"Our 2018 National Defense Strategy also prioritizes investing in technological innovation to increase lethality," Mattis said in prepared testimony to the Senate Armed Services Committee. "Cyber, advanced computing, big data analytics, artificial intelligence, autonomy, robotics, miniaturization, additive manufacturing, directed energy, and hypersonics are the very technologies that we need to fight and win wars of the future."
Military planners have long eyed hypersonic flight at up to five times the speed of sound as a means to defeat conventional missile and air defenses.
Earlier this year, Russian President Vladimir Putin said Russia had successfully tested a hypersonic cruise missile.
US Department of Defense researchers responded to Putin’s remarks by announcing that the 2019 defense budget puts the US on track to test a series of hypersonic prototypes in the coming years.