Bill Nelson steps down as NASA chief as Trump begins second term

On January 23, 2025By Littum

Bill Nelson has stepped down as NASA administrator, ending half a century of public service.

Nelson and NASA Deputy Administrator Pam Melroy left the agency on Monday (Jan. 20), the day Donald Trump began his second term as president. Trump has named Janet Petro, who most recently served as director of the Kennedy Space Center (KSC) in Florida, as NASA’s interim chief.

“As I leave public office today after 53 years, thank you for the great privilege of a lifetime of serving the people of our country. I am humbled and grateful,” Nelson said in a Monday X post.

Nelson, a member of the Democratic Party, began his US government career in 1972 when he was elected to the Florida House of Representatives.

He won a seat in the US House six years later, representing Florida’s 9th congressional district. The district is close to the state’s famous Space Coast, which is home to both KSC and the Cape Canaveral Space Force Station.

In January 1986, Nelson flew on the STS-61-C mission of the space shuttle Columbia, becoming the first sitting member of the US House to reach the final frontier. The pilot of that flight was Charlie Bolden, who served as NASA chief during the Obama administration. STS-61-C was also the mission immediately preceding the STS-51-L flight of the space shuttle Challenger, which ended in tragedy just 73 seconds after liftoff on January 28, 1986.

Related: ‘We will pursue our manifest destiny into the stars.’ President Trump wants astronauts to raise the American flag on Mars

a man in a white three-button shirt and blue pants smiles while holding a peeled grapefruit in a cramped space shuttle cabin

Former NASA Administrator Bill Nelson peels a grapefruit on NASA’s Space Shuttle Columbia during an Earth orbit as part of the STS 61-C mission, which flew between January 12 and January 19, 1986. (Image credit: NASA via CNP/Getty Images)

In 1990, Nelson attempted to become the Democratic nominee in Florida’s gubernatorial race, but lost the primary to Lawton Chiles. Four years later, Nelson won office as Florida’s treasurer, insurance commissioner and fire marshal. He was re-elected to this post in 1998, but resigned in January 2001 after winning a seat in the US Senate.

Nelson was re-elected to the Senate in 2006 and 2012, but narrowly lost to Republican Rick Scott in 2018. Nelson was appointed to NASA’s advisory council in 2019, and President Joe Biden nominated him to be NASA administrator in February 2019. The Senate unanimously confirmed him two months later.

Nelson’s tenure as NASA chief was eventful, with the launch of the $10 billion James Webb Space Telescope, the Europa Clipper probe, the asteroid-crushing DART spacecraft, and the Artemis 1 moon mission, among other high-profile efforts.

Artemis 1, as its name suggests, was the first mission in the Artemis program for lunar exploration, which began during the first Trump presidency.

Petro is Trump’s pick for interim NASA chief, but the president has someone else in mind for the full job — billionaire tech entrepreneur and private spaceflight veteran Jared Isaacman, whom Trump formally nominated on Monday.

IN another X post on Monday, Nelson offered some advice to Isaacman — or whoever gets the job if the Senate doesn’t confirm Trump’s first choice.

“We are merely temporary stewards of this extraordinary space agency. Humanity’s dream in the stars is bigger than any of us — bigger than any person, any nation and any generation,” Nelson wrote in a two-page “letter to the next NASA- administrator.”

“As a former administrator, as a proud American, I’m rooting for you,” he added. “Your success is NASA’s success, and NASA’s success is the nation’s success. I am at your service to help in any way I can.”