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“星尘”彗星探测器

　　美国航空航天局（NASA）两个已成功完成既定任务的探测器现在又接受了新的任务。称为“星尘”和“大冲撞”（又译“深度撞击”）的这两个探测器将利用其已得到飞行验证的设备开展原先并未安排的新的研究工作，包括对彗星开展新的观测，并将对太阳系外行星进行研究。

　　NASA主管科学任务署工作的副局长阿兰·斯特恩说：“这些延寿工作很令人激动。它们将使我们能首次重新造访一颗彗星，使得到探测的彗星数量再增加一颗，并在已知有大型行星的恒星周围搜寻小型行星。而通过利用已在太空中飞行的探测器，我们只需用从头启动一项新任务所需费用的15%就可做到这一点。”他说：“给这两个老探测器安排的这些新任务不仅体现了创新思维和规划，还很好地反映了我们是如何更好地利用所拥有的预算的。”

　　“大冲撞”探测器的新任务称为“系外行星观测与大冲撞延长研究”（EPOXI），由两项很重要的研究工作组成，即“大冲撞延长研究”（DIXI）和“系外行星观测与特征研究”（EPOCh）。“大冲撞”已在2005年完成其基本任务。在DIXI研究任务下，“大冲撞”将飞越还从未被探测过的彗星波星（Boethin）。这是一颗很小的短周期彗星，也就是说它会频繁地从木星轨道以外的地方回到内太阳系。DIXI项目将弥补因“彗核之旅”（CONTOUR）探测器2002年失败而损失的一些科学成果。“彗核之旅”的一个目标便是对多颗小行星进行比较研究。在DIXI任务下，“大冲撞”定于2008年12月5日飞越波星。

　　EPOCh研究任务将利用“大冲撞”探测器来观测几颗邻近的明亮恒星，观察围绕这些恒星运行的已知巨行星先后通过恒星前方和后方的过程，所得到的数据将用于研究这些巨行星的特征和确定它们是否具有环、卫星或与地球大小相仿的行星。EPOCh任务设备的灵敏度将超过目前地面和天基天文台的能力。EPOCh还将测定地球的中红外光谱，为未来的系外行星大气研究工作提供比较数据。搜寻系外行星的工作将在今年在飞往波星彗星的途中进行。

　　将利用“星尘”探测器进行的另一项新选定的任务称为“坦普尔1新探测”（NExT）。在该任务下，“星尘”将再度造访坦普尔1彗星。这项研究将首次观测到彗核近距离飞过太阳后产生的变化。这将是人造探测器首次回访一颗彗星。NExT还将使对坦普尔1彗核的测绘时间延长，使它成为迄今得到最详细测绘的彗核。这项测绘将帮助回答一些图像上反映出的重大彗核“地质学”问题。这些图像是“大冲撞”探测器2005年7月4日与坦普尔1交会时发回的。图像反映出该彗核上的一些区域可能有液体或粉状物流动。在NExT任务下，“星尘”探测器定于2011年2月14日飞越坦普尔1。

　　“星尘”是1999年2月7日发射的。它在飞行了20多亿英里（1英里合1.609公里）后于2004年1月从距怀尔德2彗星相距不到150英里的地方飞过，采集到了有可能给彗星成分及不同彗星之间成分差异带来新认识的样品。携带样品的容器已在2006年1月回到地球，但探测器其它部分仍留在太空中。

NASA's next moon rocket is still on the drawing board, but already scientists are dreaming up big new things to do with it. "The Ares V rocket will be able to launch missions whose volume or mass or both can be handled no other way," says Philip Stahl, an internationally respected optical engineer now at NASA's Marshall Space Flight Center. Maybe, he says, we should use it "to launch big space telescopes."

How big? Consider the following: Ares V will be able to place almost 130,000 kg (284,000 lbs; 8% more than the Saturn V rocket of the 1960s) into low Earth orbit. Designed to deliver cargo to the Moon, the rocket would be large enough to carry primary mirrors 8+ meters wide. For comparison, Hubble's mirror measures 2.4 m.

"How does a typical astrophysicist work?" Stahl asks. "He builds a giant telescope on top of a mountain and uses it for decades, and every few months or years he swaps out instruments or does other upgrades to keep it going." The Hubble Space Telescope operates in this fashion, with the space shuttle doing the servicing and Earth-orbit playing the role of mountain peak.

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The Lockheed Martin Multifunction Utility/Logistics and Equipment (MULE) robotic vehicle's Engineering Evaluation Unit (EEU) recently reached a major milestone in demonstrating autonomous navigation over complex obstacles, such as steps and gaps. The EEU autonomously climbed a 30-inch step and bridged a 70-inch gap without operator intervention, using only parametric descriptions of the obstacles and the vehicle's self-awareness.

This capability exceeds the performance of other high-mobility vehicles, such as the HMMWV. Although a smaller vehicle, the MULE is able to address complex obstacles, such the ones used for the demonstration at a testing facility, by employing its specialized articulating suspension.

"We've now demonstrated mobility that exceeds the HMMWV or any other small combat vehicle," said Joe Zinecker, program manager for the FCS MULE at Lockheed Martin Missiles and Fire Control. "The MULE can keep up with dismounted Soldiers, and will not be restricted to roads or trails like most other vehicles. We are eager to provide this capability to our Soldiers as early as 2013."

The EEU represents a full-scale MULE vehicle, and is the largest and most sophisticated robotic vehicle yet constructed by Lockheed Martin Missiles and Fire Control and its partners in Unmanned Ground Vehicle development. The EEU was designed and built in only 13 months by Lockheed Martin and subcontractors MillenWorks and BAE Systems. Since December 2006, the team has incorporated a series of hardware and software enhancements, and has subjected the EEU to a variety of risk mitigation challenges.

The MULE/ARV-Assault Light, a 3.5-ton class vehicle for the Future Combat Systems Program, offers an extraordinary capability that will support the U.S. Army's transformation to a lighter and more mobile fighting force. The robot's unique mobility will enable it to go everywhere the Soldier can go and more. It will allow Soldiers of the transformed Army to use technology to perform a number of dull, dirty and dangerous jobs performed by Soldiers today, freeing troops to focus more effectively on the success of their mission.

The MULE/ARV-Assault Light's highly mobile platform is a unique 6x6 independent articulated suspension. Coupled with in-hub motors powering each wheel, the suspension system provides extreme mobility in complex terrain, far exceeding that of vehicles utilizing more conventional suspension systems. The ARV-Assault Light version will be armed with a line-of-sight gun and an anti-tank capability. It is designed to provide immediate, heavy firepower to the dismounted Soldier.

The Transport MULE configuration is designed to support the Future Force Soldier by providing the volume and payload capacity to carry the equipment and supplies to support two dismounted Infantry Squads. Multiple tie-down points and removable/foldable side railings will support virtually any payload variation. It is suited to support casualty evacuation needs as well.

Lockheed Martin's experience in unmanned systems is unmatched with proven capabilities across all domains including air, land, sea and space. An integrated system-of-systems approach allows Lockheed Martin to meet the challenges of network-centric warfare where both manned and unmanned technologies work collaboratively, increasing the affordability of the technology, the efficiency of the total force and ultimately, the success of their missions.

The US space agency has postponed until September the launch of space probe Dawn on its eight-year mission to unlock the mysteries of the origins of our solar system. It was the second delay for the mission in as many days. "Primary reasons for the move were a combination of highly limited launch opportunities for Dawn in July and the potential impact to launch preparations for the upcoming Phoenix Mars Lander mission, set for early August," the National Aeronautics and Space Administration said in a statement Saturday.

"A September launch for Dawn maintains all of the science mission goals a July launch would have provided," NASA further assured.

Dawn's launch was originally scheduled for Saturday, but because of weather was first delayed until Monday.

Even then, NASA said, a ship tasked with tracking the probe's launch into orbit would not have been in place by Monday as expected.

Dawn's eight-year mission will shed light on the earliest moments in the birth of the solar system 4.6 billion years ago by examining the two celestial bodies Ceres and Vesta in the asteroid belt between Mars and Jupiter.

Dawn is scheduled to enter orbit around Vesta in October 2011, proceed to Ceres in May 2012 and then begin orbiting Ceres in February 2015 -- traveling a total distance of 5.1 billion kilometers (3.2 billion miles).

Dawn's launch window, said NASA earlier, will remain open until the end of October, when the two asteroids begin pulling away from each other, making a rendezvous with both practically impossible. This will be the first NASA mission to orbit two separate objects.

NASA says the mission should provide a better understanding of the building blocks that formed the terrestrial planets and how the two "protoplanets" followed different evolutionary paths.

The space explorer, measuring 1.64 meters (5.3 feet) long and 1.27 meters (4.1 feet) wide when its solar array is retracted, is equipped with a high-definition camera and two spectrometers to study the two massive asteroids.

Ceres, discovered in 1801, is spherical and has a diameter of about 960 kilometers (596 miles). Scientists believe it may have a layer of thick ice under its crust, covering a rocky core.

Vesta, discovered in 1807, is smaller than Ceres but the third largest asteroid in the solar system. With a diameter of 520 kilometers (323 miles), Vesta has a rocky surface without a trace of water and a hot interior.

After having cancelled the Dawn project previously, NASA revived the mission in 2006 after an investment of 449 million dollars.

It is the ninth mission out of 10 planned in NASA's Discovery program that employs unmanned vehicles to explore space, often focusing on asteroids.

NASA has scheduled a news briefing for 11:30 am (1530 GMT) on Monday to explain the situation with Dawn and preview the launch of the Phoenix Mars Lander.

NASA's next Mars mission will look beneath a frigid arctic landscape for conditions favorable to past or present life. Instead of roving to hills or craters, NASA's Phoenix Mars Lander will claw down into the icy soil of the Red Planet's northern plains. The robot will investigate whether frozen water near the Martian surface might periodically melt enough to sustain a livable environment for microbes. To accomplish that and other key goals, Phoenix will carry a set of advanced research tools never before used on Mars.

First, however, it must launch from Florida during a three-week period beginning Aug. 3, then survive a risky descent and landing on Mars next spring.

"Our 'follow the water' strategy for exploring Mars has yielded a string of dramatic discoveries in recent years about the history of water on a planet where similarities with Earth were much greater in the past than they are today," said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters, Washington. "Phoenix will complement our strategic exploration of Mars by being our first attempt to actually touch and analyze Martian water -- water in the form of buried ice."

NASA's Mars Odyssey orbiter found evidence in 2002 to support theories that large areas of Mars, including the arctic plains, have water ice within an arm's reach of the surface.

"Phoenix has been designed to examine the history of the ice by measuring how liquid water has modified the chemistry and mineralogy of the soil," said Peter Smith, the Phoenix principal investigator at the University of Arizona, Tucson.

"In addition, our instruments can assess whether this polar environment is a habitable zone for primitive microbes. To complete the scientific characterization of the site, Phoenix will monitor polar weather and the interaction of the atmosphere with the surface."

With its flanking solar panels unfurled, the lander is about 18 feet wide and 5 feet long. A robotic arm 7.7 feet long will dig to the icy layer, which is expected to lie within a few inches of the surface. A camera and conductivity probe on the arm will examine soil and any ice there. The arm will lift samples to two instruments on the lander's deck. One will use heating to check for volatile substances, such as water and carbon-based chemicals that are essential building blocks for life. The other will analyze the chemistry of the soil.

A meteorology station, with a laser for assessing water and dust in the atmosphere, will monitor weather throughout the planned three-month mission during Martian spring and summer. The robot's toolkit also includes a mast-mounted stereo camera to survey the landing site, a descent camera to see the site in broader context and two microscopes.

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        新华网北京７月９日电（卢俊）“尼日利亚通信卫星一号”日前成功交付用户，卫星总设计师兼总指挥周志成接受采访时说，这不仅标志着中国航天首次整星出口任务顺利完成，也表明我国通信广播卫星事业在自主创新的道路上实现重大跨越。

    “尼日利亚通信卫星一号”由中国空间技术研究院研制生产，从西昌卫星发射中心发射升空经过一段时间的在轨测试后，于７月６日在尼日利亚首都阿布贾正式交付尼方使用。

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Russian Space Agency head Anatoly Perminov recently congratulated Yury Solomonov, general designer of the Moscow Heat Technology Institute, on the successful submarine launch of a new sea-based strategic missile, the Bulava, which was developed by his institute. The launch was part of a series of flight tests. Such publicity given to an event so ordinary and routine may seem strange, but only at first glance.

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