Investigators Continue Probing Theories of Shuttle Disaster

Broadcast: Apr 02, 2003

 

The investigation¹ into what caused the break-up of the U.S. space shuttle Columbia supports the theory that a left wing panel broke off during its mission, possibly playing a role in its ¹⁾demise². But ²⁾corrosion³ along the wing's front edge might also have played a part.

Investigators⁴ have narrowed the location where devastating⁵ superheated atmospheric⁶ gases entered the shuttle during its re-entry to somewhere near the leading edge of the left wing. That is where sensors⁷ from a recently recovered data recorder show that temperatures heated up first, right after Columbia re-entered the atmosphere from its 16-day flight.

The investigators do not know where the breach⁸ in the wing was, but they say their probe points to several theories.

One option is that one of protective panels beneath the left wing detached.

One of the investigators, Air Force Major General John Barry, says the object that flew off the shuttle on its second day of flight almost certainly was one of these panels, called carrier panels. He cites analysis of data from military radars¹⁰ that observed the debris¹¹ floating in space and also tests of different types of materials that could have fallen away from the shuttle in orbit.

"We've got a lot of radar⁹ cross-section feedback, and there have been 29 various materials examined at Wright Patterson Air Force Base," said Gen. Barry. "We've concluded that, right now, only the carrier panel remains¹² a viable¹³ candidate for the day-two object."

The investigators are also considering whether tiny holes in the wing's edge could have contributed to Columbia's demise.

They have learned that it is common for the front edges of shuttle wings to have pinholes from corrosion. General Barry says the cause of the corrosion could be zinc¹⁴ oxide¹⁵ leaching¹⁶ down from aging paint on the shuttle launch tower. Another culprit might be ³⁾oxidation, perhaps from weathering.

NASA requires patching of ⁴⁾pinholes larger than one millimeter. General Barry says investigators are trying to determine if the corrosion weakened one of the reinforced carbon panels along the left wing's front edge, known as an ⁵⁾RCC panel. If so, it might explain how an RCC panel could be damaged by pieces of hard insulating foam¹⁸ that fell from the shuttle's external fuel tank during launch. Such damage is not proven, but has emerged as a leading possibility for the left wing breach.

"We're doing some more study," General Barry said. "We want to examine all of these issues with the pinholes as closely as we possibly can to try to get to the bottom of the question - the question being, if something hit the RCC and it was an aged¹⁷ RCC with pinholes or oxidation underneath¹⁹ that, would that be a contributing aspect to this mishap²⁰."

The shuttle accident investigators are planning tests in which fuel tank foam will be hurled²¹ at high speed at old and new RCC panels to see what damage they can cause.

David McAlary VOA news, Washington.

1)    demise [di5maiz]n.死亡,消灭，停止活动

2)    corrosion[kE5rEuVEn]n. 侵蚀, 腐蚀状态

3)    oxidation[Cksi5deiFEn]n. [化]氧化

4)    pinhole n. 针孔, 小孔

5)    RCC放射化学中心

1 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。

2 demise   

n.死亡；v.让渡，遗赠，转让

参考例句：

• He praised the union's aims but predicted its early demise.他赞扬协会的目标，但预期这一协会很快会消亡。
• The war brought about the industry's sudden demise.战争道致这个行业就这么突然垮了。

3 corrosion   

n.腐蚀，侵蚀；渐渐毁坏，渐衰

参考例句：

• Corrosion is not covered by the warranty.腐蚀不在保修范围之内。
• Zinc is used to protect other metals from corrosion.锌被用来保护其他金属不受腐蚀。

4 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》

5 devastating   

adj.毁灭性的，令人震惊的，强有力的

参考例句：

• It is the most devastating storm in 20 years.这是20年来破坏性最大的风暴。
• Affairs do have a devastating effect on marriages.婚外情确实会对婚姻造成毁灭性的影响。

6 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

7 sensors   

n.传感器，灵敏元件( sensor的名词复数 )

参考例句：

• There were more than 2000 sensors here. 这里装有两千多个灵敏元件。 来自《简明英汉词典》
• Significant changes have been noted where sensors were exposed to trichloride. 当传感器暴露在三氯化物中时，有很大变化。 来自辞典例句

8 breach   

n.违反，不履行；破裂；vt.冲破，攻破

参考例句：

• We won't have any breach of discipline.我们不允许任何破坏纪律的现象。
• He was sued for breach of contract.他因不履行合同而被起诉。

9 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。

10 radars   

n.雷达( radar的名词复数 )；雷达装置

参考例句：

• Servos for large radars and launchers are either electro-hydraulic or all-electric. 大型雷达和发射装置的伺服系统，不是电动-液压式的，就是全电动式的。 来自辞典例句
• Range-velocity simultaneous pull-off is one of effective measures for countering PD radars. 距离-速度同步拖引干扰是对抗PD雷达的有效方法。 来自互联网

11 debris   

n.瓦砾堆，废墟，碎片

参考例句：

• After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
• Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。

12 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

13 viable   

adj.可行的，切实可行的，能活下去的

参考例句：

• The scheme is economically viable.这个计划从经济效益来看是可行的。
• The economy of the country is not viable.这个国家经济是难以维持的。

14 zinc   

n.锌；vt.在...上镀锌

参考例句：

• Brass is formed by the fusion of copper and zinc.黄铜是通过铜和锌的熔合而成的。
• Zinc is used to protect other metals from corrosion.锌被用来保护其他金属不受腐蚀。

15 oxide   

n.氧化物

参考例句：

• Oxide is usually seen in our daily life.在我们的日常生活中氧化物很常见。
• How can you get rid of this oxide coating?你们该怎样除去这些氧化皮？

16 leaching   

n.滤取，滤去v.（将化学品、矿物质等）过滤( leach的现在分词 )；（液体）过滤，滤去

参考例句：

• The lack of humus and the excessive leaching make this soil almost useless for agricultural purpose. 缺少腐殖质和过度淋滤使这种土壤对农业几乎无用。 来自辞典例句
• The deep oxidation and groundwater leaching solubilizes much of the loosely bound uranium. 深部氧化和地下水淋蚀使大部分固定得比较松散的铀溶解。 来自辞典例句

17 aged   

adj.年老的，陈年的

参考例句：

• He had put on weight and aged a little.他胖了，也老点了。
• He is aged,but his memory is still good.他已年老，然而记忆力还好。

18 foam   

v./n.泡沫，起泡沫

参考例句：

• The glass of beer was mostly foam.这杯啤酒大部分是泡沫。
• The surface of the water is full of foam.水面都是泡沫。

19 underneath   

adj.在...下面，在...底下；adv.在下面

参考例句：

• Working underneath the car is always a messy job.在汽车底下工作是件脏活。
• She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。

20 mishap   

n.不幸的事，不幸；灾祸

参考例句：

• I'm afraid your son had a slight mishap in the playground.不好了，你儿子在操场上出了点小意外。
• We reached home without mishap.我们平安地回到了家。

21 hurled   

v.猛投，用力掷( hurl的过去式和过去分词 )；大声叫骂

参考例句：

• He hurled a brick through the window. 他往窗户里扔了块砖。
• The strong wind hurled down bits of the roof. 大风把屋顶的瓦片刮了下来。 来自《简明英汉词典》