NEW YORK, May 30 : Blue Origin faces a months-long setback after the explosion of a rocket damaged its launch pad, company and industry sources said, scrambling schedules for Amazon satellite launches and bolstering SpaceX's dominance in the commercial launch market. The mishap, which occurred during a test fire of the engines for the New Glenn rocket's launch next week, comes at a critical time for Jeff Bezos' business empire. His companies Blue Origin and Amazon are seeking to establish