Once in space, ion engines steadily propel a spacecraft until it travels faster than it would have using a chemical rocket.
一旦进入太空，离子发动机将稳步推进航天器，最终达到的速度会比使用普通火箭的更高。
The exhaust velocity, though, is enormous—more than ten times that of a chemical rocket—and this makes ion propulsion extremely efficient.
但其排气速度却异常惊人，大约为化学燃料火箭的十倍—这使得离子推进器的效率非常高。
The push power be produced is very tiny but the key point is that compare to produce same push power ion propulsion needs lesser fuels than traditional rocket.
由此产生的推力非常微小，但关键的一点是，对于产生相同的推力而言离子推进器所需的燃料要比传统火箭少。
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。
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.
由于“黎明”号的离子火箭发动机是能够完成从一个小行星移动到另一个小行星上的技巧。曾早些时候，这种技巧在美国国家航空航天局被称作“深太空一号”任务中首次开创。
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.
由于“黎明”号的离子火箭发动机是能够完成从一个小行星移动到另一个小行星上的技巧。曾早些时候，这种技巧在美国国家航空航天局被称作“深太空一号”任务中首次开创。
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