The new movie “Gravity” is the closest most of us will ever come to going into space, and that may be for the best.

Watching Sandra Bullock and George Clooney as marooned astronauts, spinning out of control, bouncing off each other like yo-yos, is enough to make you forget your idyllic dreams of zero gravity. As Ms. Bullock tumbles and scrambles across arrays of solar panels and other spacecraft appendages, grabbing frantically at anything lest she float off to infinity — in 3D, no less — you feel every bounce.

“Gravity” opens this week, but it has already won rapturous reviews at film festivals in Venice and Toronto. So when the distributor, Warner Brothers, offered me a chance to watch the movie with an actual astronaut, I happily tagged along.

My companion was Michael J. Massimino, who flew missions in 2002 and 2009 to service the Hubble Space Telescope — the same telescope the astronauts in “Gravity” were sent to repair. An engineer with a doctorate from M.I.T., he was delighted by the movie’s fidelity to much of the space experience. During one scene, he nudged me, thrilled to point out that a tool Ms. Bullock was using looked just like his favorite space wrench.