SAN DIEGO — As director Luc Besson and his wife Virginie Besson-Silla laid out in meticulous detail a vision for “Valerian and the City of a Thousand Planets” — based on the French comic series “Valerian and Laureline” — their passion for the heavy genre material was certainly palpable. But it was difficult to ignore the specter of other attempted franchise launches from respected filmmakers that crashed on the rocks of “unproven intellectual property.”

“Finding Dory” broke Andrew Stanton out of director jail after his 2012 Edgar Rice Burroughs adaptation “John Carter” forced Disney to take a $200 million write-down. Warner Bros. took a hit on the titanically budgeted “Jupiter Ascending” last year from Lana Wachowski and Lilly Wachowski, after holding it over from 2014 to delay the pain. Unless it’s tied to successful preexisting brands (“Guardians of the Galaxy,” “Star Wars: The Force Awakens”), space opera just seems like a difficult sell these days.

“Valerian” stars Dane DeHaan and Cara Delevingne as a pair of 28th century agents who guard against temporal paradoxes at a time when humans can travel through space and time. Footage presented at the San Diego Convention Center Thursday revealed a sci-fi mish-mash reminiscent of movies like “Star Wars,” “Stargate” and Besson’s own “The Fifth Element,” as well as video games such as “Mass Effect” and “Portal.” There were “Blade Runner”-like flourishes as well, with imaginatively opulent design elements recalling the dense Rouge City environment of Steven Spielberg’s “A.I: Artificial Intelligence” (in a sequence featuring Ethan Hawke chewing the scenery as a fast-talking pimp of the future).

Many of those properties were no doubt influenced by “Valerian and Laureline,” so the circle is complete. And the Comic-Con crowd was sold. But the film will depend on that energy stretching far beyond walls of Hall H; a hefty $180 million price tag makes it the most expensive European production to date.

Besson-Silla is producing on behalf of EuropaCorp, which is financing, producing and will distribute.

“Basically I grew up with it,” Besson said of the source material, which was created by Pierre Christin and Jean-Claude Mezieres in 1967 and has since sold more than 10 million copies in 21 languages. “It was just not possible [to make a film version]; it’s 10 percent humans and 90 percent aliens!”

Though the mountain seemed unscalable, Besson nevertheless secured the film rights, just in case he could crack it. He also developed a relationship with Mezieres, tapping him for conceptual design duties on “The Fifth Element.” Contrary to recent patterns, that 1997 film — starring Bruce Willis and Milla Jovovich — was a smashing global success for the genre.

Besson said he had a version of the movie that really worked for him on the page, but then James Cameron’s “Avatar” hit theaters in 2009 and caused him to strive for better. “I threw my script in the garbage and I started again,” he said. “Eventually, after a couple of years, I came up with a good script — I think.”

Before presenting footage of the film, which is set for release July 21, 2017, Besson was honored with Comic-Con’s Inkpot Award, given to individuals for their contributions to the worlds of comics, science fiction/fantasy, film, television, animation and fandom services. The director held off on accepting right away, however, telling the audience that, if after they saw the footage they still thought he deserved it, then he would take it.

They approved, but the real test for a risky prospect like this will be global appeal. Can “Valerian” succeed where others have failed, or is there just no room for big, ballsy, unfamiliar properties to break through the franchise clutter?