火星探索简史

张燕

Since 1960， humankind has launched dozens of missions to Mars in an effort to get to know our planetary neighbor better. Some of the missions were flybys， gathering information in brief bursts. Others were long-standing orbiters that lasted years as they traveled around the Red Planet.

1960s—early 1970s： Flybys & photographs

The first attempts to reach Mars happened near the dawn of space exploration. Considering that the first satellite， the Soviet Unions Sputnik， launched in 1957， it is extraordinary that only three years later the Soviet Union space program looked to extend its reach to Mars. The Soviet Union made multiple attempts in the 1960s to reach the Red Planet， and NASA soon followed with its Mariner 3 spacecraft. These first few missions failed to make it even close to Mars.

While those first several missions didnt reach their target， NASAs Mariner 4 finally did. The spacecraft launched on Nov. 28， 1964， and was the first to fly by Mars on July 14， 1965. It sent 21 photos of the Red Planet back to Earth.

Two days after Mariner 4 launched， the Soviet Union tried again with Zond 2. The spacecraft passed by Mars but the radio failed and it did not return any planetary data.

NASA also sent Mariners 6 and 7 in 1969， both of which reached Mars and sent back a few dozen photos. Coincidentally， all of these spacecraft flew over areas of Mars that were cratered. This gave astronomers the false first impression that Mars looked like the moon.

In 1971， the Soviet Union finally met with success after several attempts to reach the Red Planet. Its Mars 2 orbiter， which launched on May 19， 1971， arrived on Nov. 2. However， the Mars 2 lander crashed on the surface and was no longer operable. Mars 3， a lander and orbiter mission， launched on May 28， 1971， and arrived on Dec. 3. The lander worked for only a few seconds on the surface before failing， but the orbiter worked successfully.

The image of Mars changed with the arrival of NASAs Mariner 9 in November 1971. The spacecraft， which launched on May 30， 1971， arrived at Mars when the entire planet was engulfed in a dust storm. Whats more， something mysterious was poking above the plumes of dust. When the debris settled to the surface， scientists discovered those unusual features were the tops of dormant volcanoes. Mariner 9 also discovered a huge rift across the surface of Mars， later called Valles Marineris—after the spacecraft that discovered it. Mariner 9 spent nearly a year orbiting the Red Planet， and returned 7，329 photos.

1970s—1980s： Landings on Mars， and attempts to reach Phobos

As the Soviet Union continued its Mars series of spacecraft， it garnered partial success; out of four spacecraft aimed for the Red Planet， only one orbiter and one lander briefly returned data in 1974.

Meanwhile， NASA sent two pairs of orbiters and landers toward Mars in 1975. Viking 1 and Viking 2 both arrived at the Red Planet in 1976， and sent their lander to the surface while the orbiter remained working above. The Viking program represented the first extended exploration of Mars， as each spacecraft lasted years and transmitted reams of information back to Earth.

Hopes of finding life on the Red Planet， however， were dashed when the probes could not definitively prove the existence of microbes on the surface.

The Viking missions also revealed that the composition of Mars was almost identical to certain meteorites found on Earth. This suggested that some meteorites found on Earth were originally from Mars.

The Soviet Union also made two attempts to reach one of the moons of Mars， Phobos， in the 1980s， but both missions failed.

1990s： Faster， better， cheaper

NASAs next attempt to reach the Red Planet came in the 1990s， when Mars Observer launched to the planet on Sept. 25， 1992. The spacecraft was lost just before it was supposed to achieve Mars orbit on Aug. 21， 1993. While the loss of communication was never fully explained， the most likely cause was a fuel tank rupture that caused the spacecraft to spin and lose contact with Earth.

The loss was especially painful because the spacecraft had cost so much; an estimated $813 million， which was nearly four times the original budget for the project， according to NASAs Jet Propulsion Lab. The exorbitant cost and the spacecrafts failure sparked a new move within NASA to create better， faster and cheaper missions that would take advantage of advanced computer electronics and new team management techniques. NASA called it the Faster， Better， Cheaper， or FBC program.

In the meantime， NASAs Mars Global Surveyor （MGS） left Earth on Nov. 7， 1996， and arrived at Mars on Sept. 12， 1997. Its mission was extended several times until NASA lost contact with it in 2006. MGS mapped the Red Planet from pole to pole， revealing many ancient signs of water， such as gullies and hematite （a mineral that forms in water）. Data from MGS helped NASA decide where to land its future Mars rovers. MGS also took pictures of public interest， including re-imaging the famous “face on Mars”1.

In 1991， the Soviet Union was dismantled and the Soviet space program was inherited by Russia and Ukraine. The Russian space agency continued their quest for Mars with their Mars 96 mission， which launched on Nov. 16， 1996. However， the orbiter， two landers and two penetrators were lost after the rocket failed.

On the other side of Earth， the FBC programs first mission was a great success. The Pathfinder lander and Sojourner rover arrived at Mars in July 1997. The lander was the first to use a set of airbags to cushion the landing， and Sojourner was the first rover to trundle around on Mars.

Japan was next to enter the mission-to-Mars arena with Nozomi， which launched on July 4， 1998. The spacecraft made it to Mars but failed to enter orbit.

2000s to present： Rovers and orbiters galore2

The discovery of ancient water evidence on Mars sparked a renaissance in Mars exploration.

NASAs Mars Odyssey launched March 7， 2001 and arrived at the Red Planet on Oct. 24， 2001. The orbiter is still conducting its extended science mission. It broke the record for the longest-serving spacecraft at Mars on Dec. 15， 2010. The spacecraft has returned about 350，000 images， mapped global distributions of several elements， and relayed more than 95 percent of all data from the Spirit and Opportunity rovers.

The European Space Agency launched its lander-orbiter called Mars Express/Beagle 2 on June 2， 2003. The lander was lost on arrival on Dec. 25， 2003， but the orbiter completed its prime mission in November 2005 and is currently on an extended mission.

NASAs two rovers， Spirit and Opportunity， were sent to the surface of Mars in 2004. Each discovered ample evidence that water once flowed on the Red Planet. Spirit died in a sand dune in March 2010， while Opportunity continued work for nearly another decade. Opportunity fell silent during a sandstorm in summer 2018 and NASA declared the mission over in early 2019.

Another NASA orbiter， the Mars Reconnaissance Orbiter， launched on Aug. 12， 2005. It began orbiting the planet on March 12， 2006. The mission has returned more data than all previous Mars missions combined.

On Aug. 4， 2007， NASA launched a stationary lander called Mars Phoenix， which arrived at Mars on May 25， 2008， and found water ice beneath the surface. Phoenixs solar panels suffered severe damage from the harsh Martian winter， and communication with the $475 million lander was lost in November 2008. After repeated attempts to re-establish contact， NASA declared Phoenix broken and dead in May 2010. The damage was confirmed in orbital photos taken at the Red Planet.

The Russian space agency， Roscosmos， made another attempt to reach Phobos with the Phobos-Grunt mission， which launched in 2011 and crashed on Jan. 15， 2012， after failing to leave Earth orbit. Phobos-Grunt was also carrying Chinas first attempt at a Mars orbiter， along with an experiment run by the U.S.-based Planetary Society designed to study how a long journey through deep space affects microorganisms.

NASAs more powerful rover， called Curiosity， arrived at Gale Crater in 2012 to search for signs of ancient habitable environments. Its major findings include finding previously water-soaked areas， detecting methane on the surface and finding organic compounds. Opportunitys design has inspired another rover， temporarily called Mars 2020， which will continue with more advanced investigations when it arrives on the Red Planet.

NASAs MAVEN （Mars Atmosphere and Volatile Evolution）， launched in November 2013， achieved orbit on Sept. 21， 2014， and continues to observe changes in the Martian atmosphere to better understand why it thinned over billions of years.

NASA sent the Mars InSight to the Red Planet in 2018， and the spacecraft safely landed that November. As of early 2019， the lander is setting up its instruments to examine the interior of Mars.

India successfully arrived at Mars in 2014， when MOM （Mars Orbiter Mission） successfully arrived in orbit. The spacecraft is far enough from Mars to image the entire planet， and it has already transmitted many images back to Earth.

For its part， the European Space Agency plans to return to Mars with two missions later this decade. The ExoMars program， which is a collaboration with Russia， launched an orbiter called the Trace Gas Orbit （TGO） and a demonstration lander called Schiaparelli in 2016. Although Schiaparelli crashed on the Martian surface， TGO is still operational. The next tranche of ExoMars is the Rosalind Franklin rover and its companion lander， which are scheduled to leave Earth in 2020.3

自1960年以來，人类为了更好地了解我们的行星近邻，对火星进行了数十次探测。其中一部分仅仅是飞越火星，在短暂掠过时收集信息;另外一些则是长期绕轨飞行器，围绕火星飞行了数年。

1960年代至1970年代初：飞越及拍照

在太空探索的萌芽时期，人类就已开始尝试去往火星。考虑到苏联在1957年发射人类第一颗人造卫星伴侣号后仅仅三年就将太空探索范围扩展到了火星，这实在是非同凡响。苏联在1960年代曾多次尝试到达火星，而美国国家航空航天局（NASA）也迅速跟进发射了探测器水手3号。然而最初的这些尝试甚至都没能靠近火星。

最初的尝试屡屡失败之后，NASA的水手4号终于取得成功。这架探测器于1964年11月28日发射，1965年7月14日飞越火星，成为完成此举的首个探测器。它将21张火星照片发回了地球。

水手4号发射两日后，苏联再次尝试，发射了探测器2号。这架探测器虽然也经过了火星，但因无线电系统故障，未能传回任何与行星相关的资料。

1969年，NASA又先后发射了水手6号和水手7号，它们先后抵达火星并分别传回几十张照片。巧合的是，这些探测器飞越的都是火星的环形山区域，这让天文学家产生了错误的第一印象，即火星表面与月球相似。

1971年，数次尝试后，苏联抵达火星的努力终获成功。1971年5月19日发射的火星2号轨道器于11月2日抵达火星。然而，火星2号着陆器在星球表面撞毁，无法继续运行。1971年5月28日发射的火星3号着陆器及轨道器于12月3日抵达火星。着陆器在火星表面仅仅工作数秒就坏了，而轨道器则成功运行。

NASA的水手9号于1971年11月抵达火星，扭转了人们对这个星球的印象。这架探测器发射于1971年5月30日，到达火星时正值沙尘暴笼罩整个星球。除此之外，还可以看到团团尘雾中探出些神秘的东西。当尘埃落定，科学家发现那些不寻常的东西原来是休眠火山的顶部。水手9号在火星表面还发现了一道巨大的裂缝，这道裂缝后来被命名为“水手号峡谷”，以此纪念发现它的探测器。水手9号环绕火星飞行了近1年，并发回了7329张照片。

1970年代至1980年代：火星登陆及尝试抵达火卫一

苏联继续向火星发射探测器，其不懈努力仅获得部分成功：在向火星发射的四架探测器中，只有一架轨道器和一架着陆器于1974年短暂发回了一些数据。

与此同时，1975年，NASA向火星发射了两对轨道器和着陆器。海盗1号和海盗2号于1976年抵达火星，并将它们的着陆器送至火星表面，而轨道器则继续在空中工作。海盗计划代表了对火星的首次长时间探测，每一架探测器均工作数年，并向地球传回大量数据。

然而，数次探索都未能在火星表面找到微生物存在的确切证据，在火星上发现生命的希望就此落空。

海盗计划还发现，火星的成分与在地球发现的某些陨石几乎完全一致。这表明，地球上发现的部分陨石源自火星。

苏联在1980年代还两次尝试抵达火星的卫星之一——火卫一，但均告失败。

1990年代：更快、更好、更经济

NASA于1990年代再次尝试抵达火星：1992年9月25日发射了火星观察者号。该探测器本应在1993年8月21日到达火星轨道，却在预计抵达的前一刻失去联络。失联问题始终未得到充分解释，最有可能的原因是油箱破裂导致探测器急速旋转，从而失去与地球的联系。

由于该探测器成本高昂，这次损失尤其惨重：NASA喷气推进实验室的数据显示，总成本估约8.13亿美元，将近该计划最初预算的4倍。过高的成本和探测器的失灵在NASA内部引发了新举措：利用先进的计算机电子设备和新的团队管理技巧，来策划更好、更快且成本更低的探测行动。NASA称之为“更快（Faster）、更好（Better）、更经济（Cheaper）”计划，即FBC计划。

与此同时，NASA在1996年11月7日发射的火星全球探勘者号（MGS）于1997年9月12日抵达火星。其探测任务时间多次延长，直到2006年NASA与之失去联系。MGS绘制了火星从北极到南极的详细地图，发现了许多可以证明曾经有水存在的古老痕迹，例如冲沟和赤铁矿（一种在水中形成的矿物质）。MGS提供的数据有助于NASA决定其日后火星车的着陆点。MGS也拍摄了一些大众感兴趣的照片，包括重新拍摄了著名的“火星脸”。

1991年，苏联解体，俄罗斯和乌克兰继承了其航天计划。1996年11月16日，俄罗斯联邦航天局发射了火星96探测器，继续对火星的探索。然而，发射火箭出现故障，轨道器、两个着陆器及两个钻探器均毁于一旦。

在地球另一端，FBC计划的首次探测任务取得巨大成功。探路者号着陆器和旅居者号火星车在1997年7月抵达火星。该着陆器首次使用一组气囊为着陆提供缓冲，而旅居者号则首次漫游火星各地。

日本于1998年7月4日发射希望号，从此加入火星探索行列。该探测器抵达了火星但未能进入火星轨道。

21世纪初至今：火星漫游和轨道飞行发展迅速

在火星上发现曾经有水的古老证据再次激发了火星探索的热潮。

NASA的火星奥德赛号2001年3月7日升空，并于2001年10月24日抵达火星。这一轨道器至今仍在执行经过延期的科考任务，并于2010年12月15日打破了火星探测器服役时长纪录。该探测器已传回约35万张图像，绘制了多种元素在整个火星的分布图，勇气号和机遇号火星车所获资料中超过95%也由它作为通信中继传回地球。

2003年6月2日，欧洲航天局发射了火星快车/小猎犬2号（又译猎兔犬2号）着陆器-轨道器。着陆器于2003年12月25日抵达火星时失联，但轨道器于2005年11月完成主要任务，至今仍在延长服役中。

NASA的两架火星车——勇气号和机遇号——于2004年抵达火星表面。它们都发现了火星曾经存在水流的大量证据。勇气号在2010年3月葬身一处沙丘，而机遇号继续工作了将近十年。机遇号在2018年夏的一次沙暴中销声匿迹，NASA最终于2019年初宣布此次任务结束。

NASA的另一架轨道器——火星勘测轨道飞行器——于2005年8月12日发射升空。它于2006年3月12日开始环绕火星飞行。这一次传回的数据比之前所有火星探测任务的总和还多。

2007年8月4日，NASA发射了火星凤凰号静止着陆器。它于2008年5月25日到达火星，并发现了火星地表下的水冰。凤凰号的太阳能板在火星的严冬中遭受严重损伤，这一耗资4.75亿美元的着陆器在2008年11月失联。反复尝试重建联系未果后，NASA于2010年5月宣布凤凰号损毁。火星轨道器拍摄的照片证实了凤凰号的损伤。

俄罗斯联邦航天局2011年发射了火卫一—土壤号，再次尝试探测火卫一，但该探测器因脱离地球轨道失败，于2012年1月15日坠毁。火卫一—土壤号还搭载了中国的第一架火星探测器，美国行星学会则打算借用它开展实验，研究长途宇宙飞行对微生物的影响。

NASA另一架更强大的火星车好奇号于2012年抵达盖尔环形山，探索火星古老宜居环境留下的痕迹。它的主要发现包括：找到曾经有丰富水源的区域，探测到火星表面的沼气，以及找到有机化合物。机遇号的设计为新的火星车设计带来了灵感，该火星车暂时命名为火星2020号，将在抵达火星后采用先进技术继续展开一系列勘探。

2013年11月，NASA发射了马文号（火星大气与挥发物演化探测器），它于2014年9月21日抵达火星轨道，将持续观察火星大气变化，以更好了解为何火星大氣在数十亿年中日渐稀薄。

2018年，NASA发射了火星洞察号，该探测器于当年11月安全着陆。截至2019年年初，该着陆器正在安置各种仪器，以探测火星内部。

2014年，印度发射的莫姆号（火星轨道器）成功入轨，标志其成功到达火星。该探测器距离火星的距离足以令其拍摄到整个星球的图片，它已将多张照片传送回地球。

欧洲航天局计划于2010年代末执行两次探测任务重返火星。一个是与俄罗斯合作的“火星太空生物”项目（ExoMars），于2016年发射了微量气体轨道器（TGO）及示范性着陆器斯基亚帕雷利号。虽然斯基亚帕雷利号着陆时坠毁了，但TGO仍能正常运行。ExoMars项目的下一步计划是于2020年发射罗莎琳德·富兰克林号火星车及配套着陆器。           □