President Donald Trump has laid out new details of his ambitious plan to build a “Golden Dome” missile system to protect the United States from foreign attacks, saying it will be complete before he leaves office.

I would love to be able to build a system that actually worked 100 percent of the time,” Sen. Mark Kelly said at POLITICO’s Security Summit, echoing doubt about President Trump’s ambitious Golden Dome initiative.

The concept behind the missile defence system was that it would provide a way of effectively making nuclear weapons obsolete. Through the application of a defensive system that incorporated both land and space-based missiles, it was believed that any nuclear warhead fired would be destroyed before it was able to re-enter the Earth’s atmosphere.