An 80,000-year trip is the optimistic version of this plan.
That’s the number the Fermi Explorer Mission is working with. A nonprofit, announcing today, says it intends to launch a spacecraft toward Alpha Centauri by the end of 2029. The star system sits 4.4 light-years out. If everything works, the spacecraft could take up to 80,000 years to get there.
And the route it flies wasn’t found by the team’s engineers. It came out of an AI system.
The trick is going toward the sun first
The trajectory the AI produced does something counterintuitive. The spacecraft first slows down, letting its orbit swing in close to the sun, closer than Mercury gets. On each close pass, it fires its engine. The solar panels are catching four times the light down there, and a burst of thrust delivered at high speed buys more energy than the same burst anywhere else.
Because the engine only runs near the sun, the panels can stay small. Small panels mean a light spacecraft. Light spacecraft mean the $15 million budget holds.
None of the individual maneuvers are new. The combination is. The Fermi team hadn’t considered it, according to a paper that has not been peer-reviewed.
A year of failing first
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. The wall they kept hitting was power. Give the spacecraft enough of it and the thing gets heavy, and heavy means it burns more fuel.
Then Johnston mentioned the problem on a podcast hosted by Alex Wissner-Gross, a physicist who cofounded Physical Superintelligence. Wissner-Gross offered to run it through the lab’s system, called Get Physics Done. It’s 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.
A week later, it had the trajectory. Johnston was surprised.
Three days, a billion tokens, one babysitter
The system worked mostly on its own for three days, running on a billion tokens, said Matt Pines, the cofounder and CEO of PSI. Mostly. An astrophysicist on PSI’s staff steered it toward 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,” Pines said.
He’s blunt about what it can’t do. The model lacks a human researcher’s judgment and taste. 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,” Pines said of research judgment.
PSI launches today with $58 million in funding led by Breakthrough Energy, the climate-focused investment group founded by Microsoft cofounder Bill Gates.
The last attempt at this never left the ground
In 2016, billionaire tech investor Yuri Milner announced Breakthrough Starshot, an interstellar mission to send humanity’s first spacecraft to Alpha Centauri. Powerful lasers would push tiny probes to a fifth of the speed of light, fast enough to arrive within 20 years. Milner pledged $100 million toward a proof of concept.
A decade later, nothing has launched.
“We didn’t want to do another Breakthrough Starshot,” said Philip Johnston, the cofounder and president of the Fermi Explorer Mission. “We’re dead set on something actually launching.”
Fermi’s $15 million, currently coming from individual private donors, is a fifteenth of what Milner put up for a proof of concept alone. The way Fermi gets there is by giving up on speed entirely.
“We are not constraining ourselves to doing it in a human lifetime,” Johnston said. “Let’s just figure out the way to get to another star.”
The scale problem, in Voyager units
Alpha Centauri is about 25 trillion miles from Earth. Voyager 1, one of the fastest objects humans have ever launched, has been flying since 1977 and has covered less than 1% of that distance. At its speed the trip would take more than 70,000 years.
The Fermi spacecraft will carry cargo weighing at least one kilogram: artistic and scientific payloads, messages and a copy of the Golden Record, the gold-plated disc of Earth’s sounds and images NASA attached to its two Voyager probes in 1977 as a message to whoever might find them.
Johnston fully expects to be beaten. “We’re pretty confident that we will not be the first to arrive,” he said, because spacecraft technology should keep improving. Run the math and it’s not close. An engine a thousand years from now that’s just 20% faster than today’s would put a later-launched probe at Alpha Centauri more than 10,000 years ahead of Fermi’s.
What launching would prove about the silence
The mission is also aimed at a question Enrico Fermi posed in 1950. The galaxy holds hundreds of billions of stars, most far older than our sun. Even a civilization crawling between stars could spread across the whole thing in a few million years, which is nothing against the galaxy’s age. So if intelligent life is out there, we should have seen signs by now.
Two easy answers: reaching another star is too hard, or nobody else bothered. Once Fermi’s probe launches, we become a civilization that both can and wants to reach another star, and neither answer holds up as the reason the galaxy sits unexplored.
What’s left is worse, Johnston said. Maybe life like ours is almost unimaginably rare. Or maybe intelligent life is common and tends to die out before it spreads.
“One of those reasons could be that once you hit superintelligence, that for some reason is self-destructive,” Johnston said. “Maybe in the next 50 years, there’s some great filter that we do not pass through. That all intelligent civilizations, for some reason, do not pass through.”
Which is a strange thing to hear from a man whose route to the stars was drawn by an AI.
