HTV - 2，一架巡航速度设计为20马赫的无人超音速飞机，于上月试飞失败。

HTV-2, an unmanned hypersonic aircraft designed to travel at Mach 20, failed during a test flight last month.

youdao

HTV - 2，一架巡航速度设计为20马赫的无人超音速飞机，于上月试飞失败。

HTV-2, an unmanned hypersonic aircraft designed to travel at Mach 20, failed during a test flight last month.

youdao