US President-elect Donald Trump’s pick for Nasa administrator, tech billionaire Jared Isaacman, said on Wednesday that the private astronaut missions he has planned with Elon Musk’s SpaceX “may wind up on hold for a moment,” as he prepares to enter government service leading the US space agency.

“The future of the Polaris programme is a little bit of a question mark at the moment,” Isaacman, who was tapped by Trump last week to lead NASA, said in response to a question at the Spacepower 2024 conference in Orlando. “It may wind up on hold for a moment.”

Isaacman, a private astronaut and billionaire founder of payment processing company Shift4 Payments, owns the Polaris programme, a series of private missions on SpaceX vehicles that has made him a key associate of Musk.