Every time a sci-fi movie depicts sounds in space, everyone always complains. "Hey, this is unrealistic. No sounds sould be heard in the vacuum of space."
I really think people complain about it only because they are smartasses. They don't complain about other, completely equivalent situations where the camera should not be picking up the sounds being heard, but they always complain when we are talking about space. In other words, these people are applying a double standard to the expectations they put on the sountrack of a movie, making them hypocrites and smartasses.
For example, imagine the following scenario: Two people are sitting at a table inside a restaurant, close to a window, and chatting. The camera films from the outside, ie. the other side of the window. Regardless, we can hear their conversation just fine. Also, for example the sound of traffic does not interfere with hearing the conversation (if it's heard at all).
More commonly the camera might be filming the two people from behind one of them, so that one of them is significantly closer to the camera than the other, yet both people's voices are about the same. The person closer to the camera is not heard louder than the other.
People are completely ok with this because it's a filming convention. In the fictional reality of the movie the camera does not exist, ie. it isn't really there. Consequently, there is no microphone attached to the camera either (because there is no camera). Instead, the film-making convention is that the soundtrack depicts what the subjects being filmed are hearing, not what the (inexistent) camera is "hearing". In the case of several subjects (like in this case, two), it's an "average" of what the subjects are hearing, it's the sound as heard from somewhere between the two people.
This is a filming convention dictated by both practicality (it would be impractical to have the soundtrack always be what the camera itself is "hearing") and story-telling: There is no "camera" nor "microphone" in the fictional reality being shown, and thus it's unreasonable to expect the sountrack to be that which is picked up by a microphone attached to the camera.
There are only two exceptions to this rule:
However, as already said, in normal situations there is no camera and there is no microphone in the fictional reality of the movie.
Moreover: Depicting the sountrack as if picked up by the (inexistent) microphone attached to the (inexistent) camera in an obvious way breaks the fourth wall. Now the movie is aknowledging that there is a microphone attached to a camera, even though there shouldn't be (in the fictional reality of the movie).
This is actually almost as wrong as eg. showing the camera on a mirror, or showing the shadow of a member of the film crew which shouldn't be there. It breaks the fictional reality of the movie and the fourth wall.
Everybody accepts this. Everybody accepts that the soundtrack is that of the subjects being filmed, not that of the camera. Everybody accepts that eg. a window glass between the camera and the subjects is irrelevant with respect to the soundtrack. Everybody accepts that the distance between the camera and the people is irrelevant with respect to how loud their voice can be heard. If the subject of the scene is the two people talking, then the sountrack should be that of the two people talking.
This convention is no different when filming a space scene. If the movie is filming a space ship, the soundtrack will often be that which can be assumed to be heard from somewhere in the space ship (eg. the sound of the propulsion system). If the movie is filming a space ship exploding, the soundtrack will be that of the explosion (even if it isn't completely physically accurate, even if we assumed there was a microphone in the middle of the explosion).
A completely mute soundtrack will sometimes be used for outer space scenes for emphasis. This can be cool, but it shouldn't be taken as an achievement of realism, but just as another filming convention. Like an acceptable artistic license. (In other words, the movie makers are slightly toying with the fourth wall by having a completely mute soundtrack, as "heard" in the vacuum of space, even though there should be no camera nor microphone there.)
Hearing the space ship is no more wrong than having a mute soundtrack in this situation. Both are valid filming conventions. So stop complaining about it already.
If you demand for the soundtrack to be mute in outer space scenes, you are actually demanding for the movie to aknowledge the existence of the camera and a microphone attached to it in the movie's own reality, even though there shouldn't be any such things. You are demanding for the fourth wall to be broken. That's not reasonable, so stop it.
(This is not to say that in some cases having sound in space indeed breaks willing suspension of disbelief. If the camera is filming people inside a spaceship, and obviously depicting what they are hearing, and then another spaceship explodes, and these people can hear the explosion, that is, indeed, stretching the filming convention more than what is reasonable.)