LOS ANGELES — The sci-fi saga known as “The Expanse” has attracted a huge fan following in part because it gets the details of life in space so right, from how to handle zero gravity to what happens when you open up your helmet visor in a hard vacuum.

But there’s one space reality that the producers have thrown out the air lock.

In space, no one can hear your spaceship scream, because there’s no medium to transmit the sound waves. But in “The Expanse,” as in “Star Wars” and other space operas, spaceships whoosh, crash and roar with regularity.

“We actually tried with Season 1 to do it realistically, to not have the ships make a sound,” showrunner Naren Shankar said last week in Los Angeles at the National Space Society’s International Space Development Conference.

“The problem is, it’s a huge element in appreciating the drama,” he said. “What you can’t accurately convey when you take the sound out of it is the incredible mass of these things, the incredible speeds at which they move. And those things have dramatic effect.”

Shankar said the show’s producers decided to use sound to “guide the audience to understand what’s happening” when spaceships get revved up.

“It’s poetic license,” he said. “But at the end of the day, if something is scary, I want it to scare the shit out of people. I want the sounds to scare them.”

Another feature that’s fudged a bit has to do with propulsion: The spaceships of “The Expanse” don’t resort to faster-than-light travel, as other space shows such as “Star Wars” and “Battlestar Galactica” do. But they do zoom faster than what’s possible with any known technology. That’s thanks to the Epstein drive, an invention that involves fusion power, magnetic coil exhaust acceleration and a lot of hand-waving.

Other twists, however, hew more closely to the laws of physics.

For example, in one scene, two characters out in the vacuum of space touch their helmets together to carry on a conversation without using their radios. It’s analogous to the old trick of putting a glass up against the wall to hear what’s going on in the next room.

And speaking of helmets, there’s another scene in which a spacewalker opens up his helmet to remove a loose wire that’s stuck inside. Some viewers wondered whether anyone could survive that scenario in real life, but the trick is that the spacewalker takes a big breath before opening the visor, and then lets the breath out during the few seconds that the helmet’s open.

“That was to put to rest that trope that your mask bursts and your head explodes,” Shankar said.

Zero gravity also poses conundrums galore for space shows: The makers of “The Expanse” try to avoid hand-waving explanations of artificial gravity. If a ship is accelerating at a rate of 1 G, no problem. But if not, then spacefliers have to strap in, engage magnetic boots to keep their feet on the ground, or deal with the challenges of zero-G.

“The Expanse” relies on Hollywood tricks like wire harnesses, blue-screen backgrounds and some serious special effects to show how astronauts tumble in zero-G. “The wire work really hurt my junk,” one of the show’s stars, Cas Anvar, complained. “It does!”

One scene tested the limits of zero-G science: How do you drink a beer in space? In the scene, Anvar’s character is sipping on a beer as he’s cruising along in the Rocinante, the spaceship he’s piloting, with “I’m So Lonesome I Could Cry” twanging on the sound system.

As Anvar sings along, he takes an occasional pull on an old-fashioned beer can.

“Right when it was really rolling, I went, ‘Holy crap, how does carbonated beverage perform in zero gravity?’ Because no one had talked about it or thought about it. … I took a sip of it, and I covered it up with my hand, because I had no idea,” Anvar said.

“Then we asked our astronaut friend, Rick Mastracchio, and he said that they’ve done some stuff with carbonation … and it’s really quite gentle. There’s nothing very violent. He said, ‘What you did was pretty good,’ ” Anvar recalled. “But that was an example where one element of the science, we had to improvise on set in order to try not to blow all the other hard work that we’ve done.”

It turns out that carbonated beverages are too messy for the International Space Station’s current drink menu, but Australia’s 4 Pines Brewing is working with Saber Astronautics on a beer bottle that’s specially designed for zero-G sipping. (There’s even an Indiegogo crowdfunding campaign.)

“The Expanse” keeps true to the science in part because Shankar has a Ph.D. in electrical engineering and applied physics. It also helps that the writers of the books on which the show is based — Daniel Abraham and Ty Franck, known collectively under the pen name James S.A. Corey — are science-savvy as well.

And if need be, the show’s producers and writers can call upon the pros. At last week’s panel, the show got an endorsement from Bobak Ferdowsi, an engineer at the Jet Propulsion Laboratory who’s known as NASA’s “Mohawk Guy.”

“That adherence to real science gives you an internally consistent set of rules,” Ferdowsi said. “That makes it, at some level, even easier than if you have these weird, arbitrary rules and you have to constantly fight with your intuition.”

You could argue that one of the big reasons why the show is surviving its near-death experience on the Syfy channel, and going on to a fourth season with Amazon Studios, is because the production values impressed Amazon CEO Jeff Bezos, a huge science-fiction fan.

“The show is extraordinary,” he said on Friday when he announced that Amazon would be picking up the series.

So, can the quest for authenticity ever be overdone? That happens, Shankar admitted. He’s had to sacrifice some of his science geekery to obey Hollywood’s laws governing space and time.

“There was this moment where the Rocinante was out traveling around, and they were coming back to Tycho Station,” he recalled. “What we wanted to do is, when the Roci docked at Tycho, we wanted to have a shot of the screen where we had a relativistic time-delay resynchronization, so the clocks would sync with the speed of the ship. And it’s in there! … And then we cut the scene.”

New episodes of “The Expanse” air on Wednesdays on the Syfy channel. Season 3 wraps up on June 27. The series will move to Amazon Prime’s streaming service for Season 4, but that’s another story.