Warning: Some spoilers for “Life” are ahead if you haven’t seen the movie.

• “Life” is a space horror movie starring Jake Gyllenhaal, Ryan Reynolds, Rebecca Ferguson, and more.
• The plot is about a Mars sample return mission gone terribly wrong.
• The film’s creators worked with real scientists to make it more believable.
• NASA is actually working on getting a Mars sample to Earth and is worried about contaminating the planet.

Big-budget science-fiction movies aren’t supposed to be documentaries.

They are, however, supposed to take us on journeys to far-flung places, immerse us in vivid alternate realities, and make us wonder “what if?”

But reality itself is a powerful filmmaking spice that, justly applied, helps suspend our disbelief — and sometimes scream our guts out.

Such is the case with the new movie “Life”, whose makers consulted a NASA-trained medical doctor, a Mars spacecraft engineer, and a geneticist to help produce their horrifying spectacle.

While the film, directed by Daniel Espinosa, whiffs on quite a lot of science, it does go far enough to be wildly entertaining. In fact, Business Insider’s Jason Guerrasio even argues it may be a cult classic in the making.

We join the story just as a Mars sample return spacecraft is being caught by a small crew aboard the International Space Station (ISS). With red dirt in hand, NASA astronauts go about analysing the grit behind several “firewalls” of protection.

After an extraterrestrial microbe is discovered in the soil, it’s revived in a soup of water and nutrients. Then, to the astonishment of the crew, it springs to life. “Calvin,” as the life form is soon called, quickly divides and grows into a starfish-size creature with incredible strength and intelligence.

What could possibly go wrong?

To understand what doses of reality went into the movie, we called up Dr. Kevin Fong ― a medical doctor, space medicine expert who’s trained with NASA and ESA for about a decade, and a paid science consultant for the new Sony Pictures film.

And to answer some of those “what if?” questions on aliens, we spoke to Catharine A. Conley, a planetary protection officer for NASA who gets paid to help humankind avert extraterrestrial disasters in the real world.

Astronaut doctor on set

“Life” features not one but two characters who are doctors, so filmmakers brought Fong on board to answer their pressing questions.

A lot of the early work happened by email, he says, but soon enough Fong was invited to join the set: an elaborate and modular reconstruction of the space station inside a giant green-screen studio.

“They paid more attention to detail than I’d seen in the space agencies,” Fong told Business Insider. “Although the modules are different than what they actually are on the space station, it was very close.”

The producers occasionally asked Fong to lend his expertise in physiology and emergency care to actor Jake Gyllenhaal (who plays long-duration astronaut David Jordan), actress Rebecca Ferguson (who plays Center for Disease specialist Miranda North), and others in various scenes.

“There are a couple of quite dense medical scenes, where I’d say, ‘I’d hold this tool like that,’ or ‘I wouldn’t hold that in the way you are,’ and ‘here’s some terminology I’d use in this situation.’ On the set, it came across as a very believable,” Fong says.

He was especially impressed with a cardiac arrest scene, saying it was “about as faithful as one could be” in a movie.

While he hadn’t seen the movie, at least at the time Business Insider interviewed him, Fong didn’t walk away thinking it’d be a documentary.

“I think it pays dividends to any movie producer to go as far as you can in suspending disbelief,” he says. “But I’m not expecting ‘Apollo 13.’ You have to make the drama more realistic without getting in the way of the story.”

Fong also said that while there are definitely parallels to the “Alien” space horror movie franchise, “Life” is imminently more believable.

“Around the time ‘Alien’ was made, you needed to imagine some far-flung place,” he says. But with the ISS floating just 250 miles above Earth, he added, “this is happening right on your back door.”

Fortunately for us, NASA has put decades of thought into protecting planet Earth.

Defending the planet from real-life Martians

At first blush, the idea of a Mars sample return mission might seem far-fetched. But NASA researchers hope to do just that in the future.

In fact, both Congress and President Trump essentially codified that mission for the space agency by passing the NASA Transition Authorization Act of 2017 into law in March.

The first line of defence for a Mars sample is Catharine Conley, who is NASA’s sole planetary protection officer. She has worked in that role since 2006, and helps ensure Earth’s microbes don’t reach other worlds — and other worlds’ microbes don’t reach Earth, at least in an uncontained way. (And that includes keeping dead bodies off of other worlds.)

“The phrase that we use is, ‘break the chain of contact with Mars,'” Conley told Business Insider.

Conley also hadn’t seen the movie, but said if a Mars sample was flying toward Earth, it would be aimed slightly off-course from the planet. That way if something goes wrong, the capsule full of red dirt (and maybe a harmful microbe) wouldn’t enter our atmosphere in an uncontrolled way, break open, and induce panic.

Yet before such a capsule would ever leave Mars, she says, space law requires that an inter-governmental, multi-space agency committee convene to review the mission and make a recommendation on what to do.

“You’d want the international community to weigh in because it’s a of a high-enough concern,” she said . “There’s a lot of checks and balances.”

A Mars sample return mission — ostensibly to seek fossilized signs of ancient life, not actual microbes — wouldn’t be the first to test the mettle of protections for Earth: Apollo 11 astronauts had to stay quarantined for three whole weeks in a trailer before emerging.

In fact, she says, planning for a Mars sample return mission started with the nuclear-powered Viking landers of the 1970s and has been going ever since.

Plans “got the most carefully laid out” in the early 2000s, she said, but by the time she arrived, bringing a sample to the space station had long been ruled out. The reason? It seemed far too expensive, and containing a disastrous microbe inside the ISS seemed pointless.

“The space station is going to fall down at some point,” she said.

Instead, Conley says scientists would make sure an extra-robust capsule carefully reenters Earth’s atmosphere, is quickly retrieved, and hurried away to a Biosafety Level 4 laboratory — the most high-security grade of research facility on the planet.

“I would love to find life elsewhere,” Conley said — if for no other reason than to compare it to life here on Earth, where the only organisms we know of exist. “If Earth and Mars life are related, that makes things a lot more complicated.”

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