万花筒 2013-05-16&05-18 美X-51A破高超音速记录：6分钟冲刺5.1马赫

 This was the flight of the Boeing X51A Waverrider. The company and the US military says it’s made aviation history. The unmanned craft achieved the longest ever hypersonic flights by a jet fuelled-propelling.

 

It hurtled alone at 5 times the speed of sound for 3 and a half minutes. It covered 213 nautical¹ miles in just over 6 minutes across the skies of California. The US Air Force says the craft was intended to demonstrate the new technology, not as a prototype for new weapons. It was the last 4 X51A craft built by Boeing. The end of the dramatic journey was a little less than glorious. It was crashed into the Pacific ocean in a controlled dive.

1 nautical   

adj.海上的，航海的，船员的

参考例句：

• A nautical mile is 1,852 meters.一海里等于1852米。
• It is 206 nautical miles from our present location.距离我们现在的位置有206海里。