President Donald Trump has named a four-star Space Force general to oversee the development of Golden Dome -- the massively expensive space-based missile defense system promised during the first days of his second term.

Canadian Prime Minister Mark Carney says his government is talking to the U.S. about joining President Donald Trump's future Golden Dome missile defense program.

An idea for a space-based boost-phase defence system called Brilliant Pebbles was proposed towards the end of the 1980s. Rather than having large satellites with multiple missiles, it entailed having around 1,000 small individual missiles in orbit. It would have also used about 60 orbiting sensors called Brilliant Eyes to detect launches.

U.S. President Donald Trump picked a design for his Golden Dome missile defense system and named a leader of the ambitious $175 billion defense program. Here are details on Golden Dome, where the idea comes from and how it will work.