President Donald Trump's May 21 announcement of the Golden Dome, an ambitious missile-defense shield set to cost at least $175 billion, opened eyes in Washington, D.C. It should open some eyes on Wall Street, too.

The White House’s $175-billion plan to protect the U.S. from nuclear annihilation will probably cost much more—and deliver far less—than has been claimed, says nuclear arms expert Jeffrey Lewis

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.