Lawyers for Elon Musk’s SpaceX alleged in a lawsuit Thursday that the National Labor Relations Board’s in-house courts are unconstitutional and the agency should be prohibited from taking enforcement actions against it…

The filing comes on the heels of NLRB prosecutors issuing a complaint against the company accusing it of illegally firing eight employees who had circulated a letter in 2022 criticizing Musk, its combative CEO. The letter criticized him “for issuing inappropriate, disparaging, sexually charged comments on Twitter,” their lawyers told the NLRB. (Musk also owns the social media platform and rebranded it as X.)

SpaceX is seeking an injunction against the NLRB barring it from moving forward with that case against the company while the constitutional concerns are litigated.