History Main / SpaceFriction

** However, in "Out of Gas", the engine breaking down seems to result in ''Serenity'' coming to an immediate halt. It never actually stopped, but losing engine power meant losing oxygen and heat, and it happened while they were out in the middle of nowhere, on a course that would take weeks to get anywhere. The ship's appearance of inertness, while also helping add to the theme of helplessness, is easily explained by the fact the space is big. [[Franchise/TheHitchhikersGuideToTheGalaxy Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is.]] The only visible reference points in any shot in that episode are stars which are who-knows-how-many light years away and of course, the further away something is, the less it appears to move in reference to the viewer.
** The Serenity RPG sourcebook explains it as a byproduct of the workings of the "pulse drive" used to accelerate the ship to relativistic speed for interplanetary travel. They apparently fiddle with gravity to reduce the ship's inertia, then fire the main engine (on a Firefly, the glowy bulb at the stern) to kick the ship to high speed. Cutting or losing power to the pulse drive causes all that inertia to come back, and the ship drops back to the speed it was at before you fired the drive.

For that matter, the entire notion of only having enough fuel to travel so far is a little suspect: if you've got enough fuel to reach top speed, you've got enough fuel to go anywhere; once you reach top speed, you can just shut the engine off and coast, though this is assuming you're flying along a ballistic trajectory. Of course, it would become a problem if you don't have enough fuel to ''stop'' at the end - or if, for whatever reason, you have to turn somewhere, or if your engine fuel doubles as power generator fuel, which would cause a black-out in your ship (which, if it comes up in a SpaceFriction plot, generally means the crew has a few hours to restore power before running out of air). Even so, this would result in a broken-engined ship perhaps missing its target or crashing into another, not stopping dead.

Note that there is ''a tiny bit'' of friction in interstellar space. The interstellar medium isn't a complete vacuum and, depending on what part of the galaxy you're in, there can be as much as one whole ''atom'' of hydrogen per cubic centimeter of space. This is still more rarefied than the best laboratory vacuum, however, and will only matter if you're going ''extremely'' fast -- as in sizeable-fraction-of-the-speed-of-light fast. (Due to quantum mechanics, the electric fields of virtual photons[[note]]temporary photons that pop into existence just long enough to affect other stuff[[/note]] also slow objects down, but this only changes the speed at which the objects rotate.)

* In ''Film/StarTrekIIITheSearchForSpock'': the ''Excelsior'' is accelerating up to transwarp, when Scotty's sabotage kicks in, everything breaks down and it coasts to a stop. Semi-justified in that the thrust was given by the defunct Transwarp Drive, a Phlebotinized engine that's probably not subject to Newtonian mechanics. Justified under RuleOfFunny, as that breakdown is accompanied by a humorous "engine sputtering to a stop" noise.
** Since Scotty made several 'improvements' in ''Excelsior'' he might as well program it to stop (decelerate). Or it might be an emergency measure that a ship losing main power in space dock will automatically come to a halt on thrusters.
*** To clarify, Federation starships have three separate propulsion systems: Warp engines, which alter the space around a starship and allow it to bypass...well, physics, and are powered by a matter/antimatter reactor; impulse engines, which propel a starship at sublight speeds and are powered by several fusion reactors; and thrusters, which utilize a chemical reaction and are usually used for precision maneuvers, and are probably very similar to RCS thrusters on contemporary real life spacecraft. If Scotty only sabotaged the warp drive, Excelsior would still be able to maneuver with the remaining two systems.
*** In addition, the Impulse engines use AppliedPhlebotinum to "lower the apparent mass of the ship and facilitate slippage of the continuum" [[note]]TNG Technical Manual pg 77[[/note]], in other words to go far faster than should be possible. Now ask, "what happens when you turn the AppliedPhlebotinum ''off''?"
** It may simply be that the [[AppliedPhlebotinum subspace field generators]] of the impulse engines allowed the ''Excelsior'' to move faster than Newtonian physics would allow. When the engines failed, the ship simply coasted to a vastly lower speed of which Sir Isaac would approve. This also explains the ''Film/StarTrekIVTheVoyageHome'' examples.

** It could well be that most vessels will have some form of "emergency stop" procedure to prevent them from accidentally bumping into a planet or drifting off when it loses power. Not to mention making it easier to salvage said vessels. The Miranda class USS Saratoga's odd angle is a bit of a strange one though, perhaps it was just beginning to attempt a turn when the damping field got it?

** The reason for the rocket pack fuel gauge thing was because they weren't adrift in space, but rather orbiting Mars. The guy without the fuel was invariably going to end up crashing into the planet - he needed fuel to escape the gravitational pull of Mars and get back to the shuttle. Anyone who went to get him would have succumbed to the stronger gravity as well and therefore he did the noble thing and removed his helmet...

* In Alistair Reynold's RevelationSpace a character wonders why an interstellar light-hugger ship is aerodynamically shaped given that space is a vacuum. She is told that at 0.999c the interstellar medium is dense enough to almost function as an atmosphere as far as friction goes.
** This is an accurate use of this trope, the interstellar medium's tiny amount of friction at low velocities, less than a fraction of 1% the speed of light, becomes a lot of friction when moving at high velocities, just below the speed of light.
** Just note that Creator/AlastairReynolds writes ScienceFiction ''and'' is an astronomer.

*** Is probably a joke about warp-drive

** Averted in ''Series/{{Battlestar Galactica|Reimagined}}'', the remake. Vipers can turn on just about any axis, and the visual effects always show thrusters on the sides of the fighters engaging when this happens. One of Starbuck's favorite maneuvers is to flip her Viper end-over-end to point her guns directly at the enemy fighter following her, making it so that her bird is travelling backwards. During 4x09, The Hub, the show even uses [[spoiler: unpowered Vipers tethered to Cylon raiders to escape enemy detection before a battle. One of the pilots says "What's going to stop us when the Raider in front of us stops?"]]
** The reimagined BSG has several notable aversions. In the pilot, Boomer and Helo's raptor takes damage and starts leaking fuel. Boomer gets round this by shutting the engines down and letting their momentum carry them to their destination.
** Another example comes during the Resurrection Ship arc. Starbuck shuts down the engines on her stealth ship and flies it right through the Resurrection Ship on thrusters alone. She goes completely unnoticed until she powers her engines back up again, at which point she's jumping out anyway.

However, the reason these things happen is friction. On a straight road, with good tires, you can coast quite a long way on even a slight downgrade. In space, where there is no friction between the car and air to contend with, you can coast even at top speed almost ''forever'' (albeit perhaps not in a perfectly straight line, due to gravitation), or until you hit something, which, given how big space is, is astronomically unlikely.

'''Matt Groening''': Yeah, that's the future for ya...

* Averted in ''Series/StargateUniverse'', noticeably in episode "Darkness", where the ''[[CoolStarship Destiny]]'' uses the atmosphere of a gas giant for braking when out of power for sub-light engines.

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* Averted in [[{{Tintin}} Tintin's adventure on the moon]]. The rocket kept going forward even when the engines were shut off (it was mostly kept on to make an artificial gravity for the crew) and had to turn around and fire the engines towards the moon to kill all the speed they built up.
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* In Film/StarTrekNemesis, After Captain Picard [[RammingAlwaysWorks rams the Scimitar]] causing much of ''Enterprise's'' hull to penetrate that of the other vessel, Shinzon reverses his engines to separate the two ships. It works quite nicely, and all without any opposing thrust from ''Enterprise''.
* ''TransformersTheMovie'' (the animated one) had a variation of this; Astrotrain, in space shuttle mode, pleads to his passengers to "jettison some weight, or we'll never make it to Cybertron". This seems to be an excuse to throw the other, dying Decepticons out of Astrotrain, but note that his engines were still on and burning brightly for some reason.
** Parodied [[http://knoledge.org/mormegil/rfc-tftm.php here]].

* Averted in ''Dark Planet''. The hero's solution to a [[SpaceMines minefield]] blocking the path to the objective is to cut all power except life support and cool the hull to ambient temperature, then go straight through the minefield on inertia. The result is that the mines mistake the ship for a derelict and allow it to pass.
* Averted in ''WesternAnimation/WallE,'' most notably in the space dance scene. When WALL•E uses the fire extinguisher to fly about, he kept going even after he had stopped firing the fire extinguisher and had to fire in the opposite direction to stop his movement.

* Averted in ''Series/StargateUniverse'', noticeably in episode "Darkness", where the ''[[CoolStarship Destiny]]'' uses the atmosphere of a gas giant for braking when out of power for sub-light engines.

* BattlefleetGothic averts this by forcing ships to take a command check to burn reverse thrusters in order to stop.
** The Warp Rift unofficial rules for [[StealthInSpace running on minimum power in order to avoid detection]] avert this, stating that ships continue on the exact same vector as they were on before shutting down unless the ship uses minimal thrusters to slow down.

* The PC game ''Inner Space'' averts this...but since the areas you play in are kinda small, you're more likely to slam into something than coast for very long.

* Possibly Averted in ''VideoGame/{{Freelancer}}''. While ships do slow down when you reduce their thrust, the existance of a "Kill Engine" button which allows the player to make use of newtonian physics (Complete with realistic acceleration if the player uses the afterburner) suggests that the aerial-style movement is a product of the designs of the ships.
** This was previously done in ''VideoGame/TachyonTheFringe''. Ships have a top speed, but with the clever use of afterburners and inertia, the ship's speed can nearly double. Of course, as soon as you reactivate the engines, your speed goes back to top speed. Not to mention all the banking and barrel-rolls.

* Much of the drama in ''Film/{{Gravity}}'' comes from the fact that an object set in motion doesn't slow down until it hits something else. This includes both space debris and the protagonists themselves.

** The FSOpen project actually implemented real-world physics at one point: more as a proof-of-concept thing than anything else. After all, the engine was designed around {{Old School Dogfight}}ing, so playing with "Newtonian physics" completely broke the AI and all game balance.

* In the game ''BattleCruiser'' by 3000 AD (possibly also the prequels and sequels in the same series). When you stop applying thrust you will eventually stop. But if you shut down all power to the engine you will go on with constant speed until you turn.

*** That’s obviously a joke about warp-drive

* "VideoGame/KerbalSpaceProgram". Learning how to control the orbit of your ship without friction is one of the challenges of the game, especially once you need to move that orbit out of [[AvertedTrope 2-D Space]].

* In the DoctorWho episode "The Beast Below", the Doctor can tell something strange is going on because [[GenerationShips Starship UK]] is moving through space despite the engines not running. Which is obviously impossible.

* ''Series/{{Firefly}}''. The cut-off-our-engine-and-coast trick is used to approach Niska's space station without being detected.
** However, in "Out of Gas", the engine breaking down seems to result in ''Serenity'' coming to an immediate halt.
*** The ship never actually stopped, but losing engine power meant losing oxygen and heat, and it happened while they were out in the middle of nowhere, on a course that would take weeks to get anywhere.
*** The ship's appearance of inertness, while also helping add to the theme of helplessness, is easily explained by the fact the space is big. [[Franchise/TheHitchhikersGuideToTheGalaxy Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is.]] The only visible reference points we have in any shot in that episode are stars which are who-knows-how-many light years away and of course, the further away something is, the less it appears to move in reference to the viewer.
*** The Serenity RPG sourcebook explains it as a byproduct of the workings of the "pulse drive" used to accelerate the ship to relativistic speed for interplanetary travel. They apparently fiddle with gravity to reduce the ship's inertia, then fire the main engine (on a Firefly, the glowy bulb at the stern) to kick the ship to high speed. Cutting or losing power to the pulse drive causes all that inertia to come back, and the ship drops back to the speed it was at before you fired the drive.

* ''CowboyBebop'' - in one episode, the Bebop is out of fuel, but the characters are unconcerned and are just killing time while the ship coasts to its destination. Despite this, ''CowboyBebop'' is not entirely a realistic series using Newtonian flight physics. There are plenty of occasions where the ships behave in Newtonian-correct ways (maneuvering thrusters, braking with forward-firing engines...), but plenty more when they don't (the [[OldSchoolDogfight dogfights in space]], for instance, follow atmospheric flight patterns). The dogfights, however, may get a RuleOfCool exemption.
* ''OutlawStar'' operates similarly, but the dogfights definitely follow a more 3D style of maneuvering. In one episode, the Outlaw Star even rides a "stream of aether" using its parachutes.
* ''{{Planetes}}'' did its research. Most of the early story was about collecting debris that were dangerous precisely because items in space never slow down or stop.
* Macross handpicked a number of physics rules to abide by and it's pretty consistent with those, but then there are the ones it dislikes and rapes constantly.

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* Averted in [[{{Tintin}} Tintin's adventure on the moon]]. The rocket kept going forward even when the engines were shut off (it was mostly kept on to make an artificial gravity for the crew) and had to turn around and fire the engines towards the moon to kill all the speed they built up.

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* In the arcade classic ''{{Asteroids}}'', you can drift for about 2-3 screen's worth before coming to a stop, depending what speed you're going. The arrow buttons work like thrusters, requiring reverse thrust to slow down.

Note that there is ''a tiny bit'' of friction in interstellar space. The interstellar medium isn't a complete vacuum and, depending on what part of the galaxy you're in, there can be as much as one whole ''atom'' of hydrogen per cubic centimeter of space. This is still more rarefied than the best laboratory vacuum, however, and will only matter if you're going ''extremely'' fast -- as in sizeable-fraction-of-the-speed-of-light fast. (Due to quantum mechanics, the electric fields of virtual photons[[hottip:*:temporary photons that pop into existence just long enough to affect other stuff]] also slow objects down, but this only changes the speed at which the objects rotate.)

* Averted in ''WesternAnimation/WallE,'' most notably in the space dance scene. When WALL•E uses the fire hydrant to fly about, he kept going even after he had stopped firing the fire hydrant and had to fire in the opposite direction to stop his movement.

A form of HollywoodScience. See also SpaceIsAir. Related to FrictionBurn. Contrast FrictionlessReentry.

** Just note that AlastairReynolds writes ScienceFiction ''and'' is an astronomer.

*** To clarify, Federation starships have three separate propulsion systems: Warp engines alter the space around a starship and allow it to bypass...well, physics, and are powered by a matter/antimatter reactor; impulse engines, which propel a starship at sublight speeds and are powered by several fusion reactors; and thrusters, which utilize a chemical reaction and are usually used for precision maneuvers, and are probably very similar to RCS thrusters on contemporary real life spacecraft. If Scotty only sabotaged the warp drive, Excelsior would still be able to maneuver with the remaining two systems.

* Played painfully straight in the classic [[Atari8BitComputers Atari 8-bit]] game ''VideoGame/StarRaiders''. Not only is sublight travel performed by setting your spaceship's engines to fire continuously (consuming energy in the process), but if they get damaged abruptly brings you to a halt, leaving you to sputter to the nearest starbase for repairs.