Hypersonic missiles are defined as missiles with a velocity of Mach 5 (five times the speed of sound) or above. The main limit on hypersonic speed is materials technology. For the purpose of this analysis, ordinary strategic nuclear ballistic missiles, although they have hypersonic speed, will not be treated here. What will be discussed are new weapons -- maneuvering hypersonic "aeroballistic" missiles, hypersonic boost-glide vehicles, and powered hypersonic cruise missiles. These constitute the new capabilities that are generally referred to as “hypersonic missiles." Russia has achieved an enormous advantage in hypersonic weapons while, on the other hand, the U.S. is playing catchup. Unlike U.S. programs, all Russian hypersonic weapons are apparently nuclear-armed or nuclear-capable.
The Russians are also well ahead of the U.S. in ordinary strategic ballistic missiles because they have been modernizing while we have not done so since the 1990s. In the case of ICBMs, our Minuteman force is vintage 1970. In 2012, Moscow Institute of Thermal Technology Corporation General Designer Yuri Solomonov said, “Strategic nuclear weapons developed by the Russian defense sector are 10-15 years ahead of what the West or the East may do.” This appears to be an understatement. Ordinary nuclear-armed ballistic missiles, if they carry missile defense countermeasures and maneuvering R.V.s, have many of the advantages of hypersonic missiles except against the most time urgent targets.