Duffy takes over from Janet Petro, who had served as acting NASA administrator since Trump was inaugurated on Jan. 20.

Former Wisconsin Congressman Sean Duffy has been tapped by President Donald Trump to take the helm of NASA, the president announced this week.

Meanwhile, Duffy must navigate tensions between the White House budget, which would cut nearly a quarter of the agency’s funding, and the Senate’s version, which appears set to back an increase of NA...