Tesla CEO Elon Musk on Friday openly criticised former Amazon founder and billionaire Jeff Bezos on Twitter, saying he has taken retirement only to file lawsuits against SpaceX. Earlier this month, Bezos-owned space firm Blue Origin sued NASA for picking Musk-owned SpaceX for its prestigious $2.9 billion Moon lander programme.

After the lawsuit, the US space agency put SpaceX's contract on hold for the second time. Replying to a follower, Musk tweeted: "Turns out Bezos retired in order to pursue a full-time job filing lawsuits against SpaceX..." Amazon this week urged the US Federal Communications Commission (FCC) to dismiss plans by SpaceX to launch another cluster of satellites to power its ambitious space internet service called Starlink.