2013年5月1日,X-51A完成了其第四次也是最成功的一次飞行,导弹以马赫数5.1的速度飞行约420 km。洛马公司臭鼬工厂目前正在争取高速打击武器(HSSW)的研发项目,并相信2020年能研制出用于实战的速度为马赫数6的高超声速导弹,且其成本将降低一个数量级。2010年,X-51A飞行器进行了首次飞行试验;2012年中期,美国空军研究实验室开始为潜在 On May 1, 2013, the X-51A completed its fourth and most successful flight, with approximately 420 km of missiles flying at Mach 5.1. Loma’s Skunk Factory is currently working on a High Speed ​​Strike Weapon (HSSW) R & D project and believes it is possible to develop Hypersonic missiles at Mach 6 speeds in real terms by 2020 at an order of magnitude lower cost. In 2010, the first flight test of the X-51A aircraft was carried out. In mid-2012, the U.S. Air Force Research Laboratory began to work as a potential