dude, I think Rocket queen is in B because all the power chords played are in the B major scale (B5, Db5, E5, Gb5, Ab5, Bb5) and they are played in different ways. B5 for example is played:

e-x-
b-x-
g-x-
d-9-
a-9-
e-7-

and

e-x-
b-x-
g-4-
d-4-
a-2-
e-x-