Cold Equations run in Literature.
- The Trope Namer is of course The Cold Equations, the classic 1954 sci-fi short by Tom Godwin famous for averting the Always Save the Girl trope. A young girl stows away on an emergency rocket carrying vital vaccines to an exploration outpost, not knowing that its fuel has been precisely calculated and her extra weight is enough to cause disaster.
- In Black Man, a Super-Soldier has smuggled himself on board a spacecraft travelling from Mars to Earth. However Cryonics Failure means he wakes up too early. Because he can't call for a rescue without abandoning his mission, his only recourse is to thaw and eat the other passengers. Unsurprisingly he's got a major screw loose by the time he gets to Earth.
- A non-space example shows up in The Book of Questions, a book with scenarios with no clear-cut answer intended to provoke thought. It involves getting trapped in a cave-in with another miner. You have a gun with two bullets and sleeping pills. You know that there is only enough air for one sleeping person to survive for six hours and it's likely to take at least six for the rescuers to reach you. After agreeing to that conclusion, the other miner takes the sleeping pills, hands you the gun, and says it's your decision.
- Arthur C. Clarke's excellent short story "Breaking Strain" is about a two-man spaceship that (after a micrometeor strike) has only enough oxygen for one of them to survive the trip. It follows one of the characters' thoughts as he becomes more and more tempted to murder his companion and save himself. It has two different Adaptation Expansions: the novel Venus Prime 1: Breaking Strain, in which the story's aftermath is investigated, and the film Trapped in Space (which expands the crew to six people and has a more And Then There Were None kind of plot with successive murders).
- The Cthulhu Mythos short story The Preserved Ones by Christopher Geeson has the nuclear bunker version. When the remaining survivors emerge they discover Earth has been taken over by the Mi-Go, and having already crossed the moral horizon with this trope, find it easy to justify becoming Les Collaborateurs in a Vichy Earth as just another necessary evil to survive.
- In The Dark Forest, following a Curb-Stomp Battle in which a single alien probe wipes out most of the human space fleet, two small groups of ships survive: the "Starship Earth", consisting of the Ultimate Law, Natural Selection, Blue Space, Deep Space and Enterprise, and the Bronze Age and the Quantum going off in a different direction. Both groups run the numbers and find that they do not have enough fuel to get to another system alone, nor are they able to effectively transfer people to one ship, but there are enough supplies within the fleets to get one ship out of the system. The resultant engagements, which feature heavy use of infrasonic H-bombs in order to kill crews without damaging supplies, are referred to as "Battles of Darkness", and kill thousands of people. To be fair to the crew of the Blue Space, the victor of the "Starship Earth" incident, they did at least hold a funeral ceremony for the casualties on the other four ships. In a broader sense, this is also the nature of interspecies relations for most of the galaxy: due to the difficulty of establishing trust, and the finite resources of the universe, pretty much all surviving species have concluded that every other species is by definition taking up resources they could use and are likely to be a threat, typically leading directly to "dark forest strikes": system kills.
- Discworld:
- Snuff all but invoked the trope name with the concept of the "dreadful algebra" of survival. When faced with lean times, a goblin mother will eat her child. Their religion involves the construction of pots to store certain bodily excretions, and the most precious of these is the jar in which a goblin mother will place the soul of her devoured child, to be reborn when food is more plentiful.
- The Last Hero references this when the crew aboard a makeshift spaceship note that there isn't as much oxygen as there should be. Food shows up missing, and they briefly theorize that they have picked up an alien intruder, in a shout-out to Alien. Turns out it's the Librarian, who stowed away before takeoff. Luckily, Discworld's moon has breathable air, so they are able to land there and refill.
- The Dragonriders of Pern story "Rescue Run" had this problem turn up when the rescued colonists try to smuggle in several hundred kilos of precious metals (which turned out to be less valuable than the homemade medicines and seeds they packed legitimately), throwing the mass calculations off. Instead of spacing people, the crew spaces the metal, along with some furniture.(bending one of the retrieved platinum plates) "Individually, these don't weigh very much, but they damn near coated the ship with them. Ingenious."
- In Down to a Sunless Sea by David Graham, at one point the narrator's Boeing and his new girlfriend's Antonov are fleeing to Antarctica to escape the nuclear devastation of the entire civilised world. Unfortunately, they run into heavy clouds which are lethally contaminated with fallout, and the Antonov doesn't have the fuel to make the trip at the higher altitude required to clear the fallout. So the Russian co-pilot calls for volunteers and opens the Anti's cargo doors, and leads a procession of about one-third of the passengers on the long drop into oblivion. In some editions of the book, it turns out that they were the lucky ones when all was said and done.
- In Dune Messiah it is Fremen tradition that blind men must leave the tribe go to the desert in self exile, and probably get eaten by a Sand Worm. Paul ends up blinded and must do the same to ensure the Fremen would be loyal to his children Leto II and Ghanima.
- Flashman at the Charge. Flashman and Scud East are in a horse-drawn sled being pursued by Russian Cossacks, and have to Bring News Back of a Russian plan to invade India. So Flashman decides it's time for an Emergency Cargo Dump. Amoral bastard that he is, instead of making a Heroic Sacrifice Flashman throws overboard a Russian princess they're carrying. He then suffers Laser-Guided Karma when the sledge crashes, pinning him beneath it, and Scud decides to leave him to his fate under the same trope.
- In Gone, Astrid debates whether or not killing Little Pete is worth it if it ends the FAYZ. She kills him in Plague.
- In the Heechee Saga book Gateway, it's one of the many occupational hazards of space travel when all your ships are alien craft with preset trips of unknown length. The ship will go somewhere, but there's no telling where, or how long it will take until the ship starts decelerating, meaning you damn well better have enough supplies to last the trip. If you haven't reached the midway point of the outbound voyage by the time a quarter of your food is gone, you draw straws... loser goes into the fridge. At least a couple of trips return with nothing aboard but corpses. The protagonist Robinette Broadhead also finds himself in an accidental version when a two-ship expedition is trapped by a black hole; one ship has to be flung into the black hole to provide the boost for the other ship to escape. He suffers Survivor Guilt when his ship survives at the cost of his companions when he had been trying to sacrifice himself.
- Judge Dee: In The Willow Pattern, the Judge is running the capital due to a plague shutting down the government. There's also a famine, so he has the grain warehouses under military guard to prevent looting. The Heat Wave doesn't help, and a riot is preventing by the soldiers firing into the crowd, killing thirty people.'By shooting those thirty men,' Judge Dee said gravely, 'you saved uncounted thousands of citizens from starvation. If the mob had succeeded in plundering and burning the Granary, a few hundred people would have eaten their fill tonight, but that would have been all. If doled out in the regular rations, on the other hand, the stores will supply the population of the entire city with their basic food for at least another month. It was not a pleasant duty, but it couldn't be helped.'
- The Langoliers: Eventually, the characters figure out how to get out of being trapped in the past - fly through the time rift backwards. However, they have two problems. First, the titular Langoliers (who eat the past) are actively trying to stop the plane, and second, they must be asleep to survive going through. The solution to the first problem involves throwing a passenger out as a distraction to the Langoliers, and the second, by lowering the cabin pressure to knock them all unconscious, for which someone must be awake to restore it so they'll wake up on the other side. The first victim chosen is Craig Toomy, who's been having a violent breakdown throughout the novel, and the second is Nick, who volunteers in order to atone for accidentally killing children.
- Averted in a short story by Lino Aldani. A ship is stranded on Titan, one of Saturn's moons, and can't return to Earth because of sixty-two kilograms overweight. The crew can't leave their cargo (it's an important cure for an epidemic back on earth), but they consider a lot of different options... In the end, every member of the crew got one arm amputated, so No One Gets Left Behind.
- The Martian. Johannsen tells her father that the crew of Hermes have made a secret pact that if their food resupply mission goes wrong, the others will commit suicide straight away. Johannsen, who is the youngest and smallest crewmember, will then have the maximum amount of food for the return journey to Earth. But that still won't be enough to survive, so she'll be required to eat the bodies of her crewmates.
- Stanisław Lem played with this scenario in Moon night. And an entirely sensible punchline turned it into great Black Comedy.
- On the Edge of Gone functions on a deconstruction of the Cold Equation, as a comet is about to hit Earth and only a limited number of people can leave in space ships, so only the most fit and useful are allowed on the ships. Then the comet actually hits, and most of their initial assumptions of who will or won't be useful fall apart. As well as their assumption that they have to leave Earth behind at all.
- Oxygen by John B. Olson and Randall S. Ingermanson. A bomb explodes on a NASA spaceship heading for Mars, leading to the venting of much of their oxygen supply. The crew might survive if all but one of them are placed in a drugged coma. The question is: can you trust that one person who's going to be conscious?
- Jack McDevitt's Priscilla Hutchins series has a couple of examples:
- In The Engines of God, Hutch is piloting a spaceship which crashes into a Big Dumb Object, shutting down their fusion engine. The spaceship starts to lose heat (so much that it starts snowing inside) and the oxygen pumps fail, leaving them with only a week's worth of air in the shuttle and the nearest rescue ship ten days away. A Lottery of Doom is half-heartedly suggested, but Hutch tells everyone to sleep on it, then sneaks out with the intention of committing suicide (as pilot it's her responsibility to ensure the safety of the others). At the last moment Hutch realises all they have to do is melt the 'snow' (actually frozen atmosphere) to get the needed oxygen. Later on another pilot is looking at his shuttle — named after a pilot who famously performed a similar sacrifice — and bemoans the fact that such exciting heroics don't happen now that spaceflight has become routine and safe.
- In Chindi, Hutch is piloting a ship being sent for standby duty at a research station near an unstable star. When she's nearly there, she realizes that the list of Academy personnel on the station includes a teacher, which suggests that the researchers may have their families there—but due to a bureaucratic snafu, her ship is only large enough to carry the listed personnel! At which point, an EM pulse from the star fries everyone's communications systems, and the explosion that caused the pulse looks like it will destroy the station. A number of researchers volunteer to go down with the station, so that others might live, but fortunately, someone back home noticed the snafu, and when communications go out, hurriedly redirects another ship, which arrives just in the nick of time.
- In Scavenger Alliance, Scavenger Blood reveals Cage and his followers' plan to escape the coming firestorm: to leave behind "burdens" like the sick, injured, elderly and small children, allowing them to move faster and saving all the supplies for themselves. They also plan to kill any of the able-bodied who aren't on board. The fact that Hannah is on board with this is the final straw that pushes Blaze to lock her away with the others.
- Subverted in The Seventh Tower, when Tal accidentally seals himself and Crow into a corner by producing a shield of solid magic to protect them from a spiritshadow. Tal accidentally makes the shield airtight and he can't dispell it. Tal considers killing Crow (and Crow is clearly considering killing Tal) but both decide it was better to to try to wait out the spell than to take the selfish way out.
- A Song of Ice and Fire, among the families of the North, in the continent of Westeros, it is common during winters—which can span decades—for old men to announce they are "going hunting" and leave their homes so so as to leave a little more food for the young. In times of war, instead of "going hunting", the old men enlist in join the armies in order to die in battle.
- In Peter David's Star Trek: New Frontier novel, "Stone and Anvil", Mackenzie Calhoun, a former teenage warlord now on the Command path in Starfleet Academy, creates an unusual solution to the Kobayashi Maru test — firing on the Maru's leaking engines, with the resulting blast destroying two Romulan Warbirds and allowing him to retreat, thus 'beating' the scenario. When debriefed by the scenario proctors, one of them mentions it was an acceptable albeit unorthodox solution, stating that sometimes a Starship captain has to make very hard choices. Brutal choices dictated by the cold equations of space.
- Subverted in Starquake, the sequel to Dragon's Egg. When the crew of a starship discover they'll be stuck in orbit for six months, with an insufficient food supply, The Spock of the group calculates that they'll need to kill and eat two crewmembers to survive. Then she points out that they'd never feel at ease again among humans if they did, and suggests they Face Death with Dignity instead. They are later rescued by the Cheela, who are by then a Higher-Tech Species with few of the Terrans' limitations.
- Watership Down
- Cowslip's warren is—unknown to the rabbit protagonists who've just arrived there—a free-range rabbit farm with willing inmates. The farmer puts out food and kills any rabbit predators, enabling the rabbits to live easy lives with the occasional loss from a snare or two. When Hazel, Fiver and the others turn up, they quickly decide to invite the strangers to join their warren without warning them of the danger.Fiver: Don't you see? The farmer only sets so many snares at a time and if one rabbit dies, the others will live that much longer.
- Not that the main characters don't think this way at times. During the raid on Nuthanger Farm, the domesticated hutch rabbits freeze up once they're out in the open, with the farm cat prowling about and the dog barking at them, so Bigwig suggests leaving them behind if needed."If it comes to the worst," said Bigwig, "we can leave the hutch rabbits and bolt. Elil take the hindmost, don't they? I know it's tough, but if there's real trouble we ought to save our own rabbits first. Let's hope that doesn't happen, though."
- Cowslip's warren is—unknown to the rabbit protagonists who've just arrived there—a free-range rabbit farm with willing inmates. The farmer puts out food and kills any rabbit predators, enabling the rabbits to live easy lives with the occasional loss from a snare or two. When Hazel, Fiver and the others turn up, they quickly decide to invite the strangers to join their warren without warning them of the danger.
- The Redeker Plan in World War Z was a strategy used in the zombie war, which involved isolating smaller though well supplied groups of survivors in such a way that the undead would converge on them, ultimately dooming them. This would have the effect of distracting the hordes away from the larger populations (giving them time to regroup and prepare for an attack themselves), and perhaps even reducing their numbers in the process.
- Xandri Corelel: During the Second Zechak War, the Zechak took over Halcyon, a mining planet in a strategic location, and filled it with slaves so they could manufacture powerful weapons. The Starsystems Alliance tried to take the planet back, but the Zechak easily defeated their armies. Fearing that the Alliance's planets might be invaded if the Zechak kept Halcyon, Admiral losTavina ordered the surface of the planet destroyed, making it useless to the Zechak, but also wiping out millions of innocent slaves.