Gravity director Alfonso Cuaron's movie starring Sandra Bullock and George Clooney as two astronauts having an especially bad day in space is a hit with film critics and audiences.
Reviews by actual rocket scientists, however, have been mixed.
Hayden Planetarium astrophysicist Neil deGrasse Tyson has pointed out some of the movie's scientific liberties on Twitter under the phrase "Mysteries of Gravity", while Michael Interbartolo, who flew the shuttle for Nasa, has critiqued the realism of the trailer on the science fiction website Blastr.
Second-man-on-the-moon Buzz Aldrin has praised the movie's portrayal of zero gravity, but said the shots of the earth from space looked too clear.
Audiences love to dissect science fiction movies. In 2011, Nasa released a list of what its staff considered the 10 most and least scientifically accurate films.
Gravity seems likely to fall somewhere in the middle. In the film, space debris creates a terrifying hazard for astronauts working on the Hubble Space Telescope and that's a real danger astronauts confront. The look of the Hubble and the International Space Station are faithfully drawn from Nasa documentaries, public domain photographs and US and Russian space objects that production designer Andy Nicholson bought on eBay.
For the filmmakers, that kind of realism was necessary, but not the sole consideration, Gravity producer David Heyman said.
"We wanted to give the impression of being up in space, and it was fundamental to Alfonso's approach that it look and feel very real," Heyman said. "But this is a fiction. It's a story, it's not a documentary. It was important that it be truthful, not that it be 100 per cent real."
Some Nasa employees advised on Gravity. Bullock spoke to astronaut Catherine "Cady" Coleman, who has logged more than 4,330 hours in space aboard the Columbia shuttle and the ISS, while astronaut Andrew Thomas consulted with the filmmakers.
But Nasa did not provide the kind of production support it did for the 2011 action movie Transformers: Dark of Moon. One person who worked on Gravity said Nasa declined to advise on it in an official capacity because of its portrayal of the dangers of space travel.
Astronaut Mike Massimino, who has joined in question-and-answer sessions at screenings, said that overall he saw it as a plus for the agency. "I would go so far as to say I think it's going to inspire some young people. The exposure of it will hopefully get people interested in what Nasa is doing," he said.
"The way the characters are portrayed is as real people. A lot of times astronauts are shown as stiff, smart mathematicians. The Sandra Bullock character is very human."
As for what's realistic and what's not, Coleman said that space debris was "no question a worry". "We track everything bigger than half an inch," she said.
One of the chief critiques that space scientists have had of Gravity is the portrayal of the Hubble and ISS as being in relatively close proximity. Other changes include the visors, which were altered so the actors' faces appear unobstructed in close-ups, and the time it takes an astronaut to decompress upon entering the space station. In one scene, Bullock takes off her space suit to reveal a flattering jog bra and shorts. In reality, according to Coleman, astronaut undergarments are "way not cute," consisting of one-piece long johns, cooling tubing and a diaper.
Massimino said he was surprised by some of the remarkably faithful details in the movie.
"This shows what it's like to be in space as far the views, the space suits, the look and feel of the payload bay," he said.