Today, tomorrow, learn English naturally. 天天自然学英语
Big, dead European satellite will crash back to Earth this month
A dead European satellite will come crashing back to Earth later this month, in a fiery death dive that its handlers will monitor carefully.
The incoming spacecraft is the European Space Agency's (ESA) European Remote Sensing 2 (ERS-2) satellite, which launched to Earth orbit in April 1995 and wrapped up its Earth-observing duties in September 2011.
ESA began preparing for ERS-2's demise even before its primary mission ended, performing 66 engine burns in July and August of 2011. Those maneuvers "used up the satellite's remaining fuel and lowered its average altitude from 785 km [488 miles] to about 573 km [356 miles] in order to greatly reduce the risk of collision with other satellites or space debris and to ensure the satellite's orbit would decay fast enough for it to reenter Earth's atmosphere within the next 15 years," ESA officials wrote in an FAQ about the coming reentry.
ERS-2 "was the most sophisticated Earth-observation spacecraft ever developed and launched by Europe," according to the FAQ. At the time of liftoff, it weighed 5,547 pounds (2,516 kilograms). Now, without fuel, it tips the scales at about 5,057 pounds (2,294 kg).
That's plenty hefty, but ERS-2 is far from a space junk outlier; objects of similar mass reenter Earth's atmosphere every week or two on average, ESA officials wrote.
And far larger objects have crashed back to Earth recently. For example, the 23-ton core stage of China's Long March 5B rocket comes down uncontrolled about a week or so after each liftoff, a design feature that has drawn the ire of NASA officials and others in the space community.
These dramatic reentries have occurred three times in the past three years; Long March 5B vehicles lofted the three modules for China's Tiangong space station, in April 2021, July 2022 and October 2022.
ERS-2's fall has been much more protracted, unfolding over the past 13 years. But the satellite is now low enough to be pulled down relatively quickly by atmospheric drag, and the process will only accelerate over the coming days. (This fall is uncontrolled; ERS-2 is out of fuel and therefore can perform no more engine burns.)
It's too soon to predict where and when ERS-2 will hit the bulk of Earth's atmosphere. But chances are good it will reenter over the ocean, as water covers about 70% of our planet's surface.
The satellite will break apart when it hits an altitude of about 50 miles (80 km), according to the FAQ. Most of the resulting fragments will then burn up in the atmosphere. Don't worry too much about the ones the make it down to the surface, for they'll contain no toxic or radioactive substances, according to ESA.
And you'd have to be really, really unlucky to get hit by one of them — or any piece of space junk, for that matter.
"The annual risk of an individual human being injured by space debris is under 1 in 100 billion," ESA officials wrote in the FAQ. That's roughly 65,000 times lower than the risk of being hit by lightning.
ESA will keep us updated about ERS-2's dramatic return to Earth over the coming days. So keep checking back here at Space.com — we'll pass along the important details, including whether or not you may be able to see the satellite's remains streaking through your skies.
注释：
demise: n; v
表示"死亡;转让"，means "the time when something ends; transfer by a lease or by a wil"，如：Upon his demise his house passed to his son. 他故世后，房子便传给了儿子。The demise of the old man's property cause much dispute upon his death. 老人死时，财产的让渡问题引起许多争执。
ire： n
表示" 愤怒"，means "anger"，如：The next day, the parents directed their ire at Mr.Jiang. 接下来的几天，这些家长将怒火转向了蒋先生。
protract: v
表示" 延长；伸出"，means "lengthen in time; cause to be or last longer"，如：To protract the suspense, he paused for a considerable period of time before telling us the result of the experiment. 为了延长悬念，他在告诉我们实验结果之前停顿了相当一段时间。
streak: v
表示"闪现"，means "move quickly in a straight line"，如：The cat streaked across the road with a dog behind it. 有只狗在后面，这只猫飞快地越过马路。
中文简要说明：
从太空拍摄的照片显示，一颗巨大的失效卫星ERS-2正在坠向地球大气层，科学家表示，它应该不会造成危险。
太空网(Space.com)报导，欧洲遥测2号卫星ERS-2于1995 年发射，在16年间从太空观测我们的星球，直到2011年任务结束。据欧空署的说法，在ERS-2 的主要任务结束之前，他们就为ERS-2 的报废做准备，2011 年7 月和8 月进行了66 次引擎喷射，以耗尽卫星的剩余燃料，并将它的运行高度从785公里，降低到356公里，好降低与其他卫星或空间碎片相撞的风险。
不过，这个已失效的卫星在往后的10几年仍然持续绕行地球，直到今年1月才有所变化。从1月14日、1月28日、1月29日和2月3日拍摄的照片显示， ERS-2仍处于300多公里的高度，但是最近几天它高度急剧降低，以每天下降超过10公里的效率在下落，目前已跌至200公里左右。
欧空署官员写道，ERS-2「是欧洲有史以来开发和发射的最先进的地球观测卫星」。它的重量达到2,294 公斤，算是相当大了。
欧空署表示，当它到达大约80公里时，它就会开始碎裂，多数碎片都会完全烧毁在大气层里，而且燃料已经耗尽，所以这些碎片都不含有任何有毒或放射性物质。
留言微信公众号《自然学英语LearnNaturally》，可咨询更多！