The sad story of astronaut Lisa Nowak, who in 2007 was arrested on charges of threatening another female NASA employee as a result of jealousy over her relationship with a third astronaut Nowak had had a relationship with, is the very loose inspiration for director-writer Noah Hawley’s feature debut. At the time the tale became tabloid fodder, with reports that Nowak used adult diapers to allow her to make a desperate drive from Houston to Orlando to accost her quarry; it even (or perhaps inevitably) became ripped-from-the-headlines grist for an episode of “Law & Order.”

But while Hawley and his co-writers Brian C. Brown and Elliott DeGuiseppi certainly don’t ignore sensationalist elements in the final lap of “Lucy in the Sky,” which deals with that frantic road trip, their film attempts to be a serious rumination on how the protagonist’s unhappy life and her obsession with escaping its emotional pull by continuing to fly into the vast quiet of space led to her psychological unraveling. It’s a concept that might have made for a compelling portrait, had not Hawley’s penchant for gimmicks over straightforward storytelling fatally compromised the film.

In this version, Lucy Cola (Natalie Portman) is an ambitious astronaut who yearns to return to space and dedicates herself to acing the various tests that entails, even endangering her own life in the process. One can somewhat understand her desire, since her home life is not entirely satisfying. Her husband Drew (Dan Stevens, with whom Hawley has worked on FX’s “Legion”) is an understated, dweebish NASA personnel analyst, her daughter Blue Iris (Pearl Amanda Dickson) is somewhat troubled, and her beloved granny (Ellen Burstyn) is not only ill, but a constant reminder of how unhappy her childhood was.

No wonder she’s attracted to fellow astronaut Mark Goodwin (Jon Hamm), a handsome, macho womanizer who’s about to go off on a mission himself. They have a passionate fling, but his wandering eye eventually lights on another astronaut, Erin Eccles (Zazie Beetz), who’s not only younger but unencumbered, it seems, by family ties. That makes Lucy jealous, and as her emotions get the better of her, their boss (Colman Domingo) tells her that he’s, at least temporarily, removing her from consideration for upcoming flights. When she breaks into Mark’s office computer and finds that it was he who raised concerns about her stability, it sets Lucy off (her grandmother’s death adds another element to her distress), and she impulsively decides to confront him and Erin on their rendezvous. In Hawley’s revised narrative, she takes her increasingly concerned daughter along, which further contributes to her plan falling apart.

The cast is certainly committed down the line, with Portman standing out with a highly engaged performance, Texas drawl and all. But Hawley and his cinematographer Polly Morgan undermine the cast’s work with tricks meant to enhance the dramatic urgency but actually diminish it. The most obvious is the decision to switch repeatedly from widescreen to the compressed Academy aspect ratio, creating a boxier image; the change is apparently meant to suggest Lucy’s claustrophobic inner life as compared to the breadth of her experience in space, or simply gazing at the stars, but the effect is more confusing than enlightening.

There’s also the sequence of Lucy traversing the hallway of the hospital en route to her nana’s room, done in the vertiginous style of a character floating against the backgrounds rather than simply passing them by. And there are persistent references to butterflies, bees and other insects that are meant to have some metaphorical import but come across merely as strange.

Then comes the final road trip sequence, shot and edited (by Regis Kimble) so frenetically that it almost turns into farce, which comes across at odds with what has to that point been a pretty serious, if often histrionic, character study. Unless one knows about the Nowak case, moreover, it will also come out of left field, especially given Lucy’s apparent lack of concern for Blue Iris in all the tumult.

In sum, “Lucy in the Sky” is a film with an impressively ambitious reach, one that extends literally into the stratosphere. Unfortunately, it remains obstinately earthbound because the ambition too often goes awry.