[IV/3 IV][.]
[I][.]
x2
The intro's twice-played IV-I plagal motion (associated with religious/supernatural themes, although not strongly) establishes the key. The melody of the vocalizing (during the second repeat of IV-I) spells out the notes-of-the-chord descending (IV in root position, and then I in first inversion). All very straightforward and concordant so far, matching the mood of the beginning of the story.
[ii . . .] [. . . .]
b3 b3 b3 b3 b3 b3 b3 2 1 5 b3 2
4 4 4 4 4 4 4 3 2 6 4 3
Didn't know what time it was the lights were low-ow-ow
*L* L75%
Relative to the key, the persistent 4 in the melody is suspenseful. But laid on that bed of ii, it softens into a mellow b3 (for ii+b3). If you experiment, and sing 5 instead of 4 here (to get ii+4 instead), then you get a very different, and more sinister feel. More suspenseful, but arguably not in keeping with the mood at this point.
The melody essentially spells out the notes of the ii chord but throws in a +2 (relative to the harmony) for good measure (on "lights" and on the final "ow"). On that final "ow", if you sing 2 instead of 3, then you end on a plain-sounding ii+1. Instead, the 3 of the key gives a far more interesting and suspenseful ii+2 (a sus2, essentially). For this suspense to be relieved, either the melody or the harmony is going to have to bend. We'll see which it is in the next phrase.
A lyrical rhyme occurs at the 75% mark of this phrase (and the next), at bar 2, beat 3. 75% is the most frequently occuring location for rhymes in pop.
[I . . .] [. . . .]
3 2 3 3 3 3 2 3 5 3 2
2 3 3 3 3 2 3 5 3 2
I leaned back on my ra-di-o-o-o
*L* L75%
That +2 only lasted for half a beat, and it's the harmony that now capitulates, as is usual in pop. It was the melody that caused the disagreement with its +2 (a 3 relative to the key, which is held over to this phrase). The harmony restores agreement by turning that sustained 3 from a ii+2 into a I+3. This little cycle of protagonist-antagonist drama may be too brief to be enjoyed consciously, but it is enjoyed all the same.
This time 3 persists in the melody. Relative to the harmony, though, there's been some degree of consistency with persistent +b3s and now +3s. Among them, the melody leans back on a couple of very brief but perfectly timed +2s, which sound wonderfully naughty. And again the melody gets into trouble by walking us back down to another of those suspenseful +2s, which disagree with the harmony, and leaving us there. So that's going to have to be settled again.
[V . . .] [V7 . . .]
5 5 5 5 5 5 5 6
2 2 2 2 2 2 3 4 5 6 5 5 6 2 2-3
Some cat was lay-in' down some rock-'n'-roll, lot-ta soul, he said
Again, the +2 only lasted for half a beat, and again the harmony is the one to make the peace by turning that sustained 2 from a I+2 into a V+5 (this time, 2 persists in the melody, so we've been taken 4-3-2). Two identical pieces of delicious drama in a row, now. But that drama has backed the harmony into a suspenseful corner of a different kind. Now the harmony has been pushed up to the precarious dominant, hovering over the tonic like a hammer wanting to fall. And then that's cranked another turn with V7. Again, whether we're consciously aware of this tension yet or not, we certainly will be when the payoff comes in the chorus.
[I . bIII IV][ii]
This little turnaround (the bIII probably substitutes for V; it certainly would if it were a bIIIaug5) takes the song back to ii and another three phrases of verse that repeat the music of the first three. Except that there's something different in place of the turnaround.
[III][II . . .]
1 2
2 3
There's a
[I] [vi]
1 1' 2 1 b7 1 b7
1 1' 7 6 5 6 5
star-man wait-ing in the sky
What there is, is dramatic staccato piano tapping out two bars of the non-diatonic major versions of iii and ii, like morse code, and then exploding into the resolution-to-I-on-a-strong-beat that the ear has been craving (and the beat doesn't get any stronger than the beginning of a phrase). The roots of these chords are diatonic at least and they move 3-2-1 to take us home. Characteristic to good pop is a hook like this: a resolution to I right at the start of the chorus and then a swing away from it immediately. David's "star-man" leaps the octave from F3 to F4, soaring upward as dramatically as the octave in Judy's "some-where" leap. And the melody is a +1. But hooks like these work with any variant of I (as long as the root is 1) and generally also with any melody note. But I+1, as is used here, is wonderfully effective.
The chorus then travels iii-V-V7. This time, it uses a far more standard dominant-to-tonic (descending root movement of a fifth) to resolve back to the "starman" hook on I than the stepwise descent that was used the first time.
The repeat of the hook finds itself back at V7, but this time the cadence is interrupted, not perfect. The harmony moves to IV then iv-I. This IV-vi-I can be interpreted as the common cadence I-i-V. Then the hamony moves vi7-ii (another descending root movement of a fifth) and then finishes on a gentle stepwise slump back into I.