The U.S. Air Force's AGM-183A hypersonic missile failed the second air-launched flight test, and the rocket engine failed to ignite.

Iran PressAmerica: The Lockheed Martin-developed missile’s booster rocket did not ignite, in what was the second failed launch attempt of the prototype weapon after an initial test in April also went awry.

The U.S. Air Force insisted that the failed launch still provided valuable test data and showed several first events. The project will continue to develop in the direction of deployment in the early 2020s. The US Air Force confirmed last week that the overall test plan for the AGM-183A test launch is the same as the test plan that failed in April. 

The US is in a hypersonic missile arms race with China and Russia. Beijing and Moscow see hypersonic missiles as a way to get a jump on Washington, as the M5-plus weapons can evade the existing US missile defence shield and travel so quickly that targets have little to no warning before impact.

The United States has failed in several missile tests in recent months, including the Minuteman III ballistic missile.