Though NASA's "Artemis" Moon mission was announced in Trump's first term, he has since openly mused about heading straight to Mars, prompting concerns that China or others could fill the gap on the lunar surface.

The notion has gained traction as Elon Musk -- the world's richest person and SpaceX chief who has long eyed a human mission to Mars -- became a key Trump ally and advisor.

"We will prioritize sending American astronauts to Mars," businessman Jared Isaacman told the Senate committee overseeing his appointment.

"And along the way, we will inevitably have the capabilities to return to the Moon and determine the scientific, economic and national security benefits for maintaining a presence on the lunar surface," he said.

Musk founded his successful space company with the idea of making humanity a multiplanetary species.

Isaacman, an e-payments billionaire, is a close Musk ally who has flown to space twice with SpaceX as a private astronaut.

He did not appear to view a bid for Mars as incompatible with the Artemis mission, telling senators he did not see any "tough trades here."

"I absolutely want to see us return to the Moon," he said, adding that he did not think NASA would have to make "a binary decision of Moon versus Mars, or Moon has to come first versus Mars."

"I think we could be paralleling these efforts and doing the near impossible, which is exactly why the American taxpayers funded NASA in the first place," he said.

A "first step" would be a return to the Moon, he said, adding: "we should be doing both."

Texas Senator Ted Cruz underscored the strategic value of the Moon when it came to US national security back on Earth.

"We must stay the course -- an extreme shift in priorities at this stage would almost certainly mean a red moon, ceding ground to China for generations to come," the Republican, whose state hosts NASA's massive Johnson Space Center, told the hearing.

"I am hard pressed to think of a more catastrophic mistake we could make in space than saying to Communist China, 'the Moon is yours,'" Cruz continued.

But Isaacman insisted both a moonshot and a Mars-shot were possible.

"We can chart a course for Mars in line with the president's vision to return to the Moon before the Chinese can get there," he said.

Isaacman has also reportedly intervened at the last moment to prevent NASA from suffering the deep cuts made at other agencies by Musk's so-called Department of Government Efficiency.