Rover Takes a Deep Look Into Mars
| Yesterday, after a 3-year, 21-kilometer journey at top speeds of less than 0.2 kilometer per hour, the Opportunity rover finally arrived at Mars's Endeavour crater. The intrepid explorer had already poked into 11 craters, the largest 750-meter-wide, 70-meter-deep Victoria, and analyzed rocks and soil along 33 kilometers of track. But the geologic story it read there always spoke of an ancient martian wasteland of windblown dunes pocked by the occasional acid-laced puddle. Now that it has arrived at 22-kilometer-wide, 300-meter-deep Endeavour, Opportunity may be on the brink of rock from earlier, more hospitable times in martian history. NASA's Mars Reconnaissance Orbiter has detected clay in rock of the crater rim exposed by the far larger impact explosion that created Endeavour. And the presence of clay tells geologists that water altered the rock under far milder, presumably more habitable conditions than those that produced the rock Opportunity or any other rover has analyzed to date. NASA's $2.5 billion Curiosity rover scheduled to launch this November, if successful, will not likely reach its clay-bearing target in Gale crater until 2013. |
经过了3年，以最高每小时不超过0.2公里的速度，“机遇”号探测器在经过21公里的行程后终于到达火星的“奋进”号陨石坑。这台勇敢的探测器已经在11个陨石坑里挖掘过，其中最大的是750米宽、70米深的“维多利亚”号陨石坑，分析了沿途33公里路线上的岩石和土壤。然而，它在那里看到的地质情况总是说明曾经存在一个古代火星荒原，荒原上有风蚀的沙丘，沙丘上点缀着微显酸性的坑塘。现在，“机遇”号来到了22公里宽、300米深的“奋进”号陨石坑，它现在接近的岩石可能源自火星史上一个较早的、更加适于居住的时期。美国国家航空航天管理局的火星侦探卫星已经发现，暴露在“奋进”号陨石坑边缘上的岩石中有泥土，而形成该陨石坑的那次撞击性爆炸规模要大得多。到今天为止，根据“机遇”号和其他探测器的分析，泥土的出现向地质学家们表明：是水改变了那块岩石，当时的气候条件比岩石诞生时要温和得多，大概也更加适合居住。美国国家航空航天管理局花费25亿美元打造的“好奇”号探测器计划于今年11月份发射，如果成功的话，到2013年将会到达拥有泥土的目标——“盖尔”号陨石坑。 |
