Dawn Spacecraft

The Dawn spacecraft entered the asteroid belt and orbited and explored the giant protoplanet Vesta in 2011-2012. As of August, 2015, it is in orbit about and exploring a second new world, dwarf planet Ceres.

“黎明”号航天器于2011年至2012年进入小行星带，并围绕和探索了巨行星前体行星维斯塔。截至2015年8月，它正在围绕并探索第二个新世界——矮行星谷神星。资料来源：NASA/ Dawn Mission site

The Dawn spacecraft was launched on September 27, 2007 and achieved orbit around Vesta on July 15, 2011. It used a gravity boost from Mars in February 2009 to assist on its journey to the asteroid belt. Leaving its Vesta orbit on September 4, 2012 it reached Ceres on March 6, 2015. Among its instruments are framing cameras, a visible and infrared mapping spectrometer, and gammma and neutron detectors.

黎明号探测器于2007年9月27日发射，于2011年7月15日进入灶神星轨道。它利用2009年2月从火星获得的重力助推，协助其前往小行星带。2012年9月4日离开灶神星轨道，于2015年3月6日抵达谷神星。其仪器包括成像相机、可见和红外映射光谱仪以及伽马射线和中子探测器。

Dawn accomplished the largest propulsive acceleration of any spacecraft to date, with a change in velocity of more than 4.2 miles per second (6.7 kilometers per second), due to its ion engines. The engines expel ions to create thrust and provide higher spacecraft speeds than any other technology currently available. The Dawn ion propulsion system ionizes xenon atoms with an electron beam, accelerates the resulting ions with >1000 volts to achieve an ejection speed as high as 40 km/s (89,000 mi/hr), which is about 10 times the ejection speed for typical propellants. This leads to an efficiency high enough that it can be powered by the energy collected by the onboard solar collectors as long as the spacecraft is less than twice the Earth's distance from the Sun.

黎明号实现了迄今为止航天器最大的推进加速度，其速度变化超过每秒4.2英里（6.7公里/秒），这是由于其离子引擎的作用。引擎通过喷射离子产生推力，并提供比任何其他现有技术更高的航天器速度。黎明离子推进系统利用电子束使氙原子电离，然后在超过1000伏的电压下加速这些离子，达到最高40公里/秒（89000英里/小时）的喷射速度，这大约是常规推进剂喷射速度的10倍。这使得其效率足够高，可以由航天器上的太阳能收集器收集的能量持续供电，只要航天器距离太阳的距离不超过地球距离的两倍。