US tested hypersonic missile in mid-March but kept it quiet to avoid escalating tensions with Russia

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, according to a defense official familiar with the matter.

The Hypersonic Air-breathing Weapon Concept (HAWC) was launched from a B-52 bomber off the west coast, the official said, 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...