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.

The White House until recently had considered a plan for SpaceX, Musk's rocket and satellite venture, to partner with software maker Palantir and drone builder Anduril to construct crucial elements of the project, dubbed "Golden Dome." The administration had instructed the Pentagon to prioritize a network of satellites for the purpose, these people said.

But a new framework for the system, which would seek to track and prevent possible missile attacks against the United States, is now being considered that could reduce the role of SpaceX. One possibility, the three people said, could initially forego SpaceX's satellite capabilities and focus on the expansion of existing ground systems for missile defense, instead.