Republican senator Marco Rubio and Democrat Bill Nelson have opposed President Donald Trump‘s choice for NASA administrator, Oklahoma Congressman Jim Bridenstine.

Bridenstine was nominated on Friday but the senators have said a politician shouldn’t head the agency.

“The head of NASA ought to be a space professional, not a politician,” Nelson said in a brief written statement to POLITICO.

Nelson serves as the ranking member on the Senate’s Committee on Commerce, Science & Transportation, which oversees NASA and would hear Bridenstine’s nomination.

“I just think it could be devastating for the space program. Obviously, being from Florida, I’m very sensitive to anything that slows up NASA and its mission,” Rubio told POLITICO.

“It’s the one federal mission which has largely been free of politics and it’s at a critical juncture in its history,” Rubio said.

“I would hate to see an administrator held up — on [grounds of] partisanship, political arguments, past votes, or statements made in the past — because the agency can’t afford it and it can’t afford the controversy.”

Rubio said he would prefer an an administrator who has “respect of the people who work there from a leadership and even a scientific perspective.”

He added that he has relayed his thoughts to the White House.

Azeez