Factual error: When Ryan enters the space station and removes her spacesuit, she is shown wearing only a tank top and boy shorts. In reality, according to NASA's official webpage, astronauts wear a liquid cooling and ventilation garment and an absorption garment (space diapers) under their suit. (00:38:45)
Gravity (2013)
Directed by: Alfonso Cuaron
Starring: George Clooney, Ed Harris, Sandra Bullock, Basher Savage, Eric Michels, Orto Ignatiussen
Factual error: When Sandra Bullock and George Clooney manage to get to the ISS, she gets entangled with some ropes and manages to grab Clooney's safety rope. Clooney's speed should be very close to Bullocks' and the ISS', hence. The parachute ropes should be able to withhold the forces of deceleration (the mass of two people is very small, compared to Soyus or ISS), so no more pulling or having to sacrifice himself... This is due to the fact that there's no drag in space to constantly change Clooney's velocity (revert to Newton's First Law).
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Suggested correction: The parachute ropes are of course strong enough to hold the relatively low kinetic energy of the drifting astronauts, but that is not the reason why Clooney detaches. The rope is not attached firmly to Bullocks' leg. There are some loops loosely wrapped around her leg, and while both astronauts are still drifting away from the ISS (seen in a shot a few seconds earlier), those loops slip away from the foot one by one. Before the last loop slips away from the foot, untethering and condemning both astronauts, Clooney detaches himself to lessen the kinetec energy that pulls on the rope by reducing the total mass of the "system of two astronauts", so that there is a better chance that the last loop will remain attached to Bullock.
Once Clooney had stop moving all that would have been need was a slight pull from Bullock to pull him towards her. The momentum was lost when he stopped moving. So no need to cut himself loose.
It all happens in free fall. As soon as the cord withstood inertia resulting from George's body mass pulling on it, George would bounce back towards Sandra. The entire scene was completely unrealistic.
Clooney stopped moving in relation to Bullock. But both were still moving in relation to the ISS (look at the scene again; there is a wide shot that establishes this), with both their masses pulling on the parachute cords, straining the tenuous connection of the cords looped around Bullock's foot. To lessen the strain, Clooney detaches itself from the two-astronaut-system, reducing the mass and kinetic energy pulling on the cords.
Clooney and Bullock - when they were connected to each other - never actually stopped moving in relation to the ISS.
Actually parachute cords can withstand hundreds of pounds of force, making them very difficult to snap.
The danger wasn't the ropes snapping, the danger was that they would slip off her foot, and they would both be lost to space.
Factual error: The shuttle's original mission was to service Hubble, yet when the shuttle is wrecked, Kowalsky moves with Stone to the ISS, which just happens to be "a short hike away." Hubble orbits at an altitude of 350 miles/560km, while the ISS does so at an altitude of about 250 miles/410km. Furthermore, even if they had been able to see the ISS from Hubble's orbit, they would have only seen it speed ahead, as their orbital velocities are very different: 7.66km per second for the ISS and 7.5km per second for Hubble. (00:23:20)
Matt Kowalski: Half of North America just lost their Facebook.
Ryan Stone: It's time to stop driving. It's time to go home.
Matt Kowalski: Houston, I have a bad feeling about this mission.
Mission Control: Please elaborate.
Matt Kowalski: Well, it reminds of a story.
Question: Any idea what chemical substance is used in the fire extinguisher? I initially assumed it couldn't be straightforward liquid H2O as I couldn't see any spherical droplets floating around, but could it be an aerosol?
Answer: A quick internet search revealed that the International Space Station uses both carbon dioxide and water-based foam extinguishers. The Space Shuttle used Halon 1301 fire extinguishers, but these were fixed nozzles built into the shuttle compartments.
Question: How was Ryan able to swim after the capsule splashed down in the water? Isn't readjusting to earth's gravity pretty difficult when you've spent a long time in space?
Answer: Swimming does not have the same gravity related constraints that walking on land has. It is not until she is on land where she shows signs of facing difficulties with the Earth's gravity. Also, when she swims up to the surface, she is rushing so she doesn't drown and in doing so, uses up most of her energy because she has been in space and is only now readjusting to Earth's atmosphere, so when she is above water and swimming over to land, she visibly shows signs of being exhausted and out of breath as she used up most of her limited energy attempting to swim up to the surface.
Swimming still has gravity related constraints, though right?
Gravity pulls water towards the earth, yes. But for a swimmer, the water provides buoyancy and supports them. The closest thing you can come to weightlessness on Earth (not including the flight training where they take you into a plane that glows up then drops) is in water, because it floats you.
She is swimming up to the surface at the fastest speed she can, so she doesn't drown. Perhaps there are some gravity related constraints to her swimming, but she is trying to fight against it so she can get to the surface. When she is above the surface and swimming/floating back to the shore, she is visibly exhausted, so it is apparent that she used up most of her energy in trying to fight against the gravity related constraints.
Answer: The movie opens with a servicing mission to the Hubble Space Telescope on the Space Shuttle - which had already been decommissioned for two years by the time the movie came out, but we'll let that slide. Because the Shuttle was powered by fuel cells that had a limited supply of hydrogen, it meant that realistically, Space Shuttle missions rarely exceeded two weeks in space, with an absolute maximum of 17.5 days. Two weeks in microgravity is not enough to cause significant loss of muscle and bone density, so Dr. Stone would be able to swim just fine. If you look up old footage of the astronauts disembarking the Shuttle after landing, you'll see they mostly walked out and down the stairs on their own.
Answer: Yes.
Question: On the Russian vessel, shortly after Ryan boards via the airlock, there's a readout in English concerning oxygen. Shouldn't the readout, and indeed virtually everything on that ship, be written in Russian?
Answer: The International Space Station is serviced and manned by representatives from several countries. It stands to reason that because of this, instructions for spacecraft and equipment would be printed in several languages. As the movie shows, in the case of an emergency it would not make sense to have spacecraft and equipment be effectively "locked out" to those who don't speak a particular language when that problem can be easily solved by printing instructions in multiple languages.
