It's a song about freedom, isolation and loneliness.
Off topic: it reminds me a lot of the Firefly (Joss Whedon) episode 'Out of Gas' because in that episode you're shown the reality of the abandonment and isolation of space when the ship's engine fails in the middle of nowhere, and the in the song the signal sound is very picturesque of Malcolm Reynold's signal which he sends out into space in a desperate attempt to save himself and his crew.
It's a song about freedom, isolation and loneliness.
Off topic: it reminds me a lot of the Firefly (Joss Whedon) episode 'Out of Gas' because in that episode you're shown the reality of the abandonment and isolation of space when the ship's engine fails in the middle of nowhere, and the in the song the signal sound is very picturesque of Malcolm Reynold's signal which he sends out into space in a desperate attempt to save himself and his crew.