History Headscratchers / Gravity

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*** That is basically what Ryan does when her fire extinguisher runs out of CO2 --she tosses it away to push herself towards the Tiangong. However, she was only a few feet away from it, moving parallel to it, and only needed a slight nudge in a vaguely approaching vector to come within arm's reach (and even then, she almost missed it anyway.) Matt, OTOH, is moving away in a perpendicular vector from the nearest stable structure. Assuming he could have detached the MMU quickly enough, he would have needed the (empty) unit to be massive enough that tossing it away in a ''perfectly parallel'' vector wouldn't just completely counteract his forward motion, it would push him back in an exactly opposite direction. Early MMUs tend to be bulky, but the frame he wore in the movie doesn't seem much different from [[http://en.wikipedia.org/wiki/Simplified_Aid_for_EVA_Rescue a SAFER module]]. Those are designed to be lightweight and portable. Matt would have had to detach his whole backpack, O2 included, to A: completely counteract his own mass, and never mind B: pushing himself back. It would have been incredibly improbable for him to do A (it's impossible to know his velocity in relation to either Ryan or the ISS) but even then, he would have needed her to anchor herself first, then toss him a line (because waiting for her to get to the Soyuz or even just replenish her own O2 would deplete what little oxygen he had in his suit.) Those are far too many assumptions to make about mass, velocity, and his and Ryan's remaining O2, within the few seconds before he drifted out of range.

*** Maybe. Kowalski is a veteran astronaut who knows how things move in space. In his judgement his only option to save Ryan was to unteather himself.

** So you're saying that it can be done, though? I mean, there's ''no reason'' that she can't use them or at least try using them.

* How many kids did Ryan have? After the hallucination sequence she said to herself she was coming home to someone.
** She "asking" Matt to tell her daughter --her late daughter, since Matt was dead too-- that she was coming home. As in, her own home.

* The ISS has a standard crew of 6; in fact, [[http://www.collectspace.com/news/news-093013a.html the mock patch]] for the then-fictional Expedition 42 has six names on it. If they had to cram themselves into the one intact Soyuz, would it be controllable, let alone survivable?

* In the Soyuz, it's made clear that the air jets can completely maneuver the pod from all angles. Correct me if I'm wrong, but the fuel and the air jets are two separate things, right? If so, why didn't she just air jettison herself over to Tiangong?

** Or, the debris is at the same altitude, but orbiting in the opposite direction. (17,500 mph x 2) More likely, the debris itself is in a perpendicular orbit at the same altitude, effectively forming a trail or even a ring that the orbits of the Explorer/ISS and their crews intersect each time they go around the earth every 90 minutes. The relative motion between them would make it seem that the characters in the movie are standing still, and it's the debris that's coming to them but really it's the other way around.

** Or, the debris is at the same altitude, but orbiting in the opposite direction. (17,500 mph x 2) More likely, the debris itself is in a perpendicular orbit at the same altitude, effectively forming a trail or even a ring that the orbits of the Explorer/ISS and their crews intersect each time they go around the earth every 90 minutes.

** Or, it's at the same altitude, but orbiting in the opposite direction. (17,500 mph x 2) More likely, the debris itself is in a perpendicular orbit at the same altitude, effectively forming a trail or even a ring,that orbit of the Explorer/ISS and their crews intersect each time they go around the earth every 90 minutes.

** It could be that the debris are in orbit with high eccentricity, and that their periapsis coincidentally intersects with the shuttle and space stations. You could also have multiple debris, each debris cluster orbiting with different inclinations, if they are that unlucky.

* If the debris is orbiting at the same altitude as the shuttle and space stations, how can it have a much higher velocity? I've played enough Kerbal Space Program to know that orbits of similar altitudes will always be similar speeds.