Nonprofit Plans Interstellar Launch on a Trajectory an AI Discovered

A nonprofit called the Fermi Explorer Mission has announced that it intends to launch a spacecraft toward the Alpha Centauri star system, 4.4 light-years from Earth, by the end of 2029. The mission could take up to 80,000 years to arrive. The spacecraft will follow a novel trajectory discovered by an AI system built by Physical Superintelligence (PSI), an AI physics research lab. PSI launched the same day with $58 million in funding led by Breakthrough Energy, the climate-focused investment group founded by Microsoft co-founder Bill Gates.

It is not the first attempt at an interstellar mission. In 2016, investor Yuri Milner announced Breakthrough Starshot, a plan to use lasers to propel tiny probes to a fifth of the speed of light so they could reach Alpha Centauri within 20 years, backed by a $100 million pledge. A decade later, nothing has launched. "We didn't want to do another Breakthrough Starshot," said Philip Johnston, co-founder and president of the Fermi Explorer Mission. "We're dead set on something actually launching." His mission, funded by individual private donors, is estimated to cost just $15 million. It will carry at least one kilogram of cargo, including artistic and scientific payloads and a copy of the Golden Record, the disc of Earth sounds and images NASA attached to its Voyager probes in 1977.

Johnston's team spent a year failing to find a route for a small, solar-powered, low-cost spacecraft to reach Alpha Centauri. Then Johnston mentioned the problem on a podcast hosted by physicist Alex Wissner-Gross, a co-founder of PSI. Wissner-Gross ran the problem through Get Physics Done, an open-source AI system that breaks a physics question into smaller tasks and decides which simulations to run, using AI models including Anthropic's Claude and OpenAI's GPT. A week later, working mostly on its own for three days, the system proposed a trajectory the team had not considered: the spacecraft would first swing close to the sun, closer than Mercury, firing its engine on each pass when its solar panels receive four times the sunlight. This generates more thrust per burst of fuel than firing anywhere else, allowing the panels and the spacecraft to stay small.

"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," said Matt Pines, PSI's co-founder and chief executive, who added that the system still lacks a human researcher's judgment about which approaches are worth pursuing. Even if the Fermi probe launches on schedule, Johnston said, "we're pretty confident that we will not be the first to arrive" at Alpha Centauri, since future spacecraft are likely to be faster.