A 2021 science fiction / drama film directed by Joe Penna, starring Anna Kendrick, Daniel Dae Kim, Shamier Anderson, and Toni Collette. The story is loosely based on The Cold Equations.
The crew of three people, Commander Marina Barnett (Collette), physician Zoe Levenson (Kendrick), and botanist David Kim (Kim), embark on a journey to Mars. Soon after liftoff, they find an injured ground personnel, Michael Adams (Anderson), behind one of the service panels. It turns out that he was accidentally locked in there during liftoff. What is worse, the incident damages the carbon-dioxide scrubbing system (CDRU), meaning that they do not have enough oxygen for the whole two-year trip. After consulting with mission control, it looks like there is no safe way to keep everyone alive.
Stowaway provides examples of:
- 20 Minutes into the Future: Mars missions have been going on for at least a decade by the time the film is set, but (Artistic License aside) there is nothing that would not be possible with current technology.
- Accidental Astronaut: The plot revolves around a technician who is stuck behind a service panel of the spacecraft and is accidentally launched into space.
- Artistic License – Physics: The creators have gone a long way to do the science right as much as possible, but at times, Rule of Cool or Rule of Drama overrides scientific accuracy.
- There is a comment that if they had enough spare oxygen, they could just vent out excess carbon-dioxide. In reality, that's not that simple; you need carbon-dioxide filters even if you have a lot of excess oxygen around.
- When Zoe loses her grip on the tether line and uses her hands and feet to try to slow herself down, friction should have punctured her spacesuit. Instead, she only suffers a slightly harder-than-optimal landing and losing the oxygen canister.
- Liquid oxygen requires extremely low temperatures to store. Any remaining oxygen in the booster should have boiled away by the time they try to retrieve it.
- The dropped oxygen canister is shown moving relatively straight "down" from the ship's frame of reference, but moving quite rapidly against the starfield, staying "in sync" with the spinning ship. In reality, relative to the stars it would simply continue in the direction it was traveling when it left the spinning tether system, and would not move perpendicularly against the background. From the still-spinning ship's frame of reference, it would look like it was curving away from the characters, as they continue spinning while the object does not.
- The direction of movement of the starfield isn't consistent between shots from different angles, and some shots show the starfield behind the characters spinning as if they were rotating around their habitat module "below" them, rather than a central point "above" them.
- Artistic License – Engineering:
- The ship has only one carbon scrubber system. In comparison, the Apollo program had two systems - one for the command module and one for the lander, as famously pointed out in Apollo 13 - with backup parts for each, and those were for only a few days' use. Multiple levels of redundancy and alternate methods should have been built in for a trip intended to spend a whole year between planets. The lack of sufficient backup oxygen is partly justified by the penny-pinching corporate decisions alluded to as well as the extra man, but the nonexistent systems redundancy still seems unbelievable by current spaceflight standards.
- Bittersweet Ending: Michael survives, but Zoe dies.
- Black Dude Dies First: This is one of the main questions of the film, as "black dude" Michael is the stowaway putting a strain on the life support system, as well as being completely untrained for space operations. They come very close to demanding that he kill himself, but it's ultimately subverted when Zoe sacrifices herself to save him and the rest of her crew.
- Centrifugal Gravity: The spaceship spins connected by a tether to a counterweight. In a clever idea, the counterweight is the spent booster.
- Chekhov's Gun: Using a spent booster for Centrifugal Gravity is a neat idea, right? It also provides a convenient way to have some difficult-to-access oxygen supply when they need it later.
- Cold Equation: Not surprisingly, as the story is based on the Trope Namer. The plot revolves around not having enough oxygen for the entire crew to survive the trip.
- Danger Deadpan: As astronauts, one would expect this from the crew. However, by the end, even the commander loses her composure.
- Dramatic Space Drifting: When Zoe loses the oxygen canister, the camera lingers on it falling/floating away for a few seconds.
- Face Death with Dignity: Zoe, having completed her oxygen retrieval spacewalk to allow the rest of the crew to survive, already severely burned and irradiated from the solar storm, sits calmly on the edge of habitat module as she allows it to finish killing her, looking toward Mars.
- Foreshadowing:
- During launch, the crew nearly aborts because of engine under-performance. It turns out that there was nothing wrong with the engine, instead they had extra mass on board: the eponymous stowaway.
- When Michael is about to kill himself with an overdose of insulin in order to save the main crew, Zoe tells him a story about how despite not being a life guard, she risked her life and almost drowned saving another man who was drowning in rapid waters, but was saved at the last minute. This foreshadows how Zoe decides to sacrifice herself to save Micheal and the rest of her crew at the cost of her life.
- Heroic Sacrifice: The crew considers several survival options that involve one or more of the team dying to allow the others to live. In the end, a solar storm makes leaving the ship's radiation-protected core suicidal, but waiting for the storm to pass would result in losing the remaining oxygen due to a leak, dooming two of the crew. Retrieving the leaky oxygen canister means only one needs to die. Zoe agrees to fight through the storm and die of radiation poisoning so the others could live.
- Hope Spot: The film zig-zags between finding solutions to the oxygen shortage and losing it, the situation going between having enough oxygen for all four of the crew and only two of them.
- Inside a Wall: Michael, who was doing maintenance work on the ship before launch, is stuck behind a service panel. When he is discovered, they are on the way to Mars with no way to turn around.
- Never Trust a Title: Generally, a stowaway is a person who intentionally hides to get free passage on a craft. This is not the case in this film, and the idea isn't even really entertained much.
- No OSHA Compliance: Someone back on the launch pad didn't do a headcount before launch, and someone else sealed a panel blocking Michael in. More broadly, the private company who built the ship cut corners when turning it from a two-person to a three-person craft and skipped redundant safety features.
- Thrown Out the Airlock: Discussed by Zoe, when she asks whether they could just ask Michael to walk out the airlock. They don't do that.
- Vomit Discretion Shot: As they settle into the artificial gravity of the space station, Michael vomits into a barf bag, but he is far enough in the background and out of focus that the viewer only hears him retching.
- Whole-Plot Reference: The plot not only resembles The Cold Equations, but also the Tintin comic book Explorers on the Moon, particularly because the "stowaway" was left on board by accident.
