国家地理-2008-04-24 Spacewalks 太空行走，看上去很美

Floating free in the hostile vacuum of space, astronauts push the boundaries of exploration. Join them on an incredible journey as spacecraft Voyager explores the solar system.

From planetary orbit, the earth and heavens look serene¹. But the vacuum of space is a hostile environment, lacking oxygen and permeated³ by radiation. Since the advent⁴ of manned space flight in the 1960s, humankind has been exploring this inhospitable realm from the relative safety of spacecraft. But occasional extravehicular activities have led astronauts to leave these confines and explore the unknown. In order for astronauts to survive in space, spacesuits provide a self-contained environment. Their tough material, along with heating and cooling elements, protect astronauts from extreme temperatures, ranging from around 250 degrees Fahrenheit⁵ to minus 250 degrees. The suits are pressurized with pure oxygen, allowing astronauts to breathe and keep their blood from boiling in the vacuum of space.

The first venture outside the spacecraft was made by Soviet⁶ cosmonaut Alexey Leonov in 1965, lasting⁷ only 12 minutes. This feat⁸ was duplicated a few months later by American astronaut Edward White during the Gemini 4 mission. Although these excursions were meant to test the feasibility of humans to exist outside the spacecrafts, spacewalks have become a relatively⁹ common part of missions in the space shuttle era. On spacewalks, astronauts have performed vital tasks that could not be accomplished¹⁰ from inside the shuttle. They've been able to recover lost satellites, restoring them to their proper orbit. They have serviced orbiting bodies, like replacing the solar panels on the Hubble Space Telescope. And they have become the construction crew for the International Space Station.

Conducting spacewalks is dangerous, and astronauts work in pairs, tethered to the spacecraft for safety. Walking in these spacesuits is not as easy as it seems. The thick pressurized gloves make grasping tools difficult, while the weightlessness of space creates its own issues. To ensure spacewalk missions are successful, astronauts practise their planned excursions at NASA’s Neutral Buoyancy Laboratory. Immersed in a tank of water, the astronauts neither sink nor float, creating a sensation close to weightlessness. For every hour a task is scheduled on a mission, up to 10 hours is spent practising underwater.

As NASA moves forward on the maintenance and construction of the International Space Station, spacewalks will continue to be vital to the process.

permeate²: v.
if liquid, gas etc permeates¹¹ something, it enters it and spreads through every part of it

the advent of sth:
the time when something first begins to be widely used

extravehicular activity: n.Abbr. EVA
Activity or maneuvers¹² performed by an astronaut outside a spacecraft in space.

duplicate: repeat

tether: v.
fasten (an animal) within a limited area

 

1 serene   

adj. 安详的，宁静的，平静的

参考例句：

• He has entered the serene autumn of his life.他已进入了美好的中年时期。
• He didn't speak much,he just smiled with that serene smile of his.他话不多，只是脸上露出他招牌式的淡定的微笑。

2 permeate   

v.弥漫，遍布，散布；渗入，渗透

参考例句：

• Water will easily permeate a cotton dress.水很容易渗透棉布衣服。
• After a while it begins to permeate through your skin.过了一会，它会开始渗入你的皮肤。

3 permeated   

弥漫( permeate的过去式和过去分词 )； 遍布； 渗入； 渗透

参考例句：

• The smell of leather permeated the room. 屋子里弥漫着皮革的气味。
• His public speeches were permeated with hatred of injustice. 在他对民众的演说里，充满了对不公正的愤慨。

4 advent   

n.(重要事件等的)到来，来临

参考例句：

• Swallows come by groups at the advent of spring. 春天来临时燕子成群飞来。
• The advent of the Euro will redefine Europe.欧元的出现将重新定义欧洲。

5 Fahrenheit   

n./adj.华氏温度；华氏温度计(的)

参考例句：

• He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
• The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。

6 Soviet   

adj.苏联的，苏维埃的；n.苏维埃

参考例句：

• Zhukov was a marshal of the former Soviet Union.朱可夫是前苏联的一位元帅。
• Germany began to attack the Soviet Union in 1941.德国在1941年开始进攻苏联。

7 lasting   

adj.永久的，永恒的；vbl.持续，维持

参考例句：

• The lasting war debased the value of the dollar.持久的战争使美元贬值。
• We hope for a lasting settlement of all these troubles.我们希望这些纠纷能获得永久的解决。

8 feat   

n.功绩；武艺，技艺；adj.灵巧的，漂亮的，合适的

参考例句：

• Man's first landing on the moon was a feat of great daring.人类首次登月是一个勇敢的壮举。
• He received a medal for his heroic feat.他因其英雄业绩而获得一枚勋章。

9 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

10 accomplished   

adj.有才艺的；有造诣的；达到了的

参考例句：

• Thanks to your help,we accomplished the task ahead of schedule.亏得你们帮忙,我们才提前完成了任务。
• Removal of excess heat is accomplished by means of a radiator.通过散热器完成多余热量的排出。

11 permeates   

弥漫( permeate的第三人称单数 )； 遍布； 渗入； 渗透

参考例句：

• Studies show that water vapor quickly permeates plastic packaging material. 研究证明水蒸汽能迅速渗入塑料封装材料。
• Democracy permeates the whole country. 民主主义（的思想）普及全国。

12 maneuvers   

n.策略，谋略，花招( maneuver的名词复数 )

参考例句：

• He suspected at once that she had been spying upon his maneuvers. 他立刻猜想到，她已经侦察到他的行动。 来自辞典例句
• Maneuvers in Guizhou occupied the Reds for four months. 贵州境内的作战占了红军四个月的时间。 来自辞典例句