It didn’t take long for newcomer Diego Luna to learn an important lesson in Star Wars dress code: There are no buttons in space.

Early on in filming Rogue One: A Star Wars Story (in theaters Thursday night), 12/15 the latest in the mega-popular sci-fi franchise, the Mexican actor stopped by the costume shop when something wasn’t fitting quite right. “I go, ‘Well, just put a button here,’ ” Luna says. “And they were like: ‘What are you talking about? There’s no buttons in Star Wars. Everything just folds together.’ And I’m like, ‘No, you’re kidding me.’ ”

Turns out the costume designers knew their stuff. “I opened the books, looked for buttons. That’s true,” says Luna, who stars as Rebel Alliance intelligence officer Capt. Cassian Andor. “It's something no one even wrote. It’s a rule, period.”

After the huge success a year ago of the seventh “saga” film, Star Wars: The Force Awakens, Rogue One tries to keep that momentum going by kicking off a series of stand-alone films that go back and expand George Lucas’ galaxy far, far away in new, creative ways. And to be different, Lucasfilm brass rounded up a couple of rule breakers to take some chances with Rogue One: British superfan director Gareth Edwards (Godzilla) and ex-convict action heroine Jyn Erso, played by Oscar-nominated British actress Felicity Jones.

“We just totally went out on a limb, but to be honest, the scariest way of making Star Wars would be not to take a risk,” says Edwards, 41. “If you just played it safe and did what was expected, you really wouldn’t be following in the footsteps of George. You have to gamble.”

Rogue One is set in a time of cosmic turmoil just before the events of Lucas’ original 1977 Star Wars (now subtitled A New Hope). In fact, the opening crawl of the first movie is pretty much the new film’s plot synopsis: In a period of civil war, the Rebels notch their first victory against the evil Empire, and during the battle, Rebel spies steal the secret plans for the bad guys’ superweapon battle station, the Death Star.

Serving time at an Imperial prison camp for forgery of Imperial documents, possession of stolen property, aggravated assault and resisting arrest, Jyn is busted out by the Rebels and asked to head up this suicide mission, primarily because her father, Galen (Mads Mikkelsen), is apparently one of the key figures in getting the Death Star fully operational.

There are lots of throwbacks and easter eggs for the hardcore Star Wars fan base, but they won't see that signature opening crawl of past movies. Nor should you expect any Jedi or crazy lightsaber battles, though Darth Vader, the original Lucas über-baddie, does show up.

"In a way, we're trying to break the Star Wars mold and reimagine what it could be," says Riz Ahmed, who plays Imperial cargo pilot Bodhi Rook, a guy who's trying to defect to the Rebels and is a wanted man when Rogue One begins. "Only a fan (like Edwards), someone who reveres these stories, should have the license to do that."

While it probably won't do Force Awakens business (with its $248 million debut standing as the largest of all time), Exhibitor Relations senior box office analyst Jeff Bock predicts Rogue One will still break the top 10 list of North American openings. More important, the film keeps the franchise in the public eye and whets the appetite for Star Wars: Episode VIII (in theaters Dec. 15, 2017).

"For Star Wars fans and people who grew up with it and got (a movie) seemingly every decade, it’s kind of a treat," Bock says.

For those who loved Daisy Ridley’s young Force Awakens Jedi-in-training Rey, there are shades of her in Jyn, especially considering her tragic backstory as a youngster. But Jones went more old school for her inspirations, combining the innocence and hope of Mark Hamill’s Luke Skywalker with the maverick nature of Harrison Ford’s Han Solo before ultimately embracing Jyn's own individuality.

“She’s very much an outsider. She definitely doesn’t identify with the Empire,” Jones says. “There’s a lot of anger in there with what they’ve done to her and her family, so that’s also fueling her. So whenever she does see a Stormtrooper, she’s pretty mean."

In creating this familiar yet fresh landscape — with many never-before-seen planets and worlds — Edwards melded the old and new whenever he could: For example, X-Wings fly in Rogue One dogfights the same as they did nearly 40 years ago, but U-Wings also enter the picture, boasting an X-Wing’s jets and the front of a Snowspeeder (see: The Empire Strikes Back).

Edwards says the biggest risk he took was creating realistic battle scenes that took the audience right into the trenches as the Rebels and Imperial forces tussle, whether in the streets of Jedha City or the tropical shores of the planet Scarif.

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The result is a more brutal and grittier Star Wars movie than seen before, says Ben Mendelsohn, who stars as the villainous Imperial officer Director Orson Krennic. “It really is a muscular, tough film.”

When developing Rogue One, Edwards took old World War II photography and Photoshopped Rebel helmets on soldiers’ heads. When passersby would check out the artwork in the Lucasfilm offices, their reactions were all the same, Edwards says: “That looks amazing. I want to see that film.”

So he threw his actors right into battle, including filming in extreme heat in the Maldives for one of the Rebellion's more epic showdowns with the Empire.

“There’s nobody coming in and spraying you with sweat. That is the real deal,” Jones says. “We’d be running through water that’s coming up to your waist, like you’re in the army, and as a pack of Rebels with a helicopter going overhead capturing everything."

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The actress admired Edwards’ obsession "with capturing something very authentic and naturalistic,” and co-star Ahmed liked that the filmmaker would get up and close personal with them during filming: “When your director there is literally in the trench with you holding the camera, running and gunning, it’s clear that’s the energy, so you soak it up.”

As much as Edwards tried out new filmmaking techniques, making a movie that was definitely Star Wars was paramount, so he dug into the Lucasfilm archives and embraced a lot of the same inspirations Lucas himself had four decades ago, such as Akira Kurosawa’s 1958 period drama The Hidden Fortress. It featured two Asian characters who were slaves and bickered with each other as best friends. They became the fan-favorite droids C-3PO and R2-D2 in Lucas’ original Star Wars trilogy, and in Rogue One, the duo become the basis for two members of the central Rebel squad, assassin Baze Malbus (Jiang Wen) both CQ and blind monk warrior Chirrut Imwe (Donnie Yen). both CQ

Edwards points out Lucas’ love of classic storytelling archetypes — the original trilogy, after all, revolved around “chosen one” farmboy Luke, smuggler Han and Princess Leia (Carrie Fisher) — but the Rogue One director expanded that mind-set with his main crew.

Cassian is the kind of Rebel spy fans have never seen before (“He’s a very lonely man who has a lot of information he wished he didn’t have,” Luna reports), while K-2SO (played via performance-capture by Alan Tudyk) is a reprogrammed Imperial droid that's a combo of Han’s Wookiee co-pilot Chewbacca and C-3PO. The 7-foot-1 robot is “this tall gentle giant who’s loyal to Cassian but also spouts statistical information that you might not want to hear during stressful moments,” Edwards says. “It’s all the same ingredients but baking a different cake to some extent.”

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Rogue One examines the fact that many of the personalities in the story aren’t just good or evil, black or white. There are multiple sides and opposing factions within them — even in the Empire, where the working-class Krennic doesn’t get along with some of his more aristocratic antagonists as he feels the pressure to deliver the Death Star on time or else earn the Emperor’s wrath.

“He takes up certain mannerisms of the Empire and the upper echelon sometimes to feel as though he blends in,” Mendelsohn says. “And then there’d be other times where he would just be like: ‘Why am I even bothering? These guys are all idiots.’ ”

Many of the characters have their own backstories and reasons for being pulled into the conflict, Edwards says, and no one really is really happy to be there. In that way, he conceived of Rogue One as a mirror to the first Star Wars.

“Luke grows up in a nice home, but he just dreams of leaving so he can go to war and adventure. But in our film, the people tend to have grown up in war and they dream of finding a more peaceful life where they can go back home,” Edwards says. “I think it’s true of life: Most people who end up soldiers, it might be exciting to start with, but the reality is the world’s much better when it’s peaceful.

“Star Wars is robots and spaceships and explosions, but beneath it is a message that you can do anything you believe if you just never give up.”

In lieu of Jedi, the closest person Rogue One has to a samurai warrior is Chirrut, a blind good-hearted soul who’s very connected to the Force. “When you can’t see, you have to feel it with your heart,” says Yen, a Hong Kong action-movie legend who shows off his considerable martial arts skills with Chirrut’s staff. (“I kind of played down a little bit. What are you going to do in a universe where everybody has laser guns?” he says with a chuckle.)

Even though the Jedi are all but wiped out at this point in Star Wars history, Jyn still tells her group, “May the Force be with us.” Edwards calls it “the spiritual anchor of the movie," though it has seen better times by the looks of Jedha, once a Mecca for the Force that is now under Imperial occupation.

“Symbolically it’s supposed to represent the Empire winning against this belief system and that really everyone’s faith is fading away, and if we’re not careful, the future is going to be this machine and not this more spiritual human way of dealing with things,” Edwards says.

“You can’t make Star Wars without touching on the Force. I grew up believing in the Force as a kid and I’m still wondering if it might be true. You shouldn’t get to watch A New Hope every day and then grow up to make a Star Wars movie. I’m starting to think it might actually be real.”