Good sci-fi films make it easy to suspend disbelief. Bad ones don’t. Take “The Space Between Us,” which asks us to believe NASA would be dumb enough not to check if one of their astronauts is pregnant before a mission to Mars. 

Nonetheless, astronaut Sarah Elliot (Janet Montgomery) shacks it up with an anonymous beau, hightails it to Mars and gives life to a son before succumbing to complications resulting from childbirth. Back on Earth, mission director Nathaniel Shepherd (Gary Oldman) decides to keep the child a secret to avoid public outrage at NASA’s carelessness.

Sarah’s son, Gardner (Asa Butterfield), grows up on Mars under the guardianship of one of the scientists, Kendra (Carla Gugino), and dreams of life on Earth. He’s formed an online friendship with a troubled Colorado girl, Tulsa (Britt Robertson). This idea pushes the boundaries of reasonability, as “The Space Between Us” takes place in the near future, and human technology doesn’t seem advanced enough to feasibly allow the kids to Skype each other without signal delay between Earth and Mars.

When Gardner uncovers a video of a man he believes to be his father, he resolves to finally journey back to Earth and find the only family he has left. NASA manages to shuttle him back, but Shepherd realizes Gardner’s body is unsuited for our planet’s environment, and he will die if he does not return to Mars. 

But Gardner couldn’t care less about his impending demise — he flees from NASA, meets up with Tulsa and sets out on a journey that involves crashing a plane into a barn, stealing random cars and appropriating strangers’ electronic devices. But Bonnie and Clyde get away with their crimes and, because they’re in love, that somehow makes their felony-ridden road trip completely okay.

Yes, this isn’t just a sci-fi movie — it’s a teen romance sci-fi movie. So sit back and enjoy the incessant use of pop songs and scene after scene of Gardner professing his undying love for Tulsa. His compliments are so cheesy that you’ll be wondering if the filmmakers were trying to make cinematic fondue.

And that’s a shame, because Butterfield and Robertson play their underwritten characters very well. When the movie casts light on Gardner’s fish-out-of-water moments, such as his disarmingly sweet attempts at chivalry and his first experience with rain, “The Space Between Us” offers glimpses of a more authentic tale beneath its commercial aspirations. Tulsa is similarly charming when she’s not causing property damage and determinedly leading the naive Gardner across the American West.

The adult characters, on the other hand, are dumb, but at least they aren’t one-dimensional villains. Shepherd and Kendra pursue Gardner because they are acting in his best interests, not because they want to deny him happiness. Oldman and Gugino are talented enough to shine even when the writing doesn’t do them any favors.

All in all, 90 percent of “The Space Between Us” is tolerable enough. The same can’t be said for the outright ridiculous climax, which features a double twist, an impromptu spaceship launch and nonsensical medical jargon. It’s so mind-numbingly stupid that even the teen demographic will raise their eyebrows. Gardner might be able to win Tulsa’s heart, but his movie won’t win ours.