Nature《自然》| 美国航天局真的能在2024年前让人类重返月球吗?

Can NASA really return people to the Moon by 2024?

Donald Trump wants US astronauts back on the Moon. But his ambitious plan faces formidable political, financial and technical challenges.

特朗普希望美国宇航员重返月球。但他雄心勃勃的计划面临着巨大的政治、财政和技术挑战。

自1972年阿波罗计划结束以来，美国宇航局从未开发过月球着陆器。来源:美国国家航空航天局/ Getty

Five decades after sending humans to the Moon, NASA is tasked with repeating the feat — and doing it by 2024, the ambitious deadline set by US President Donald Trump’s team. But it is unclear how the space agency will surmount some formidable technical, political and financial challenges to pull off a lunar landing in just four and a half years.

在将人类送上月球50年后，美国宇航局的任务是重复这一壮举，并在2024年之前完成，这是美国总统唐纳德·特朗普团队设定的最后期限。但目前还不清楚美国宇航局将如何克服一些艰巨的技术、政治和财政挑战，在短短四年半的时间里实现登月。

“If the pieces come together in the right way they can pull it off,” says Ryan Watkins, a lunar scientist with the Planetary Science Institute who is based in St Louis, Missouri. “But they have to come together.”

密苏里州圣路易斯行星科学研究所的月球科学家瑞恩·沃特金斯说:“如果有天时地利人和，他们就能成功。”“但他们必须齐心协力。”

NASA’s leaders have yet to make key decisions about how the Moon effort, called Artemis after Apollo’s twin sister, will proceed. The agency does not have a rocket ready to fly humans into deep space, and it has not developed a lunar lander since the Apollo programme ended in 1972. Then there is Congress, which controls NASA’s budget and seems increasingly uninterested in paying for the Moon mission.

美国国家航空航天局的领导人还没有就“阿耳忒弥斯”计划如何进行做出关键决定。“阿耳忒弥斯”是以阿波罗的孪生姐妹阿耳忒弥斯命名的。该机构还没有准备好将人类送入深空的火箭，而且自1972年阿波罗计划结束以来，它也没有开发过月球着陆器。其次是制着NASA的预算的国会似乎对支付登月任务的费用越来越不感兴趣。

Even as NASA scrambles to meet its ambitious goal, China is making steady progress towards landing astronauts on the Moon by the mid-2030s. The country has launched a series of uncrewed lunar missions over the past decade, and in January its Chang’e-4 probe became the first spacecraft from any nation to land on the Moon’s far side. Chinese officials say that four more robotic missions will follow, starting with Chang’e-5, which could launch as early as December and bring back Moon rock and soil. Lunar researchers expect that these missions will carry out scientific experiments and lay the groundwork for a future Moon base.

就在美国国家航空航天局(NASA)忙于实现其雄心勃勃的目标之际，中国朝着在本世纪30年代中期实现宇航员登月的目标正取得稳步进展。在过去的十年里，中国已经发射了一系列无人登月任务，今年1月，中国的嫦娥四号探测器成为第一个登上月球背面的航天器。中国官员说，接下来还将有四次机器人任务，从嫦娥五号开始。嫦娥五号最早可能在12月发射，并带回月球岩石和土壤。月球研究人员预计，这些任务将进行科学实验，并为未来的月球基地奠定基础。

“In the next one to two decades, we will definitely see a Chinese astronaut landing on the Moon,” says Christoph Beischl, a researcher at the London Institute of Space Policy and Law.

伦敦空间政策与法律研究所的研究员Christoph Beischl说:“在未来的一到二十年里，我们肯定会看到中国宇航员登陆月球。”

Off-the-shelf help

现成的帮助

NASA is gambling that commercial partners can help it to reach the Moon again by taking over some crucial tasks that it handled during the Apollo era. These include flying scientific and technical experiments to the lunar surface to lay the groundwork for an eventual crewed mission. In May, the space agency announced that it had signed contracts with three companies that will each carry as many as 14 experiments to the Moon aboard small robotic landers.

美国国家航空和宇宙航行局(NASA)正押注商业合作伙伴可以通过接手阿波罗(Apollo)时代的一些关键任务，帮助它重返月球。其中包括飞往月球表面进行科学技术实验，为最终的载人任务打下基础。今年5月，美国宇航局宣布已与三家公司签署合同，每家公司将搭载小型机器人登陆器向月球进行多达14项实验。

One of the firms, Orbit Beyond of Edison, New Jersey, intends to send a lander to the Mare Imbrium lava plain on the Moon as early as the third quarter of 2020. The probe will carry NASA instruments, including one to monitor the level of cosmic radiation to which astronauts would be exposed, said Jon Morse, Orbit Beyond’s chief science officer, at a space-resources conference in Golden, Colorado, in June. Radiation-monitoring experiments have previously gone to the Moon, including one delivered by Chang’e-4.

其中一家名为Orbit Beyond of Edison的公司计划最早在2020年第三季度向月球上的死海熔岩平原发射着陆器。“超越轨道”的首席科学官乔恩莫尔斯(Jon Morse)今年6月在科罗拉多州戈尔登(Golden)举行的空间资源会议上说，探测器将携带NASA的仪器，其中包括一个用来监测宇航员将暴露在宇宙辐射水平的仪器。此前，包括嫦娥四号在内的一些月球辐射监测实验也曾在月球上进行过。

Mare imbrium平原将进行美国宇航局的一个实验，以测量辐射暴露。

Over the next few years, NASA envisions that private companies will continue to fly lunar probes that grow progressively more complex. These might culminate in a robotic mission to collect Moon rocks and scout landing sites for a crewed mission.

在接下来的几年里，NASA预计私营公司将继续发射越来越复杂的月球探测器。这些可能会在机器人收集月球岩石和侦察着陆地点的任务中达到峰值。

Meanwhile, the agency plans to keep developing its heavy-lift rocket and Orion crew capsule, which would carry astronauts into deep space. Both the rocket and Orion have been repurposed from earlier versions that NASA had been working on to send astronauts to visit an asteroid and later Mars. The first uncrewed test of the rocket–capsule combo is scheduled for no earlier than mid-2020, with the first crewed test no earlier than 2022.

与此同时，该机构计划继续开发其重型火箭和猎户座乘员舱，将宇航员送入深空。这枚火箭和猎户座火箭都是美国国家航空和宇宙航行局(NASA)在早期版本的基础上重新设计的，早期版本的任务是派遣宇航员去访问小行星和后来的火星。火箭-太空舱组合的首次非载人试验计划不早于2020年年中，首次载人试验不早于2022年。

Down to Earth

脚踏实地

The response from Congress, which controls NASA’s budget, has been tepid. On 25 June, the Democrat-controlled House of Representatives approved a 2020 spending bill for NASA that ignored the Artemis request. The Republican-controlled Senate has yet to act on NASA’s proposed budget for 2020, including the agency's request for Artemis funding.

控制NASA预算的国会对此反应冷淡。6月25日，民主党控制的众议院通过了一项NASA 2020年开支法案，该法案忽视了阿尔特弥斯的要求。共和党控制的参议院还没有就NASA 2020年的预算提案采取行动，其中包括该机构对阿耳特弥斯项目的资金要求。

Protracted battles with Congress over funding helped to kill two attempts by Trump’s predecessors to return to the Moon. A plan that George H. W. Bush proposed in 1989 never won over Congress. And George W. Bush’s Moon programme, announced in 2004, was cancelled by Barack Obama in 2010 — but not before it kicked off the development of the heavy-lift rocket that Trump now wants to use.

特朗普与国会在资金问题上旷日持久的斗争，帮助扼杀了特朗普的前任两次重返月球的企图。老布什(George h.w. Bush) 1989年提出的一项计划从未赢得国会的支持。乔治·w·布什(George W. Bush)在2004年宣布的登月计划，在2010年被巴拉克·奥巴马(Barack Obama)取消——但那是在该计划启动特朗普现在想要使用的重型火箭研发之前。

Trump first proposed sending astronauts to the Moon in 2017, and within months NASA said it would aim to do so by 2028. But earlier this year, the Trump administration accelerated the deadline for Artemis to 2024. NASA administrator Jim Bridenstine has indicated that this was to limit how long politicians can argue over it. If Trump is re-elected he would be in office until January 2025, meaning a lunar landing could theoretically take place during his presidency.

2017年，特朗普首次提出将宇航员送上月球，几个月内，美国宇航局表示，计划在2028年前实现这一目标。但今年早些时候，特朗普政府将阿特米斯的最后期限提前到了2024年。美国宇航局局长吉姆·布里登斯汀表示，这是为了限制政客们对此争论的时间。如果特朗普再次当选，他的任期将持续到2025年1月，这意味着在他的总统任期内，理论上可以实现登月。

So far, nearly everything about Artemis is different from Apollo, says Teasel Muir-Harmony, a curator and space historian at the Smithsonian National Air and Space Museum in Washington DC. In 1961, President John F. Kennedy called for a Moon landing as a way to highlight the United States' position as a global superpower, and both chambers of Congress supported that goal from the beginning.

华盛顿特区史密森国家航空航天博物馆馆长兼空间历史学家提塞尔·穆尔-哈莫尼说，到目前为止，有关阿尔特弥斯的几乎所有事情都与阿波罗不同。1961年，美国总统约翰·f·肯尼迪(John F. Kennedy)呼吁登月，以此凸显美国作为全球超级大国的地位，国会两院从一开始就支持这一目标。

"These types of programmes are extremely expensive and rely on political will, and there was bipartisan support and interest in Apollo," she says. Whether or not Trump can muster that level of backing "is going to be really critical to the outcome of Artemis".

她表示:“这类项目极其昂贵，依赖于政治意愿，而且得到了两党支持，而且对阿波罗计划也很感兴趣。”特朗普能否获得如此程度的支持，“将对阿特米斯的结果至关重要”。

China, meanwhile, faces different hurdles to putting people on the Moon. It has sent astronauts to space laboratories in low-Earth orbit, and plans to complete a space station in 2022, but has no experience ferrying people farther afield, which requires more advanced spacecraft and landing technology. The country's biggest challenge is likely to be developing a rocket that is up to the job, says Beischl. “Everything else, you can build on what you’ve already got."

与此同时，中国在载人登月方面面临着不同的障碍。中国已将宇航员送入近地轨道的太空实验室，并计划在2022年建成一个空间站，但没有将人送往更远地方的经验，这需要更先进的航天器和着陆技术。Beischl说，中国面临的最大挑战可能是开发一种能够胜任这项工作的火箭。“其他一切，你都可以在已有的基础上继续。”