“勇气”号首次完全站直身体（图）

                               
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NASA最新公布的“勇气”号登陆火星演示图
继展开两个前轮后，“勇气”号又成功地伸出了两个后轮。至此，这辆过去大半年来一直蜷缩着的火星车，终于首次完全站直了身体。“勇气”号身子目前已彻底舒展，为在火星表面行驶做好了准备。

　　美国宇航局喷气推进实验室的机械工程师沃里斯10日说，在从地球到火星近7个月的旅行中，“勇气”号绝大多数时间蜷缩在四面体形状的登陆舱中，“这并不是火星车想保持的形状”。过去几天来，在地面人员的控制下，“勇气”号成功地在火星上完成了一系列伸展程序，全身都已站直。沃里斯说，这是人类发射的无人探测器迄今完成的最复杂的展开动作之一。

　　“勇气”号身子虽已站直，但“手”和“腿”并没有完全解除束缚。今后几天中，科学家们计划释放火星车中间两个轮子，切断连接火星车和登陆舱的第三根也是最后一根缆线，首次松开装备有多种科学仪器的火星车机械手臂。之后，火星车将从现在的位置顺时针旋转120度，从西北方向驶下登陆舱，涉足火星表面。科学家们说，由于“勇气”号身体展开进度比原先估计要快，火星车最早14日左右就有可能漫步火星。(记者 毛磊)

Mars rover preparing for move to surface
Strategy changes as balky airbag can't be budged
By MARK CARREAU
Copyright 2004 Houston Chronicle
PASADENA, Calif. -- NASA's Mars rover began to stand up Friday in preparation for rolling from its lander to the planet's surface next week.

Meanwhile, a key science instrument aboard the $410 million Spirit offered its first hints of mineral evidence that the landing site may once have been a crater lake.

A final attempt by engineers to reel in two puffy sections of a deflated airbag in front of the rover was unsuccessful. Since the fabric might obstruct Spirit's 10-foot traverse off the front of its lander, mission managers plan to roll off to the right.

With the change in strategy, Spirit won't be ready for its first trek across the rocky Martian soil until late Thursday or Friday.

A three-day procedure prepares the 384-pound rover for ground operations: So far, it has been raised on a jack while the front wheels unfolded and locked into place. Two more sets of wheels await deployment and a restraining cable must be severed with an explosive charge before the much anticipated rolloff.

The spacecraft landed on Mars late Saturday, the descent slowed by a parachute and the inflation of two dozen airbags to cushion the impact.

Not all of the deflated airbags retracted, and some of the fabric billowed up 30 inches to 35 inches in front of Spirit.

Engineers feared the stubborn material might snag the rover's solar arrays or a science instrument, so they decided on steering away from it to reach the soil.

While it waits, Spirit has lost no time surveying its surroundings, which scientists believe is the floor of a 3-billion-year-old crater caused by an asteroid or comet strike.

The first scan of Gusev Crater has revealed small amounts of carbonates, a class of mineral that forms in water on the Earth, said Phil Christensen, an Arizona State University planetary geologist who supervised the survey.

Another source of the carbonate, though, could be the interaction between the soil and the planet's atmosphere, which is rich in carbon dioxide.

"We have a bunch of ideas and we don't know which one is right yet," said Steve Squyres, the Cornell University astronomer who serves as Spirit's chief scientist.

Spirit's mission is to look for evidence that the cold, arid planet was once warm and wet enough for some form of life.

Earlier this week, scientists speculated the lake bed may be layered over by lava from an inactive, nearby volcano.