Inertial Dampening

"Lt. Ford: It's strange not pulling any G-s.

Maj. Sheppard: Yeah... Kinda miss it. Although at this rate of acceleration, we'd be dead by now.

Lt. Ford: Yeah?

Maj. Sheppard: Oh yeah. Without inertial dampening, we'd be hit by so many G-s, our eyes would pop, the skin would pull away from our faces, our brains would squish up to the back of our skulls, and our internal organs would be crushed into these chairs. What about that sandwich? Calmly glances at Ford, who is now looking a little green"

- Stargate Atlantis

Inertial Dampening (or "Damping", if you prefer your inertia dry) is a piece of Applied Phlebotinum, designed to allow humans to accelerate and decelerate at high rates without becoming humorously colored paste on the walls.

Its intention is to "take away" inertial effects; i.e., when accelerating, you are not pressed back into your seat (or liquefied and wedged into your seat.) For the most part, it's an invisible seatbelt substitute for crew and cargo.

Sometimes Inertial Dampening has a "lag", where a sharp turn or quick deceleration will momentarily cause a reaction (quick fall into the console or press back due to high accelerations).

Inertial Dampening is generally not Tim Taylor Technology. An overloading IDF [Inertial Dampening Field] has the opposite effect of most Applied Phlebotinum, causing a greater inertial effect, usually culminating in a Star Trek Shake. Generally, however, the Star Trek Shake has no relation to the direction of inertia; i.e., the ship is traveling forward, but the crew feels a right-to-left effect.

Though often left unmentioned, Inertial Dampening is a requisite side-technology to any spaceship that can turn or accelerate faster than an ocean liner. It's the reason why The Bridge has No Seat Belts. Note that the physical Hand Wave that accompanies many forms of Faster Than Light Travel dictate that the ship does not accelerate in the traditional Newtonian or, for that matter, Einsteinian fashion, and so the inertial dampener is mostly for maneuvering and orbit changes.

In hard Sci Fi, especially written but occasionally not, a more realistic method is used to cushion acceleration shock. Immersion in a fluid equal in density to the body would theoretically cause buoyancy forces to act counter to any accelerations; this is sometimes coupled with cryonics. Some method to allow the subject to continue to breathe in the fluid would be required, be it oxygenated liquids or a circulatory gas-exchange system. Since people riding around in bathtubs are not interesting on-screen (except from a voyeur's point-of-view) this has only rarely trickled down to the big and small screens; the exploration ship in Event Horizon and presumably the cryonics pods in the Alien series are the exceptions. Another relatively hard way would be use of dynamical Artificial Gravity to compensate inertial forces.

See also Artificial Gravity.

Anime and Manga
"Kallen : Will those increase the synchronization rate ?
 * In Neon Genesis Evangelion, the LCL fluid filling the Eva units' cockpits protects the pilots from the G-forces involved in piloting a Humongous Mecha -- among other things.
 * Averted in Starship Operators. All the crews need to strap themselves in before acceleration, and acceleration ranges to at most around 10g for some ships..
 * Barely addressed in Code Geass. The flying Humongous Mechas do sharp U-turns at velocities that would turn the pilot into paste all over the cockpit's walls (and probably dismantle the mechas themselves). Handwaved by Rakshata with the new pilot suits :

Rakshata : No. But they will increase the survival rate."


 * Not exactly. Those pilot suits are for stopping the pilot from dying when their mecha explode. Of course, when their mecha explode, they're launched from the exploding hulk in rocket-powered cockpits, so you really do want your pilot suit to inflate and stop you from breaking your neck when your head smashes into your control panel.
 * All too present in Macross series' Schematized Prop. Not only the system dampens inertia, it converts it into storable energy required for transformation (that is, unless this troper read the description wrong...)
 * It is not perfect however, and not only Guld have paid for it in one of the most awesome Heroic Sacrifice ever, unmanned (Ghost variants) and cyborg-piloted (VF-27 Lucifer) Variable Fighters are outright stated to have better maneuverability than ordinary human/Zentraedi piloted ones.
 * Averted in Gundam all over the place. The World Building specifically comments that the facilities for sending people into space are slower than the ones used to transport objects because humans can't tolerate that level of Gs. In two separate series (Gundam Wing and Gundam 00), The Rival uses a machine that is incredibly fast but has little to no safety features in order to keep up with the Gundams; both pilots end up exhibiting Blood From the Mouth, and in Wing, we even see the Rival black out and suffer a heart attack from the stresses involved, despite being young and healthy.

Comic Books

 * Averted: In the Tintin (Comic Book) adventures Destination Moon and Explorers on the Moon, the crew of the Moon-Rocket faints from the pressures caused by take-off and landing.
 * Depending on the writer, this is often the reason why Iron Man can suddenly rocket off, take huge punches, fall from orbit and just crawl out of the crater. Other times it is simply Hand Waved.
 * One of Don Rosa's Scrooge McDuck stories had the Beagle Boys get their hands on a raygun that "completely" removed inertia from objects (really having none at all would be a bizarre idea, but it was cut down to minimum so that anything short of air resistance would instantly stop the object's movement), as well as one that removed "all" friction. The results were interesting to say the least.

Fan Fiction

 * "A ship can't pull 10,000 Gs without some form of inertial compensation."

Film

 * The classic sci-fi movie Forbidden Planet offered one of the earliest examples of this trope. In the beginning when the ship decelerates, we see the crew climb into strange booths which presumably neutralize their inertia.
 * Likewise This Island Earth.
 * It's not certain that inertia is the issue in Forbidden Planet. The spacecraft is "decelerating" from its FTL cruising speed to the sub-light speeds it'll need to rendezvous with (and eventually land on) the destination planet. The crew had to do something involving those booths to survive the process, but whether this was due to plain old high G forces or to some completely weird effect of their FTL technology is never made clear.
 * Inertial dampening seems to be built into the protective bubble surrounding the makeshift spacecraft in The Explorers. In small words, "you don't get squished."
 * Subverted in Spaceballs: When the Eagle 5 comes out of "hyperactive", we see that Vespa's luggage is strewn about all over the place (of course, a crash landing will also do that, but the hyperdrive probably helped). Of course, we've just been exposed to the reason why you should buckle up in Ludicrous Speed. Smoke em if you've got em!
 * Also subverted when coming out of ludicrous speed causes Dark Helmet to fly across the bridge and crash into the front of the ship.
 * The 2009 Star Trek film has Sulu as helmsman forgetting to turn Inertial Dampening off. It's Played for Laughs (Pike asks about the parking brake; Sulu realizes it's a joke but doesn't get the connection, and Spock asks if he disengaged the external inertial dampers).
 * In Alien, as the Nostromo is landing, Dallas warns the crew that the inertial damping is switching off and they should be prepared for "a little jolt". Turns out to be no so little...

Literature
"Unfortunately, the Bergenholm, while it could completely neutralize inertial mass, never quite knew what to do with gravitational mass, which seems to come and go as the circumstances require."
 * In the Star Wars Expanded Universe novels, fighter pilots often "dial down" their ships' inertial dampening fields in order to better feel the weight and pull of their machines. The official reason for Jek Porkins' dying when he did in A New Hope was that he liked keeping his dampener on full and literally couldn't feel that he wasn't holding.
 * In later books, they use their dampers to counter the gravity manipulating dovin basals that the enemy was using as shields, propulsion, and to kill their shields, effectively making them shields for the shields.
 * Also from the expanded universe, it is revealed that IG-88 always has his ship's dampeners off, since he doesn't need them. This allows him to perform maneuvers that would otherwise kill an organic being, often giving him the edge.
 * Taken to the logical extreme in EE Doc Smith's Lensman novels, where entire spaceships, including their contents, are rendered inertialess. The consequences of this technology are explored in great detail.
 * Perhaps the most interesting consequence is that the technology does not remove inertia, but rather suspends it. When the inertialess drive is shut down you have exactly the same inertia you had when you turned it on. If you neglect to shut off your inertialess drive and match velocities with your destination, heaven help you. Your restored inertia will either fling you into space at thousands of miles an hour, or fling you into the GROUND at thousands of miles an hour.
 * Moreover, inertialess drive technology allows Doc Smith to Justify using Space Friction. If an inertialess ship collides with a particle of interstellar hydrogen it comes to a screeching halt because the hydrogen ion has inertia and the ship doesn't. Therefore, Doc Smith spacecraft must keep up continuous thrust to move while inertialess, and their speed is directly related to the power of their engines because the faster they go the more friction they encounter from interstellar dust and gas. Speeds eventually reach the point where the fastest ships have to be teardrop shaped for streamlining.
 * Reducing your space ship's inertial mass to 0 also means you no longer have to worry about it becoming infinite as you approach light speed. This is, in fact, how ships in the Lensmen universe accomplish Faster Than Light Travel.
 * Spoofed in Backstage Lensmen, a parody by Randall Garrett.

""Inertial control!" Sir John boomed out delightedly, tapping his cane on the floor. "I still say it's impossible, but, by God, it's exceedingly useful.""
 * In the Honor Harrington stories (and others by David Weber), inertial sinks (called "inertial compensators" in the Honorverse) are required to deal with, by "absorbing" the inertia otherwise generated, the ridiculously high accelerations ships can generate. Failure of the system, either through combat or sabotage, is considered terrifying by crews as undergoing 300 or more Earth gravities of acceleration instantaneously turns people into chunky salsa.
 * Weber makes a point of describing this effect at least once in any book which involves space combat or high system-stress situations (basically all of them). The best was "Turning the entire crew into something vaguely resembling tuna paste."
 * The later books of the Rendezvous With Rama series have the immersion version of this trope. In an interesting twist, the characters at first don't realize just what the hell the tanks are for and have to be herded into them at quite literally the last minute by the ship's robotic crew.
 * The novel The Forever War, uses the immersion in a fluid method. Since the spaceships tend to change velocity at high speeds, support for internal organs is needed as well. This is accomplished by injecting the characters with special substances and placing them in special suits, wherein they are then surrounded by extremely high pressure fluid, equal to several kilometers underwater. The results of the pressure failing are not pleasant.
 * Adamist spacecraft in Peter F Hamilton's Nights Dawn Trilogy do not have any sort of Inertial Damping system at all. The crew lie on acceleration couches, which help cushion their body from the g-forces produced by combat maneuvers. If the acceleration climbs too high, the crews have to put the the ship on autopilot go into stasis.
 * Edenist ships with their fine control of gravity field generation can provide a sort of counter-acceleration force of up to a few gees, letting their crew perform better than Adamist ships at moderate acceleration but ultimately requiring the same sort of suspended animation devices to use excessive acceleration.
 * Used better than most in Alastair Reynolds' Redemption Ark as both a means of speeding up the usual slower-than-light starships (achieving this by accelerating at 1g for years at a time) and . Unfortunately for the crews, these inertial dampers effect all matter within the field - ship, crew, crew's blood - making it almost a requirement that ships either keep part of the ship outside the field for the crew to live in (under all 10 Gs worth of acceleration) or going the whole hog and putting everybody in cryostasis, though one character with full-body cybernetics is able to stay up and about.
 * Not to mention the fact that while the dampers were being developed it had a nasty habit of negating technicians' inertia and flinging them against the wall at kilometres per second. Nothing was left but the proverbial (and in this case literal) thin red paste covering the wall.
 * Also averted a lot in the RS novels: Boris is killed when the ship's thrust is put into reverse and he goes flying into the ceiling at 10G. Likewise Morwenna is turned into red jelly when Quaiche's ship races off under extreme acceleration. Ultra suits fill up with 'gel-air' to protect their occupants from vicious accelerations.
 * The fluid immersion type of damping is used in Ben Bova's novel Jupiter to counteract the planet's high gravity.
 * In the Halo novel Ghosts of Onyx this is actually a plot point at one point. Dr. Halsey takes and unconscious Kelly (a SPARTAN) and commandeers a ship for them. Unfortunately, Halsey does not have armor like Kelly and ends up nearly dying from the effects of their taking off since she didn't have time to reinstall the ship's inertia dampening system. Halsey is fine, but in rough shape for a while.
 * In Michael Crichton's Sphere (At least the book, possibly the movie too) the spaceship discovered at the bottom of the ocean features water-filled chair systems to help counteract high g-forces.
 * Justified Trope in Alan Dean Foster's Humanx Commonwealth series by the unique method of FTL propulsion. The ship generates an artificial gravity field ahead of it, to which the ship is then attracted. This motion pushes the field further in front of the ship, which pulls it forward, and so forth. (How this removes the problem of Newton's Third Law is left unstated.) Since this force acts equally on all parts of the ship, including the crew, there's no differential of acceleration and therefore no issue with G forces splattering everyone. A variant use of the drive provides the sensation of gravity so the crew can walk around, and combat vessels use a more sophisticated version of it to provide real Inertial Dampening for combat situations. When the drive is shut off or damaged, the ship and its crew are truly in free fall and normal rules of inertia apply.
 * Endymion plays with this in the most Squicky way possible. A ship is developed that can go at extreme speeds without the use of the, now lost, hyperspace gates. As a result the acceleration kills the pilot and copilot instantly then collects their liquefied remains in a little dish to be rebuilt later..
 * This is standard (and indeed essential) technology in the Perry Rhodan universe, where starships routinely feature acceleration rates of hundreds of kilometers per second squared (or in other words, tens of thousands of Gs). A portable device is installed on the protagonists' original rocketship as early as their impending return to Earth from the moon, in order to protect the ill alien scientist that they're also taking along.
 * In Sergey Lukyanenko's A Lord From Planet Earth trilogy, all Human Aliens (there are no Starfish Aliens in that universe) use black spheres of Applied Phlebotinum that absorb extra G-forces by increasing in density. The catch is the crew then has to spend weeks to months in higher-than-normal gravity, while the spheres "give back" the absorbed gravity (the "give back" is usually set to 1.5g). An alternative is to jettison the dense spheres. This is the last resort, as the spheres are expensive. Also, their gravity field can cause them to become a navigational hazard. A ship may have several dozen of these devices onboard.
 * This is Seeder technology, though, so nobody quite understands how it works. Of course, the Seeders are actually.
 * The Star Trek novel Federation, (Which was written well before First Contact) has Zefram Cochrane's first FTL trip taking the better part of a year, even though he only spent a few weeks actually going FTL, the rest of the time was used for accelerating and decelerating since inertial dampening hadn't been discovered yet. Upon returning to the solar system (specifically the moon Titan) he's told that the book's Big Bad has recently left Earth headed to Titan, and he has only 2-3 days to escape, which confuses him since, as he states, even using fluid tubes to cushion the inertia no human could survive the acceleration needed to make the trip that fast. Turns out the guy had stolen a ship equipped with the first prototype of an inertial dampening system.
 * On a later return to Earth, he rides in a hover limo with inertial dampeners, and later travels on a sublight spacecraft whose only means of propulsion is inertial control.


 * Any Iain Banks Sci-Fi book the rules of physics are always played straight. In the cases where the characters are Culture and they're travelling in a Mind-operated starship, especially in GSVs where there are so many layers of forcefields and acceleration adjustments for upcoming ships trying to reach them at great velocities that they don't actually have a physical hull. In the case of The Algebraist, where the societies were more primitive and didn't yet have this technology, there were special measures taken to protect any creature travelling at any acceleration rate, with at one point the main character having to be restrained and insulated when the ship he was in was travelling at 20+ Gs. Military spacecraft crew battle stations are in gel-filled gimballed spheres to best allow them to remain conscious and functional under rapidly fluctuating acceleration vectors.
 * Another example from The Algebraist is with the humanoid Divers who enter the inner layers of gas giants to converse with their denizens. They have to be completely encased and filled with a special gel-fluid within a specialised pod in order to survive the extreme gravity and environment changes.
 * In Harry Harrison's Alternate History novel Tunnel Through The Deeps (AKA A Transatlantic Tunnel, Hurrah!), Augustine Washington's helicopter is sabotaged, preventing him from getting from the Atlantic colony (US where the revolution failed) to the heart of the British Empire in time to meet the Queen. A man approaches him and offers to test a new method of rapid intercontinental travel. They submerge Washington (with a breathing apparatus) into a fluid-filled rocket that is launched in a ballistic trajectory, allowing him to safely get from America to Britain in a few hours. The best part is that all calculations were done using a mechanical computer.
 * This troper read a novel once, in which inertial absorbers allowed a ship to rapidly accelerate to near-light speeds without suffering the effects of Time Dilation.
 * Averted in CJ Cherryh's Alliance Union series. In addition to its primary purpose of traveling through hyperspace, a starship's FTL drive can be used to make instantaneous changes in velocity. Since this involves no acceleration, a starship can quickly achieve relativistic velocities without having to worry about inertia.
 * For all its hardness, Poul Anderson's Tau Zero does have inertial dampening technology. It only works when travelling very close to the speed of light, though, so the heroes' Ram Scoop has to accelerate at a measly 1g for the first year of its journey.
 * The "balanced drive" in Charles Sheffield's McAndrew stories uses a flat plate of superdense matter at the front of the ship, with the crew pod trailing behind at just the right distance so that acceleration g-forces in one direction and the plate's gravity in the other add up to a comfortable 1g. This would actually work, except for the slight engineering problems of making the superdense plate, keeping it compressed, and accelerating its huge mass.
 * Lacuna plays this straight with their gravity generating drives, which are also used as inertial dampeners in the ship. Strong movements can still be felt however.

Live Action TV
"Carter: Inertia dampers?
 * Star Trek, as usual, is one of the few Sci Fi settings to provide even a weak explanation. The IDF is tied in to the gravity generators, and applies a G-force opposite what the crew would feel, cancelling it out. The system takes inputs from the engines, so forces from acceleration are accounted for in real-time, but external forces can't be predicted, thus the Star Trek Shake. A similar system, the structural integrity field, is a Hand Wave on how such wimpy-looking structures hold up to the incredible forces involved; the ship is held up mostly by forcefields. One of the technical manuals comments that if the ships didn't have inertial damping, the crew would be instantly turned into chunky salsa when the ship accelerates.
 * Which was then demonstrated in an Expanded Universe novel - a 22nd-century ship was hit with a massive force that blew the dampeners and pulverized the entire crew (and any object not welded solidly to the bulkheads) into an organic paste about 1 inch thick.
 * Firefly offers a possibly non-canon explanation of its systems in the paper RPG sourcebook. Included is a unified generator system coupled directly to the reactor (back in the "bulb") that provides Artificial Gravity, nullifies the ship's weight, and absorbs the inertia of the crew. Also, there's a mass-neutralizing drive that serves as a slower-than-light warp engine.
 * It's assumed by some that the "Passive Laser Restraint System" on Knight Rider's KITT is some sort of system of this nature, but it remains unexplained.
 * In Stargate SG-1, when Carter and O'Neil prepare to test the X-302 fighter, they run through a checklist. The following exchange takes place.

O'Neil: Cool. And check.

Shortly thereafter:

O'Neil: Phasers?

Carter: Sorry, sir."

"Sheppard: "What you said was: 'Fire up the engines.' What you should have said was: 'Turn on the inertial dampers.'"
 * Also shown in Stargate Atlantis, when Shepard is in a dogfight IN SPACE with McKay onboard. After feeling the G's from a few hard turns, he asks 'I thought these things had inertial dampers on them'. Apparently they do, but considering how many sudden changes in acceleration are involved in dogfighting, it probably takes a bit to catch up.
 * There was also the time Sheppard intentionally accelerated a starship without the inertial dampers activated, because he was the only one who could fly the ship, but was being held hostage by people who wanted it. He was sitting down, but they were standing up, and were sent flying.

Everyone else: Oh Crap!"


 * The Puddle Jumpers are also 10,000 years old. It's possible the inertial dampers aren't at peak operating condition, probably having missed a few state inspections.
 * In the episode where O'Neill becomes a teenager (It Makes Sense in Context), he is scheduled to give Air Force pilots a presentation in dogfighting Goa'uld Death Gliders using F-302s. He points out that the inertial dampers only compensate about 90% of the acceleration during tight maneuvers, especially during a climb.
 * Andromeda has "GFG Lenses" (Gravity Field Generator) that reduce the ship's effective mass down to about 1 kg. This helps to explain the quick flip-abouts that the rather large Andromeda Ascendant seems capable of.
 * One episode has the Eureka Maru stuck in a mine shaft of sorts. They end up literally getting out and pushing the ship after reducing the ship's effective mass to almost nothing.
 * In a rare non-spaceship example from Doctor Who the brakes on the Doctor's Cool Car Bessie apparently work by "absorbing inertia, even yours."
 * UFO. The Little Green Men palor of the alien attackers is due to the green liquid filling their spacesuits, which cushions their bodies during months of faster-than-light travel.
 * Babylon 5 Minbari and Centauri combine this with (Reactionless Drive). Their gravitic drives move ships around without thrusters and generate artificial gravity and Inertial dampening while they are at it. Humans have to use rotating ship sections which make ship quite crumbersome and provide weak point to shoot at. Narn in the other hand just strap themselves on their cockpits.
 * The key reason Earth Alliance agrees to join the new Interstellar Alliance is the promise of this technology. As a result, new human ships are now much faster and much more maneuverable. In fact, the new Warlock-class destroyers (which use Artificial Gravity instead of rotating sections) are supposed to be a one-to-one match against the dreaded Minbari Sharlin-class warcruisers.

Tabletop Games

 * Averted in the roleplaying game Jovian Chronicles. Most ships in the setting are actually built with their decks vertically arranged so that the g-force of acceleration (or deceleration for the second half of the trip) simulates gravity. (not unlike Tintin (Comic Book)'s rocket)
 * Necron ships in Warhammer 40000 use inertialess drives. How they work is never really explained but they allow their ships to reach superluminar speeds without the use of warpdrives, apparently by enabling them to instantly and massively accelerate. Apparently the technology needed to build such engines is incredibly advanced and far beyond the reach of any of the other factions.
 * Gravitic Compensators in GURPS: Spaceships negate 99% of the force of acceleration, which is good for empires with extremely powerful engines because GURPS accounts for the effect of extreme changes in speed on characters.
 * The standard Ion Drive engines in Starfire can bring a ship from a dead stop to 1/10 of light speed instantly, and stop the ship again just as quickly. Presumably, they suspend the ship's inertia in a manner similar to the Inertialess Drive of the Lensman series, except that the ship and all aboard it still behave in an inertial manner while they're at speed.

Video Games

 * In Deus Ex, a prototype weapon has these as a safety feature. They are called "kinetic bleeders"
 * The Arwing fighters in the Star Fox series have "G-Diffusers". At one point in Star Fox 64's first mission, Falco's diffuser goes on the fritz, and he does indeed fly slower and take smoother turns for a while.
 * Actually that's their reactor systems.
 * Portal's heroine has these built into her legs, as a justification for her being completely immune to falling damage (which would be quite a pain in such a game).
 * In the computer game Anachronox, you can read a bit of background that talks about the discovery of Anachronox and when a ship entered into an area that sped them up to faster than light speeds and when they stopped at a point far across the galaxy, they would have been amazed, except for the fact that intertial dampers hadn't yet been invented and so they ended up as messy spots on the wall. The next ship to enter did have inertial dampers and was just fine.
 * The reason the pilot capsules in Eve Online are filled with liquid is partly because it reduces inertia and partly because it allows the pilot to better mindlink with the ship (as the capsule is essentially a sensoty deprivation tank).
 * One of many components in your fighter, in the Wing Commander series, that can fail as you take damage, though the games don't model any actual effects of its loss other than any collision being fatal. In the novels, it's noted to be fast, but not instantaneous.
 * In Sword of the Stars, the Liir use a specialized drive to prevent inertia -- since their ships are filled with liquid and are a lot heavier than those of land-based species, they use a drive called 'stutterwarp' that performs millions of short-range (in the range of millimetre-long) teleportations per second, slowly driving their ships in a direction without causing inertia.
 * Mass Effect avoids this trope handily. Using the eponymous technology, ships engines form a field that changes the mass of everything within it, allowing travel at light speed, while everything within stays still because of its relative mass within the field. Of course, this doesn't change what happens when a ship is struck by projectiles.
 * It should be pointed out that, in the case of dreadnoughts, the projectiles they fire have the kinetic force in the kiloton range (i.e. equivalent to a nuclear blast), while the people inside of the target ship, even if mass effect generators are off-line, get slightly buffeted to the side.
 * Presumably, AMS Compatibility in Armored Core 4/for Answer also directly influences tolerance to G-forces. That particular universe is filled with hyper-maneuverable Humongous Mecha that can hit upwards from 100 kph in an instant acceleration to any lateral direction, repeatedly.

Web Comics

 * Averted (and played for laughs) in Freefall.
 * Since Artificial Gravity is used for propulsion in Schlock Mercenary and ships routinely reach high fractions of c, it's explicitely said that gravity-based inertial dampening is its own field of engineering, "Inertiics", and that said engineers make a lot of money making sure that people aren't hurt or injured by unwanted acceleration. This field is so advanced that it is implemented in a limited form in powered armor (which compensate for an impact with a gravitational tug, as acceleration only kills you when applied unevenly). The narrator also notes at one point that, due to the staggering magnitude of the g-forces involved in ship movement, the last thing you ever want to hear your shipboard AI say is "brace for acceleration", as that is very likely to be the last thing you hear at all.

Real Life

 * In Real Life, high-speed trains such as Pendolinos damp out the centrifugal effect on curved sections of track by tilting the car bodies, thereby ensuring that passengers don't suffer from nausea. However, as British Rail learned with its failed APT project, if the damping effect is too good passengers can still feel nauseated because their eyes tell them they should be feeling a force and their bodies don't.
 * All fast corners on railways are banked (known as Cant in the UK or Superelevation elsewhere) to some extent for the same reason, and also to prevent rail and wheel wear from flange contact (the wheel profile is what steers a train, other than on very sharp corners the flanges should not touch the rails). The problem is as the banking is fixed, it must be a compromise so as not to discomfort passengers or cause inside flange contact on slow or stopped trains. The limit for normal lines is usually 6 inches, but dedicated high speed lines can be higher. The benefit of tilt is that it can vary with speed, and can allow up to 9 deg of additional banking at top speed.
 * Real Life: Beginning in the 1940s and 1950s, as aircraft performance improved, aircrew, especially fighter pilots, began to faint in the cockpit during particularly hard maneuvers. This is very bad, for obvious reasons. Aircrew were issued with special G-suits beginning in WWII; these take the form of trousers which inflate during hard maneuvers. This keeps blood in the upper body; that way, the pilots don't faint or lose too much peripheral vision. They must use special breathing techniques and undergo centrifuge training to be able to stand it, however. Early G-suits were water-inflated; later models switched to air inflation. The recent, famous Libelle suit, from a German firm, uses "passive fluid bladders" to cushion and protect the pilot, and by all means works very well. The name means "dragonfly" in German; the dragonfly is designed in much the same way. Liquid immersion has been tried in real life; a Dr. R. Flanagan Gray took a ride in a water-filled centrifuge capsule at one point, safely sustaining 31 Gs for several seconds. Another man, a Colonel John Stapp, volunteered as a human guinea pig, experiencing extreme decelerations during rocket-sled tests. Later, a Captain Eli Bleeding sustained 83 g for a brief instant...well, negative g, anyway. The research had civilian applications; it went a long way towards improving automobile safety. John Stapp was present when the act mandating the inclusion of seatbelts in all new US vehicles was signed into law by President Johnson.
 * The JU87 "Stuka" dive bombers when pulling out of a dive could produce high enough G force to cause the pilot to temporarily black out. For this reason, once the bomb was released, the pull out was automatic, the pilot regaining control once the plane was climbing on full throttle.
 * For that matter, the seatbelts in your car sort of qualify. After all, they're intended to protect you from forces which might otherwise turn you into chunky salsa, at least in some circumstances, no?
 * For one, they're built with some give to bleed off some of the inertia during sudden stops. Secondly, when worn properly, they concentrate the force over the hips and the entirety of the ribcage, two extremely hardy bits of human physiology. That's one of the reasons that children are encouraged to either not use the shoulder belt or else use a device which changes its angle. Otherwise, the strap goes across their neck and things can get messy during a crash.
 * Funnily enough, the hypothetical Alcubierre drive, which would get around the speed-of-light limit by essentially moving spacetime instead of the ship, sounds an awful lot like Star Trek's warp drive, but wouldn't require any inertia compensation while in use: since the ship isn't moving locally, everyone and everything on board remains in free-fall.