Russia used a hypersonic missile against a Ukrainian arms depot in the western part of the country on March 18, 2022. That might sound scary, but the technology the Russians used is not particularly advanced. However, next-generation hypersonic missiles that Russia, China and the US are developing do pose a significant threat to national and global security.
I am an aerospace engineer who studies space and defense systems, including hypersonic systems. These new systems pose an important challenge due to their maneuverability all along their trajectory. Because their flight paths can change as they travel, these missiles must be tracked throughout their flight.
A second important challenge stems from the fact that they operate in a different region of the atmosphere from other existing threats. The new hypersonic weapons fly much higher than slower subsonic missiles but much lower than intercontinental ballistic missiles. The US and its allies do not have good tracking coverage for this in-between region, nor does Russia or China.