"The Cold Equations" is a Novelette by Tom Godwin, first published in Astounding Science Fiction in 1954, which has been done as a radio play for the X Minus One radio drama of the 1950s, an episode of The Twilight Zone (1985), and a 1996 made-for-TV movie for the Sci Fi Channel. Also, Stowaway (2021) is based on the same premise.
Barton, the pilot of an Emergency Dispatch Ship (EDS) dropped from the Hyperspace cruiser Stardust, discovers there's a stowaway on board, a young girl named Marilyn. His ship is taking a load of vaccines to the planet Woden, it has just enough precious fuel to make the deceleration and landing with no reserve, and if they don't land safely, a six-man survey team will die. The EDS is designed to already be as light as possible, and there is no way to reduce the weight of the ship to compensate for Marilyn's mass. Typical practice as required by regulations is to immediately jettison stowaways. However, the situation is complicated because Marilyn is an innocent who just wanted to see her brother (who is stationed on Woden) and didn't know that stowing away on an EDS would carry a penalty any worse than a stiff fine.
The cruiser informs Barton there is no way it can retrieve Marilyn (other lives depend on their strict timetable as well), and that there's no other ships in the area. He already knows there's no ships on Woden that can come out to meet him. There's nothing on the ship that isn't necessary and can be jettisoned. Marilyn can't land the ship by herself either as she's no pilot, so Barton can't sacrifice himself. Barton doesn't like the only choice available, and realizes that he's going to have to live with the thought of what he's going to have to do for the rest of his life.
Failing to reduce the ship's mass — by spacing Marilyn — will mean the ship will crash, and Barton, Marilyn and the survey team will die. Marilyn eventually accepts that there is no alternative. After calling her brother over the radio to say goodbye she walks willingly into the airlock, and Barton ejects her into space.
The point of the story is that in space, sometimes the cold equations leave no alternative, and balancing the equation means someone dies.
This story provides examples of:
- Always Save the Girl: The whole point of the story is to avert this trope. Marilyn can't be saved, neither a brilliant technical solution nor a noble self-sacrifice is possible. The only choice is whether to kill her, or to force Barton and the survey team to die along with her.
- Anthropic Principle: The premise of "The Cold Equations" is that a character finds himself in a situation where he has no choice but to Shoot the Dog. Thus, a requirement of the story is that it is set up such that there is no Third Option.
- Big Brother Worship: Marilyn's motive. She has a big brother who works out on the frontier, she only sees him once every few years, and so she saves up money and sneaks aboard a ship she thinks is on its way to where he is. The irony is that even if the Cold Equation hadn't been in play, the ship was on its way to a different survey team on an entirely different continent of Woden, not to where her brother was stationed.
- Cold Equation: This is the Trope Namer: the ship can handle X weight and has Y fuel and no amount of technobabble or heroic spirit is going to balance the equation when Marilyn is added in.
- Deconstruction: Of a type of Invincible Science Hero common in literature of the day. He'd get himself in trouble, then Techno Babble up a Deus ex Machina solution to the problem. Barton, placed in a similar scenario, tries his utmost to science up an answer, but the simple fact is the numbers don't work out that way. Marilyn has to die, and there's nothing he can do about it. Unsurprisingly, The Cold Equations ended up contributing to the death of the archetype it subverted.
- Didn't Think This Through: Apart from the factors that force Marilyn to be Thrown Out the Airlock, she doesn't consider that she might be easily discovered on a ship that small, that the ship might not be going to the part of the planet her brother is on, or how she'll get back.
- Downer Ending: There's no solution to the problem that does not result in Marilyn having to be executed. In fact, there's no explicit confirmation that Barton actually reaches his destination and delivers the vaccines, so the entire thing could end up being All for Nothing.
- Emotions vs. Stoicism: Explored. On Earth people have achieved sedentary comfort and can afford to indulge tawdry displays of emotion like Missing White Woman Syndrome. But out in the frontier where mankind is still exploring and conditions are much more hostile, only those who are or achieve the mindset of The Stoic survive long and those who make a living out on the frontier accept that there are certain... well, cold equations that cannot be bent or exempted because of sentiment. The reactions of Marilyn's family nicely highlight this: her parents, being from Earth, are predicted to hate Barton and not understand why he killed their daughter, while Marilyn's brother Gerry is contacted over the radio and, despite his horror, understands at once that Marilyn is doomed and that no one can save her.
- Explosive Decompression: Marilyn describes how people die this way in space, and is disturbed that her family will have that mental image of her demise.“I wish—” She swallowed. “The way I’ll die — I wish they wouldn’t ever think of that. I’ve read how people look who die in space — their insides all ruptured and exploded and their lungs out between their teeth and then, a few seconds later, they’re all dry and shapeless and horribly ugly. I don’t want them to ever think of me as something dead and horrible like that.”
- Face Death with Dignity: Marilyn is able to achieve this and by the end walks calmly into the airlock, having accepted her fate.
- Genius Thriller: Played with. Barton does everything he can to try to figure out how to save Marilyn with the resources he has on hand, but unfortunately the science facts are completely against him.
- Hard Truth Aesop: There are times when you must make sacrifices for the greater good, including letting a girl whose only crime was trespassing die.
- Also sometimes there will be truly absolutely no other choice you can make other then the one you are given regardless of how bad it may be or how much you don't want to do it. No matter how much you want to look for a better solution there isn't always going to be one.
- I Did What I Had to Do: Throwing the girl out the airlock is necessary to get the vaccines to the survey team. Barton doesn't want to do it but there is no other way.
- Informed Attribute: Many of the issues raised on the "Headscratchers" page boil down to the fact that the ship is stated to be a bare-bones emergency delivery vehicle, but has many features (an airlock, a closet big enough for a stowaway to hide in, a cabin big enough to walk around in) that might appear to be superfluous, and the story doesn't go into detail to explain them.
- Kill the Cutie: Marilyn is killed by necessity.
- Little Stowaway: Deconstructed. Marilyn is an eighteen year old girl who wants to join her brother in creating new space colonies. When the ship she's stationed on makes a stop by the planet he's on, she hides on the ship that's sent to land. The pilot is forced to send her out the airlock, because they don't have enough fuel to make it to their destination with an extra person on board.
- MacGuffin: The vaccines that Barton is delivering. They could be substituted with anything else that's necessary to save several lives, and the story wouldn't change.
- Men Are the Expendable Gender: A secondary theme of the story. Barton is fully prepared to jettison the stowaway before he realizes it's a girl, and he spends a fair bit of time afterward angsting about what he will have to do solely because of Marilyn's gender. He states flat-out that he would have no issue with jettisoning a male, regardless of their age or reasons or the promise they had ahead of them, but because Marilyn is not of the expendable gender he does everything in his power to spare her, and when he realizes he can't, he treats her graciously (gives her time to prepare, connects her with her brother so they can say goodbye) in a manner he certainly wouldn't have treated a male.
- Missing White Woman Syndrome: Barton notes that "On Earth [Marilyn's] plight would have filled the newscasts... Everyone, everywhere, would have known of Marilyn Lee Cross and no effort would have been spared to save her life." In space, however, there's no room for that kind of emotion.
- My Greatest Failure: It is implied at the end that Barton will be forever haunted by the events of this story.
- No OSHA Compliance:
- While the Rocket Equation does limit the amount of fuel to be used in the EDS, the idea that a futuristic space shuttle would have fewer fail-safes or backups than a 20th century airplane (modern aircraft are always given a large enough fuel supply that, even if there's a delay due to weather or problems at the landing site, they can typically circle the runway for several minutes, or possibly even hours, regardless of the distance of the trip) is more than a little strange. Either the OSHA does not exist in the future, or someone decided that a shuttle that can literally hold only one person and a small amount of cargo, and just barely enough fuel to get them from point A to point B, is a good idea, something that in the 20th and 21st century would never leave the design phase. Possibly justified in that it's stated the EDS is a small emergency vehicle meant to be disposable, not intended for regular passenger service. note
- It's mentioned that rocket fuel takes up a lot of space on the cruisers, that they can only carry a limited amount, and that they have to ration precisely in order to reserve it for future emergencies, so the lack of a fuel reserve on the EDS is perhaps justified. Of course, this still doesn't excuse the total lack of a preflight inspection (as even the most cursory one would still have found the girl before takeoff), so OSHA still has lots of citations to hand out here. note
- Poor Communication Kills: Civilians apparently aren't made aware of the reason sneaking aboard a ship is punished with being put into space and the only caution Marilyn is given is a big UNAUTHORIZED PERSONNEL KEEP OUT! sign. Spelling out for civilians why they are to keep out probably would have saved Marilyn's life.
- Replacement Goldfish: Marilyn recalls that when she was six years old her kitten Flossy was killed by a car, and her brother Gerry told her that Flossy had only gone away for the night to grow a new fur coat and would be back in the morning. She believed the story and accepted the kitten that appeared the next day as her own, but would find out years later that Gerry had woken up the owner of the local pet store at four in the morning and strongarmed him into selling him a kitten that resembled the one that had died.
- Science Hero: A deliberate aversion — no-one pulls a technological Ass Pull to save the girl.
- Settling the Frontier: Gerry Cross and the other members of the survey team Barton is on his way to save are doing this, and in keeping with the trope's description, the dangers colonists face out on the frontier are fierce.
- Shoot the Dog: Either Barton spaces Marilyn, or she dies anyway, along with him and six other people. He spaces her.
- Swiss-Cheese Security: When Marilyn is asked how she boarded the ship, she says, “I just sort of walked in when no one was looking my way." The whole situation could have been avoided by a 30-second pre-launch check. Or, you know, maybe a lock on the door?
- Take a Third Option: The fact that there isn't one is the entire point. The story was written to be a subversion of early 1950s Science Fiction and its omnipotent men of SCIENCE! optimism.
- Thrown Out the Airlock: The only option in the end is to space Marilyn.
- Too Good for This Sinful Earth: Every quality about Marilyn note and every word she speaks is meant to evoke reader sympathy for her. She didn't sneak aboard the EDS for nefarious reasons, she just wanted to see her brother who is providing for her family with his high-paying job on the frontier. She's not a spoiled rich girl who thinks she can buy her way out of trouble, she's a hardworking girl from a poor family who saved up because she thought she would just get in trouble and have a fine to pay. She even offers to work and cook once they get to Woden for her upkeep.
- Zeerust: The EDS navigates by receiving trajectory calculations from the cruiser's computers... which would have been perfectly plausible if they were still using computers from the 1950's. Even the Apollo lunar landers (which started flying less than two decades after this story was published) had their own onboard guidance computers.