Some experts are worried about the cost and timeline of U.S. President Donald Trump's proposed "Golden Dome" missile defence system, which Canada has expressed interest in joining. They also say it could set off a space-based arms race that would escalate global tensions.

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.

The Conversation U.S. asked Iain Boyd, an aerospace engineer and director of the Center for National Security Initiatives at the University of Colorado Boulder, about the Golden Dome plan and the feasibility of Trump’s claims. Boyd receives funding for research unrelated to Golden Dome from defense contractor Lockheed Martin.