So this this was filmed on locaton in near-Earth orbit! 👀
(At around 3m 50s) In the opening scene, as Kowalski flies very close to the camera, astronauts holding a movie camera and boom mic appear to be reflected in his helmet visor. This is an in-joke by director Alfonso Cuarón. The production crew's "reflections" were added with CGI to make it look like the scene was actually filmed in space, and that the post-production team failed to digitally paint-out those reflections.
I have the Blu Ray and tried to see for myself, but can't quite make out the aforementioned reflection. Has anyone noticed it? Maybe one of you has this movie in 4K and can check, and possibly post a screenshot? share