President Trump's missile defense project, called the "Golden Dome for America," aims to protect the U.S. from foreign threats. But it has a steep price and has been criticized by China as threatening to increase the risks of militarizing space and a global arms race.

U.S. President Donald Trump unveiled a plan for his ambitious "Golden Dome" missile defense shield this week, stating it will cost $175 billion and take about three years to develop — but some experts say the price tag could be many times higher.