How AI plotted an interstellar journey to Alpha Centauri

AI 如何规划前往半人马座阿尔法星的星际之旅

EXECUTIVE SUMMARY A nonprofit organization called the Fermi Explorer Mission announced today that it intends to launch a spacecraft to our nearest star system by the end of 2029. It’s a hugely ambitious mission—if all goes well, the spacecraft could take up to 80,000 years to arrive at Alpha Centauri, which is 4.4 light-years away.

执行摘要 一个名为“费米探索任务”（Fermi Explorer Mission）的非营利组织今日宣布，计划在 2029 年底前向距离我们最近的恒星系统发射航天器。这是一项极其宏大的任务——如果一切顺利，航天器可能需要长达 8 万年的时间才能抵达 4.4 光年外的半人马座阿尔法星（Alpha Centauri）。

And the spacecraft will follow a novel trajectory discovered by an AI system developed by Physical Superintelligence (PSI), an AI physics research lab. PSI is launching today with $58 million in funding led by Breakthrough Energy, a climate-focused investment group founded by Microsoft cofounder Bill Gates.

该航天器将遵循一条由人工智能物理研究实验室“物理超级智能”（Physical Superintelligence，简称 PSI）开发的 AI 系统所发现的新颖轨道。PSI 于今日正式启动，并获得了由微软联合创始人比尔·盖茨创立的气候投资集团“突破能源”（Breakthrough Energy）领投的 5800 万美元资金。

It’s not the first time this has been tried. In 2016, the billionaire tech investor Yuri Milner announced an interstellar mission called Breakthrough Starshot to launch humanity’s first spacecraft to Alpha Centauri. The plan was to use powerful lasers that would propel tiny probes to a fifth of the speed of light—fast enough to reach Alpha Centauri within 20 years. Milner pledged $100 million toward a proof of concept. But a decade later, nothing has launched.

这并非人类首次尝试此类任务。2016 年，亿万富翁科技投资者尤里·米尔纳（Yuri Milner）宣布了一项名为“突破摄星”（Breakthrough Starshot）的星际任务，旨在发射人类首个前往半人马座阿尔法星的航天器。该计划拟利用强大的激光将微型探测器推进至光速的五分之一，从而在 20 年内抵达目的地。米尔纳为此承诺投入 1 亿美元用于概念验证。然而十年过去了，仍无任何航天器发射。

“We didn’t want to do another Breakthrough Starshot,” says Philip Johnston, the cofounder and president of the Fermi Explorer Mission. “We’re dead set on something actually launching.” To do that, “we are not constraining ourselves to doing it in a human lifetime,” says Johnston. “Let’s just figure out the way to get to another star.”

“我们不想重蹈‘突破摄星’的覆辙，”费米探索任务的联合创始人兼总裁菲利普·约翰斯顿（Philip Johnston）表示，“我们一心只想让航天器真正发射升空。”为了实现这一目标，约翰斯顿说：“我们不再局限于在人类寿命内完成任务。我们只想找到前往另一颗恒星的方法。”

The new mission, currently funded by individual private donors, is expected to cost just $15 million. The spacecraft will carry cargo weighing at least one kilogram. That will include artistic and scientific payloads, messages, and a copy of the Golden Record, a gold-plated disc of Earth’s sounds and images that NASA attached to its two Voyager probes in 1977 as a message to any civilization that might find them.

这项新任务目前由私人捐赠者资助，预计成本仅为 1500 万美元。航天器将携带至少一公斤重的货物，包括艺术和科学载荷、信息，以及一份“金唱片”（Golden Record）的副本。1977 年，NASA 在其两艘旅行者号探测器上附带了这张镀金唱片，记录了地球的声音和图像，旨在向可能发现它们的任何文明传递信息。

Engineering an interstellar journey is extremely difficult. Alpha Centauri is about 25 trillion miles away from Earth. One of the fastest objects that humans have ever launched, the Voyager 1 probe, has been flying since 1977 and has covered less than 1% percent of that distance. At its speed, the trip would take more than 70,000 years.

星际航行的工程难度极大。半人马座阿尔法星距离地球约 25 万亿英里。人类发射的最快物体之一——旅行者 1 号探测器自 1977 年起飞行至今，所覆盖的距离还不到总路程的 1%。以其当前速度，走完这段旅程需要超过 7 万年。

Johnston and his team spent a year trying, and failing, to find a way for a small, solar-powered spacecraft costing only $15 million to reach Alpha Centauri. They kept running into the knotty problem of how to give the spacecraft enough power without making it too heavy (and thus more fuel-guzzling).

约翰斯顿及其团队花了一年时间尝试寻找让一艘仅耗资 1500 万美元的小型太阳能航天器抵达半人马座阿尔法星的方法，但均以失败告终。他们始终面临一个棘手的难题：如何在不增加航天器重量（从而导致更耗燃料）的前提下，为其提供足够的动力。

After the Fermi team struggled to find a workable route, Johnston mentioned the problem in a podcast hosted by Alex Wissner-Gross, a physicist who cofounded PSI. Wissner-Gross offered to run it through an AI system the lab developed, called Get Physics Done. It’s an open-source software that takes a physics research question, breaks it into smaller tasks, and decides which simulations to run, using AI models including Anthropic’s Claude or OpenAI’s GPT.

在费米团队苦于寻找可行路径时，约翰斯顿在 PSI 联合创始人、物理学家亚历克斯·威斯纳-格罗斯（Alex Wissner-Gross）主持的播客中提到了这个问题。威斯纳-格罗斯提议利用实验室开发的名为“Get Physics Done”的 AI 系统来解决。这是一款开源软件，它能接收物理研究课题，将其拆解为更小的任务，并利用 Anthropic 的 Claude 或 OpenAI 的 GPT 等 AI 模型决定运行哪些模拟。

A week later, the AI system turned up a novel trajectory, to Johnston’s surprise. It combined well-known orbital maneuvers in a way the Fermi team had not considered, according to a paper that has not been peer-reviewed. It suggested that the spacecraft could first slow down so its orbit swings in close to the sun—closer than Mercury. On each close pass, it would fire its engine so that the solar panels get four times the light, and a burst of thrust delivered at high speed would buy more energy than the same burst anywhere else. Because the engine would run only near the sun, the solar panels could stay small and the spacecraft light.

一周后，令约翰斯顿惊讶的是，该 AI 系统提出了一条新颖的轨道。根据一份尚未经过同行评审的论文，该方案以费米团队未曾考虑过的方式结合了已知的轨道机动。它建议航天器先减速，使其轨道摆动至靠近太阳的位置——比水星更近。在每次近距离掠过时，航天器启动引擎，使太阳能电池板获得四倍的光照，此时高速喷发的推力所产生的能量远超在其他任何位置。由于引擎仅在靠近太阳时运行，太阳能电池板可以保持较小尺寸，从而使航天器保持轻盈。

The system conducted the research mostly on its own for three days, running on a billion tokens, says Matt Pines, the cofounder and CEO of PSI. An astrophysicist on PSI’s staff steered it to follow the mission’s requirements, asked for a cost analysis and clearer charts, and checked the output for errors. “The fact that it came up with an entirely different mission profile, one that was creative and not one [the Fermi team] had considered—that was the more surprising aspect,” says Pines.

PSI 联合创始人兼首席执行官马特·派恩斯（Matt Pines）表示，该系统在消耗了 10 亿个 Token 后，基本独立完成了为期三天的研究。PSI 的一名天体物理学家引导其遵循任务需求，要求其进行成本分析并绘制更清晰的图表，同时检查输出结果是否存在错误。“它提出了一个完全不同的任务方案，既有创意又在（费米团队）考虑范围之外，这才是最令人惊讶的地方，”派恩斯说道。

Still, the model lacks a human researcher’s judgment and taste, he says. It has no reliable sense of which problems are interesting or which approaches are worth pursuing, so it often gets stuck chasing dead ends or failing to explore different approaches. “I don’t think we’ve yet figured out how these models can internally represent something like that,” he says of research judgment.

不过，他指出，该模型仍缺乏人类研究人员的判断力和品味。它无法可靠地判断哪些问题是有趣的，或者哪些方法值得追求，因此经常陷入死胡同，或无法探索不同的路径。“我认为我们还没有弄清楚这些模型如何能在内部表征这种研究判断力，”他谈到研究判断时说。

Even if the Fermi probe launches, “we’re pretty confident that we will not be the first to arrive” at Alpha Centauri, says Johnston, since he expects spacecraft technology to improve. If an engine a thousand years from now is even 20% faster than today’s, a spacecraft launched then would still beat Fermi’s probe to Alpha Centauri by more than 10,000 years.

即使费米探测器成功发射，约翰斯顿也表示：“我们非常有信心，我们不会是第一批抵达半人马座阿尔法星的。”因为他预计航天技术会不断进步。如果一千年后的引擎速度比现在快 20%，那么届时发射的航天器仍将比费米探测器早一万多年抵达目的地。

But the Fermi project isn’t just an interstellar mission driven by engineering ambition. It’s also a quest to answer one of the oldest open questions in physics. In 1950, the physicist Enrico Fermi posed a puzzle: The galaxy has hundreds of billions of stars, most of them far older than our sun. Even a civilization traveling slowly between stars could spread across the whole galaxy in a few million years, which pales in comparison to how old the galaxy is. If there is intelligent life somewhere, we should have seen signs of its existence by now.

但费米项目不仅仅是一项由工程雄心驱动的星际任务，它也是为了回答物理学中最古老的未解之谜之一。1950 年，物理学家恩里科·费米（Enrico Fermi）提出了一个难题：银河系拥有数千亿颗恒星，其中大多数比我们的太阳古老得多。即使是一个在恒星间缓慢旅行的文明，也能在几百万年内遍布整个银河系，这与银河系的年龄相比微不足道。如果宇宙中存在智慧生命，我们现在应该已经看到了它们存在的迹象。

That means either reaching for another star is too difficult or other intelligent species simply haven’t bothered. But once the Fermi probe launches, we will become a civilization that can and wants to reach another star, meaning that neither explanation might be what’s keeping the galaxy unexplored. That could point us toward more unsettling possibilities, says Johnston. Maybe life like ours is almost unimaginably rare. Or maybe intelligent life is common but tends to die out before it can spread. If the latter is true, “one of those reasons could be that once you hit superintelligence, that for so…

这意味着要么前往另一颗恒星太难，要么其他智慧物种根本没兴趣。但一旦费米探测器发射，我们将成为一个能够且愿意前往另一颗恒星的文明，这意味着上述两种解释可能都不是银河系未被探索的原因。约翰斯顿认为，这可能会指向更令人不安的可能性：也许像我们这样的生命极其罕见；又或者智慧生命很常见，但往往在扩散之前就灭绝了。如果后者属实，“原因之一可能是，一旦你达到超级智能水平，那么……”