Not all Hollywood blockbusters are about rampaging dinosaurs, time-traveling cyborgs or spandex-clad heroes.



Some big-budget movies get by just fine focusing on real-life moments of danger and drama. "Apollo 13" is one of those films.



Released 20 years ago today on June 30, 1995, here are 20 things you need to know about how director Ron Howard and star Tom Hanks worked to deliver one of the best space movies in the history of always.



1. It may be one of the most iconic lines in movie history, but "Houston, we have a problem" isn't exactly what was said during the mission. Jim Lovell actually said, "Houston, we've had a problem." The edit was made for the film because "we've had" implies that the problem is over.



2. On that note, Jim Lovell wasn't the only astronaut to speak that famous line. Jack Swigert first radioed in with "Okay, Houston -- we've had a problem here." But because the transmission was partially garbled, Lovell's recording is the one most often replayed and remembered.



3. The filming of "Apollo 13" was made more complex by the fact that director Ron Howard elected not to use any pre-existing footage of the real Apollo 13 mission.



4. Brad Pitt was supposedly offered the role of Jim Lovell, but turned it down for the starring role in David Fincher's "Seven."



5. John Travolta also turned down the lead role before it was ultimately given to Tom Hanks.

6. "Apollo 13" reunited "Forrest Gump" co-stars Tom Hanks and Gary Sinise. Weirdly enough, one scene between Hanks' Gump and Sinise's Lieutenant Dan involved the latter promising that he would become an astronaut if Gump became a shrimp boat captain. Sarcastic or not, at least he made good on his promise.



7. The cast and crew spent 13 days flying aboard NASA's KC-135 airplane in order to achieve the zero gravity effect needed for filming, also known as the "Vomit Comet." The Zero-G effect lasted a mere 23 seconds at a time.



8.The command module for the Apollo 13 craft was named Odyssey, in honor of the film "2001: A Space Odyssey."



9. Because of his role in the film, Hanks had an asteroid named after him in 1996. It's called "12818 Tomhanks (1996 GU8)."



10. The real Jim Lovell played the navy captain in the film responsible for rescuing the Apollo crew at sea. Lovell even wore his old captain's uniform for the scene.

11. This film was one of two times Ed Harris played a character tasked with guiding astronauts back to Earth after a mechanical disaster. He provided the voice of Houston Mission Control in "Gravity."



12. The film's plot and its emphasis on astronauts using random spare parts to perform vital repairs lead in part to inspiring the reality series "Junkyard Wars."



13. Because of their altered flight trajectory, the Apollo 13 crew members are believed to have traveled further from Earth than any humans in history. Decades later, that record still stands.



14. For the scene in which Bill Paxton's character Fred Haise throws up, the crew used a can of Beef-a-Roni stew to simulate vomit. After losing a bet with Hanks, Paxton wound up eating the leftover stew.

15. Ron Howard's brother, Clint (pictured above), played a significant role in the film as flight controller Seymour Liebergot.



16. Several other of Howard's family members had cameo roles in the film, including his father (a priest), mother (Jim Lovell's mother) and his wife and daughter (crowd members).



17. Ron Howard said that someone attending a test screening gave a negative review of the film, claiming that if the story had happened in real life, the astronauts "would never have survived."



18. The movie features a scene where Paxton's character plays the song "Spirit In the Sky" while Lovell laments that it should have been the theme music from "2001" (Strauss' "Also Sprach Zarathustra"). Ironically, that iconic piece of classical music was played during the actual Apollo 13 mission.



19. Hanks, Paxton and Kevin Bacon all underwent rigorous training at the U.S. Space Camp in Huntsville, Alabama. Part of that training involved learning the function of each of the 500 buttons and switches in the spacecraft.

20. While the line "Failure is not an option" was spoken by Ed Harris in the film, it was never actually spoken by anyone during the Apollo 13 mission.