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登陆火星--“恐怖7分钟”

科技环境

美国宇航局的"好奇号"探测器将于8月5日登陆火星。是成功，还是撞毁或烧毁，取决于短短的7分钟。

美国宇航局的火星科学研究室--又称"好奇号"（Curiosity）探测器进入火星大气层时将面临严峻的7分钟。在7分钟内，它必须从1.3万英里（2.1万公里）的时速减速至零。这生死攸关的时段被称为恐怖7分钟。

预计8月5日晚（太平洋时区，欧洲时区为8月6日早晨）"好奇号"将登陆。不过，信号从"好奇号"传递至地球需要14分钟，是登陆时间的两倍。所以，当美国宇航局得到信号时，"好奇号"已经着陆7分钟了，--无论是生是死。

"盲登"

这次登陆也被称为"盲登"，因为美国宇航局所依赖的卫星出了故障。但火星探索项目的负责人麦克-丘斯宸（Doug McCuistion）说，这对登陆本身并没有影响，只是数据收集的时效性受到影响。在美国宇航局的请求下，欧洲宇航局的探测卫星"火星快车号" （Mars Express）将观测登陆。自2003年12月起，"火星快车号"一直在火星轨道上，当时"猎犬2号"（Beagle 2）火星探测器登陆失败。

"火星快车号"行动负责人丹尼斯（Michel Denis）说，欧洲宇航局将为美国宇航局自身的追踪系统提供备份支持，以防万一。"对宇航科学来说，这将是伟大的一天。"丹尼斯相信"好奇号"将成功登陆，尽管他也承认在宇航项目中没有保证一说。

Testing during March and April 2009 inside the world's largest wind tunnel, at NASA Ames Research Center, Moffett Field, Calif., qualified the parachute for NASA's next Mars rover. The parachute for NASA's Mars Science Laboratory mission, to be launched in 2011 and land on Mars in 2012, is the largest ever built to fly on an extraterrestrial mission. This image shows the qualification-test parachute beginning to open a few seconds after it was launched from a mortar into an 80-mile-per-hour (36-meter-per-second) wind. The parachute uses a configuration called disk-gap-band. It has 80 suspension lines, measures more than 50 meters (165 feet) in length, and opens to a diameter of nearly 16 meters (51 feet). Most of the orange and white fabric is nylon, though a small disk of heavier polyester is used near the vent in the apex of the canopy due to higher stresses there. Pioneer Aerospace, South Windsor, Conn., built the parachutes for testing and for flying on the Mars Science Laboratory. The wind tunnel used for the testing is part of the National Full-Scale Aerodynamics Complex, operated by the Arnold Engineering Development Center of the U.S. Air Force. NASA's Jet Propulsion Laboratory, Pasadena, Calif., is building and testing the Mars Science Laboratory spacecraft for the NASA Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology. Image Credit: NASA/JPL-Caltech

美国宇航局基地的模拟测试

落地后即可运行

"好奇号"登陆时必须完成一系列高度复杂的操作，由探测器上的电脑控制完成。首先，火星大气层将帮助"好奇号"时速减缓1.2万英里。火星的大气层比地球稀薄100倍。其次，探测器将释放出一个降落伞，降落伞可承受6.5万磅的力量。探测器的热护盾在370英里时速时脱落，降落伞也将脱离，届时，制动火箭系统将激活。

时速从70英里减至2英里后，探测器将在"天空起重机"（sky crane）这一软着陆缓冲系统的帮助下，从25英尺（7.62米）的高度降落至火星地表。

欧洲宇航局的丹尼斯认为，"好奇号"一旦成功着陆，就可进入运行状态，"它会像一辆新买的车一样"。

Curiosity's Sky Crane Maneuver, Artist's Concept This artist's concept shows the sky crane maneuver during the descent of NASA's Curiosity rover to the Martian surface. The entry, descent, and landing (EDL) phase of the Mars Science Laboratory mission begins when the spacecraft reaches the Martian atmosphere, about 81 miles (131 kilometers) above the surface of the Gale crater landing area, and ends with the rover Curiosity safe and sound on the surface of Mars. Entry, descent, and landing for the Mars Science Laboratory mission will include a combination of technologies inherited from past NASA Mars missions, as well as exciting new technologies. Instead of the familiar airbag landing systems of the past Mars missions, Mars Science Laboratory will use a guided entry and a sky crane touchdown system to land the hyper-capable, massive rover. The sheer size of the Mars Science Laboratory rover (over one ton, or 900 kilograms) would preclude it from taking advantage of an airbag-assisted landing. Instead, the Mars Science Laboratory will use the sky crane touchdown system, which will be capable of delivering a much larger rover onto the surface. It will place the rover on its wheels, ready to begin its mission after thorough post-landing checkouts. The new entry, descent and landing architecture, with its use of guided entry, will allow for more precision. Where the Mars Exploration Rovers could have landed anywhere within their respective 93-mile by 12-mile (150 by 20 kilometer) landing ellipses, Mars Science Laboratory will land within a 12-mile (20-kilometer) ellipse! This high-precision delivery will open up more areas of Mars for exploration and potentially allow scientists to roam "virtually" where they have not been able to before. In the depicted scene, the spacecraft's descent stage, while controlling its own rate of descent with four of its eight throttle-controllable rocket engines, has begun lowering Curiosity on a bridle. The rover is connected to the descent stage by three nylon tethers and by an umbilical providing a power and communication connection. The bridle will extend to full length, about 25 feet (7.5 meters), as the descent stage continues descending. Seconds later, when touchdown is detected, the bridle is cut at the rover end, and the descent stage flies off to stay clear of the landing site. The Mars Science Laboratory spacecraft is being prepared for launch during Nov. 25 to Dec. 18, 2011. Landing on Mars is in early August 2012. In a prime mission lasting one Martian year (nearly two Earth years) researchers will use the rover's tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and for preserving clues about whether life existed. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, Calif., manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington. More information about Curiosity is at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . Image credit: NASA/JPL-Caltech

“天空起重机”操作

大小很重要

"好奇号"探测器与一辆运动型多功能车（SUV）大小相似，7英尺高，9英尺宽，10英尺长，2000磅重。"好奇号"是目前最大、设备最齐全的外星探测器。

与"好奇号"相比，1997年首次登陆的"索杰纳号"（Sojourner）火星车则形同侏儒，后者只有23磅重。2004年登陆的"勇气号"和"机遇号"火星探测器为400磅重。

此外，"好奇号"的时速也比"机遇号"的最高时速超出0.1英里，为3.35英里。

速度并非一切，生存下来最重要。"机遇号"仍在继续探测一个命名为"奋力"（Endeavour）的大型撞击坑。它已行进21.4英里，仍在发送宝贵的数据。

Curiosity Touching Down, Artist's Concept This artist's concept depicts the moment that NASA's Curiosity rover touches down onto the Martian surface. The entry, descent, and landing (EDL) phase of the Mars Science Laboratory mission begins when the spacecraft reaches the Martian atmosphere, about 81 miles (131 kilometers) above the surface of the Gale crater landing area, and ends with the rover safe and sound on the surface of Mars. Entry, descent, and landing for the Mars Science Laboratory mission will include a combination of technologies inherited from past NASA Mars missions, as well as exciting new technologies. Instead of the familiar airbag landing systems of the past Mars missions, Mars Science Laboratory will use a guided entry and a sky crane touchdown system to land the hyper-capable, massive rover. The sheer size of the Mars Science Laboratory rover (over one ton, or 900 kilograms) would preclude it from taking advantage of an airbag-assisted landing. Instead, the Mars Science Laboratory will use the sky crane touchdown system, which will be capable of delivering a much larger rover onto the surface. It will place the rover on its wheels, ready to begin its mission after thorough post-landing checkouts. The new entry, descent and landing architecture, with its use of guided entry, will allow for more precision. Where the Mars Exploration Rovers could have landed anywhere within their respective 93-mile by 12-mile (150 by 20 kilometer) landing ellipses, Mars Science Laboratory will land within a 12-mile (20-kilometer) ellipse! This high-precision delivery will open up more areas of Mars for exploration and potentially allow scientists to roam "virtually" where they have not been able to before. In the depicted scene, Curiosity is touching down onto the surface, suspended on a bridle beneath the spacecraft's descent stage as that stage controls the rate of descent with four of its eight throttle-controllable rocket engines. The rover is connected to the descent stage by three nylon tethers and by an umbilical providing a power and communication connection. When touchdown is detected, the bridle will be cut at the rover end, and the descent stage flies off to stay clear of the landing site. The Mars Science Laboratory spacecraft is being prepared for launch during Nov. 25 to Dec. 18, 2011. Landing on Mars is in early August 2012. In a prime mission lasting one Martian year (nearly two Earth years) researchers will use the rover's tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and for preserving clues about whether life existed. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, Calif., manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington. More information about Curiosity is at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . Image credit: NASA/JPL-Caltech

模拟登陆图

可能是最后一次登陆

25亿美元（21亿欧元）的价格也使得"好奇号"成为美国宇航局最昂贵的火星探测器。由于预算高达10亿美元，这恐怕也是美国宇航局在可预见的未来最后一次火星登陆使命。

这一为期两年的使命任务是探索"盖尔"撞击坑（Gale Crater）,它位于火星赤道附近，再就是搜寻生命迹象。

"好奇号"有着相应的装备。六轮探测器可以向岩石发射激光，测量其化学组成，拍摄高清晰的火星地貌视频。

探测器配备有传感器、摄像机，有一支长长的机械手臂，有一个铲子可以收集土壤样品，一个钻头可以钻入岩石，一个高敏感度的镜头可以检测12.5微米的微观结构。

欧洲宇航政策研究所（ESPI）的胡斯罗伊（Peter Hulsroj）说："火星探测使命有助于宇航事业的整体发展。'好奇号'迈出美妙的一步。"

自1960年以来，美国、欧洲、俄罗斯、日本先后启动40次火星使命，然而，超过一半撞毁、运作不灵或者失去踪迹。

Context of Curiosity Landing Site in Gale Crater This oblique, southward-looking view of Gale crater shows the mound of layered rocks that NASA's Mars Science Laboratory will investigate. The mission's selected landing site is just north of the mound inside the crater. Gale crater is 96 miles (154 kilometers) in diameter and holds a layered mountain rising about 3 miles (5 kilometers) above the crater floor. The landing site contains material washed down from the wall of the crater, which will provide scientists with the opportunity to investigate the rocks that form the bedrock in this area. The landing ellipse also contains a rock type that is very dense and very bright colored; it is unlike any rock type previously investigated on Mars. It may be an ancient playa lake deposit, and it will likely be the mission's first in checking for the presence of organic molecules. The area of top scientific interest for Mars Science Laboratory is at the base of the mound, just at the edge of the landing ellipse. Here, orbiting instruments have detected signatures of both clay minerals and sulfate salts. Scientists studying Mars have several important hypotheses about how these minerals reflect changes in the Martian environment, particularly changes in the amount of water on the surface of Mars. The Mars Science Laboratory rover, Curiosity, will use its full instrument suite to study these minerals and how they formed to give us insights into those ancient Martian environments. These rocks are also a prime in checking for organic molecules. This three-dimensional perspective view was created using visible-light imaging by the Thermal Emission Imaging System camera on NASA's Mars Odyssey orbiter. Three-dimensional information was derived from observations by the Mars Orbiter Laser Altimeter, which flew on NASA's Mars Global Surveyor orbiter. Color information is derived from color imaging of portions of the scene by the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter. The vertical dimension is not exaggerated. The Mars Science Laboratory spacecraft is being prepared for launch during the period Nov. 25 to Dec. 18, 2011. In a prime mission lasting one Martian year -- nearly two Earth years -- after landing, researchers will use the rover's tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and for preserving clues about whether life existed. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate in Washington. Arizona State University, Tempe, operates the Thermal Emission Imaging System. The Mars Orbiter Laser Altimeter was operated by NASA Goddard Space Flight Center, Greenbelt, Md. The University of Arizona, Tucson, operates the High Resolution Science Imaging Experiment. JPL manages Mars Odyssey and Mars Reconnaissance Orbiter for NASA's Science Mission Directorate. Image Credit: NASA/JPL-Caltech/ASU/UA

"盖尔”撞击坑

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