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National Geographic’s “Mars” has a split personality. It isn’t a documentary, at least not entirely. It’s not a drama, either.

Instead, the six-episode series is a drama about the first human mission to Mars, sharing screen time with a documentary about the real people working to get us there.

The format is ambitious, and if some parts don’t entirely work, there’s still a lot to like and learn in “Mars,” from Ron Howard and Brian Grazer’s Imagine Entertainment and RadicalMedia.

A year and a half in the making, “Mars” is the biggest project to date for National Geographic and marks what CEO Courteney Monroe calls a turning part in the network’s transformation, using “the power of storytelling to change the world.”

See for yourself: The first episode is streaming now, free, at channel. Or wait to watch on your big-screen TV, while prepping via the digital companion series “Before Mars,” or the National Geographic Magazine cover story, or the companion book “Mars: Our Future on the Red Planet,” or all the supplementary material on the website.

In 2033, the six-member international crew of the spaceship Daedalus (in Greek mythology, Daedalus built wings, resulting in disaster for his son, Icarus) is preparing to leave on a seven-month flight to the planet most like Earth, where they will attempt to “build a home for humankind on Mars.” Some, or all, may die on the mission, they are warned.

Then, in the present, an impressive array of scientists and other experts, including SpaceX founder Elon Musk, astronomer Neil deGrasse Tyson and representatives from NASA, the Jet Propulsion Laboratory, the European Space Agency and more, weigh in.

Colonizing Mars can save us from extinction, Musk says. But could it really happen? “It’s not just science fiction anymore,” says Ann Druyan, the “Cosmos” writer and widow of Carl Sagan.

“We hear from our big thinkers giving context for the actual engineering that’s taking place toward that mission in the future,” executive producer Justin Wilkes said when Nat Geo introduced “Mars” to TV critics this summer in Los Angeles.

The miniseries is “actually science fact,” Wilkes says. “Everything that you’re seeing is real. It’s going to be what that mission will actually entail.”

Back on the spaceship, it’s all fun and games until the entry and landing go awry, leaving the crew wondering how to survive. (“Grow potatoes!” anyone who enjoyed “The Martian” might yell at this point.)

Speaking of “The Martian,” it’s that best-selling book and the recent Matt Damon movie that has Mars on the mind of the public. But scientists like Robert Braun, the former NASA chief technologist who served as a consultant on “Mars,” have been looking toward the Red Planet for many years.

The miniseries gets it right, Braun says. “I work on a lot of real missions, robotic missions to Mars. And one of the best things about this series was getting a chance to work with writers, producers, staff that really cared about that. It was much more than I was the science guy off in the corner. It was very interactive, and that helped a lot to make it real.”

Covering even more bases, Nat Geo put “Martian” author Weir on its panel as well.

He’s one of the talking heads in the documentary portions and points out that “Mars is a very different place than the Earth. If you’re not used to working and living on Mars, you don’t expect it to be the way it is. The sky’s different colors. The sound travels differently. The atmosphere is much different. Gravity’s much different. ... But this team, I can tell you, was very careful about getting it accurate.”

Fans of “The Martian” might wish for more humor than “Mars” offers in the first two episodes, provided for preview. Director Evergardo Gout promises smiles at some points.

But Weir says he loves the fact that the entertainment industry and the space industry are working in tandem.

“The more scientifically accurate, space-related content that gets made, the more public interest there is in the space program,” Weir says. Then, “the more funding it gets. ... So I think this is actually part of the process that will get us to Mars in real life.”

What “Mars” • Three stars out of four • When 8 p.m. Mondays • Where National Geographic • More info