History Literature / ProjectHailMary

* CyanidePill: Since the trip to Tau Ceti is [[SuicideMission one-way]], the crew of the ''Hail Mary'' were given the supplies to commit suicide via their method of choice rather than slowly starve to death once they'd completed their mission. On screen options include nitrogen asphyxiation, a chinese military pistol, and a kilogram of heroin. [[spoiler:The fact that Grace didn't note his own choice is an early clue that he didn't go voluntarily.]]

* ExposedExtraterrestrials: Averted, Eridians wear clothes despite not having eyesight, albeit ones made in weird colors. Rocky breaks out some celebratory party clothes when [[spoiler: he and Grace solve the astrophage problem]], which are not decorated and make more noise.

** Dubois's preferred eventual euthanasia being an nitrogen asphyxiation apparatus, with a supply of the needed gas. This comes into play when [[spoiler: the nitrogen gas is needed to ]]

* ChekhovsGun: [[spoiler:Subverted with the ''Hail Mary'''s "zero all rotation" button, which Grace takes note of during his early explorations of the ship's controls. Although it appears to be the perfect solution to his misadventure above Adrian that leaves the ship in an out-of-control spin, Grace resists the temptation to use it for fear that it will not work properly because of the ship's damage. He finds a more creative solution instead.]]

** Any time scientific discussions occur on Earth, the important details will be explained in simpler terms for the benefit of characters who aren't scientists or don't have the specialist knowledge to understand a more in-depth explanation. Conveniently, this also keeps important exposition from getting too technical for the audience to follow.

* GoMadFromTheIsolation: With astrophage taking care of propulsion issues, this is the new limiting factor for interstellar travel. That's why a completely untested (in humans, anyway) hibernation system was the ''single'' piece of experimental equipment that Stratt allowed on the ''Hail Mary''.

* YourNormalIsOurTaboo: Eridians consider eating in someone else's presence, or even ''talking'' about eating, to be extremely offensive.

* AchievementsInIgnorance: The Eridians managed to create a manned interstellar ship on their first try despite lacking fundamental scientific knowledge of how space or physics works, which astounds Grace. Unfortunately, the consequences of this results in [[spoiler: radiation killing off everybody aboard except Rocky]].

** Rocky roughly describes humans as leaky space blobs and, by his people's standards, he's basically correct.

* SpaceIsolationHorror: {{Downplayed}} for Grace, but strongly implied for Rocky. 46 years of isolation undoubtedly helped give him extra motivation to cooperate with and befriend Grace even if they hadn't shared the goal of saving their planets from the astrophage.

* WhatHappenedToTheMouse: Rocky has a mate who he names a planet after. He is worried that they may have moved on while he is in space. We never find out if this happened or even if they are still alive when he returns to Erid.

* InnocentAliens: This might be a result of who survived, but both are quite benevolent to each other.

* WhatHappenedToTheMouse?: Rocky has a mate who he names a planet after. He is worried that they may have moved on while he is in space. We never find out if this happened or even if they are still alive when he returns to Erid.

* DownToTheLastPlay: Invoked by the title. A Hail Mary pass is a desperate, down-to-the-buzzer play that is understood to have little chance of success. Its name was popularized as Dallas Cowboys Quarterback Roger Staubach (who happened to be Catholic) stated in an interview that he recited the eponymous prayer in his mind as he launched a particularly memorable (and successful) one of those.

* SpaceIsolationHorror: {{Downplayed}} for Grace, but certainly implied for Rocky. 80 years of isolation undoubtedly helped give him extra motivation to cooperate with and befriend Grace even if they hadn't shared the goal of saving their planets from the astrophage.

* SpaceIsolationHorror: {{Downplayed}} for Grace, but certainly implied for Rocky. 80 years of isolation undoubtedly helped give him extra motivation to cooperate with and befriend Grace even if they hadn't had the goal of sav8ng their planets from the astrophage.

* SoleSurvivor: Grace and Rocky are the sole survivors of their respective missions. Grace's crewmates died of unspecified medical complications during their comas; Rocky's died of [[spoiler: radiation poisoning]] because the Eridians [[AliensNeverInventedTheWheel didn't know that was a thing]].

** Most of the scientific talk aboard the ''Hail Mary'' happens like this, thanks to Grace and Rocky's limited vocabulary in each other's languages.

* LoopholeAbuse: The medical droid on the ''Hail Mary'' uses the onboard clock to strictly regulate the dosage of painkillers. Grace simply tells it to change the clock time and asks it for more drugs.

* YouWakeUpInARoom: How the novel starts. Grace wakes up to find he's hooked up to medical equipment in a small room alone with no memory of how he got there.

* TheEngineer: Ilyukhin in the flashbacks, though she dies during the transit to Tau Ceti. Rocky takes over the role in the main plot

** The ship and project (and, by extension, the book) are named for the [[https://en.wikipedia.org/wiki/Hail_Mary_pass Hail Mary pass]] - a desperate, last-second play with little chance of actual success.

** Grace names Rocky, a freakishly-strong {{heavyworlder}}, after [[Franchise/{{Rocky}} Rocky Balboa]]. When Rocky names one of Tau Ceti's planets after his mate, Grace chooses "Adrian" as its English name.

* TheAloner: Grace thinks he is the only living person for light years around. [[spoiler:The actual loner was Rocky, who arrived in Tau Ceti ''decades'' before Grace.]]