【双语新闻】火星侦察轨道器传回照片 显示深沟与岩屑

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　　The Mars Reconnaissance Orbiter on Friday returned the first test images from its super high-resolution cameras, the most powerful photographic equipment to be trained on the Red Planet in NASA's search for water and life.

　　The black-and-white photos, taken by three cameras, show deep channels and layered surface debris around the planet's midsection, features that probably were formed by water, said Alfred McEwen, a mission scientist and University of Arizona professor of planetary science.

　　The images were taken from an altitude of 1,547 miles above the surface, about three times higher than the orbiter will be when it formally begins its science mission in November.

　　The spacecraft, which reached orbit on March 10, is to map about 1 percent of the Martian surface for future landings by robotic probes and human astronauts.

　　The resolution of the test images is comparable to those captured by the less powerful cameras of three other orbiters circling Mars, but the tests show that cameras survived the seven-month space trip that began in August.

　　NASA scientists will use the images to calibrate the cameras, and will later combine the images to create broader view and to add color. They are available for viewing at www.jpl.nasa.gov.

　　Over the next seven months, the orbiter will \"aerobrake,\" dipping into Mars' atmosphere and gradually changing its elliptical orbit into a near-circle about 185 miles above the planet's surface. In the lower orbit, scientists will be able to distinguish surface objects as small as 3 feet (1 meter) wide, McEwen said.

　　The Mars Reconnaissance Orbiter has a suite of onboard instruments to map the planet's subsurface minerals, monitor its atmosphere and look for evidence of subsurface ice or water.

　　\"At this point we have an idea that water is probably abundant on Mars in the form of ice,\" McEwen said. \"It's not a matter of finding water on Mars but learning its importance in climate change ... and clearly it has been important to shaping the landscape.\"

　　The orbiter's first mission is to find landing sites for the Phoenix Mars Lander, set to arrive on Mars in May 2008 to dig for subsurface water ice, and for the 2009 arrival of the Mars Science Laboratory, a larger version of the twin robotic geologists Spirit and Opportunity, which have been traversing the planet's surface since 2004.




火星侦察轨道器首次传回照片 显示深沟与岩屑
　　美国宇航局的火星侦察轨道器3月24日首次传回了火星表面照片。利用这颗探测卫星上的超高分辨率照相机，美国宇航局将在火星上寻找水和生命的踪迹，并为未来登陆行动挑选着陆点。

　　据路透社3月24报道，参与此项任务的亚利桑那大学行星学教授艾尔佛雷德·麦克尤恩说，这批黑白照片是由火星侦察轨道器(MRO)上的3台照相机拍摄的，照片显示，火星中部地区分布有深沟和层状表面的岩屑，这些地貌有可能是水的运动造成的。

　　MRO在3月10日进入火星轨道。这批照片是在距离火星表面1547英里(约2490公里)高处拍摄的。美国宇航局的科学家们将利用这次拍摄的照片对MRO上的照相机进行校正。MRO上的设备是目前4个火星探测卫星中最先进的，它发回的数据量将超过其余3个所发回数据量的总和。

　　在以后的7个月内，MRO将缓慢沉入火星大气层，并渐渐由椭圆形轨道过渡到距火星表面约185英里(300公里)的近圆轨道。11月正式开始工作后，MRO与火星间的距离将只有现在距离火星高度的四分之一。麦克尤恩说，在这个较低的轨道上，科学家们甚至能够看清火星表面上3英尺(1米)宽的物体。MRO上携带的仪器还能够勘测地下矿藏，观察大气活动以及寻找地表下固态水的踪迹。

　　“目前我们认为，火星上可能有大量以冰的形式存在的水”，麦克尤恩说，“但找到水并不是目的，问题是要搞清水在火星气候演变过程中的重要意义。”

　　MRO的第一个任务将是为凤凰号火星登陆车和火星科学实验室寻找合适的降落点。前者将于2008年抵达火星，搜集地下固态水，后者则是勇气号和机遇号火星车的增强版，计划于2009年抵达。