The head of the Missile Defense Agency says it is only a matter of time before hypersonic weapons are added to the arsenals of America's adversaries.
"The hypersonic threat is real, it is not imagination," Air Force Lt. Gen. Samuel Greaves explained Tuesday at the Capitol Hill Club, noting that defending against hypersonics has become a top priority for the agency.
A hypersonic weapon is a missile that travels at Mach 5 or higher, which is at least five times faster than the speed of sound. This means that a hypersonic weapon can travel about one mile per second.
"Those who have access to the information know that ... the capability to deploy hypersonic weapons has been done. It's real, it's coming, it's a matter of time," Greaves said. "The question will be what have we done to prepare ourselves to mitigate or eliminate that threat five, six, or seven years from now when it shows up," Greaves added.
Greaves comments come amid that assess Russia will be capable of fielding a hypersonic glide vehicle, a weapon that no country can defend against, by 2020.
The weapon, dubbed Avangard, is designed to sit atop an intercontinental ballistic missile. Once launched, it uses aerodynamic forces to sail on top of the atmosphere.
Sources familiar with the U.S. intelligence reports assess that Avangard is equipped with onboard countermeasures that are able to defeat even the most advanced missile-defense systems. The weapon is also highly maneuverable and, therefore, unpredictable, which make it difficult to track.
During a , Russian President Vladimir Putin claimed Avangard was capable of reaching targets at a speed of 20 times the speed of sound and strikes "like a fireball." He also said that the hypersonic warhead had already entered serial production.
The intelligence reports, which were compiled this spring, found that Russia successfully tested a hypersonic glide vehicle, which could carry a nuclear warhead, twice in 2016. The third known test was carried out in October 2017 and resulted in a failure when the platform crashed seconds before striking its target.
The Kremlin is expected to conduct a fourth test sometime this summer.
Meanwhile, the Pentagon and its largest weapons supplier have shared limited details about their own efforts on similar weapons.
After securing a to build an undefined number of hypersonic conventional strike weapons, a representative noted that the company will "not be able to host any interviews on this program" due to its sensitive nature.
Similarly, a U.S. Air Force spokesman said the service will not be making any announcements in the near future regarding its work on hypersonics.