The role of Elon Musk's SpaceX in an ambitious new U.S. missile defense system is in question following the dramatic feud last week between the billionaire entrepreneur and President Donald Trump, according to three people familiar with the project.

JD Vance and Susie Wiles pushed Elon Musk to repair his relationship with President Trump after the tech billionaire blew up at the president in a dramatic and public falling out, according to people familiar with the matter. In a call last Friday, the vice president and the White House chief of staff urged Musk to put an end to the feud.

Elon Musk reached out and talked privately to President Donald Trump before the billionaire entrepreneur apologized for his harsh personal attacks.

President Donald Trump received a phone call from Elon Musk late on Monday before the billionaire expressed regret over some of the posts he made on social media last week, a White House source with knowledge of the matter said on Wednesday.