Fred Lerdahl's book Tonal pitch space (Oxford 2001) gives us a highly-developed method of examining the perceptual organization of tonal pitch spaces, generally assuming a diatonic reference. Lerdahl's system provides a concise method of illustrating the chords that arise from these spaces and the perceptual distances between them. This theory is easily adapted to non-diatonic pitch spaces. In this paper, I use Lerdahl's theories to calculate the perceptual distances between chords in Messiaen's piano prelude, "Les sons impalpables du rève..." These distance values can be organized into an enneatonic chordal pitch space, and we can trace the voice leadings through this space. The analysis shows that voice leading distance and perceptual distance are not directly related. Our journey through chordal pitch space allows us to construct time-span and prolongational reductions of the piece (as in A generative theory of tonal music (MIT Press, 1983)) and consequently discuss the hierarchical organization of the music.