interest are manmade, and were placed there because it's the route most traders take from the jump-in point to the planet.
Star Flight and Star Control 2 both have this, as they were initially games made back when 3D graphics were basically really bad wireframe and trying something on the scope or scale of EVE Online was simply impossible at the time.
The first Star Control had a 3D starmap in 1990, but it was really simple-looking and confusing. In the manual, Star Control 2 attempts to justify this by explaining it as an unusual property of Hyper Space... but this doesn't explain the two-dimensional non-hyperspace combat. Star Control 2 was a regression in this sense, since the original (1990) Star Control had a tactical game played on a 3D starmap. The map was a three-dimensional pattern of differently-coloured dots, and constantly rotated. It was darned hard to know which system connected to which, however. The melee combat was still 2D.
Star Control 3 replaced its predecessor's 2D starmap with a 3D one. It was considerably more difficult to remember where anything was and a good deal less pretty — for a start it lacked the "spheres of influence" from SC2. Of course, "circles of influence" would have been a more accurate term.
Star Wars: Empire at War restricts space combat to the 2D plane. Ships of different classes are higher "up" or lower "down" on the plane, for example Corvettes are higher "up" than battleships, and fighters, when engaged in dogfights, go all over the place, but there is no gameplay effect of this.
Sword of the Stars features a main map in complete 3D, requiring the player to pivot and zoom in order to get the full perspective. The expansion even adds the Real Space template for galaxy generation, which is just what it sounds like. In combat, however, player-controllable Z-axis movement is only possible through keyboard hotkeys, as opposed to the normal mouse-commands. Otherwise, the player can only issue orders in 2D, though ships will pathfind in 3D and move "up" or "down" as necessary. The sequel will implement limited controllable 3D combat maneuvering.
Specifically, the sequel adds two more 2D planes. The ship can be moved to any of the three planes and can even be rotated along the axis to present a weapon or an undamaged armored section.
While the starfighters in Star Wars Battlefront II are allowed to fly in three dimensions, capital ships are often right across from each other in most of the space maps. The only exceptions are Space Mygeeto and Space Coruscant, where rival ships are arranged in three dimensions and can move and navigate on their own. And the bombers' proton bombs always fall 'down' relative to the plane the capital ships are oriented in, no matter if that is actually up relative to the planet.
In StarCraft, the maps in Space take place on man-made orbital platforms and the space between them is like the water on other maps, so they are functionally no different from the maps that are on the surfaces of planets. So guardians, air units that can only attack ground, still can't attack other air units even with the freedom of space, and the siege tanks' attacks are still restricted to the surface of the platform, though they would presumably be able to hit air units in the low gravity conditions. And none of the aerial or space-faring units can fly over the enemy defences.
The shareware game Escape Velocity is limited to a 2D plane, allowing it to use very simple controls for combat, akin to Asteroids or Star Control's HyperMelee. This also makes it far easier to flood the screen with weapons fire.
In Spore, the star-chart is completely 3D, which can make it difficult to find the star you want. However, solar systems are completely flat and are all completely parallel, your own ship never has to roll at all to land on the planets or to interact with ships, in fact, every ship is also on the same plane as you. However, it's entirely possible to design a ship specifically so that it can move and attack in all directions, though this has no effect on gameplay.
And every plane and boat are also on the same level; no matter how air-tight the vehicle, it cannot function as a submarine, and no matter how many engines, the planes are completely incapable of going up or down.
While the game Cortex Command is a side-scroller which takes place mostly on the ground, in the opening cinematic it shows a flat view of a planet, and orbiting the planet exactly perpendicular to our view, is a Trade Star. So, apparently, the space station is orbiting around the poles for some reason, despite most of the action taking place closer to the equator. In the game itself, everything is completely 2D, to the point where it's impossible for even friendly entities to squeeze past each other.
The Super Robot Wars series is an interesting example, where space is actually more two-dimensional than any other type of map. In game everything takes place on a two dimensional grid but missions that take place on earth have at least three "levels", ground, air and underwater and occasionally underground. Space levels don't have this distinction.
Sins of a Solar Empire tries to avert this trope, having ships that will occasionally go up and down and be above or below others, and planets that are (slightly) above or below others. But basically it's still 2D — each planet is fixed in space, the 'phase lanes' that link planets always basically go parallel to this plane, and because of this most combat takes place on the plane. You can still move the viewpoint around in 3D, but it doesn't change anything. Partially justifed in that the game depicts a series of solar systems, which really are more or less flat, in that most of the orbiting objects sit a similar plane. The game possesses enough variation in these planes to effectively avert this trope in this regard.
Only really averted with orbital platforms - moving your ships in 3D can actually allow the fleet to bypass significant deathtraps.
Star Trek Online has an interesting mix of 2D and 3D: while there is a universal "up", ships only have 4 shields (front/back, port/starboard), and ships can only travel 45 degrees up or down, the combat space is entirely three-dimensional, allowing ships to pass over or under each other, come at each other from top or bottom (well, at a 45 degree angle) and be in or out of weapons range in a full sphere around a target.
O.R.B.: Off-world Resource Base is a game that perfectly demonstrates the issues of using a 2D interface for 3D combat, with no necessarily defined Up or Down to the game world unless you switch to the 2D map. All action takes place in three dimensions, however the design of the interface tends to cause players to use only two. Essentially, the interface first determines your x and y, and then you adjust the z to suit your needs. This does allow you to out-think the enemy in three dimensions, but it can be very difficult to grasp where exactly you've ordered an action. Mostly, you do not have to command ships during actual combat, which is a blessing since nearly all combat will take place on slightly odd planes that can be difficult to follow. In summary: commanding a capital ship to teleport itself "under" the enemy base will work perfectly, if you're so blessed as to correctly gauge the interface, however, the ship will teleport in a straight line, causing it to usually be oriented incorrectly to launch an efficient attack. It does have the forward-orienting and formation-taking ships, but is still very close to the correct model.
While not in space, Final Fantasy X has Blitzball, which takes place in a giant sphere of water. Everybody plays on the same plane, though it's definitely due to simplifying the interface. The cutscenes have them play the game in three dimensions.
The Master Of Orion series uses a 2-D Galaxy map, a 2-D system map (justified like most examples), and 2-D combat. This is generally handwaved as part of the level of abstraction in the game.
Played totally straight by the Outforce, a spatial RTS in which you can even build barriers.
On the one hand, 3D maneuvering is a critical part of combat tactics. On the other hand, the first three games have all the default stations and jumpgates in a sector laid out on the X-Y plane (i.e. flat).
X3: Reunion breaks the pattern; stations vary in altitude. Then X3: Terran Confict falls back into it: Terran sectors are laid out with their stations' geographical centers on the X-Y plane. The sector map display uses a pretty creative workaround for the conundrum of mapping 3D space onto a 2D computer screen. The default view of the sector is a top-down view of the X-Y plane. Clicking a button in the corner switches the view to the X-Z plane.
X3: Albion Prelude adds major variations in station altitude to the Terran sectors. This becomes very annoying in the Asteroid Belt since they put the sector's main dock about a dozen kilometers below the ecliptic, with its docking ports on the bottom. Given the absurdly slow ships in the game, this borders on a Scrappy Mechanic.
Artemis Spaceship Bridge Simulator has a 2D map (100 by 100 kilometers) and no provision to change the ship's pitch, limiting you to flying the ship in only two dimensions. This leads to the Captain ordering Helm to come about to "course xxx", instead of "course xxx mark xx".
The Mount & BladeGame ModStar Wars Conquest has a worldmap which is a two-dimensional representation of the Galaxy, with the space vacuum instead of Calradian land, and several kind of planets and space stations instead of the villages, castles, and towns.
Haegemonia: Legions of Iron has 3D space, but all planets and objects are roughly in the same plane, so there's no real reason to use all the space.
Nexus: The Jupiter Incident averts this completely. However, the manual movement controls are clunky. Then again, most players don't bother using them, prefering to use waypoints instead.
Parodied: a bunch of protesters surround the show's equivalent of an oil tanker. It just goes up and flies over the human barrier.
Leela: When you were planning this peace ring, didn't you realize spaceships can move in three dimensions? Free Waterfall, Sr.: No, I did not.
Likewise, the producers (several of whom have advanced degrees) explain in commentaries that they would have liked to do things like show the ship flying upside down or at odd angles, but ran out of time/money to do so. Though, in the previously referenced episode, the ship actually DID fly upside down, due to Bender flying it sober.
In Megas XLR, there are TWO coordinates indicating the location of objects in space
In Phineas And Ferb they subvert this by throwing a Logic Bomb at their evil computer, causing it to encase the entire Milky Way in an impenetrable barrier (spherical at that). There is still no sense of scale, as the tower that the computer was in jumped from Earth, to above the midpoint of the Milky Way, and encased it in less than 5 seconds.
In SpongeBob SquarePants, curiously only a few creatures actually swim. Which is treated like flying. SpongeBob once built an airplane— indeed, the episode where he does so is entirely oriented around him trying to "fly". This is from the same series where there's Fire underwater, dying of thirst underwater (for fish, so the "clean water" argument is moot), and Drowning underwater (again, they're FISH). It's fair to say the creators doesn't care about the properties of water unless they could make it funny.
Star Wars: The Clone Wars treats banking up like something that would put a strain on your fighter and could even make your fighter stall if damaged, unfortunately for Matchstick. Subverted though when Asoka has the ship turn its "bottom" towards the star destroyers to get them to send their bombers into a trap.