George Clooney and Sandra Bullock star as astronauts trapped in space in Alfonso Cuarón’s latest film, “Gravity.”

Space has become one of the most recognizable movie milieus, but most genre conventions are lacking in the new film “Gravity.” There are no titanic explosions, no movement in a vacuum without propulsion, and certainly no extraterrestrials: friendly, malevolent, Jedi or otherwise. When shrapnel, hurtling faster than a speeding bullet, hits human beings, it passes straight through them—there is no mercy in space. In its admirable fidelity to scientific accuracy and the look and feel of 21st-century intergalactic travel—the chunkiness of the space suit, the intricate obsolescence of shuttle controls still on analogue systems from the ’70s, how hypoxia caused by falling oxygen levels robs the mind of its ability to make rational decisions—“Gravity” attains a level of grounded reality that this year’s other sci-fi efforts such as “Pacific Rim” and “Elysium” can only dream of.

This is coupled with a supremely effective use of 3D, possibly representing another important step forward in this medium. The technology can depict not only gorgeous vistas of our home planet but also the yawning abysses of empty space that our heroes, astronauts Stone (Sandra Bullock) and Kowalski (George Clooney), are thrown into when debris from a terminated Russian satellite shreds their transport into ribbons of hurtling projectiles and twisted steel. Stone is sent spinning off into the void, the camera dispassionately watching her fade into another speck against the stars, then suddenly inside her helmet watching helplessly and intimately as the universe rotates and all hope seems lost.

The film’s director, Alfonso Cuarón, is the master of the long tracking shot, and in space he seems to have found a natural element for this most dreamlike of cinematographic techniques. His eye sweeps and glides, pirouetting gracefully in the zero gravity. The movie’s first shot, of Stone repairing the Hubble Space Telescope while Kowalski nonchalantly banters with Mission Control back home, clocks in at a cool 15 minutes. Never before in the movies has filmmaker and film scholar Alexander Mackendrick’s idea of the director’s vision as an “invisible imaginary ubiquitous winged witness” felt more apt. For a movie of such choking tension, of such hurtling momentum, Cuarón’s touch is surprisingly light.

The ride however, is not. From that first, terrifyingly choreographed explosion of shrapnel over their spacecraft, the astronauts and the audience are plunged into a desperate and relentless struggle for survival. Stone and Kowalski must try and make their way to the nearby International Space Station, itself speedily abandoned, in the hope that one of its ancient Soyuz transporters can get them home. At the same time, Stone is dealing with the recent death of her daughter and questions the depth of her desire to return to Earth at all. This somewhat formulaic shading-in of Stone’s character leads to arguably Cuarón’s one misstep, the straying over into sentimentality that also marred the end of his otherwise superlative “Children of Men.” As a result of this decision, Bullock’s dialogue occasionally feels excessive or banal.

Such problems are minor. Stone and Kowalski’s interactions largely seem organic rather than forced, aided by effective performances from both leads, and Bullock achieves a level of empathy we haven’t felt from her in a while. This human edge helps as the film retains its furious pace during the final frames. As oxygen levels drop and fragments of ruined satellites burn up in the atmosphere like asteroids, the film forces the audience to collectively suck in its breath in a way that most conventional blockbusters cannot hope to achieve. In eschewing the childish fantasies of his peers, and by recognizing that the best forms of escapism are grounded in profoundly human realities, Cuarón has directed the most exciting space movie in years.

—Staff writer Caleb J.T. Thompson can be reached at caleb.thompson@thecrimson.com.