In the movie Gravity the two astronauts (Bullock and Clooney) are hit twice by the fast moving debris that bring havoc to their locations. I think this is a bad scientific mistake in the movie plot.
Indeed, different objects cannot travel the same orbit at different speeds. The shape of the orbit is defined by the total energy which depends essentially on velocity. So, objects that happen to be at the same point with different velocities will follow different orbits.
It is true that orbits are closed (in classical mechanics, not counting disturbing effects) so that an object will go over and over again through the same points, and the speedier objects will be again at the point where it met the slower one, but in the meantime the slower has also moved and the two won't pass through the meeting point at the same time again.
Any further meeting would occur only after a certain number of orbits, which makes way more than the mere 90 minutes claimed in the movie.
Is there a scientifically sound explanation for this?