VOA科学技术2024--Europe Launches Spacecraft to Explore Asteroid Hit by NASA

 

A European spacecraft has been launched to explore an asteroid¹ struck in an earlier planetary defense² mission by the American space agency NASA.

The European Space Agency (ESA's) Hera spacecraft launched October 7 from NASA's Cape³ Canaveral in Florida. The spacecraft, or probe, was carried to space aboard a SpaceX Falcon⁴ 9 rocket.

Hera is headed to the asteroid Dimorphos. NASA crashed its DART⁵ spacecraft into the space rock in 2022 in an area about 11 million kilometers from Earth. The NASA mission was an experiment to test a method for changing the orbit of asteroids⁶ that might one day threaten Earth.

NASA has said its own studies of the crash showed it was successful because the force of the strike changed the asteroid's orbit around a larger asteroid, called Didymos. Data showed the strike reduced the orbital period of Dimorphos by 33 minutes.

But the Hera mission seeks to closely examine Dimorphos to get more details on how the asteroid was changed in the strike by DART. Data collected by the ESA spacecraft will be used together with information gathered by NASA to develop future planetary defense plans.

American astronomer⁷ Derek Richardson, from the University of Maryland, told reporters before the launch, "The more detail we can glean⁸ the better as it may be important for planning a future deflection mission should one be needed."

Officials from ESA have described the $400 million mission as a "crash scene investigation¹⁰." Hera project manager Ian Carnelli said the spacecraft was "going back to the crime site and getting all the scientific and technical information."

Hera's trip to the asteroid is expected to take about two years. Next year, the probe plans to get a big gravitational push as it flies past Mars. It should arrive in the area around Dimorphos in December 2026.

Before it was hit by DART, Dimorphos circled a larger asteroid from about 1,189 meters out. Scientists believe the orbit is now closer and that Dimorphos changed its shape. Astronomers¹¹ have also found evidence the asteroid is likely moving differently.

Examinations of the DART mission have suggested that rather than being a single hard rock, Dimorphos was more of a collection of rubble¹² pieces held together by gravity. Investigators¹³ have said they believe the DART crash might have "completely deformed¹⁴" the asteroid.

Ignacio Tanco is the flight director for the Hera mission. He told The Associated Press that some large rocks and other materials could still be following the asteroid. This, he said, could present a damage risk to the spacecraft.

"We don't really know very well the environment in which we are going to operate," Tanco said. "But that's the whole point of the mission is to go there and find out."

Hera will be equipped with two nanosatellites. One will land on Dimorphos and capture data on the asteroid with radar¹⁵. The other will study the makeup¹⁶ of Dimorphos from farther out.

ESA and NASA will use the data to create plans for a possible asteroid strike that could cause wide destruction on Earth. Astronomers believe an asteroid wider than one kilometer - which could cause a worldwide disaster - is estimated to strike Earth about every 500,000 years.

An asteroid around 140 meters - which is a little smaller than Dimorphos but could still take out a major city - is predicted to hit Earth around every 20,000 years.

Currently there are no known 140-meter asteroids on a path to strike Earth. However, scientists have said only 40 percent of those space rocks are believed to have been identified.

Words in This Story

asteroid - n. a rocky object that goes around the sun like a planet

glean - v. to discover something slowly or with difficulty

deflect⁹ - v. to make something change direction by hitting or touching¹⁷ it

scene - n. the place where something happens

rubble - n. pieces of broken rocks or bricks from a destroyed building or structure

1 asteroid   

n.小行星；海盘车(动物)

参考例句：

• Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
• It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。

2 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

3 cape   

n.海角，岬；披肩，短披风

参考例句：

• I long for a trip to the Cape of Good Hope.我渴望到好望角去旅行。
• She was wearing a cape over her dress.她在外套上披着一件披肩。

4 falcon   

n.隼，猎鹰

参考例句：

• The falcon was twice his size with pouted feathers.鹰张开羽毛比两只鹰还大。
• The boys went hunting with their falcon.男孩子们带着猎鹰出去打猎了。

5 dart   

v.猛冲，投掷；n.飞镖，猛冲

参考例句：

• The child made a sudden dart across the road.那小孩突然冲过马路。
• Markov died after being struck by a poison dart.马尔科夫身中毒镖而亡。

6 asteroids   

n.小行星( asteroid的名词复数 )；海盘车，海星

参考例句：

• Asteroids,also known as "minor planets",are numerous in the outer space. 小行星，亦称为“小型行星”，在外太空中不计其数。
• Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。

7 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

8 glean   

v.收集(消息、资料、情报等)

参考例句：

• The little information that we could glean about them was largely contradictory.我们能够收集到的有关它们的少量信息大部分是自相矛盾的。
• From what I was able to glean,it appears they don't intend to take any action yet.根据我所收集到的资料分析，他们看来还不打算采取任何行动。

9 deflect   

v.(使)偏斜，(使)偏离，(使)转向

参考例句：

• Never let a little problem deflect you.决不要因一点小问题就半途而废。
• They decided to deflect from the original plan.他们决定改变原计划。

10 investigation   

n.调查，调查研究

参考例句：

• In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
• He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。

11 astronomers   

n.天文学者，天文学家( astronomer的名词复数 )

参考例句：

• Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
• Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》

12 rubble   

n.（一堆）碎石，瓦砾

参考例句：

• After the earthquake,it took months to clean up the rubble.地震后，花了数月才清理完瓦砾。
• After the war many cities were full of rubble.战后许多城市到处可见颓垣残壁。

13 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

14 deformed   

adj.畸形的；变形的；丑的，破相了的

参考例句：

• He was born with a deformed right leg.他出生时右腿畸形。
• His body was deformed by leprosy.他的身体因为麻风病变形了。

15 radar   

n.雷达，无线电探测器

参考例句：

• They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
• Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。

16 makeup   

n.组织；性格；化装品

参考例句：

• Those who failed the exam take a makeup exam.这次考试不及格的人必须参加补考。
• Do you think her beauty could makeup for her stupidity?你认为她的美丽能弥补她的愚蠢吗？

17 touching   

adj.动人的，使人感伤的

参考例句：

• It was a touching sight.这是一幅动人的景象。
• His letter was touching.他的信很感人。