Donald Trump's aides scheduled a call between the U.S. president and Elon Musk for Friday after a huge public spat that saw threats fly over government contracts and included the world's richest man suggesting Trump should be impeached.

The worried reaction within space and national security agencies highlights the risks of government’s exclusive dependence on SpaceX for crucial tasks, including classified missions.

The US president says Musk has been "very disrespectful" and he has no interest in mending ties with the tech billionaire.