七个问题，快速了解“天问一号”的火星之旅
China’s Mars Mission Is Up Next to Orbit the Red Planet
MICHAEL ROSTON
2021年2月10日
China has landed on the moon three times, and even managed to bring one of its robotic lunar explorers back to Earth. Can it now pull off the challenge of landing on Mars?
中国已经三次登陆月球，甚至成功将一个月球探测机器人带回地球。如今，它能完成登陆火星的挑战吗？
The country’s space agency will complete a key step toward that goal on Wednesday when Tianwen-1, the spacecraft the country launched last July, attempts to orbit the red planet.
中国航天机构将在周三向实现这一目标迈出关键一步，届时中国去年7月发射的航天器“天问一号”将尝试环绕这颗红色星球运行。
If the arrival at Mars succeeds, China will try to place a lander and a robotic rover on the planet later this year. It would join what could by then be a trio of NASA spacecraft studying the Martian surface.
如果成功抵达火星，中国将在今年晚些时候尝试在火星上放置着陆器和机器人探测器。它将与NASA的航天器一同研究火星表面，届时这样的航天器将会有三个。
When will Tianwen-1 arrive at Mars?
“天问一号”什么时候到达火星？
China has said that the spacecraft will arrive at Mars on Wednesday. But the China National Space Administration and state media have not provided more specific information.
中国已表示探测器将于周三抵达火星。但中国国家航天局和官方媒体尚未提供更具体的信息。
China’s space agency has a penchant for secrecy around its missions. It has shown more openness in the past year, providing a live video on state media of its Chang’e-4 mission’s launch to the moon. Should it announce a more precise arrival time, we will provide it here.
中国航天局对其任务有保密倾向。在过去一年，它表现出了更大的开放性，在官方媒体上提供了“嫦娥四号”探月任务的现场视频。如果有更准确的到达时间，我们会在这里提供。
What will the spacecraft do on Wednesday?
航天器在周三会做什么?
Tianwen-1 launched from China last July, taking advantage of a period when Mars and Earth were closest to each other during their journeys around the sun. This allows a relatively short transit between the two worlds.
“天问一号”去年7月从中国发射，利用了火星和地球绕太阳公转时期内距离最近的一段时间。这使得两个行星之间的传输距离相对较短。
To catch up with Mars, the spacecraft has fired its engines on several occasions, correcting its course so it can approach the red planet at the correct angle. The most recent engine firing occurred on Feb. 5, and the probe sent back pictures of the red planet from a distance of about 1.3 million miles.
为了追上火星，该航天器多次启动发动机，调整轨道，以便以正确的角度接近火星。最近一次发动机点火是在2月5日，探测器从130万英里外发回了火星的照片。
On Wednesday, the engine will light up again, expending much of the spacecraft’s remaining fuel in a braking maneuver. That should slow it considerably, and allow the probe to be captured by Martian gravity. There it will circle at a safe distance, joining the other cast of robotic explorers in Martian orbit and preparing for that later surface landing attempt.
周三，发动机将再次点火，在制动操作中消耗航天器的大部分剩余燃料。这将大大降低它的速度，让探测器被火星引力捕获。在引力范围内，它将以一个安全的距离环绕火星，与其他机器人探测器一起在火星轨道上运行，并为稍后的地面登陆尝试做准备。
Could anything go wrong?
会出什么差错吗?
The history of spaceflight is littered with failed voyages to Mars, including a Chinese mission in 2011 that never got out of Earth’s orbit after the Russian rocket it was traveling on failed. And a few spacecraft have stumbled during this final step of preparing to enter Martian orbit.
太空飞行的历史上充满各种失败的火星之旅，包括2011年中国的一次火星任务，由于搭载的俄罗斯火箭发生故障，该任务并未脱离地球轨道。一些航天器在准备进入火星轨道的最后一步中出现了失误。
For instance, in 1999, NASA’s Mars Climate Orbiter suffered a navigation error — English units were not converted to metric — and the spacecraft burned in the Martian atmosphere. In 1992, NASA lost contact with its Mars Observer spacecraft days before it was to arrive at Mars, perhaps because of a fuel line rupture. After a Soviet mission in 1974, Mars 4, failed to fire its retro rockets, the spacecraft sailed away from Mars.
例如，1999年，NASA的“火星气候探测者号”(Mars Climate Orbiter)遭遇了一次导航错误——英制单位没有转换成公制单位——航天器在火星大气中烧毁。1992年，NASA的“火星观察者号”(Mars Observer)航天器在即将抵达火星的前几天与地球失去了联系，原因可能是燃料管破裂。1974年，苏联的“火星4号”发射制动火箭失败后，该航天器驶离了火星。
Still, the challenge of orbiting Mars is nothing compared with landing there.
不过，与登陆火星相比，绕火星轨道飞行的挑战根本不算什么。
When will China land on Mars?
中国何时登陆火星?
The orbiter carries a lander and a rover which will make the difficult transit to the surface. China says it will attempt to land on Mars in May, but it has not specified a date.
中国的轨道飞行器携带着陆器和探测车，它们将艰难地到达火星表面。中国表示将在5月尝试登陆火星，但没有公布具体日期。
Its destination is Utopia Planitia, a large basin in the northern hemisphere that most likely was once impacted by a meteor, and which was visited by NASA’s Viking 2 lander in 1976. One goal of the Tianwen-1 mission is to better understand the distribution of ice in this region, which future human colonists on Mars could use to sustain themselves.
它的目的地是乌托邦平原(Utopia Planitia)，这一广阔的北半球盆地很可能曾被流星撞击过，NASA的“海盗2号”(Viking 2)着陆器曾于1976年抵达这里。“天问一号”任务的目标之一是更好地了解该地区的水冰分布，未来火星的人类殖民者可以利用这些冰维持自身生存。
Landing on the red planet is perilous. Spacecraft descend at a high speed and the thin atmosphere does little to help slow the trip to the ground. Air friction still generates extreme heat that must be absorbed or dissipated. A number of Soviet, NASA and European missions have crashed. Only NASA has landed intact more than once.
登陆这颗红色星球是危险的。航天器的下降速度极高，稀薄的大气层几乎起不到减缓到达地面速度的作用。空气摩擦仍然会产生必须被吸收或散失的极端高温。苏联、NASA和欧洲的很多任务都坠毁了。只有NASA不止一次实现完好无损的着陆。
The Chinese spacecraft will spend months orbiting Mars to check systems and pick a landing spot that will not be too treacherous.
中国的航天器将耗费数月时间绕火星轨道运行以检查系统，并选择一个不会太过危险的着陆点。
Should it land in one piece, the rover will need a name. After nominations from people in China, a panel of experts selected 10 semifinalists. Among them, according to state media, are Hongyi, from a Chinese word for ambition and persistence; Qilin, a hoofed creature of Chinese legend; and Nezha, a young deity who is considered a patron of rebellious youth.
如果能完好地着陆，火星车将需要一个名字。在征集中国公众的提名之后，专家组选出了10个准候选。根据官媒报道，其中包括“弘毅”，在中文里的意思是抱负和坚持；麒麟，中国神话里的有蹄动物；以及哪吒，这位年轻的神祇被认为是叛逆青年的守护神。
What else has China accomplished in space recently?
中国最近在太空还取得了哪些成就？
Since China launched its mission to Mars in July, it has been to the moon and back.
自7月开始前往火星的任务以来，中国已经实现了月球往返。
The Chang’e-5 mission lifted off in November, collected lunar samples and then brought them back to Earth for scientists to study. It was the first new cache of moon rocks since the Soviet Union’s last lunar mission in 1976.
“嫦娥五号”于去年11月发射，收集了月球样本后，将它们带回地球供科学家研究。这是自1976年苏联最后一次探月任务以来，地球首次获取新一批月球岩石。
China’s Chang’e-4 mission, the first to land on the moon’s far side, is still in operation and its Yutu-2 rover is still studying the lunar surface more than two years after it launched.
中国的“嫦娥四号”任务首次实现了在月球背面降落，目前仍在运行，其“玉兔二号”月球车在发射两年多以后仍在对月球表面进行研究。
What else is arriving at the red planet in 2021?
还有谁会在2021年抵达火星？
The first robotic probe to arrive at Mars this year was Hope, an orbiter from the United Arab Emirates’ emerging space agency. It arrived on Tuesday, and will embark on a study of the red planet’s atmosphere, helping planetary scientists understand the weather dynamics of Mars.
今年第一个抵达火星的机器人探测器是“希望号”(Hope)，这是阿拉伯联合酋长国成立不久的太空总署发射的轨道器。它于周二抵达火星，将对这颗红色行星的大气进行研究，帮助行星科学家了解火星的天气动态。
The third new visitor to Mars will be Perseverance, NASA’s newest rover. It launched a bit later than the other two spacecraft last July, and will skip Martian orbit, heading directly to the planet’s surface on Feb. 18.
第三位火星的新访问者将是NASA的最新火星探测器“毅力号”(Perseverance)。它于去年7月发射，比另两架航天器稍晚，将跳过火星轨道，直接在2月18日飞向火星表面。
The robotic explorer would be NASA’s fifth rover on Mars, and it is very similar to Curiosity, which is now exploring the Gale crater. The new rover carries a different set of scientific instruments and will explore the Jezero crater, a dried-out lake that scientists believe could be a good target to seek fossilized evidence of extinct Martian microbial life.
该机器人探测器将是NASA在火星上的第五个探测器，与正在探索盖尔(Gale)陨石坑的“好奇号”(Curiosity)非常相似。这架新的火星车携带了一套不同的科学仪器，将探索杰泽罗(Jezero)陨石坑，科学家认为这处干涸湖泊可能是个很好的目标，可供寻找已灭绝的火星微生物化石证据。
The mission will also attempt a new first on the red planet: flying a helicopter in the wispy Martian atmosphere. NASA’s Ingenuity helicopter will be dropped off by the rover not long after landing. Then it will attempt a number of test flights in air as thin as the upper reaches of Earth’s atmosphere, aiming to demonstrate that Mars can be explored through the air as well as on the ground.
该任务还将在这颗红色星球上尝试一项创举：在稀薄的火星大气中飞行直升机。NASA的“机智号”(Ingenuity)直升机将在火星车着陆后不久被部署。随后它将在与地球大气上层一样稀薄的空气中进行一系列试飞，目标是证明火星探索既能在其表面进行，也能在空中进行。
What other spacecraft are currently studying Mars?
目前还有什么航天器在研究火星？
It’s getting a bit crowded around the red planet.
这颗红色星球的周围变得有点拥挤了。
Six orbiters are currently studying the planet from space. Three were sent there by NASA: Mars Odyssey, launched in 2001, Mars Reconnaissance Orbiter, launched in 2005, and MAVEN, which left Earth in 2013.
有六架轨道器目前正在太空中研究这颗行星。其中三艘是NASA发射的：2001年的“火星奥德赛号”(Mars Odyssey)，2005年的“火星侦察轨道器”(Mars Reconnaissance Orbiter)和2013年离开地球的“火星大气与挥发物演化任务”(MAVEN)。
Europe has two spacecraft in orbit. Its Mars Express orbiter was launched in 2003, and the ExoMars Trace Gas Orbiter lifted off in 2016 and is shared with Russia’s space program.
欧洲在火星轨道中有两架航天器。“火星快车号”(Mars Express)轨道器于2003年发射，“火星微量气体任务卫星”(ExoMars Trace Gas Orbiter)在2016年升空，并与俄罗斯的太空计划进行共享。
India operates the sixth spacecraft, the Mars Orbiter Mission, also known as Mangalyaan, which launched in 2013.
印度于2013年发射的第六架航天器火星轨道探测器（Mars Orbiter Mission，又称“火星飞船”[Mangalyaan]）正在运行。
Two American missions are currently operating on the ground. Curiosity has been roving since 2012. It is joined by InSight, which has been studying marsquakes and other inner properties of the red planet since 2018. A third American mission, the Opportunity rover, expired in 2019 when a dust storm caused it to lose power.
美国目前有两项任务正在火星表面进行。“好奇号”自2012年以来就在巡视探测。“洞察号”(InSight)也加入进来，自2018年起一直在研究火星震和这颗红色行星的其他内部特性。美国的第三个任务“机遇号”(Opportunity)漫游车因在2019年遭遇沙尘暴失去动力而结束。
