When Ridley Scott was making “The Martian,” the new science-heavy film that has Matt Damon stranded on Mars, he did what few film directors ever get the chance to do: He called NASA.

At the other end of the line, after a few relays, was James L. Green, the director of the space agency’s suitably important-sounding Planetary Science Division.

Over several teleconferences, Green guided Scott and his team through the current scholarship, ensuring that the science for the film about Damon’s astronaut-botanist Mark Watney would be as correct and the designs as accurate as possible. “We just wanted to help him paint the picture,” said Green, a high-ranking D.C.-based NASA official and a key figure in the U.S.’s Mars exploration efforts.

“You want to get the science right. Once you do that, you can put a lot of other story elements in,” Scott said. The Hollywood-NASA collaboration is underscored by the simultaneous release of “The Martian” and the revelation in the journal Nature Geoscience that researchers have discovered evidence of present-day liquid water on Mars.

Though coincidental, the timing couldn’t be better. The latest discovery advances scientists’ inquiry into how life could survive under Mars’ brutal conditions–exactly the focus of “The Martian.” “Someone just asked me if the RSLs were near Ares 3 and could Mark Watney have used the water,” Green said in a phone interview last week, referencing the acronym for the apparent water evidence and Watney’s spacecraft. “The conversation has already shifted.”

Though few endeavors match the painstaking work required for Mars research, the process of putting together “The Martian,” based on Andy Weir’s novel, came with its own brand of rigor. Scott and his team, who used rover-generated real-life images of the Red Planet, would send dozens of questions to Green on a weekly basis, on everything from radioisotope systems to the look of potential “habs,”  the residences for future Mars astronauts. The questions would be answered by Green or funneled to the right expert, then come back to Scott’s team and make their way into the production.

Green also put together a tour of NASA’s Houston facility in which the movie’s production designer, Arthur Max, met with individual specialists, snapping hundreds of photos as he went. In one such session, Max asked whether a knife-puncture of a suit could generate the thrust Watney needs to survive a critical moment of the film.

The suit designers laughed. A knife, they said, would be nowhere near an astronaut suit. Boosting these efforts was Weir’s book, which already relied on a dense level of research. The 2011 bestseller, though in the speculative-fiction realm, incorporated many scientific principles: the speed and time it would take to move to and around Mars, the craft that would be used to reach the planet, and Watney’s novel and quickly meme-ifying idea to generate food on barren Martian topography.

The cinematic display of such arcana can be jarring; for all the favorable comparisons to “MacGyver,” wonkiness might not have necessarily translated to the big-screen in 2015. “I get it, it’s scary,” said screenwriter Drew Goddard when asked about why so many movies shy away from more technical details. “But I was very emphatic from the beginning there was no point in doing this if we didn’t include as much of the science as we could.”

Green (whose Mars oversight role at NASA is roughly equivalent to that of Chiwetel Ejiofor’s Vincent Kapoor character in the film) said that he was struck by the high level of accuracy in the book and the movie. He said their fictional events were perhaps only decades into the future–citing NASA’s goal, as outlined by President Barack Obama, that humans enter the vicinity of Mars by the 2030s and land on the planet as early as the 2040s. There are, he conceded, a few moments that struck him as off including an opening sequence in which Watney and his crew (headed by Jessica Chastain’s Melissa Lewis) are pelted with debris during a fierce storm, setting off the film’s narrative.

The thin atmosphere on Mars would mean “not even enough wind to straighten an American flag,” he said. For his part, Weir said that the movie’s depiction of the Hermes,  the craft that Lewis and her crew take to Mars,  was different from his own conception and a much larger vessel than what would plausibly go to Mars. A climb down its ladder, he said, would also not be as smooth as in the film because of centripedal forces. But then he acknowledged that, for a large Hollywood movie about the future, this might be a rather small concern. “As a dork, I’m just bothered when there’s a physical inaccuracy,” he laughed.

Scott said he wanted to convey the Mars vastness above all else. “The Schiaparelli crater is almost 500 kilometers in diameter. The tallest volcano is more than 50,000 feet, which is more than 20,000 feet taller than Everest,” he said. “So you realize the scale of what we’re dealing with.” Indeed, the spectacle of intimate science work set against grandiose shots of another planet is sure to have a favorable effect on NASA and its public image at a time when the agency’s perception and funding have been at a crossroads. And even though NASA’s cooperation in the film no doubt enhances the accuracy, it could be seen as having another purpose; what is authentic to some, after all, is infomercial-y to another. Green said the agency had no script approval. In the movie, Jeff Daniels’ NASA chief can in fact be brusque, and Kristen Wiig’s public-affairs officer, as Green noted, is “a little more wimpy than the people from public-affairs department are in real life.”

But the overall level of cooperation and high NASA visibility will certainly help the agency with the public on which it relies for funding and possibly even with young people whom it hopes are inspired to enter astronomical professions. Complementing that effort, of course, is the Nature Geoscience article, which has already begun fueling pop-cultural reveries about the existence of Martian life, no matter how academic or microbial.

That article also caused some consternation among those at the film-research axis. When he read about the water discovery, Weir sent a note to Green worrying if the movie was suddenly obsolete, since Watney could now potentially find water instead of creating it through an inventive chemical process. Green’s response was a decisive no. “Classic science fiction is still a classic,” he said. “We still read H.G. Wells, and how far has science come since then?” He added, “This is all about working toward a larger goal. The news Monday just gives it more truth.”