"Russia was concerned enough about the U.S. development of a Prompt Global Strike (PGS) capability in 2010 that they included restrictions in the the new Start treaty. It now appears that China has entered the game with their "Ultra-High Speed Missile Vehicle." While some in the Russian press may question whether fears of the PGS are 'rational' it appears that the race is on to develop the fastest weapons delivery system. The hypersonic arms race is focused on 'precise targeting, very rapid delivery of weapons, and greater survivability against missile and space defenses' with delivery systems traveling between Mach 5 and Mach 10 after being launched from 'near space.'"
