Set in 1957, the film follows young Homer (Gyllenhaal) in the mining town of Coalwood, West Virgina, where almost every man works in the mine. After seeing the Sputnik satellite pass over the town while in orbit, Homer becomes inspired to seek a career in rocketry, and leave the town for a new life. He plans to showcase his homemade rockets at the local science fair, though the townsfolk believe he has no chance of succeeding.
Despite this, Homer teams up with the school geek and fellow rocket enthusiast Quentin (Chris Owen), and recruits two of his friends into helping him. Though they fail at their first few attempts, they make several successful launches after experimenting with the fuel and rocket design. However, they run into problems with the law when it is believed that one of their rockets landed astray and caused a nearby forest fire, causing them to be disqualified from the science fair. As if this weren't bad enough, Homer's father John (Cooper) is injured in a mining accident, and now Homer must leave school and take up the work in order to support the family, leaving him with no time to help prove that the forest fire was not their fault. However, the boys' science teacher (Dern) has a firm belief in what they're doing, and gives Homer a book on rocket science, from which Homer teaches himself how to calculate a rocket's trajectory, allowing him to find their own rocket and prove the group's innocence.
They enter their rockets in the local science fair and win first place, allowing them to move on to national science fair in Indianapolis. Only Homer attends, because of the school's limited funding. Their display wins there as well with flying colors, as Homer receives countless scholarship offers before returning to Coalwood as a hero.
This movie provides examples of:
- Adaptational Attractiveness: Let's just say that most teenage boys don't look like Jake Gyllenhaal, and the real Homer Hickam was no exception.
- Adaptational Ugliness: In contrast to Sonny, the real life Quentin was, though unquestionably nerdy and an Insufferable Genius, mentioned in the book to be "not bad looking" and is shown to be arguably pretty cute. His film incarnation is made out to look much more awkward, with Nerd Glasses and less style.
- Adaptation Dye-Job: As shown in the epilogue, the real-life Miss Riley had black hair. She's a blonde in the movie.
- Adaptation Name Change:
- In real life and in the book, Homer's father was named Homer H. Hickam, Sr. To avoid confusion for the audience, the film renames him John Hickam.
- Similarly, Homer was always referred to as "Sonny" due to his name being Homer H. Hickam, Jr. However, because of his father's aforementioned name change, he's always called "Homer" in the film.
- In the book, Dorothy's full name is Dorothy Plunk. The film renames her Dorothy Platt.
- Adaptation Title Change: The film's title, October Sky, is an anagram of the title of the book on which it was based, Rocket Boys.
- Adapted Out: Billy Rose, a boy who joins the gang later in their adventures and is good at tracking down rockets after tests launches, is absent from the film.
- Age Lift: In the book, the Rocket Boys are 14. The film ages them up to 16-17 to better suit the actors' real-life ages.
- All Girls Want Bad Boys: Referenced: After the boys are arrested for allegedly causing the forest fire, Quentin complains that "Now we're practically ex-cons" and that girls will never want to dance with them. He is told that he doesn't know about girls.
- Arc Words: "It's not gonna fly unless somebody [does thing]." The boys initially have to light a fuse and run away, but the film shows their progress by advancing to pulling a string to light a match by pulley, to pulling an electric switch, to pushing a button.
- Artistic License Engineering: One of the machinists at the mine suggests using SAE 1020 steel for the rocket nozzles, saying that it will 'take the heat', and that it's expensive. SAE 1020 is a common medium-carbon steel without any special properties; Nickel-Chromium stainless steel would be a far better choice, as it loses much less strength at high temperatures.
- Disproportionate Retribution: Homer's father promises this to the abusive step-father of one of Homer's friends."If I see him with a bruise, you get a scar. If I see him with a limp, you get crutches."
- Calling the Old Man Out: Homer's frustration with his dad pressuring him into following in his line of work culminates in an argument over how everyone except his dad realizes that the coal mine is done for, with Homer declaring that if he wins the science fair in Indianapolis and goes to college, he's never coming back to Coalwood.
- The Cameo: Photographer O. Winston Link, famed for his documenting the final years of steam locomotives on the Norfolk & Western (featured in the film) appears as the locomotive engineer who waves at the boys.
- Catchphrase: Quentin, the team bookworm, often uses the phrase "Prodigious!" when something good happens for the team. Roy attempts this at one point, but butchers it into "Predigenous!"
- Company Town: Coalwood.
- Composite Character:
- The film merges Sherman Siers and Jimmy O'Dell Carroll into one character named Sherman O'Dell, while the book keeps them separate.
- Mr. Bolden is an amalgamation of several machinists who helped the Rocket Boys after Bykovsky's transfer to the mines.
- Dogged Nice Guy: Homer is this to Dorothy, who ends up dating several other guys, including the captain of the football team and his brother.
- Dying Town: Coalwood.
- Eating Lunch Alone: Quentin does this, usually while reading. Homer walks up and asks about how to construct a rocket, but Quentin doesn't take it seriously until Homer actually sits down. Incidentally, the entire cafeteria takes close note of this development.
- Exact Words: After the second attempted launch lands at the mine (which wasn't empty at the time), Homer's dad forbids Homer from any more rockets "on company property." Homer waits until after he and his friends are alone to highlight the last part, and he's not discouraged when they protest that the company owns all the land for miles around.
- Failure Montage: There's a long sequence of rockets exploding on the launchpad before the boys are shown figuring out what the problem is.
- Fantasy-Forbidding Father: Homer's dad at first.
- The Film of the Book: The story is based on Homer Hickham's memoir, Rocket Boys
- Gangland Drive-By: During a dispute between the mine and the miner's union, someone fires a shot at John while he's in the kitchen, followed by the sound of tires squealing as the shooter drives off.
- I Like Those Odds:O'Dell: God's honest truth, Homer. What are the chances of a bunch of kids from Coalwood actually winning the National Science Fair?
Homer: A million to one, O'Dell.
O'Dell: (Beat) That good? Well, why didn't you say so?
- Ill Girl: The kind and encouraging schoolteacher, Miss Riley, who is revealed to suffer from Hodgkin's Disease during the third act of the film, giving the Rocket Boys that extra emotional push to pull off their last, climactic, rocket launch.
- It's All My Fault: Homer blames himself for Ike Bykovsky's death, since his father moved him out of the machine shop for helping Homer. Ike is thankful for it though, as mine work pays more and later John gave him a chance to return to the shop and he refused.
- Jerk with a Heart of Gold: John Hickam.
- Last-Name Basis: In the film, Sherman O'Dell is never referred to by his first name. Even in the ending credits, his actor, Chad Lindberg, is credited as simply "O'Dell."
- There's a blink-and-you'll-miss-it mention of his first name when the Rocket Boys win the county science fair.
- Man of the City: Mining foreman John Hickam is obsessed with keeping the mine productive to protect the jobs of his neighbors and keep the Company Town alive, while also having some Chronic Hero Syndrome every time there's a mining accident and working hard to rescue anyone in danger.
- The One Who Made It Out: Homer Hickam especially, but all of the Rocket Boys qualify. In the beginning of the movie it's mentioned in passing that it's either a football scholarship or the mines for the boys growing up, which makes Homer and the Rocket Boys even more special.
- Papa Wolf: Subverted. John is this towards Roy Lee, rather than Homer, when he sees the former being beaten by his stepfather.
- Parents Are Wrong: Homer yearns to make a career in rocketry, but his father insists that he take the "practical" route of staying in town and working in the coal mine. Eventually, Homer proves himself as a budding scientist and his father relents.
- Pom-Pom Girl: Three of the school's cheerleaders eventually start doing chants to encourage Homer and his friends as they launch rockets. One of them, Dorothy, is polite to Homer and his friends even after their temporary disgrace, although she also doesn't return Homer's obvious crush on her and starts dating his brother instead.
- Poor Communication Kills: Nobody shows the boys the rocket that caused the forest fire until after Homer uses the math book to find where their rocket landed, proving it wasn't their fault.
- Pursue the Dream Job: Homer takes a job in the town's coal mine after it seems his hobby of rocketry has caused a forest fire. He does well there but when he figures out the fire started too far away for a rocket to have started it, he begins pursuing rocketry again, determined to get out of that town and go to college. He eventually goes to work for NASA.
- Railroad Tracks of Doom: Subverted. The boys rip up the tracks of a supposedly-abandoned spur line to sell the iron for scrap. One of the boys lampshades this trope, asking if the the tracks really are unused. Sure enough, the moment they've got the heavy rail fully out of alignment, they hear a whistle... Frantically, they try to get the rail back in place, seemingly to no avail as the locomotive bears down on them... Then at the last moment, the train turns away down the main line; and the camera pulls back to reveal that the line they tore up was inactive.
- Real-Person Epilogue: The movie ends with images and footage of the real versions of the film's protagonists.
- Reasonable Authority Figure: The principal. He doesn't tolerate any nonsense from the Rocket Boys, but when the evidence suggests that they didn't start the fire, he gets the police to review the case, and he's the one who recognizes what really happened—the "rocket" that started it was a flare from the nearby airport—and as soon as he realizes this, he actively works to help the Rocket Boys pursue their goal of winning the science fair.
- Recognition Failure: One of the first people to congratulate Homer for winning the national science fair is his hero, Wernher von Braun. Homer doesn't recognize him.
- Surprisingly Realistic Outcome: After the boys win the State Fair, Principal Turner asks them which member will be the one going to Indianapolis for the National Science Fair. Coalwood being a poor mining town, the school can only afford to send one student.
- Tragic Dropout: When John Hickam is injured in a mining accident, Jim Hickam, as the oldest son, considers dropping out of school to provide for the family while John recovers, knowing that this would cost him his football scholarship to West Virginia University. Homer takes his brother's place instead, and it looks like Homer's dream of leaving Coalwood and being a rocket scientist is gone.
- Tragic Keepsake: Homer carries with him Ike Bykovsky's identification disk.
- "Well Done, Son!" Guy: Homer's mother calls out her husband on the fact that he doesn't miss a single football game featuring Homer's older brother, but he hasn't been to a single one of Homer's rocket launches. Homer sets the record straight near the end of the movie:Homer: Dad, Dr. von Braun is a great scientist. But he isn't my hero.
- "Where Are They Now?" Epilogue: All of the Rocket Boys ended up attending and graduating from college, Homer's mother retired to Myrtle Beach, Miss Riley passed away due to her Hodgkin's Disease, and John passed away in 1976 due to black lung cancer caused by the mine.