Quest for 'super-duper missile' pits US against key rivals

They fly at speeds of a mile a second or faster and maneuver in ways that make them extra hard to detect and destroy in flight.

President Donald Trump calls them a super-duper missile," though they're better known as hypersonic weapons. And they are at the heart of Trump administration worries about China and Russia.

For decades the United States has searched for ways to get ultra-fast flight right. But it has done so in fits and starts.

Now, with China and Russia arguably ahead in this chase, the Trump administration is pouring billions of dollars a year into hypersonic offense and defense.

The Pentagon makes no bones about their purpose.

Our ultimate goal is, simply, we want to dominate future battlefields, Mark Lewis, the Pentagon's director of defense research and engineering for modernisation, told reporters in March.

Critics argue that hypersonic weapons would add little to the United States' ability to deter war. Some think they could ignite a new, destabilising arms race.

A look at hypersonic weapons: