The first reason is Elon Musk, whose singular vision and hard-driving leadership propelled SpaceX through its many ups and downs. It was Musk, for example, who pushed relentlessly for SpaceX to master reusable rockets, despite industry doubters and the grumblings of his own engineers.

Following SpaceX's letter to Congress, Musk escalated his rhetoric on Thursday, declaring, "Enough is enough." He accused the FAA of "attacking @SpaceX for petty matters that have nothing to do with safety, while neglecting real safety issues at Boeing."