"Rocket" is a nice little Mixolydian progression in the key of B. The progression resolves nicely to the F3(add4) chord at the end, making this an F# Mixolydian progression.
The chords are mostly first inversion triads—E/G# - B/D# - F#/A# - F#(add4). In Roman numerals, this would equate to a IV - I - V - V progression. These inverted triad voicing are well worth looking at, sounding really nice with a touch of overdrive and tremolo. Solo over this progression using the F# Mixolydian mode (B major scale).