Endeavour astronauts complete final spacewalk

     WASHINGTON, May 27 (Xinhua) -- Two U.S. astronauts conducted the fourth and final scheduled spacewalks for space shuttle Endeavour 's STS-134 mission on Friday morning, the U.S. National Aeronautics¹ and Space Administration (NASA) announced.

    The seven-hour, 24-minute spacewalk completed by Mike Fincke and Greg Chamitoff at 7:39 a.m. EDT (1139 GMT) was the final spacewalk conducted by space shuttle astronauts(宇航员) before NASA turns over Endeavour and sister ships Discovery and Atlantis to museums. Space station crew will continue to make spacewalks for maintenance and repair tasks.

    At 5:02 a.m. (0902 GMT), Fincke and Chamitoff surpassed the 1, 000th hour astronauts and cosmonauts have spent spacewalking in support of space station assembly and maintenance. The milestone² occurred four hours and 47 minutes into the spacewalk, the 159th in support of station assembly and maintenance, totaling 1,002 hours, 37 minutes.

    The astronauts completed their mission to stow the 50-foot-long boom on the station truss and work on some new installations to extend the space station's robotic arm. After that, shuttle commander Mark Kelly called Mission Control in Houston to mark the milestone -- after 12 years of efforts.

    "Space station assembly is complete," Kelly said.

    It was the 248th spacewalk U.S. astronauts have conducted and the 118th from space station airlocks. Landing is scheduled for 2: 32 a.m. EDT (0632 GMT) on Wednesday at the Kennedy Space Center in Florida. Shuttle Atlantis is targeted to launch on July 8 for space shuttle's final flight.

    Endeavour lifted off on May 16 from the Kennedy Space Center in Florida, to deliver to the International Space Station a 2-billion- dollar, multinational³ particle detector⁴ known as the Alpha Magnetic Spectrometer (AMS).

    AMS, a particle physics detector, is designed to search for various types of unusual matter by measuring cosmic rays. Its experiments are designed to help researchers study the formation of the universe and search for evidence of dark matter, strange matter and antimatter.

    NASA's 30-year-old shuttle program is ending due to high operating costs. The Obama administration wants to spur private companies to get into the space taxi business, freeing NASA to focus on deep space exploration and new technology development.

    When the U.S. space shuttle program officially ends later this year, the Russian space program's Soyuz capsule will be the only method for transporting astronauts to and from the station.(本文由在线英语听力室整理编辑)

1 aeronautics   

n.航空术，航空学

参考例句：

• National Aeronautics and Space undertakings have made great progress.国家的航空航天事业有了很大的发展。
• He devoted every spare moment to aeronautics.他把他所有多余的时间用在航空学上。

2 milestone   

n.里程碑；划时代的事件

参考例句：

• The film proved to be a milestone in the history of cinema.事实证明这部影片是电影史上的一个里程碑。
• I think this is a very important milestone in the relations between our two countries.我认为这是我们两国关系中一个十分重要的里程碑。

3 multinational   

adj.多国的，多种国籍的；n.多国籍公司，跨国公司

参考例句：

• The firm was taken over by a multinational consulting firm.这家公司被一个跨国咨询公司收购。
• He analyzed the relationship between multinational corporations and under-developed countries.他分析了跨国公司和不发达国家之间的关系。

4 detector   

n.发觉者，探测器

参考例句：

• The detector is housed in a streamlined cylindrical container.探测器安装在流线型圆柱形容器内。
• Please walk through the metal detector.请走过金属检测器。