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嫦娥五号“奔月”在即:带回2千克月球样本,或将改写月球历史

2020-11-23 16:38

日前,“长征五号遥五”运载火箭与“嫦娥五号”探测器在中国文昌航天发射场完成技术区总装测试工作后,垂直转运至发射区,计划于本月下旬择机实施发射。

探月工程嫦娥五号任务是中国探月工程第六次任务,计划实现月面自动采样返回,助力深化月球成因和演化历史等科学研究,是我国航天领域迄今最复杂、难度最大的任务之一。

月球采样返回

苏联捷足先登,美国大肆“挖土”

在无人月球采样返回探测方面,苏联可以说是开路先锋,这也许与苏联载人登月半途而废有关,所以转向用无人空间探测器采集月球样品。

1970年9月12日,苏联发射了世界第一个无人月球采样返回探测器“月球16号”。它在月面软着陆后,用自动钻孔机采集月球样品,然后把样品封装于返回舱内。接着,上升级从月面起飞返回地球,最终返回舱于1970年9月24日在苏联境内着陆。它从月球丰饶海取回了一块101克的小样本。

苏联“月球16号”月球采样返回探测器

1972年2月14日发射的“月球20号”由于遇上了玄武岩,只从月球阿波罗尼厄斯高地采集到了55克月球样品。1976年8月18日,“月球24号”在月球危海东南部软着陆,它从2米深处挖取了月岩,并从月球危海总共获得了170克的样品。

上世纪五十年代末期,苏联在运载火箭和人造卫星技术上先行一步,因此在月球探索上也占得先机,而美国也不甘示弱。

二十世纪六七十年代,美国通过“阿波罗”计划实现了载人登月的目标。1969年7月至1972年12月,美国共实施了7次载人登月任务,成功将12名航天员送上月球。尽管载人月球采样返回技术更复杂、成本更高,但由于航天员可以到舱外活动,还能乘月球车漫步到比较远的地方去采集月球样品,所以用载人飞船从月球采样返回,不仅采集量大、选择性强,而且采集范围广。从阿波罗11号到17号,带回的月壤和月岩样品总计约381.7千克。

科学家通过对月球样品的分析发现,月壤中含有大量微小的橘红色玻璃形式颗粒,这些颗粒一般富含铝、硫和锌,是在月幔部分融化过程中形成于月球表面下约300千米深处,后因火山活动而被喷射到月球表面。月壤和月岩中氧化铁含量很高,从中可制取水和氧,未来可利用月面物质支持月球基地的运行,并为登月飞行器补充燃料。更重要的是,科学家还在采集回来的样品中发现了核聚变的理想原料氦-3。按照目前地球的能源消耗规模,月球上的氦-3用于核聚变发电后,能够满足人类约一万年的能源需求。

经过多年沉寂,俄罗斯近期又重启登月计划。今年,俄罗斯已经把载人登月作为其长期战略目标,并开展了新一代载人飞船、重型运载火箭等设备的研制。此外,俄罗斯还启动了“月球25号”的研制任务,准备降落在月球南极陨石坑。随着航天技术不断走向成熟,日本、印度、韩国等国家,甚至一些民营公司,也提出了自己的月面软着陆或巡视器计划,乃至月球旅游计划。美国也再次决定先重返月球,再前往火星。美国的月球计划核心是位于环月轨道或地月L2点的载人空间站,其多功能猎户座飞船和“航天发射系统”重型运载火箭,将为这一计划提供有力的技术支持。未来,美国还将研制基于液氢液氧推进剂的大型单级可重复使用登月舱,实现对月球表面的低成本造访,并以此为基础建设月球基地。

中国探月16年

“绕”“落”顺利完成,“回”正当时

自2004年起,中国开始实施月球探测工程。这也是我国空间探测的起点。月球是离地球最近的一个星球,又蕴含丰富的资源、能源和特殊环境,所以无论从技术、科学还是经济等方面考虑,各国在空间探测领域大都先从探月开始。

中国探月工程采用“绕、落、回”三步走发展战略,每一步都是对前一步的深化,并为下一步奠定基础。“绕”月探测是中国探月的第一步。2007年10月24日,我国发射第一个月球探测器“嫦娥一号”。这一项目用修2千米地铁的经费,打造了38万千米的天路。

“嫦娥一号”比原计划多飞行了117天,共传回1.37TB有效科学探测数据。它获取了世界第一幅全月图,以及月表化学元素分布和矿物含量、月壤分布、近月空间环境等数据,填补了我国在探月领域的空白。在超额完成各项任务后,2009年3月1日,“嫦娥一号”受控撞击了月球丰富海区域。

我国探月工程的第二步是“落”月探测,实施了“嫦娥二号”“嫦娥三号”共两次飞行任务。

2010年10月1日,作为技术先导星的“嫦娥二号”发射升空。它运行在距月面100千米高的极轨道上,主要对六项新技术进行试验验证,并对未来的预选着陆区进行高分辨率成像,同时获取更丰富和准确的探测数据。2011年4月1日,“嫦娥二号”半年设计寿命期满后,又进行了一系列拓展试验,开创了我国航天一次发射开展多目标多任务探测的先河。

“嫦娥三号”是探月二期工程的主任务。2013年12月14日,“嫦娥三号”在月面软着陆,首次实现了我国对地外天体的软着陆。12月15日,“嫦娥三号”的着陆器与巡视器互相拍照,使我国成为世界第三个掌握落月探测技术的国家。它直接获得了丰富的月球数据,并经受了着陆、移动和长月夜生存三大挑战。目前,“嫦娥三号”的着陆器仍在工作,是迄今为止世界上在月面工作时间最长的着陆器。

“嫦娥四号”原来是“嫦娥三号”的备份,由于“嫦娥三号”完成了任务,所以“嫦娥四号”被改为探月四期工程的第一个任务。2018年5月21日,我国发射世界首颗运行在地月拉格朗日2点轨道的月球中继星“鹊桥”,并于6月14日进入使命轨道。同年12月8日,世界首次在月球背面着陆的探测器“嫦娥四号”升空。

“嫦娥四号”肩负了三大科学任务:开展月球背面低频射电天文观测与研究;开展月球背面巡视区形貌、矿物组份及月表浅层结构探测与研究;试验性开展月球背面中子辐射剂量、中性原子等月球环境探测研究。利用“嫦娥四号”传回的探测数据,我国科学家获得了大量科学新发现,例如首次揭示月球背面地下结构、为解答月幔物质组成的问题提供直接证据等。

即将于本月下旬发射的“嫦娥五号”,将执行我国探月三期任务“采样返回”。探月三期的目标是实现我国首次月面自动采样返回,对返回样品进行系统分析与研究,深化对月球和地月系统的起源与演化的认识。这也将为载人登月和深空探测奠定基础。

嫦娥五号月球探测器模型。新华社发

早在2014年10月24日,我国就发射了再入返回飞行试验器。同年11月1日,试验器返回舱在内蒙古着陆。这是我国航天器第一次在绕月飞行后再入返回地球,表明我国已全面突破和掌握航天器以接近第二宇宙速度的高速再入返回关键技术,为“嫦娥五号”的“回”铺平了道路。

据中国国家航天局透露的消息,目前基本明确探月工程四期还有三次任务:“嫦娥六号”计划在月球南极进行采样返回,根据“嫦娥五号”的采样情况确定是否去月背;“嫦娥七号”将是在月球南极进行的一次针对月球的地

形地貌、物质成份、空间环境的综合探测任务;“嫦娥八号”除了继续进行科学探测试验外,还要进行一些构建月球科研基地的前期探索。

无人采样2千克

将填补月球火山活动认识上的重要空白

作为我国探月工程三期的主任务,“嫦娥五号”由上升器、着陆器、轨道器、返回器四个部分“串联”组成,将先后经历发射入轨、地月转移、近月制动、环月飞行、月面下降、月面采样、月面上升、交会对接、环月等待、月地转移和再入回收等飞行阶段,最终在内蒙古四子王旗着陆,然后将约2千克月球样品送至地面实验室开展精细研究。

任务大概过程是:“嫦娥五号”组合体进入月球轨道后将两两分离,轨道器-返回器(简称“轨返”)组合体留在轨道,着陆器—上升器(简称“着上”)组合体在月面上降落。着陆后,用着陆器上的电铲铲取月壤,自动打钻钻取岩芯,采集的样品放在上升器的返回舱里,进行无污染严密封装。

随后,上升器从月面起飞,与轨返组合体交会对接,把样品转移到返回器后,上升器与轨返组合体分离。接着,轨返组合体踏上归途,在距地球一定高度处返回器从轨返组合体中分离。最终,返回器采用半弹道跳跃再入方式进入大气层,落至预定着陆场。

如果一切顺利,“嫦娥五号”将实现我国开展航天活动以来的四个“首次”:首次在月面自动采样;首次从月面起飞;首次在38万千米外的月球轨道上进行无人交会对接;首次带着月壤以接近第二宇宙速度返回地球。

 

《自然》杂志在近期一篇题为“中国将取回40年来的第一块月球岩石”的新闻中提到,“嫦娥五号”样本将填补科学家对月球火山活动理解上的一个重要空白。之前美国和苏联的月球任务所获得的岩石表明,月球上的火山活动在35亿年前达到顶峰,随后逐渐减弱并停止。但对月球表面的观测发现,某些区域可能含有最近10亿至20亿年前才形成的火山熔岩——如果“嫦娥五号”的样本证实这段时间月球仍在活动,那么月球历史将可能被改写。

根据相关介绍,“嫦娥五号”将在月球正面最大的月海风暴洋北部吕姆克山脉附近着陆,此地从未有其他国家的探测器到访过。该地存在大约13亿至20亿年前的玄武岩,而人类目前尚未有这一时段的月球样本,“嫦娥五号”的取样将填补这一空白。获得这些年轻玄武岩的同位素年龄,将有助于推进对月球火山活动和演化历史的认识。

>>>人类为何要探测月球

●为人类开发利用月球资源做准备

月球上已知有100多种矿物,其中有5种是地球上没有的;月球上有大量的核聚变物质氦-3,可供人类使用上万年;丰富的水冰资源;利用月球高真空、低重力的特殊环境,可以生产特殊的合金、钢材光导纤维和药品等;月球观光旅游资源。

●带动和促进基础科学和高科技的发展

宇宙学、空间天文学、空间物理学、太阳系演化学;信息技术、新能源技术、新材料技术、光电子技术、机器人技术、遥测技术;带动多学科交叉、渗透、共同发展。

●促进深空探测活动的发展

为进行更大范围的深空探测做技术准备,作为未来深空探测的跳板。有国外资料显示,美国正在探索返回月球的可能性,并计划将其作为前往火星的踏脚石,而这种方法每年能够为其节省大约100亿美元的开支。

●促进国家经济可持续发展

月球探测工程技术的优化、二次开发,可以带动经济领域技术的发展,美国“阿波罗”载人登月工程就是一个典型案例。

●推进航天领域的国际合作

探月工程起点高、有特色,具有很强的科学性、探索性、创新性和开放性,适合开展航天国际合作。

作者:庞之浩 (全国空间探测技术首席科学传播专家) 杨馥溪

      The Long March 5 carrier rocket and the Chang 'e-5 probe have been vertically transferred to the launch area after completing assembly and testing at China's Wenchang Space Launch Site. The rocket is scheduled to be launched later this month.
      The Chang 'e-5 mission is the sixth mission of China's lunar exploration program. It plans to automatically sample and return the lunar surface to help deepen scientific research on the origin and evolution of the moon. It is one of the most complex and difficult missions in China's space industry.
      Lunar sampling return

      The Soviets beat us to the draw.
      In terms of unmanned lunar sampling return exploration, the Soviet Union can be said to be the pioneer, which may be related to the Soviet Union's manned moon landing halfway, so it turned to the moon with unmanned space probes to collect samples.
      On September 12, 1970, the Soviet Union launched luna 16, the world's first unmanned lunar sample-return probe. After its soft landing on the lunar surface, it collected lunar samples using automatic drilling machines and encapsulated them in the return capsule. The upper upgrade then took off from the lunar surface and returned to Earth, and the final re-entry module landed in the Soviet Union on 24 September 1970. It retrieved a small 101-gram sample from the Moon's Fertile sea.
      Launched on Feb. 14, 1972, Luna 20 encountered basalt and collected only 55 grams of lunar samples from the Lunar Apollonius Highlands. On 18 August 1976, Luna 24 made a soft landing in the southeastern part of the Moon in Weihai, where it excavated moon rocks from a depth of 2 meters and obtained a total of 170 grams of samples from weihai.
      In the late 1950s, the Soviet Union had a head start in rocket and satellite technology, and so had a head start in lunar exploration. The United States was not far behind.
      In the 1960s and 1970s, the United States achieved its goal of sending a man to the moon through the Apollo program. From July 1969 to December 1972, the United States conducted seven manned missions to the moon, successfully sending 12 astronauts to the moon. Although manned lunar sampling and return technology is more complex and costly, since astronauts can go to extraveteric activities and can also travel to distant places by lunar rover to collect lunar samples, sampling and return from the moon with manned spacecraft is not only large, selective, but also wide-ranging. The lunar soil and rock samples brought back from Apollo 11 to Apollo 17 totaled about 381.7 kilograms.
      Scientists analyzed lunar samples and found that the lunar soil contains a large number of tiny orange-red glass particles, which are rich in aluminum, sulfur and zinc. These particles formed at a depth of about 300 kilometers below the lunar surface during the partial melting of the mantle and were ejected onto the surface by volcanic activity. The high content of iron oxide in lunar soil and rocks can be used to extract water and oxygen, which can be used in the future to support the operation of lunar bases and refuel lunar landers. What's more, the scientists also found helium-3, the ideal material for fusion, in the samples they collected. At earth's current energy consumption, helium-3 on the moon could meet humanity's energy needs for about 10,000 years if used for fusion power.
      After years of silence, Russia has recently resumed its mission to the moon. This year, Russia has made manned missions to the moon a long-term strategic goal, and has launched the development of a new generation of manned spacecraft, heavy launch vehicles and other equipment. In addition, Russia has launched the "Moon 25" development mission, ready to land in the moon's South Pole crater. As space technology continues to mature, Japan, India, South Korea and other countries, and even some private companies, have put forward their own soft landing or rover on the moon, and even the moon tourism plan. The United States also decided again to return to the moon before going to Mars. At the heart of the U.S. lunar program is a manned space station in orbit around the moon, or L2, and its multi-purpose Orion spacecraft and "Space Launch System" heavy launch vehicle will provide strong technical support for the program. In the future, the United States will also develop a large, single-stage reusable lunar module based on liquid hydrogen and oxygen propellants to make low-cost visits to the moon's surface and build a lunar base based on it.
      China has spent 16 years exploring the moon
      "Round" "down" successfully completed, "back" just at the time
      Since 2004, China has carried out a lunar exploration program. This is also the starting point of China's space exploration. The moon is the closest planet to the Earth, and it contains rich resources, energy and special environment. Therefore, no matter from the technical, scientific or economic aspects, most countries in the field of space exploration start from the moon.
      China's lunar exploration program adopts a three-step development strategy of "circling, falling and returning". Each step is a deepening of the previous step and lays a foundation for the next step. "Orbiting" the moon is the first step of China's lunar exploration. On October 24, 2007, China launched chang 'e I, its first lunar probe. The project has built 380,000 kilometers of sky roads with the money to build a 2-kilometer subway system.
      Chang 'e I flew 117 days longer than planned and returned 1.37 terabytes of effective scientific data. It has obtained the world's first full moon map, as well as the chemical element distribution and mineral content, lunar soil distribution, space environment and other data, filling the gap in the field of lunar exploration in China. After overfulfilling various missions, Chang 'e-1 crashed into the moon's rich ocean on March 1, 2009, in a controlled manner.
      The second step of China's lunar exploration program is the "falling" lunar probe, which has carried out two missions, chang 'e-2 and Chang 'e-3.
      Chang 'e-2 was launched on October 1, 2010 as a technology pilot. Operating in a polar orbit 100 kilometers above the surface of the moon, it will test and verify six new technologies and provide high-resolution imaging of future pre-selected landing zones, while obtaining richer and more accurate detection data. On April 1, 2011, chang 'e-2, after its half-year design life had expired, carried out a series of further tests, marking the first time for China to carry out multi-objective multi-mission exploration in a single space launch.
      Chang 'e-3 is the main mission of the second phase of the lunar exploration program. On December 14, 2013, Chang 'e-3 made a soft landing on the lunar surface, marking China's first soft landing on an extraterrestrial body. The Chang 'e-3 lander and rover took photos of each other on Dec. 15, making China the third country in the world to master the technology of lunar landing detection. It has directly acquired a wealth of lunar data and has withstood three challenges: landing, moving and surviving a long lunar night. The chang 'e-3 lander is still working, making it the longest working lander on the lunar surface in the world.
      Chang 'e-4 was originally a backup of Chang 'e-3, but it was changed to the first mission of the lunar exploration program because it completed its mission. On May 21, 2018, China launched the world's first lunar relay star magpie, which is in a 2-point orbit around the Earth's moon Lagrange, and entered its mission orbit on June 14. Chang 'e-4, the world's first probe to land on the far side of the moon, blasted off on December 8.
      Chang 'e-4 has three scientific missions: to observe and study low-frequency radio astronomy on the far side of the moon; To explore and study the morphology, mineral composition and surface shallow structure of the patrol area on the far side of the moon; We will carry out experimental exploration of the lunar environment including neutron radiation dose and neutral atoms on the far side of the moon. Using the probe data sent back by Chang 'e-4, Chinese scientists have made a lot of new scientific discoveries, such as revealing the underground structure on the far side of the moon for the first time, and providing direct evidence to solve the problem of the material composition of the lunar mantle.
      Chang 'e-5, due to be launched later this month, will carry out the country's third lunar exploration mission to "sample and return". The goal of the third phase of lunar exploration is to realize China's first automatic lunar surface sampling return, systematic analysis and research of returned samples, and deepen the understanding of the origin and evolution of the lunar and earth-moon systems. It will also lay the foundation for manned missions to the moon and deep space exploration.
      As early as October 24, 2014, China launched the re-entry and return flight test vehicle. On November 1 of the same year, the re-entry module of the test vehicle landed in Inner Mongolia. This is the first time for China's spacecraft to re-enter and return to earth after orbiting the moon, indicating that China has comprehensively broken through and mastered the key technology of spacecraft re-entry and return at a high speed close to the second cosmic speed, paving the way for the "return" of Chang 'e-5.
      According to the China National Space Administration, it is now clear that there will be three more missions in the fourth phase of the lunar probe. Chang 'e-6 plans to conduct sampling at the South Pole of the moon and return it to the back of the moon. Chang 'e-7 will be a mission to the moon at the South Pole
      The task of comprehensive exploration of topography, material composition and space environment; Besides continuing scientific exploration experiments, Chang 'e-8 will also carry out some preliminary exploration to build a scientific base on the moon.
      No one sampled 2 kg
      Will fill an important gap in the understanding of lunar volcanism
      As a main task of lunar exploration project 3 period in our country, "chang e" 5 by ascenders, lander and orbiter, return of four sections "series", will be launched through injecting, transfer to the moon, the brake in recent months, ring in flight and the decrease of the surface and surface sampling, moon rise, rendezvous and docking, ring months waiting, transfer and then into the recovery phase of flight, finally landed in siziwang banner of Inner Mongolia, and then will be about 2 kilograms of lunar samples sent to the laboratory to carry out the careful research ground.
      The main process of the mission is as follows: chang 'e-5 enters the lunar orbit and separates the two, leaving the orbiter-reentry vehicle (" reentry "for short) in orbit, and the lander and ascender (" lander" for short) landing on the lunar surface. After landing, the electric shovel on the lander was used to scoop out lunar soil, and the core was drilled automatically. The collected samples were placed in the re-entry capsule of the riser for pollution-free sealing.
      The riser then takes off from the lunar surface and rendezvously docked with the orbital regurgator. After the sample is transferred to the returner, the riser separates from the orbital regurgator. Then, the orbital regurgitation sets off on its way home, and at a certain height from the earth the returner separates from the regurgitation. Finally, the reentry vehicle enters the atmosphere using a semi-ballistic jump reentry and lands at the intended landing site.
      If all goes well, Chang 'e-5 will be the first of four "firsts" since China launched space activities: the first automatic sampling on the moon's surface; First flight from the lunar surface; The first unmanned rendezvous and docking on the moon 380,000 km away; It returned to Earth with lunar soil for the first time at a speed close to that of the second universe.
      In a recent nature article titled "China to retrieve first Moon rock in 40 years," chang 'e-5 samples will fill an important gap in scientists' understanding of lunar volcanism. Rocks from previous U.S. and Soviet lunar missions suggest that volcanic activity on the moon peaked about 3.5 billion years ago and then tapered off and stopped. But observations of the moon's surface have found that some areas may contain volcanic lava that formed only as recently as 1 billion to 2 billion years ago -- a period that could rewrite lunar history if chang 'e-5 samples confirm that the moon is still active.
      According to the statement, Chang 'e-5 will land near the Lumke Mountains, north of the moon's largest lunar-sea storm, which has never been visited by a probe from any other country. There are basalts from about 1.3 billion to 2 billion years ago, a period of lunar samples not yet available, and chang 'e-5 samples will fill the gap. Obtaining the isotopic ages of these young basalts will help advance understanding of the moon's volcanic activity and evolutionary history.


>>> why do humans probe the moon
      ● Preparation for human exploitation and utilization of lunar resources
      There are more than 100 minerals known to exist on the moon, five of which are not found on Earth; The moon has plenty of helium-3, a nuclear fusion material that could be used by humans for tens of thousands of years. Abundant water ice resources; Special alloy, steel optical fiber and medicine can be produced by using the moon's special environment of high vacuum and low gravity. Moon sightseeing tourism resources.
      ● Drive and promote the development of basic science and high technology
       Cosmology, space astronomy, space physics, solar system evolution chemistry; Information technology, new energy technology, new material technology, optoelectronic technology, robot technology, telemetry technology; To promote interdisciplinary, penetration and common development.
      ● Promote the development of deep space exploration activities
      As a springboard for future deep space exploration, this paper makes technical preparation for carrying out a wider range of deep space exploration. The United States is exploring the possibility of returning to the moon as a stepping stone to Mars, saving it about $10 billion a year, according to foreign sources.
      ● Promote the sustainable development of national economy
      The optimization and secondary development of lunar exploration engineering technology can promote the development of economic technologies. The Manned lunar landing project of Apollo in the United States is a typical case.
      To promote international cooperation in space
      The lunar exploration project, starting from a high starting point, is characterized by its strong scientific, exploratory, innovative and open nature, and is suitable for international space cooperation.
      Pang Zhihao (chief science communication expert of National space exploration technology) Yang Fuxi

来自: 文汇