NASA paid $5 million for a probe into drug use at SpaceX after Elon Musk was filmed smoking weed. It still won't say what it found.

• Elon Musk appeared to smoke pot while taping an episode of Joe Rogan's podcast in 2018.
• One week later, NASA launched a probe into drug use at SpaceX.
• Business Insider obtained the results of the investigation — but NASA redacted them so heavily we don't know what they found.

The National Aeronautics and Space Administration probably knows quite a bit about Elon Musk's drug use, but it won't say what.