Over the weekend, militants tried but failed to blast their way into an American base in eastern Afghanistan, striking before dawn with rocket-propelled grenades and a car bomb.
Powered by ion propulsion instead of conventional rocket fuel, Dawn slid around Vesta on July 15 after a 1.7 billion-mile cruise.
以离子助推而非传统火箭燃料的“黎明号”在7月15日进入灶神星轨道之前已进行了一次17亿英里的巡航。
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Dawn is able to perform the trick of moving from one asteroid to another thanks to its ion-rocket engines, pioneered on an earlier NASA mission called Deep Space one.