新托福阅读材料：CoolingsystemfaulthitsInternationalSpaceStation

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　人类对于宇宙探索的脚步从未停止过，太空中辛勤工作着的众多卫星和宇宙空间站就是最好例证。当然，这些卫星和空间站也会有“生病”的时候。  
$ g7 N0 N4 C9 U+ s, U# M　　The crew of the International Space Station have been forced to reduce power after half the cooling system suddenly shut down over the weekend.
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　　Nasa officials insisted the three Americans and three Russians aboard were not in danger.

1 a! _# v+ c- N+ R4 ~  a　　Urgent spacewalk repairs are being discussed for this week.
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　　Without thermal controls, temperatures on the ISS's Sun-facing side can soar to 121C (250F), plunging to minus 157C (-250F) on the dark side, Nasa says.

　　"There might be a comfortable spot somewhere in the middle of the station, but searching for it wouldn't be much fun," a statement on its website adds.
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5 I; b8 u0 K! k　　The station is now operating on a single string, the Associated Press reports, and has no safeguard in case of further cooling system failures.
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- U4 T5 E' i7 G　　Alarms sound

　　Trouble arose on Saturday night when one of the two ammonia-fed cooling loops shut down, triggering alarms throughout the ISS
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　　The two ammonia lines ensure that all the station's electronic equipment does not overheat.

　　Astronaut Tracy Caldwell Dyson set in motion equipment shutdown procedures and, with crewmate Douglas Wheelock, installed a jumper cable to keep all the rooms cool.
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　　The Global Positioning System circuit, several power converters and a set of devices that route commands to various pieces of equipment were switched off.

4 H& b- i7 N7 }- s) k　　Two of the four gyroscopes - part of the space station's pointing and navigating system - were initially shut down but the crew installed a jumper cable to bring up a third gyroscope, leaving the station in a much more stable position, AP says.
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　　Flight controllers tried to restart the disabled ammonia pump early on Sunday but the circuit breaker tripped again.
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+ f9 f6 b( A: C: S* A　　Any repairs later this week almost certainly will involve replacing the faulty ammonia pump, a difficult job that would require two spacewalks, AP adds.
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4 i7 s  N+ K  k4 l5 E　　"It's pretty clear that we're going to want to have a course of action to take as quickly as possible," Nasa spokesman Rob Navias said at the Johnson Space Center in Houston, Texas.
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　　"This is not something we want to linger over."
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+ \+ a6 w* E% f" J5 J% Y　　Two spare pumps are stored on the outside of the station. Two of the Americans on board are already scheduled to conduct a spacewalk on Thursday for routine maintenance.

! Z% y6 U2 h6 N* F. Q　　No space shuttle visits to the ISS are planned before November.