[caption id="attachment_12881" align="aligncenter" width="618"] Uh-oh.[/caption] Two NASA astronauts float in the blackness far above Earth, trapped in the most desperate of predicaments. Their space shuttle is destroyed, their colleagues dead; their own oxygen supply is dwindling to critical levels; and the void around them is filled with debris from a nearby satellite, which is more than capable of perforating their flimsy suits in an instant. That’s the central conceit of Gravity, the new film from Children of Men director Alfonso Cuarón. His astronauts are played by Sandra Bullock (the more inexperienced one, but steely beneath her panic) and George Clooney (the wry veteran, calm in the face of crumbling space shuttles and brutal physics), their performances backed by several million dollars’ worth of special effects; the film proceeds in near-real time as they seek a way back to Earth, or at least some sort of safety. It all looks real (thanks to those aforementioned special effects), but to actually get a sense of how well Hollywood executed on the realism front, it helps to ask an actual NASA astronaut: Catherine “Cady” Coleman, who has spent thousands of hours aboard the Space Shuttle Columbia and the International Space Station. Career highlights (among many) include serving as lead mission specialist on the mission to deploy the Chandra X-Ray Observatory, as well as a lengthy stint as a Capsule Communicator (CAPCOM) in mission control for both the space shuttle and space station. So you could say she knows quite a bit about living in orbit. And she doesn’t think Gravity’s “villain,” that orbiting cloud of highly destructive debris, represents a terrifying threat to real-life space operations. The risk of collision is real and omnipresent, but NASA officials talk every day about objects on a potential collision course with shuttles and space stations. “You put something into a trajectory so it doesn’t run into anything,” she says. “We have the flexibility to move [a spacecraft]; we have a backup plan.” In Gravity, after that speeding debris shreds the space shuttle and leaves the two protagonists stranded in space, they first attempt to make their way to the nearby International Space Station. The pair make spacewalking look easy—and according to Coleman, working and living in weightless conditions does become second nature after awhile. “The flying part of it is what’s most fascinating to me,” she says. On the International Space Station, “I remember waking up every single morning, you open your cabin door and fly down, and it’s a perfectly ordinary thing to do.” A finger-tap or a light toe-push will send you drifting through space: “It really takes no effort.” That easiness aside, it takes a lot of hours to adequately train an astronaut to handle the combination of weightless living and extra-vehicular activity (EVA) that constitute space missions—and even then, a lot of actual learning is done in orbit. “When we get up to space and the people up there run around and show us stuff—that’s really, really effective and there was nothing like that compared to the classroom,” Coleman says. (Someone on the ground can tell a future astronaut about the intricacies of, say, zero-gravity urine collection—pee in this bag, collect samples in these labeled tubes, don’t forget to tape everything—but actually doing such things still comes with a learning curve.) An EVA outside a shuttle or space station, Coleman adds, is total sensory overload. Long before astronauts head to space, they climb into their suits and train in an enormous pool, the better to replicate the effects of zero-gravity; when they emerge from the water, techs will ask how the equipment fits, and whether any joints are rubbing or bumping the wrong way. Making sure a suit fits perfectly helps free up the astronauts’ mental bandwidth, so they can concentrate on what’s important while actually on a spacewalk: “It’s really important how your suit fits. The hardest physical thing we do in this business is work in that suit.” Coleman was aboard the International Space Station when she talked to Sandra Bullock (via VoIP) about the role. Bullock had some practical questions about living onboard a space station, and also what it feels like to actually work as an astronaut. “We’re all very privileged to do this job,” Coleman says. “They spend a lot of money making you ready, and you have a responsibility to do your job.” Combine all the time spent in orbit with the weeks of traveling between airports and launch sites, and it’s a job that becomes hard on astronauts’ families, too—one mitigated only somewhat by Skype. On the broadest level, though, every astronaut realizes they’re a part of something much larger. Experiments in space on liquids and materials help scientists back on Earth create new products; and the more we learn about human physiology in zero-gravity environments, the better prepared we’ll be as a species for eventual travel between planets. “We don’t know what those lessons will be applied to,” Coleman says, “and that’s the magic of the possibilities.” When they filmed Gravity, the filmmakers created the illusion of space by strapping the two lead actors into enormous rigs capable of spinning in tortuous directions, and layering that performance within a digital simulacrum of orbit. It looks convincing (and once the plot sends things spinning out of control, the sight of two astronauts tumbling through the void is terrifying on a primal level), but it’s still a facsimile of the real, amazing thing. Image: Warner Bros.