2006年VOA标准英语-Biggest, Most Sensitive US Mars Spacecraft

By David McAlary
Washington
10 March 2006

Mars Reconnaissance Orbiter   
  
Another U.S. spacecraft has begun orbiting Mars to study the red planet in unprecedented¹ detail. The Mars Reconnaissance Orbiter will continue the search for signs that water and possibly life could have existed on it.

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One third of all U.S. spacecraft sent to Mars since the 1960s have failed to enter orbit, but the Mars Reconnaissance Orbiter is not among them.

Mission controllers at the Jet Propulsion Laboratory in Pasadena, California cheered after the spacecraft emerged from a communications blackout behind the planet and signalled that Mars' gravity had captured it. To let this happen, the orbiter fired thruster enginers to slow its nearly 18,000 kilometer per hour speed by one-third.

"After a six-month cruise, we're finally there. It's a great feeling," said Douglas McCuistion, chief of the U.S. Mars exploration program. "I can't wait for the scientists in a few months to be able to take control of the orbiter and see what we find. They are going to be like a bunch of kids with a new microscope, I think, being able to look at things they haven't seen before and I just can't wait to hear all the 'Wows!' coming from the science community. It will be quite exciting."

The successful rendezvous² with the red planet ended a journey the Mars Reconnaissance Orbiter began last August when it launched from Florida. The 500 million kilometer voyage was smoother than expected. Mission manager Rob Lock says the spacecraft kept to its planned route so closely that in the last two days, controllers were able to cancel a pair of standby jet thruster firings that would have corrected the course if needed. "In fact, we have not done a maneuver³ since November of last year. We canceled our last two correction maneuvers⁴ on our way to Mars because our trajectory⁵ has just been spot-on [perfect] for months now," he said.

The new spacecraft joins two other U.S. orbiters and one European satellite circling Mars. But it is much bigger and is designed to go into a lower orbit with the most powerful cameras and remote sensing instruments ever sent to a planet. It will beam back more information than all previous Mars missions combined at a rate 10 times faster the older craft.

Before it can return any science, though, it will take six-months to adjust its extremely elongated⁶ 35-hour long orbit to a circular one two-hours long using atmospheric⁷ friction⁸.

"For the science teams right now, this is a period of waiting," said Richard Zurek, the chief mission scientist. He says when the Mars Reconnaissance Orbiter is finished correcting its path around the red planet, it will study the atmosphere, examine the surface for water-altered rocks in unprecedented detail, and even probe beneath the surface with radar⁹. It will also scout¹⁰ for landing sites for future robot explorers and eventually human visitors.

"We're looking forward to when we will be able to open up and operate our instruments to their full capability," he said.

1 unprecedented   

adj.无前例的，新奇的

参考例句：

• The air crash caused an unprecedented number of deaths.这次空难的死亡人数是空前的。
• A flood of this sort is really unprecedented.这样大的洪水真是十年九不遇。

2 rendezvous   

n.约会，约会地点，汇合点；vi.汇合，集合；vt.使汇合，使在汇合地点相遇

参考例句：

• She made the rendezvous with only minutes to spare.她还差几分钟时才来赴约。
• I have a rendezvous with Peter at a restaurant on the harbour.我和彼得在海港的一个餐馆有个约会。

3 maneuver   

n.策略[pl.]演习；v.(巧妙)控制；用策略

参考例句：

• All the fighters landed safely on the airport after the military maneuver.在军事演习后，所有战斗机都安全降落在机场上。
• I did get her attention with this maneuver.我用这个策略确实引起了她的注意。

4 maneuvers   

n.策略，谋略，花招( maneuver的名词复数 )

参考例句：

• He suspected at once that she had been spying upon his maneuvers. 他立刻猜想到，她已经侦察到他的行动。 来自辞典例句
• Maneuvers in Guizhou occupied the Reds for four months. 贵州境内的作战占了红军四个月的时间。 来自辞典例句

5 trajectory   

n.弹道，轨道

参考例句：

• It is not difficult to sketch the subsequent trajectory.很容易描绘出它们最终的轨迹。
• The path followed by a projectile is called its trajectory.抛物体所循的路径称为它的轨道。

6 elongated   

v.延长，加长( elongate的过去式和过去分词 )

参考例句：

• Modigliani's women have strangely elongated faces. 莫迪里阿尼画中的妇女都长着奇长无比的脸。
• A piece of rubber can be elongated by streching. 一块橡皮可以拉长。 来自《用法词典》

7 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。

8 friction   

n.摩擦，摩擦力

参考例句：

• When Joan returned to work,the friction between them increased.琼回来工作后，他们之间的摩擦加剧了。
• Friction acts on moving bodies and brings them to a stop.摩擦力作用于运动着的物体，并使其停止。

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 scout   

n.童子军，侦察员；v.侦察，搜索

参考例句：

• He was mistaken for an enemy scout and badly wounded.他被误认为是敌人的侦察兵，受了重伤。
• The scout made a stealthy approach to the enemy position.侦察兵偷偷地靠近敌军阵地。