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。

This artist's conception shows NASA's Phoenix Mars Lander as it monitors the atmosphere overhead with a laser radar and reaches out to the soil below with the spacecraft fully deployed on the surface of Mars. [Agencies]

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 world's attempts to land on Mars have ended in failures.

"I'm a little nervous on the inside. I'm 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 can't do our science without this safe landing."

Phoenix is preprogrammed to plummet through the Red Planet's 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 Phoenix's 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.

（Agencies/China Daily）

Vocabulary:

permafrost：永冻土，出现在整个北极地区和部分长期寒冷的地区。

parachute：降落伞

（英语点津Celene编辑）