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The antagonist of the film Gravity is a wave of shrapnel which circles the earth every 90 minutes. The result of a "controlled destruction" of a defunct Russian Satellite (what is this, the cold war?!) the crew of the Explorer shuttle and the ISS are threatened by this because it matches their altitude, and is traveling at a much greater velocity.

The Hubble telescope is listed as being at an standard altitude of approximately 559 km, way above the Kármán line (the boundary of the earth's 'atmosphere' and the altitude at which foreign objects experience atmospheric effects in the way of friction/heat).

Towards the end of Gravity, Mission Specialist Ryan Stone (Sandra Bullock) manages to navigate her way to Tiangong, the Chinese space-station which has been affected by the same shrapnel wave and knocked off it's orbit, back towards earth.

The debris storm has its own musical motif, which begins to play: and Stone realises that as another 90 minutes have passed, the storm has re-orbited and is on its way back...

As Stone struggles to get inside the escape capsule, now entering earths atmosphere Pieces of satellite debris begin to strike the vessel, punching dents into the side of it.

If the satellite debris was orbiting at 559km, and yet the Tiangong is crossing the Kármán line at 100km, why would the debris have descended over 400km down?

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Stone had to utilise a launcher pod to bring herself down to this altitude, so there obviously isn't enough gravitational pull to de-orbit the wrecked ISS, let alone the tiny pieces of shrapnel travelling at a much greater velocity...

The film is very, very good and a lot of extensive research has obviously gone into it, so I'm reluctant to say this is a goof... more likely either its:

A: Accurate according to some laws of physics im totally unaware of,


B: I've missed some major plot point where this is explained.

As it stands it's incredibly confusing. I know NASA spoke of a 'chain reaction' of satellites crashing into each other, but surely not at a girth of 400KM?

I know it might not go down to well, but can we limit answers to people that have seen the film; although I've done my best to try and explain the problem, there will likely be answers that will start with "I've not seen the film, but..." and end with an explanation that would immediately be ruled out by those who have seen the very specific scenario the film depicts.

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While Gravity seemed very realistic to a layman (or at least to me) and probably contained more research than many other movies of this kind, it was nevertheless not too scientifically accurate in many of its details (including relative orbital locations and orbital mechanics), as can be seen in this interview. That just as a side note not attempting to answer anything. –  Napoleon Wilson Nov 10 '13 at 22:26
Movies set their own rules: That's a given. It's only a goof when they break the rules they have themselves set. In this instance, the danger is because they are at a specific altitude...when the altitude changes, the threat matches it for no reason (other than plot, of course) unless I'm missing something? –  John Smith Optional Nov 10 '13 at 23:45
"Movies set their own rules: That's a given. It's only a goof when they break the rules they have themselves set." - True indeed. But if they don't match the reality in the first place, it's hard to say which rules they have set exactly. Is breaking a rule that you have set yourself out of nothing considered breaking or rather extending? When the movie is not respecting certain parts of orbital mechanics too well, it's not a big stretch that it gets wrong (or merely ignores) other parts of it. But as said, that's just a general thought as I don't have an idea about the specific question. –  Napoleon Wilson Nov 10 '13 at 23:52
And I should also add that I absolutely agree with Gravity being an excellent movie. –  Napoleon Wilson Nov 10 '13 at 23:54
Since this is an I haven't seen the movie answer, I'll post it as a comment. Most people view orbits as being circular in nature, where a specific altitude is kept at all times. While this is one way, there are also elliptical orbits where there is an apogee (far point of orbit)/perigee (close point of orbit). There are ways in which things could meet up in space in this way, but as has been stated, it would be highly improbable. It is definitely one of those Because it's in the script moments. Just go with it and enjoy the movie. –  Paulster2 Nov 13 '13 at 13:41

2 Answers 2

Has anyone thought of the chain react of collisions in a three dimensional sense? My guess is that shrapenel would go off in all different directions hitting other satellites at different altitudes and this would naturally snowball into a field of debris at a multitude of different altitudes thus being able to hit them at the varying altitudes depicted in the film whilst seeming like the debris following her decent home

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C: the movie is scientifically inaccurate.

You can start with how Hubble (350mi up), ISS (230mi up) & Tiangong are all in sight lines of one another. There are many many flaws.

The director said he's aware of them. (Gravity director Alfonso Cuarón says he knew of film's scientific flaws).

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Well, that's what I also commented already, yet it doesn't provide that much of an answer to the actual question. You might want to adress the OP's problem a bit more with your answer. I know it's hard to explain how something doesn't work, but you could give at least some explanations how it would behave in reality and in which way the movie was violating the rules of reality or its own rules (if it was). –  Napoleon Wilson Nov 17 '13 at 17:55
If you read the comments above, you'll see we're not discussing the scientific accuracy of the film ( we're already aware of its flaws), we're trying to address the plot flaw.... –  John Smith Optional Nov 17 '13 at 17:56

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