美“鳳凰”號(hào)探測(cè)器成功降落火星

蔣紹南

美國(guó)宇航局25日宣布，當(dāng)?shù)貢r(shí)間25日晚，美國(guó)“鳳凰”號(hào)火星著陸探測(cè)器成功降落在火星北極附近區(qū)域?！傍P凰號(hào)”此行的任務(wù)是尋找水和其它支持生命所需化學(xué)物質(zhì)的證據(jù)。

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.

美國(guó)國(guó)家航空航天局一艘有三條腿的太空飛船昨日抵達(dá)火星附近，科學(xué)家期待，這將是人類首次抵達(dá)火星北極附近，對(duì)那里的永久冰凍帶是否能維持原始生命進(jìn)行研究。

“鳳凰”號(hào)火星登錄探測(cè)器要飛速穿越大氣層，然后降落在滿是灰塵的火星表面，這期間所花的時(shí)間被稱為“恐怖七分鐘”，這樣說(shuō)不無(wú)道理。因?yàn)槭澜缟系卿浕鹦堑膰L試多半都以失敗告終。

“我內(nèi)心深處有點(diǎn)緊張，神經(jīng)質(zhì)地在發(fā)抖，”來(lái)自塔克森市亞利桑那大學(xué)的首席研究員彼得·史密斯在火星成功登陸前夕說(shuō)道?！盀檫@次安全著陸，我們把整個(gè)農(nóng)場(chǎng)都拿來(lái)做賭注了，如果無(wú)法安全著陸，以后就無(wú)法研究下去了。”

鳳凰號(hào)預(yù)定從這個(gè)紅色的行星大氣層垂直降落，并要依賴精心設(shè)計(jì)的熱擋板、降落傘和火箭來(lái)把降落速度從每小時(shí)19，300 千米減到每小時(shí)8千米。

理想情況下，“我們就能夠破繭化蝶，伸展雙翼，在火星表面化身美麗的蝴蝶，” 建造“鳳凰”號(hào)探測(cè)器的洛克希德·馬丁公司項(xiàng)目主管埃德·塞迪威說(shuō)。

該任務(wù)的控制人員周六晚些時(shí)候決定不再調(diào)整鳳凰的飛行路徑，因?yàn)榈顷懱綔y(cè)器已經(jīng)準(zhǔn)備好朝目標(biāo)著陸點(diǎn)降落。

這是自1976年美國(guó)國(guó)家航空航天局孿生姐妹“海盜”號(hào)登陸器嘗試登陸火星以來(lái)的30多年第一次實(shí)現(xiàn)軟著陸。航天局上次進(jìn)行火星著陸嘗試的時(shí)間是1999年，當(dāng)時(shí)，火星極地登陸探測(cè)器在靠近南極時(shí)，因過(guò)早關(guān)閉發(fā)動(dòng)機(jī)而墜毀。

“鳳凰”號(hào)的建造基于極地登陸災(zāi)難發(fā)生后用拆卸部件組裝的登陸器。工程師花了幾年時(shí)間測(cè)試?guó)P凰的性能，以解決所有已知問(wèn)題，但這并不能擔(dān)保那天能安全著陸。

去年夏天發(fā)射的鳳凰號(hào)行程已達(dá)679，000，000千米，時(shí)間長(zhǎng)達(dá)近10個(gè)月。它將抵達(dá)火星北部高緯度地區(qū)，這一過(guò)程會(huì)由繞其上飛行的三個(gè)火星衛(wèi)星嚴(yán)密監(jiān)視。如果成功，它將加入孿生姐妹火星漫游器“勇氣”號(hào)和“機(jī)遇”號(hào)的行列，后兩者從2004年就開始進(jìn)行火星赤道平原的探測(cè)工作了。

這項(xiàng)花費(fèi)4.2億美元的項(xiàng)目是由亞利桑那州大學(xué)領(lǐng)導(dǎo)，美國(guó)噴氣推進(jìn)所實(shí)驗(yàn)管理的。★