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美国开展新型航天器的研制工作

Since the retirement¹ of its shuttle fleet in 2011, the U.S. space agency NASA has had to rely on Russian space vehicles to carry astronauts to the International Space Station.  In the meantime, NASA’s engineers are developing components² of a new system for launching manned capsules way beyond the low earth orbit - to an asteroid³ and even to Mars.

自2011年美国航天飞机退役以来，美国宇航局不得不依靠俄罗斯航天器运送宇航员到国际空间站。与此同时，美国宇航局的工程师们正在研发一种新宇航系统的组件，以便把宇航舱送出近地轨道并到达小行星，甚至是到火星。

At NASA’s George C. Marshall Space Flight Center in Huntsville, Alabama, engineers are preparing for a crucial test of a booster engine that will help the main rocket escape the earth’s gravity. The agency says it's the largest booster ever developed for a manned spacecraft.

在位于阿拉巴马州亨茨维尔的美国宇航局乔治·马歇尔太空飞行中心，工程师们正在为一项助推引擎测试做准备。这个引擎将使火箭摆脱地球引力。宇航局说，者是为载人宇宙飞船开发的最大的助推器。

The Space Launch System, or SLS, consists of a main rocket and two solid-fuel boosters.  It will propel the new manned capsule Orion into deep space.

这个航天发射系统由主火箭和两个固体燃料助推器组成。这个系统将把新的宇航舱“奥利安”号送入太空深处。

During liftoff the engines create so much noise that the sound waves can actually damage the payload.

在升空过程中，火箭引擎会制造巨大的噪音。强劲的声波可以破坏火箭运载的设备。

That is why other NASA engineers are testing a water-based sound suppression system on a scaled-down model of the launch vehicle.

因此，美国宇航局的工程师正在一个按比例缩小的运载火箭模型上测试利用水来消音的装置。

“Past experience has shown that without this scale model testing, there could be not only problems with the design loads, with the environment, components could fail," said Space Launch System engineer, Douglas Counter. "So this is very critical.”

航天发射系统研发工程师道格拉斯?康特说:“过去的经验证明，如果没有这种比例模型实验，问题就不仅仅只和设计载荷以及环境有关，组件就可能失败。所以，这是非常关键的。”

At one of the indoor laboratories, engineers are assembling components of the system that will integrate and control all parts of the rocket.

在美国宇航局某个实验室中，工程师在组装控制系统的部件。这个系统将整合和控制火箭的各个部位。

“This is essentially⁴ the brain and nervous system of your rocket. The flight computers are your brain," said Space Launch System engineer Curt⁵ Jackson. "The various data systems, the various sensors⁶, data from the different boxes -- kind of like your nervous system --  flow to the brain.”

太空发射系统工程师柯特?杰克逊说， “这个系统基本上是火箭的大脑和神经系统。飞行计算机是火箭的大脑。各种数据、传感器和来自于不同匣子的数据类似于人的神经系统，把信息传输给大脑。

Congress has not yet approved next year’s budget for NASA so the agency is trying to save money by relying on unused components, like the RS-25 rocket engines, built for the retired⁷ shuttles.

因为国会还没有批准明年美国宇航局的财政预算，所以宇航局尝试依靠使用像RS-25火箭引擎等未使用的组件，达到节省资金的目的。这些引擎是以前给航天飞机设计的。

“We've got 16 RS-25 engines left over from the shuttle program," said engine test project manager Gary Benton.  "And, since the engine was highly reliable and reusable, we're able to take these engines and use them for the first four flights of SLS.”

引擎试验项目负责人加里?本顿说：“我们有从航天计划中遗留下来的16个RS-25引擎。由于这些引擎高度可靠并可反复使用，我们可以利用它们进行今后头四次发射。”

The rocket test stand in Mississippi, was built in the Apollo era, but project manager Richard Rauch says it was designed to be flexible for testing various engines.

火箭实验发射台在阿波罗时代建在密西西比州，但是项目负责人理查德·劳赫说，这个发射台是为方便测试各种引擎而灵活设计的。

“What we're doing is re-purposing some of that old hardware -- some of that structural⁸ hardware -- a lot of the propellant and cryopiping, to make it adaptable⁹ to what's required for the SLS core stage,” he said.

劳赫说：“我们重新利用一些旧的硬件，一些结构性硬件，还有大量的推进燃料和冷冻配管。我们可以把这些材料用到航天发射系统的核心阶段。

At another site in Louisiana, workers have already started welding sections of almost a 100 meter long main rocket.  Engineers from NASA and the main contractor¹⁰ Boeing had to design huge welding tools.

在路易斯安那州的另一个发射台地点，工作人员已进入到对近100米长的主火箭进行焊接的阶段。来自美宇航局和主要承包商波音公司的工程师必须设计出巨大的焊接工具。

NASA says the new Space Launch System is being designed to be flexible for both crewed and cargo¹¹ missions.  Testing of the core stage will begin in 2016 and the first launch is planned for 2017, though no astronauts will be on board.

美国宇航局表明，新的航天发射系统可以用于运送宇航员和物资。核心阶段的测试将在2016年开始。首次发射定在2017年，不过不是载人飞行。