Elon Musk is taking Amazon's recent protest with Federal Communications Commission against SpaceX personal, blasting Jeff Bezos, his space rival, on social media.  

The SpaceX CEO criticized Bezos in a tweet on Friday, saying it 'turns out Besos [sic] retired in order to purse a full-time job filing lawsuits against SpaceX.'  

Amazon filed a protest with the FCC on Wednesday to block SpaceX from launching another batch of its Starlink satellites. 

The petition was filed by Amazon's subsidiary Kupier Systems, which is developing its own internet satellites to compete with SpaceX's business.

Kupier's filing is not to stop Starlink altogether, but questioning SpaceX's plans that it says goes against FCC's rules.

'The SpaceX Amendment proposes two different configurations for the nearly 30,000 satellites of its Gen2 System, each of which arranges these satellites along very different orbital parameters,' Mariah Dodson Shuman, corporate counsel for Kuiper Systems, wrote in the document.

'SpaceX's novel approach of applying for two mutually exclusive configurations is at odds with both the Commission's rules and public policy and we urge the Commission to dismiss this amendment.' 

The filing follows another complaint from Bezos against SpaceX – the Amazon founder's Blue Origin is suing NASA, claiming a $2.9 billion lunar lander contract was unfairly awarded to Musk's SpaceX earlier this year.