The big powers – the US, Russia and China – and the near-big powers such as India are all hard at work on developing hypersonic weapons. As these go from research, test and evaluation to actual fielding, the race is also on to find a way to counter the weapon systems.

At least one country, Russia, thinks it has an answer in its S-500 "Prometheus" anti-ballistic missile system. The Russians claim the S-500 is capable of destroying hypersonic cruise missiles at speeds higher than Mach 5.  

A hypersonic weapon is one that is defined as achieving speeds of Mach 5 or greater. So far at least, the Russians have conducted no tests against any hypersonic targets and the S-500 still is not deployed anywhere.

The US is going in a different direction, as are the Europeans, in at least setting up some sort of space-based defense system, on the theory that such a system will permit early detection and intercept of hypersonic weapons.