The space agency executive said Mr Biden was stepping down because he needed a “trusted” manager.
“The right question here is, ‘What is NASA’s best interest as a company, and what is the best interest in America’s research program?’ He said during the flight week.
“For that, all you need is someone who has a close relationship with the President of the United States. You need someone trusted by management.
“I don’t think I would be the right person for that in a new administration.
“We’ve had a lot of success, but it’s because of relationships.
“You have to have those relationships. Whoever the president is, they have to have someone they know and trust, and there has to be someone who trusts the administration.
“That person isn’t going to be me.”
Mr. Brightenstein, a former Republican congressman from Oklahoma, was appointed in 2017 by Mr. Trump.
His appointment was criticized for politicizing the agency, and he was confirmed in April 2018 on a party basis.
Under his leadership, NASA’s goal is to return to the moon at the end of the decade for the first time since the Apollo era in the 1960s and 1970s.
NASA’s Artemis project aims to land the first woman on the moon by 2024.