VOA慢速英语--美国宇航局太空船捕捉到的小行星样本远远超过预期

A NASA spacecraft that recently collected rocks from an asteroid¹ captured far more material than expected. The American space agency says the sample was so large that it blocked the container door of the collector.

The Osiris-Rex spacecraft successfully completed its asteroid sample operation on October 20. The explorer's robotic arm touched the asteroid Bennu for a few seconds to produce dust and rock samples for collection. Bennu sits about 320 million kilometers from Earth.

The samples were then trapped in a device called the collection head. NASA discovered the blocked door of the device in images received from the team controlling the spacecraft. The blockage² caused some asteroid material to escape back out into space.

Because of this, NASA scientists made the decision to move up the timeline for completing the next step in the operation. This involves stowing, or storing, the collection head in a secure capsule within the spacecraft.

"Time is of the essence³," Thomas Zurbuchen told reporters about the change in plans. He is NASA's associate administrator⁴ for science.

The operation to stow the samples is carried out in a series of steps. After each step, the spacecraft sends information and images back to Earth. Different members of the team watch the process to make sure things progress correctly.

The spacecraft is so far away that it takes about 18 minutes for its signals to reach Earth. Any communication from ground controllers requires the same amount of time to reach Osiris-Rex. Because of this, the stowing process was expected to take several days.

Scientists believe the operation captured up to 400 grams of asteroid material. This is far more than the 60 grams NASA said it hoped Osiris-Rex would collect.

But mission leaders said they will not know exactly how much material is inside until the sample capsule gets back to Earth. The team had planned to carry out a process to measure the sample. But that plan was canceled because NASA said it could have caused even more material to spill out.

"I think we're going to have to wait until we get home to know precisely⁵ how much we have," Osiris-Rex lead investigator⁶ Dante Lauretta told reporters. "As you can imagine, that's hard. ... But the good news is we see a lot of material."

Team members had also considered doing another collection attempt. But the leaking issue led NASA to decide against the plan. "Quite honestly, we could not have performed a better collection experiment," Lauretta said.

Osiris-Rex is expected to begin its return to Earth in March 2021. The trip will take two-and-a-half years, with the spacecraft's planned arrival set for September 2023.

The mission marked NASA's first asteroid collection operation. Japan is the only other country to have successfully captured such a sample.

Asteroids⁷ are among the leftover⁸ material from the solar system's formation about 4.5 billion years ago. NASA chose to collect a sample from Bennu because its carbon-rich material is believed to hold preserved building blocks of our solar system.

Scientists say the asteroid samples may help them better understand how planets formed and how life began on Earth.

Words in This Story

asteroid – n. objects made of rock and metal which orbit the sun, but are smaller than planets

sample – n. a small amount of something that gives you information about the thing it was taken from

capsule – n. the part of a spacecraft that carries people

of the essence – phr. highly important

precisely – adv. exactly

preserve – v. keep something the same or prevent it from being damaged of destroyed

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 blockage   

n.障碍物；封锁

参考例句：

• The logical treatment is to remove this blockage.合理的治疗方法就是清除堵塞物。
• If the blockage worked,they could retreat with dignity.如果封锁发生作用，他们可以体面地撤退。

3 essence   

n.本质，实质，精华，精粹

参考例句：

• We must try to get to the essence of things.我们必须想法抓住事物的本质。
• The two things are the same in outward form but different in essence.这两件东西外表形式一样，但实质不同。

4 administrator   

n.经营管理者，行政官员

参考例句：

• The role of administrator absorbed much of Ben's energy.行政职务耗掉本很多精力。
• He has proved himself capable as administrator.他表现出管理才能。

5 precisely   

adv.恰好，正好，精确地，细致地

参考例句：

• It's precisely that sort of slick sales-talk that I mistrust.我不相信的正是那种油腔滑调的推销宣传。
• The man adjusted very precisely.那个人调得很准。

6 investigator   

n.研究者，调查者，审查者

参考例句：

• He was a special investigator for the FBI.他是联邦调查局的特别调查员。
• The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。

7 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。

8 leftover   

n.剩货，残留物，剩饭；adj.残余的

参考例句：

• These narrow roads are a leftover from the days of horse-drawn carriages.这些小道是从马车时代沿用下来的。
• Wonder if that bakery lets us take leftover home.不知道那家糕饼店会不会让我们把卖剩的带回家。