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.

"The easiest way to save money in our Budget … is to terminate Elon's Governmental Subsidies and Contracts," Trump said in a post.

A bitter flare-up with President Trump has helped reduce Elon Musk’s net worth by $98 billion. He remains the world's richest man, for now.