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?
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: During the scene in which Matt detaches himself from Ryan so that he does not pull her away with him, why didn't he bounce back towards her when the rope snapped taut? Was there something that kept pushing/pulling him away that I missed?
Answer: If they had been tightly tethered to the space station, he would have bounced back toward her. But her foot was only tangled in parachute cords, so that when the tether snapped taught all it did was begin to pull her away from the station as the parachute cords gave more and more slack, slipping more and more loose as they drifted further away.
Question: How would Stone have known where she would land? Was it just pure luck that she landed in water and not on land?
Answer: She didn't. Thing is, the Tianggong station was deorbiting already, and the Shenzou was attached. She was re-entering the atmosphere whether she wanted to or not, and the fact that she landed on (or rather, near) land was just lucky.
Question: When Matt bounces, and Ryan doesn't bounce, they make the rope snap. Aren't tether ropes very difficult to snap in real life?
Answer: Space tethers (both synthetic fiber and metallic cable) are incredibly strong and can withstand hundreds of pounds of force. Like everything else in "Gravity," the tether snapping is pure fiction.
Question: When Ryan is descending back into the atmosphere in the Shenzhou, two pieces pop off the landing module after the big tracking shot. One appears to be part of the heat shield, and the other looks like an O-ring from the window. 1) If it really was a part of the heat shield, wouldn't she along with the Shenzhou have burnt up in the atmosphere and 2) If that was a part of the window, shouldn't it pop out due to the pressure differential? Or, if I'm wrong about those two parts, what are they?
Chosen answer: The heat shield separates before landing. If it didn't the solid fuel engines behind the shield that are designed to give a soft landing wouldn't work. It doesn't separate until the capsule has slowed sufficiently to mean it is no longer needed. I don't know what the other piece that separates is but it is nothing to do with the windows. It comes from under the capsule so was behind the heat shield.
Question: Are Bullock's reactions to all the situations she encounters logical, considering she is a trained astronaut? For instance: she repeatedly noticed that she is running out of oxygen, but she still keeps talking, screaming and hyperventilating. The first thing you have to do is to get your breath under control, but she keep talking and screaming all the way... Would a person like Bullock get through all the NASA psychological tests?
Answer: Dr. Stone isn't an experienced astronaut. She is on her 1st mission, a mission that is continually disastrous and claims the lives of two people. Her panic, even considering her training, is more than justified.
"Her panic even considering her training is more than justified" I wouldn't be so sure about that. Jack Swegiert, and Fred Haise were not experienced astronauts either during the Apollo 13 accident, but they managed to remain calm, and not panic given the psychological tests they went through.
That's true but nobody died during Apollo 13, communication with Houston was not severed, the astronauts were not alone, etc. It's a different situation. Given the circumstances of her specific mission, primarily the fact two men died on the mission and she was left alone with no help, her panic does not seem to me to be unrealistic.
Answer: While she is a specialist who was cleared to be on the mission, she noted that she received only 6 months of prior minimal training and was mediocre-she noted crashing the simulations, getting sick during training, etc. not to mention having past trauma involving her daughter. Their allowing her to proceed was more about opening space to civilians and possibly for public relations purposes than about her being an astronaut.
Question: SPOILER: What part of Earth did Dr. Stone land on?
Answer: The scene was shot in Lake Powell, Arizona (as detailed here), but whether it's meant to be that specific location or just somewhere unspecified on Earth has not been made clear.
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.
Question: How did Kowalski and Ryan cause the tether rope to break? It takes more than 220 Gs of force to cause the type of tether NASA has to break - they're specifically made of a material designed to absorb a lot of shock.
Answer: There are three possible answers: 1) The tether became damaged during the start of the cascade and was hanging by threads. 2) The tether encountered a jagged edge. 3) The script said "the tether breaks" and it did because "movie logic." Remember at the start of the movie "Cliffhanger", where a climbing aid breaks out of the blue? Remember that the maker of that harness (Black Diamond) then won a millionary lawsuit for defamation against TriStar and Carolco Pictures?
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.