Just over a year ago, the Securities and Exchange Commission had launched an investigation into Elon Musk after he tweeted that he planned to take Tesla public. He was facing criticism, and a defamation lawsuit, for calling a Thai-cave rescuer a "pedo guy" and "child rapist." And when Musk took a hit off a joint during an Internet broadcast, it triggered a safety review from NASA that was concerned the billionaire maverick was going off the rails.