美“凤凰”号探测器成功降落火星

蒋绍南

美国宇航局25日宣布，当地时间25日晚，美国“凤凰”号火星着陆探测器成功降落在火星北极附近区域。“凤凰号”此行的任务是寻找水和其它支持生命所需化学物质的证据。

A three-legged NASA spacecraft was closing in on Mars yesterday for what scientists hope will be the first-ever touchdown near Mars north pole to study whether the permafrost could have supported primitive life.

The time it takes the Phoenix Mars Lander to streak through the atmosphere and set down on the dusty surface has been dubbed “the seven minutes of terror” for good reason.More than half of the worlds attempts to land on Mars have ended in failures.

“Im a little nervous on the inside.Im getting butterflies，” Peter Smith，principal investigator from the University of Arizona，Tucson，said on the eve of the landing.“We bet the whole farm on this safe landing and we cant do our science without this safe landing.”

Phoenix is preprogrammed to plummet through the Red Planets atmosphere，and will rely on the intricately choreographed use of its heat shield，parachute and rockets to slow its descent from over 19，300 kph to a 8 kph touchdown.

In the ideal scenario，“we evolve out of this cocoon and spread our wings and we turn into this beautiful butterfly on the surface，”said Ed Sedivy，program manager at Lockheed Martin Corp，which built Phoenix.

Mission controllers decided late Saturday to skip an opportunity to adjust Phoenixs flight path since the lander was well on track for its target landing site.

NASA has not had a successful soft landing in more than three decades since the twin Viking landers in 1976.The last time the space agency tried was in 1999 when the Mars Polar Lander angling for the south pole crashed after prematurely cutting off its engines.

Phoenix was built from a lander that was scrapped after the Polar Lander disaster.Engineers spent years testing Phoenix to resolve all known problems，but there are no guarantees on landing day.

Launched last summer，Phoenix has traveled 679 million km over nearly 10 months.Its arrival to the high northern latitudes will be closely watched by a trio of Mars orbiters circling overhead.If successful，it will join the twin Mars rovers，Spirit and Opportunity，which have been exploring the equatorial plains since 2004.

The $420 million mission is led by the University of Arizona and managed by JPL.

美国国家航空航天局一艘有三条腿的太空飞船昨日抵达火星附近，科学家期待，这将是人类首次抵达火星北极附近，对那里的永久冰冻带是否能维持原始生命进行研究。

“凤凰”号火星登录探测器要飞速穿越大气层，然后降落在满是灰尘的火星表面，这期间所花的时间被称为“恐怖七分钟”，这样说不无道理。因为世界上登录火星的尝试多半都以失败告终。

“我内心深处有点紧张，神经质地在发抖，”来自塔克森市亚利桑那大学的首席研究员彼得·史密斯在火星成功登陆前夕说道。“为这次安全着陆，我们把整个农场都拿来做赌注了，如果无法安全着陆，以后就无法研究下去了。”

凤凰号预定从这个红色的行星大气层垂直降落，并要依赖精心设计的热挡板、降落伞和火箭来把降落速度从每小时19，300 千米减到每小时8千米。

理想情况下，“我们就能够破茧化蝶，伸展双翼，在火星表面化身美丽的蝴蝶，” 建造“凤凰”号探测器的洛克希德·马丁公司项目主管埃德·塞迪威说。

该任务的控制人员周六晚些时候决定不再调整凤凰的飞行路径，因为登陆探测器已经准备好朝目标着陆点降落。

这是自1976年美国国家航空航天局孪生姐妹“海盗”号登陆器尝试登陆火星以来的30多年第一次实现软着陆。航天局上次进行火星着陆尝试的时间是1999年，当时，火星极地登陆探测器在靠近南极时，因过早关闭发动机而坠毁。

“凤凰”号的建造基于极地登陆灾难发生后用拆卸部件组装的登陆器。工程师花了几年时间测试凤凰的性能，以解决所有已知问题，但这并不能担保那天能安全着陆。

去年夏天发射的凤凰号行程已达679，000，000千米，时间长达近10个月。它将抵达火星北部高纬度地区，这一过程会由绕其上飞行的三个火星卫星严密监视。如果成功，它将加入孪生姐妹火星漫游器“勇气”号和“机遇”号的行列，后两者从2004年就开始进行火星赤道平原的探测工作了。

这项花费4.2亿美元的项目是由亚利桑那州大学领导，美国喷气推进所实验管理的。★