This is "The Union", by Marty O'Donnel and Michael Salvatori. Not "Excerpt From the Union". That is a rip of this that was used in the game. This is from a project called "Music of the Spheres". MotS was intended to be released seperately from the Destiny soundtrack and Destiny launch; however, after Marty was fired from Bungie, the project seems to have been lost to the sands of time and been forgotten. This is the only full movement that the public has access to. Enjoy. :)