The United States is not alone in developing hypersonic weapons, whose speed and maneuverability make them difficult to track and intercept WASHINGTON: The US Air Force said on Tuesday it had conducted a successful test of an air-launched hypersonic weapon in the Pacific Ocean. The test was conducted on Sunday after a B-52 bomber left the island of Guam carrying an Air-launched Rapid Response Weapon (ARRW), the Air Force said in a statement. Though the US Air Force called the test a success, it did not disclose the speed the weapon flew. In past tests the ARRW has flown at least five times the speed of sound. The United States is not alone in developing hypersonic weapons, whose speed and maneuverability make them difficult to track and intercept. Russia has fired hypersonic missiles at targets in Ukraine and China has tested hypersonic weapons, US military officials have said. China’s foreign ministry denied in October that it had conducted a weapons test.