As Russia and China continue their march toward fielding hypersonics, the Pentagon and its largest weapons supplier have shared limited details about their own efforts on similar weapons.
After securing a $928 million U.S. Air Force contract to build an undefined number of hypersonic conventional strike weapons, a Lockheed Martin 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.
The development comes as potential adversaries make their move in the hypersonic field. America's top nuclear commander described a grim scenario for U.S. forces facing off against hypersonic weapons.
"We don't have any defense that could deny the employment of such a weapon against us," Air Force Gen. John Hyten, commander of U.S. Strategic Command, told the Senate Armed Services Committee earlier this year.
"Both Russia and China are aggressively pursuing hypersonic capabilities," Hyten added. "We've watched them test those capabilities."
Lockheed will be responsible for designing, engineering, weapon integration and logistical support on the U.S. hypersonic project, which was announced in April.
The hypersonic strike weapon will be developed in the northern Alabama city of Huntsville, which is dubbed "Rocket City" as it was the birthplace of America's rocket program.
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. That means a hypersonic weapon can travel about one mile per second. For reference, commercial airliners fly subsonically, just below Mach 1 whereas modern fighter jets can travel supersonically at Mach 2 or Mach 3.
Previously, CNBC reported that multiple U.S. intelligence reports assess that Russia will be capable of fielding a hypersonic glide vehicle called Avangard, a weapon that no country can defend against, by 2020.
The hypersonic weapon is capable of carrying a nuclear warhead, is designed to sit atop an intercontinental ballistic missile. Once launched, it uses aerodynamic forces to sail on top of the atmosphere.
Sources, who spoke to CNBC on the condition of anonymity, previously said Russia successfully tested the weapon twice in 2016. The third known test of the device was carried out in October 2017 and resulted in a failure when the platform crashed seconds before striking its target.
Meanwhile, Russia is expected to test its hypersonic glide vehicle again this summer.