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Gravity (Movie)


Zacho
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They were left in a circular trajectory with a very small angular speed, which is, given the huge distance from the Soyuz enough to induce a considerable centrifugal force. And you can actually see they're still moving when you see Kowalski and the stars behind him.

I baffles me how many people fail to realize this. It's obvious to the point I'm facepalming at some of the comments here. This is basic Newtonian physics.

Shouldn't the "huge distance" REDUCE the centrifugal force?

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Shouldn't the "huge distance" REDUCE the centrifugal force?

Not for a constant angular velocity, which is what lajoswinkler seemed to be looking at. In fact, the centrifugal force goes up linearly with radius for a constant angular velocity.

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kind of spoiler

what doesn't make sense to me is that the shuttle and ISS both have the perfect inclination and orbital times to be hit by the cloud. like thats a 1 in a million chance givin how much space there is in LEO

If you looked more into the matter you would find that the director fully admits that the inclinations were all made the same and the stations were made close to each other at the time to make the plot work.

Other than that and Tiangong reentering for some reason, the movie was quite realistic.

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  • 2 weeks later...
Also, be sure to check this short movie, too, if you've seen Gravity before.

That's quite funny that someone worked that into their short film. And interesting, too, that two real-life stories of people being isolated somewhere and forced to rely on their own ingenuity and perseverance to get home happened in the snow.

If readers of this tread enjoyed Gravity, they should also check out documentaries about Sir Ernest Shackleton's failed trans-antarctic expedition in 1914-1917 and Joe Simpson's struggle to get down off Siula Grande in Peru ("Touching the Void"). In my opinion, those two stories were orders of magnitude better than Gravity because they were real, among other things.

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Warning: There are minor spoilers in this post, so if you haven't seen the movie yet, stop reading.

Having earned my Orbital Mechanics Ph.D. in KSP (just kidding!) I went into Gravity fully expecting to pick it apart, and not enjoy it at all.

Boy was I wrong.

Yeah, almost everything about the orbital mechanics in the movie is inaccurate, but I fully agree with the director's choice to simplify that stuff just for the sake of the plot. Even if the high-level OM stuff is off, the movie really does capture the danger and strangeness of life in orbit.

After the movie I spent a LONG time just trying to come up with a way to make the MMU transfer from the shuttle to the ISS (as depicted) more accurate AND intelligible to a non-KSP playing audience...and I couldn't. And if the two points had been in realistic orbits? Forget it. I don't think even Buzz Aldrin could work out that math in his head given the limited tools Kowalski had at his disposal, let alone have enough delta-v to manage the transfer.

I did figure a way to make the "let me go" moment work with real physics, though. Imagine the parachute lines have gotten snagged in a part of the ISS that's been knocked free from the previous debris pass. So there's a big heavy thing spinning slowly, with some of the lines being pulled outward by centripetal force, Stone gets caught up in that and is under constant acceleration, and so is Kowalski once she has hold of his tether. The rotation needn't be too fast, especially if the lines are long.

Of course, like a child's swing that's had its chain twisted, the module would eventually reach the end of its spin when the cords were completely tight, and slowly begin to turn the other way. But that could take several minutes, time that Stone didn't have. Some story points that would have to be honored are: The station itself has to be airtight, because otherwise Stone wouldn't have a way to switch suits and gain access to the Soyuz. Also, the station itself can't be rotating, or Stone would find it nearly impossible to get around inside the station (especially toward the outer ends). No matter how you slice it, Stone got really, really lucky. But that's movies.

Anyway, I totally dug it.

Edited by pebble_garden
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