In response to Chinese and Russian advances, the U.S. is building its own hypersonic arsenal.
More signs are emerging across the U.S. Department of Defense that it is taking the military threat of Chinese hypersonic weapons seriously, and redoubling efforts to field similar weapons of its own. Hypersonic weapons, which are considered High-Speed Maneuvering Weapons, travel at speeds greater than Mach 5, or five times the speed of sound. Even the fastest aircraft and conventional missiles are thought to fly in the low supersonic range. Some nuclear-tipped ballistic missiles travel at hypersonic speeds, but follow ballistic arcs and cannot execute radical maneuvering over long distances. Their extraordinary speed and precision means that a hypersonic weapon could potentially hit any target, anywhere in the world, in less than an hour.
A 2016 Air Force Studies Board report warned about the United States’ inability to defend against maneuverable high-supersonic and hypersonic conventional weapons. The report’s unclassified summary explained that the speeds, flight profiles, and maneuverability of hypersonic weapons make them largely immune to the defensive systems and networks that the United States developed to defend against either nuclear-tipped ballistic missiles or comparatively slow-flying cruise missiles. As a result, hypersonic weapons could constrain the U.S. military’s global presence and impede its ability to project force in key regions.
You can find additional information on some of the noted programs at the below links:
A Threat to America's Global Vigilance, Reach, and Power—High-Speed Maneuvering Weapons, Unclassified Summary; The National Academies of Sciences, Engineering, and Medicine; October 2016
Advanced Full Range Engine (AFRE) program, DARPA
Advanced Hypersonic Weapon (AHW) program, US Army Space and Missile Defence Command (USASMDC) / Army Forces Strategic Command (ARSTRAT)
Conventional Prompt Global Strike and Long-Range Ballistic Missiles: Background and Issues, Congressional Research Service, 24 February 2016
Hypersonic Air-breathing Weapon Concept (HAWC) program, DARPA
Tactical Boost Glide (TBG) program, DARPA