Mars Needs Moms

Let’s see… Science-fiction themes… A flat, joyless story… Motion-capture animation that results in everyone having creepy robot faces… What are the chances “Mars Needs Moms” has Robert Zemeckis’ name on it?

Sure enough, the man behind “The Polar Express,” “Beowulf,” and the Jim Carrey “Christmas Carol” is the producer of “Mars Needs Moms,” a laborious affair based on Berkeley Breathed’s charming picture book. As with “Polar Express,” the source material was too scant to be a feature-length film, so it had to be “expanded,” i.e., robbed of its simplicity and dragged out for 90 minutes.

Basically, they took a small story, made it complicated and burdensome, filmed some actors performing it, turned those actors into affectless, mechanical cartoons, converted it to 3D, and dropped it in theaters. Wheeee!

Zemeckis shares the blame with director Simon Wells (“An American Tail: Fievel Goes West,” “The Time Machine”), who co-wrote the screenplay with his wife, Wendy Wells. The Wellses stick to Breathed’s original message — kids, be thankful for your moms — but clutter it up with a convoluted sci-fi adventure tale. With all the painstaking technical craftsmanship involved in making one of these movies, you’d think they’d start off with a better script. Otherwise you’re just wasting your time, aren’t you?

Milo is a typical little boy who doesn’t like to take out the trash or eat his broccoli. (His voice is provided by Seth Dursky, who is an actual child, but the motion-capture performance was Seth Green. Why not have the kid do the whole thing? Dunno.) Milo does not appreciate his mother (Joan Cusack), though you can bet he will after Martians abduct her and he has to (spoiler alert) rescue her!

The Martians need Milo’s mom because she exemplifies Earthling maternal instincts, and the Martians don’t have any. Martian women run Mars; the Martian males live in garbage dumps. When Martian babies are born — they hatch out of the ground, like potatoes; I do not know how (or even if) the men are involved in conception — they are raised by nanny-bots, which must be programmed with the right blend of love, discipline, and nurturing. Which, as I mentioned, the Martian women don’t know anything about. So they have to extract it from Earth ladies.

So anyway. Milo tags along when the Martian spacecraft takes his mom, then runs around Mars trying to get her back. He’s aided by Gribble (Dan Fogler), a jovial slob who came to Mars as a young boy when his own mother was taken, and who now resembles the sort of creature who would live in his mother’s basement. He calls Milo “bro” and says they’ll be “best buds”; his cheerfulness would be ingratiating if it weren’t delivered by Fogler (“Balls of Fury,” “Good Luck Chuck”) in his typical trying-too-hard, please-laugh-at-me style.

There is also assistance from Ki (Elisabeth Harnois), a free-thinking Martian girl who rejects the matriarchy’s ban on art and beauty and paints walls, Banksy-style, with psychedelic designs. Ki learned to speak English from 1960s American television, which is amusing for a little while.

Another nice thing: Milo experiences the joy of reduced gravity and bounces around the way a kid really would. I liked that.

Eh, and that’s it. “Mars Needs Moms” is never aggressively bad. It’s never aggressively anything. A film about a rambunctious boy who goes to Mars and saves his mom — produced by the guy who directed “Back to the Future”! — ought to be a magical adventure. It ought to be fun, anyway, which this isn’t. This is as cold and inert as a nanny-bot.

C (1 hr., 28 min.; PG, mild action and peril.)