President Donald Trump tapped Transportation Secretary Sean Duffy to serve as the interim administrator of NASA on Wednesday, July 9. The role has been vacant since Trump withdrew his initial nominee, billionaire private astronaut Jared Isaacman, at the end of May.

The president previously rescinded his nomination of Jared Isaacman as the space agency’s next leader, citing the entrepreneur’s ties to Elon Musk.

Trump withdrew Musk-ally and billionaire Jared Isaacman’s nomination for the NASA administrator role in May and has since labeled him a “blue blooded Democrat.”