The first Trump administration floated a space weapon concept in March 2018: a neutral particle beam in space. But it ultimately shelved the idea because of the massive amount of power needed to destroy a missile with directed energy.

An executive order said the United States faced a “catastrophic threat” from advanced aerial weapons. But a defense system like Israel’s may not be feasible in the country, which is more than 400 times larger.

When it comes to protecting U.S. territory from missiles fired by such nuclear-powered countries as Russia, China, and North Korea (which is Trump’s goal in ordering this project), something like Iron Dome would have no capability whatsoever; and