Silent Running Mode

But only whiffs of paraffin
Or creamy rings that fizz and fade
Show where the one-eyed Death has been

That is the custom of "The Trade."

—The Trade by Rudyard Kipling

Sometimes the only way to survive against the enemy's ships is to be stealthy. In this situation, the ship and crew tries to be as quiet as possible, knowing that the slightest sound and/or energy reading could be picked up by the enemy's sensors and draw their fire. This often involves deactivating all non-essential systems on the ship for awhile.

This trope is almost invariably featured in a Sub Story. This trope has also been Recycled in Space, and many a Cool Ship has been called upon to do submarine-style silent running. Often this depends on the unrealistic conviction that there is sound in space, but it could be denoted as minimizing heat discharge or something similar to prevent detection by sensors. Not to be confused with the film Silent Running.

Examples of Silent Running Mode include:

Film

• Das Boot
• Down Periscope both plays this straight and subverts this trope at different points in the movie, including the time that an all-hands singalong to "Louie Louie" is a vital part of their disguise. This might be a reference to the The Hunt for Red October example below.
• In movie version of The Hunt for Red October, they switch on the silent propulsion system and the crew start singing the Soviet National Anthem. One of the crew worries that they'll be heard. Ramius says to let them sing.

Jonesy (on the USS Dallas): The Russian disappeared. One minute he was steady 4000 yards off the bow and....then he was gone. And for a second, I thought I heard.....
Capt. Mancuso: Heard...what?
Jonesy: I thought I heard singing, sir.
Capt. Mancuso: Singing?
Jonesy: ...Yes, sir.

• The Matrix, when the Nebuchadnezzar has a close call with the sentinels.
• Star Wars: Han's whole Cling-to-the-star-destroyer-and-drift-away thing in The Empire Strikes Back counts, and if not, several times in the Expanded Universe (Thrawn trilogy?)
• The Wrath of Khan used the nebula as a variant. It worked by having the radiation emitted by it scrambling the sensors of both ships.
  • Also The Undiscovered Country which has a Klingon Bird of Prey that can fire while cloaked - Uhura even says something to the effect of "if they're here, they're rigged for silent running."
• "Hide and seek" in The Last Starfighter.
• Wing Commander: Numerous examples, ranging from individual fighters to an entire fleet of ships, using the "energy and heat signatures" version of the trope. For best effect, they typically attempted to conceal themselves in the clutter of an asteroid or debris field, or in the case of the fleet, by putting themselves in low orbit over a planet. At one point, the heroes' Battle Star is attempting to lay low inside of an asteroid's crater, while the Kilrathi methodically drop warheads into each crater trying to find the one the Terrans are sheltering in.
  • They also assume that Space Is Noisy, so everyone must stay quiet and whisper lest the enemy ships hear them.
• Done twice in Master and Commander. First, Captain Aubrey has his men tow a crippled HMS Surprise into the fog to avoid further bombardment by the French frigate, the Acheron. Then later when the Acheron sneaks up on the Surprise again, Captain Aubrey uses a decoy to distract his opponents and keeps the lights of the stern at the Surprise well doused, all the while running a course east in order to bring the ship on the Acheron's tail the very next morning.

Literature

• Referenced in The Areas of My Expertise in a table of short words and abbreviations used by submariners to conserve oxygen. It contains the term "SR" for Silent Running mode. It claims that the term comes from the movie Silent Running, because it is the sub-mariners' favorite movie.
• Yep, The Thrawn Trilogy. Kaarde starts out Dark Force Rising hiding on an asteroid, passive-scanning Myrkr being taken over by the Empire. He only gets caught because Thrawn knows Kaarde is exactly the sort of person to do that, and he only escapes because his Force-sensitive copilot turned everything back on before Thrawn's Interdictor Cruisers finished generating a gravity well trap.
• One of the common concepts of the tactics used in the Honor Harrington books is that the spaceships used in the battles are virtually invisible when the "wedges" that normally propel them are powered down, and the rare obedience to physics means that a powered-down ship is not motionless and can coast on a ballistic course with virtually no chance of detection. They're almost incapable of maneuvering, though. Honor uses this trick, along with a ridiculous amount of luck, to get the drop on a Havenite fleet guarding the Cerberus system, from which she and a few hundred thousand POWs and Peep political prisoners are attempting to escape.
  • Specifically, a ship without its wedge powered is invisible to gravitic sensors; it continues to emit everything else (heat, EM, etc) as normal, and still presents a perfect target for radar and laser systems. However, lots of commanders in the Honorverse don't bother with anything but the gravitics, since gravitics operate at FTL speeds as opposed to light-speed EM-based methods, and it's assumed that any ship attempting aggressive action will have to have its wedge running. Basically, Honor's entire plan hinged on the Peeps being terminally lazy and failing to check their EM sensors. In a later novel, she and Michelle Henke hung a giant pair of fuzzy dice on the tactic for the benefit of a gaggle of hero-worshiping midshipmen, dissecting all of the myriad ways the Peeps could have spotted Honor coming light minutes away and turned her entire fleet into space junk with a single salvo. Paraphrased below:

Michelle Henke: Dame Honor's tactic may not have been the single most outrageous, gutsiest, all-or-nothing, do-or-die throw of the dice in the history of the Royal Manticoran Navy. If it wasn't, however, I cannot imagine the action that was.

• In Stephen Baxter's novel Exultant, when an asteroid base goes into steatlh mode, everyone around the base is quiet. One character points out that there's no reason for this, but another responds that it's purely psychological—being quiet helps everyone feel that they're being stealthy.
• World War Z. Attempted during a battle between two Chinese submarines. Underwater zombies mess it up.
• Given that Glen Cook's Passage at Arms is basically a Sci-Fi retelling of Das Boot, it's not surprising at all that it has this trope up the wazoo. Cook even invents a special spaceship type for this, a so-called "climber", that "climbs" into the higher levels of hyperspace inaccessible to other types of ships. In his typical Shown Their Work fashion he amply lampshades that the main problem for such ships is overheating.

Live Action TV

• The Star Trek: The Original Series episode "Balance of Terror." A virtual remake of the 1957 film The Enemy Below.
  • Martian Successor Nadesico has its own "Balance/Enemy Below" episode that reference both the original and the remake. It was also a bit silly.
  • The Star Trek: The Next Generation episode "Face of the Enemy" specifies that a Romulan ship's systems have to be perfectly balanced and calibrated in order for its cloaking device to work; this was exploited when a Federation sympathiser created an engine imbalance to 'poke a hole' in the cloak and allow Enterprise to detect it.
    • In Star Trek: Deep Space Nine, the show's main Cool Ship, the Defiant, had a cloaking device. Since in the earlier seasons the Big Bad Dominion had weaponry that could easily destroy Federation starships, the Defiant's only real defence upon being approached by a Jem'Hadar ship was to cloak, go to Silent Running Mode and pray they weren't noticed.
• The only time anyone was able to destroy a minbari battleship in Babylon 5, Captain Sherridan was hiding his light cruiser in an asteroid field. He then had the nuclear warheads on board modified into mines, while the battleship kept searching for them. The human ship then send out a distress call, which immediately gave away their position and had the minbari chase right after them.
• The pilot episode of Firefly, where the characters had to do this against both the Alliance and the Reavers, the former to keep from getting boarded and searched, and the latter to keep from getting raped to death, their flesh eaten and their skins sewn to the Reavers' clothing. And if they're very, very lucky, it'll happen in that order.
  • Likewise when rescuing the Captain from Niska's space station.
• Airwolf liked to do this all the time. Well, not literally all the time, because then they wouldn't get to draw attention to it, but that switch was flipped fairly often.
  • One episode involved a group of criminals infiltrating a base in a helicopter (a normal one). They did this by shutting off the engine just before getting close, letting the inertia of the spinning rotor land them safely without making much noise.
• Ditto Blue Thunder, the other show about a super-advanced helicopter.
  • Also an important aspect of the movie on which the series was based.
• Red Dwarf did a version of it, when every system aboard Starbug but for the bare minimum needed to survive was switched off in an attempt to hide from a simulant's scanners. Their cover was blown when a robot (who was the robot equivalent to an alcoholic) bumped into a control panel, turning some of the ship's electronics back on.
  • An earlier episode establishes the concept when hiding from simulants, though the AR machine prevents it.
• Mildly invoked in the episode "Justice" from Smallville. While infiltrating a Lex Corp complex, Green Arrow turns off his communication feed with Watchtower by saying, "Switching to silent running." Presumably, this is so he can plant explosives throughout the complex without having to listen to potential objections from Chloe.
• A rare version from the Age of Sail. In the Horatio Hornblower TV series, Hornblower manages to sail his tiny cutter into the middle of the Spanish fleet in some fog. They try Dressing as the Enemy and being very quiet. It doesn't work.
  • Truth in Television: Horatio Nelson did something similar. It worked for him.

Western Animation

• Futurama: "Nobody make a smell!"
• In the Space Ghost Coast to Coast episode "Flipmode", Space Ghost is putting on a murder mystery dinner set in a submarine. At one point (high on natural gas) he yells, "We're in silent running here. Moltar, we are in silent running! (louder) Do you understand the concept of silent running?!"

Tabletop Games

• Rogue Trader has Silent Running - it's not foolproof, but the other ships need to succeed on a search attempt, and it's much harder for Space Mines to notice silent ships. There are active stealth systems, but they give bonuses for Silent Running rather than replace it. Since silent running involves shutting down non-essential systems, it reduces cruising speed, makes ship actions that require a roll harder to perform and on each manoeuvre a helmsman must pass a test (which depends on manoeuvrability, thus it's much easier to do on a frigate than on a battleship) to avoid giving away the ship's presence. Certain activities (like firing ship-scale weapons, or sensor jamming) are inherently not "silent", of course. As with anything, there are systems that improve performance, including drives made for silent running; naturally, modifications used by Space Pirates have similar effect. There's an expensive passive sensor suite allowing to use Detection without penalty, while the Stryxis have sensors that operate on principles other than EM and can be used normally in Silent Running. Conversely, the Rak'Gol ships use badly shielded fission drives that are hard to hide, while the Orks (except the Blood Axes who learned from de Humies too much) are not into subtlety, so they have a minor penalty; certain Human ships are not made for this, too. "Disengage" action consists of running out of the enemy sensor range, then drifting away in silent running.

Video Games

• Possible, but rarely used in Mechwarrior 4. Mechs could shut down completely to remove themselves from electronic detection. This wouldn't make you invisible, but a good observation point could let you set up an ambush.
• In the Fallout series of games there is a perk named silent running that takes the phrase much more literally.
• Included in the Silent Hunter Series, and frequently necessary for survival.
• All Stealth-Based Missions involve this in Nexus the Jupiter Incident.
  • Ditto for Star Trek: Bridge Commander.
• Shattered Horizon allows players to switch off the non-essential systems of their suits to avoid giving off light, showing up on radar, or being affected by EMP grenades. However, doing so disables the suit's thrusters, HUD, and audio simulation, so if you're spotted you're pretty much a sitting duck until you can get it switched back on.
• The Normandy of Mass Effect can briefly use one of these.

Real Life

• Submarines—all (or nearly all) are designed to be as silent as possible.
  • Interestingly, diesel subs are in general much quieter than nuclear boats. That's because on the nuclear sub the reactor cooling must be on all the time, lest it suffers a meltdown, and cooling pumps tend to be quite loud. Also, being a large and heavy contraptions, they are exceedingly difficult to completely isolate from the hull. Even with the newest reactor designs, where the cooling could be driven by the natural convection on the low power settings, the rush of coolant itself through the tubes creates a fairly loud hum, and the reactor is even more difficult to completely soundproof. Diesel subs, on the contrary, can turn off virtually all their systems in a silent mode, the batteries or fuel elements are intrinsically silent, and electric motors on the low power produce virtually no noise. So the loudest sounds on a diesel sub would probably be from the crew moving around.
• See this article. It was and to a lesser degree still is possible to move a whole strike fleet very close to the target if it doesn't give away itself. By the same token, planes may be run into an ambush where the first sign of a missile ship they see is a radar suddenly locking them from below.
• In the Sixties the CIA realised they needed a stealth helicopter for infiltrating countries like North Korea. Although realising a completely silent helicopter was impractical, they took a standard Huey and worked on reducing the noise signature of each component—modifications included replacing analogue components with early electronics and adding an extra rotorblade. Eventually they came up with an aircraft that when flown at a particular speed, along with nap-of-the-earth flying, was unlikely to be detected unless you were specifically listening for it.
• During World War II, the Soviet Union organized "night bomber" regiments. In addition to flying when they'd be hard to see, they often switched their engines to idle and glided in over their targets, so the only sound of their approach was air hissing over their wings and fuselages. One such regiment had all-female flight crews, and the Germans they were attacking called them Nachthexen -- Night Witches.