As Elon Musk and President Donald Trump traded jabs on their rival social media platforms, their feud has escalated beyond a public spat, threatening billions of dollars in federal contracts and throwing the future of America's space program into question.

President Trump has threatened to cut the US government’s ties with Elon Musk’s businesses after the former “first buddy” fell out with the commander in chief. As Musk began slashing away at what he called government waste with the Department of Government Efficiency earlier this year,