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　　As Discovery begins its 39th and final mission into Earth's orbit Thursday, America’s 30-year space shuttle program comes one step closer to its scheduled end this April.
发现号航天飞机2月24日下午升空，开始它第39次、也是最后一次飞行任务。美国历经30年的航天飞机计划将按计划于4月结束。
The aging fleet of reusable spacecraft has become an American technology icon¹, ferrying astronauts and mobile laboratories into space and helping² in the construction and resupply of the International Space Station.
这批日渐老化、可以重复使用的航天器已经成为美国技术的象征。这些航天飞机曾经把宇航员和活动实验室送入太空，协助建立国际空间站，为空间站运送物资。
Discovery has been a regular visitor to Earth's orbit since its maiden³ flight in 1984. It is the oldest and longest-serving vehicle in the U.S. space agency’s shuttle fleet. Discovery’s final flight follows several delays due to technical problems and repairs to its external fuel tank, but NASA’s mission launch director Mike Leinbach says the shuttle is still space-ready.
发现号1984年进行首次航天飞行之后，成为地球轨道的常客。发现号是美国太空总署航天飞机机队里最老、服役年头最长的一架航天飞机。美国航空航天管理局的发射主任迈克·莱因巴克说，这次发现号的最后飞行，曾经因为技术问题以及修理外油箱而几度延期，但它仍旧能承担太空飞行任务。
"It’s her 39th mission and [there] would have been quite a few left in her had the program been extended, but it wasn’t," he says. "It is a kind of bittersweet to get the last flight out of her, but she’s going to perform perfectly⁴ fine in orbit and bring the crew home safely."
他说：“发现号是一架很棒的航天飞机。这次是它第39次飞行。如果太空飞行计划延长，它还可以飞许多次。可是计划没有延长。 这次看着它做最后一次飞行，我们心里真是苦甜参半。但是它将在圆满完成任务，把宇航员平安带回家。”
Discovery’s 11-day mission is a supply run to the International Space Station. On board are 3,855 kilograms of cargo⁵ including a large supply closet, a replacement⁶ radiator⁷ and a humanoid robot helper named Robonaut 2.
发现号在这次11天的任务中，要为国际空间站运送补给物资。机上装载了3,855公斤货物，包括一个大型储藏柜，一架替换的散热器和一个名叫太空机器人2号的人形机器人。这个头戴金盔、身着白衣的机器人将协助宇航员在空间站内外进行维修以及其它工作。
Over its long career in space, Discovery has been a real work horse says Valerie Neal, shuttle curator at the Smithsonian’s National Air and Space Museum in Washington. "It’s delivered satellites. It’s picked up and repaired satellites. It’s flown scientific laboratories. It delivered the Hubble Space Telescope and then returned twice to service it. It flew twice to the Russian Space Station MIR and then 13 times to the International Space Station."
华盛顿史密森国家航空航天博物馆航天飞机展出部主任瓦莱莉·尼尔说，在漫长的太空任务中，发现号是一匹担负重任的骏马，“它运送过人造卫星；它拦截和修理过人造卫星；它载运过科学实验室；它运送过哈勃太空望远镜并且两度飞回去进行修护。它两次飞到俄罗斯和平号空间站，13次飞到国际空间站。”
The Discovery is linked to many historic firsts. It was first to return to space after fatal accidents destroyed its sister ships, Challenger and Columbia. It was the first to have a woman pilot. And Neal says that, despite the inevitable⁸ dangers of spaceflight, Discovery has played a major role in making it more routine.
发现号有许多历史上第一次的纪录。它是在两架姐妹航天飞机挑战号和哥伦比亚号先后遇难后，重返太空的第一架航天飞机。它是第一架载有女性宇航员的航天飞机。
“Certainly since the space shuttle began to fly, we’ve had people going up five, six, seven eight, nine times a year," she says. "We had no precedent⁹ for flying into space for 30 years in the same vehicles over and over. That’s approaching routine spaceflight."
瓦莱莉·尼尔说，尽管太空飞行有着不可避免的危险性，发现号在使太空飞行常规化发面发挥了主要作用，“的确，自从航天飞机开始飞行后，我们每年5次、6次、7次、8次，甚至9次送人进入太空。”
NASA plans two more missions, one each for the remaining two orbiters, Endeavor and Atlantis, before the Shuttle program ends later this year.
美国航空航天局计划，今年在航天飞机项目结束之前，再进行两次太空飞行，分别由奋进号和亚特兰蒂斯号执行。
NASA will then have to rely on European, Russian and Japanese rocket launches to carry astronauts and supplies into orbit until commercial U.S. space ferries become fully¹⁰ operational, possibly within the next five years. In the meantime, plans are still being worked out for putting Discovery and the other retired¹¹ space shuttles on permanent museum display.
在那之后，美国航空航天局将暂时依靠欧洲、俄罗斯和日本的火箭，将宇航员和供应物资送入轨道，直到美国的商业太空飞行准备就绪为止。这可能需要5年的时间。与此同时，有关方面正在计划将发现号和其它退役的航天飞机送入博物馆，永久性展出。