According to CNN, "The US successfully tested a hypersonic missile in mid-March but kept it quiet for two weeks to avoid escalating tensions with Russia as President Joe Biden was about to travel to Europe," where he was scheduled to participate in the extraordinary session of NATO as well as in the G7 summit.
The US-based television network reported referring to its anonymous defense official familiar with the matter that "the Hypersonic Air-breathing Weapon Concept (HAWC) was launched from a B-52 bomber off the west coast…, in the first successful test of the Lockheed Martin version of the system. A booster engine accelerated the missile to high speed, at which point the air-breathing scramjet engine ignited and propelled the missile at hypersonic speeds of Mach 5 and above."
The defense official refused to give further details, according to CNN, and the agency only added that "the missile flew above 65,000 feet [over 19.8 kilometers] and for more than 300 miles [almost 483 kilometers]. But even at the lower end of the hypersonic range — about 3,800 miles per hour -, a flight of 300 miles is less than 5 minutes".
The US test is the second test of a HAWC missile, and it is the first of the Lockheed Martin version of the weapon. Last September, the Air Force tested the Raytheon HAWC, powered by a Northrop Grumman scramjet engine.