The space agency’s administrator said Mr Biden would step down if he needed a “reliable” person in charge.

“The right question here is, ‘What is NASA’s greatest interest as an agency and what is in the best interests of America’s search program?’ “He told Aviation Week.

“All you need for that is someone close to the President of the United States of America who needs to be trusted by your administration.

“I don’t think I’ll be the right person for this in the new administration.

“We have had a lot of success, but it’s because of the relationship.

“You have to have these relationships. No matter who the president is, they have to have someone with whom they know and trust, and someone who depends on the administration.

“That person isn’t going to be mine.”

Mr. Trump appointed Mr. Bridenstein, a former Republican congressman from Oklahoma, in 2011.

His nomination for the agency’s politicization was criticized and he was confirmed in April 2018 on the party line.

Under his leadership, NASA’s goal is to return to the moon in the late 1940s and 1970s for the first time since the Apollo era.

NASA’s Artemis program aims to land the first woman on the moon by 2024.