Ten years ago, a European Space Agency rocket took off with a spacecraft called Rosetta, on a mission to perform the most detailed study of a comet.While asteroids are large rocks, almost like small planets, comets are mostly made of ice,says Ralph Cordey, the business manager for Airbus Defense and Space, which built the Rosetta spacecraft.“We know today that our Earth has a great deal of water on it,we don't know exactly where it came from and it's likely that comets had a lot to do with that process," said Cordey.It took more than 10 years for Rosetta to make three swings around Earth and one around Mars - gathering enough speed to reach the comet named 67P / Churyumov-Gerasimenko, 400,000 kilometers from Earth.For the last two-and-half years many of its onboard systems were in the sleep mode to save energy, says Airbus engineer Simon Barraclough.“So when we're close to the Sun, a lot of things are on. When we're further from the Sun, a lot of things are off," said Barraclough.A 'wake-up call' in January brought cheers in the mission headquarters in Darmstadt, Germany,as a signal from Rosetta indicated that its computer was wide awake again.The spacecraft will soon start orbiting the comet at a distance of about 10 kilometers, taking measurements and mapping its surface.
10年前，欧洲航天局发射了名为罗塞塔的航天器来完成对一颗彗星最详尽的研究。尽管小行星都是大的岩石，几乎和小的星球差不多，而彗星是由冰构成的，欧洲航天防御暨航天公司的商业经理科尔代如是说，罗塞塔航天器就是这家机构建造的。“我们现在知道地球上有大量的水，而我们并不知道这些水到底从哪里来，彗星很可能在其中扮演了很大角色。”罗塞塔花了10多年的时间才将其在地球附近的三个翼和水星附近的一个翼获得足够的速度从而抵达彗星67P/Churyumov-Gerasimenko，这颗彗星距离地球40万公里。Airbus的工程师西蒙・巴拉克罗说，在过去两年半里，航天器上的很多系统都处于休眠状态以节能。“所以当我们接近太阳时，很多系统都打开了，当航天器远离太阳时，很多系统都关闭了。”一月份的一个“醒来呼叫”令德国达姆施塔特任务中心响起了欢呼声，当时来自罗塞塔的信号表明其电脑再次完全醒来。这颗航天器将很快开始在距离这颗彗星约10公里的地方轨道航行，测量温度并绘制彗星表面地图。
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