There is no way around the fact that Star Trek: The Motion Picture is a flawed mess, and that one of the biggest problems with the film is the overreliance on the special effects. Much of this is because of the post-production crunch which meant that effects sequences hadn't been completed in time to be edited down, and as a result there are long stretches in the film where nothing really happens. The effects are quite expensive and are admittedly impressive for their era, but unfortunately that's all they are.
Of course, this basically meant that Jerry Goldsmith was scoring to yards and yards of black leader. They had some of the timings down but most of the effects, especially for the V'Ger sequences, had not been completed. Another problem plagued the score, however, which was that the theme hadn't really been finalized when the score had commenced recording. The first sessions included several key sequences of the film, and while several cues recorded then were indeed used in the film, such as "Floating Office" and "Transporter Malfunction," the score for those key moments, while beautiful, didn't really work. The answer, as Robert Wise pointed out and Goldsmith sheepishly agreed later, was that he didn't have a theme yet.
One of these sequences was "Leaving Drydock." The piece that Goldsmith originally composed for the scene featured a pronounced nautical flavor that Wise objected to (Horner's score for the first Star Trek sequel would feature a return to that aesthetic). The music also has an element of lightness to it that reminds one of his work on The Blue Max. However, as pretty as it is - and it certainly is that - it really doesn't move the scene along. It just kind of reflects the attractive images with attractive music. The piece doesn't complete the sequence, which means that this may have been when it became apparent that this approach wasn't working. This is the sequence with the original cue (there is no other sound in the clip):
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When Goldsmith came up with that now-iconic theme, he emphasized the more militaristic aspect in the subsequent re-scoring of the scene. The result not only was more effective by having a solidified theme which had been introduced in the main title and been developed in several cues (most noticably in "
The Enterprise"), but also by giving the sequence a forward momentum that it needed very much. This is what appears in the film (with full soundtrack this time), and one can immediately hear how the scene has changed:
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