A nonprofit organization called the Fermi Explorer Mission has announced plans to launch a spacecraft toward the Alpha Centauri star system by the end of 2029. Alpha Centauri is the closest star system to Earth, located about 4.4 light-years away—roughly 25 trillion miles. If all goes according to plan, the spacecraft would take up to 80,000 years to reach its destination, far longer than a human lifetime. The trajectory for the mission was discovered by an AI system developed by Physical Superintelligence (PSI), an AI physics research lab. PSI is backed by $58 million in funding led by Breakthrough Energy, a climate-focused investment group co-founded by Microsoft co-founder Bill Gates. This is not the first attempt to send a probe to Alpha Centauri. In 2016, billionaire investor Yuri Milner announced the Breakthrough Starshot mission, which aimed to send tiny probes propelled by powerful lasers at a fifth of the speed of light. Milner pledged $100 million for a proof of concept, but no spacecraft has yet launched. Philip Johnston, cofounder and president of the Fermi Explorer Mission, said the team wanted to avoid repeating the same approach. “We’re dead set on something actually launching,” he said. The Fermi mission is currently funded by private donors and is expected to cost $15 million. Johnston emphasized that the mission does not aim to reach Alpha Centauri within a human lifetime. Instead, the goal is to develop a method for interstellar travel. The spacecraft will carry at least 1 kilogram of cargo, including artistic and scientific payloads, messages, and a copy of the Golden Record—a gold-plated disc of Earth’s sounds and images sent aboard NASA’s Voyager probes in 1977. Engineering an interstellar journey is extremely challenging, given the vast distances involved. The fastest object humans have ever launched, Voyager 1, has only covered a fraction of the distance to Alpha Centauri since 1977. Johnston and his team spent a year trying to design a route for a small, solar-powered spacecraft that could reach Alpha Centauri for under $15 million. They faced challenges in providing enough power without making the spacecraft too heavy. They turned to Alex Wissner-Gross, a physicist and cofounder of PSI, who recommended using an AI system called Get Physics Done. This open-source system breaks down physics research questions into smaller tasks and uses AI models to determine which simulations to run. A week later, the AI system found a novel trajectory that surprised Johnston. The path involved slowing the spacecraft to swing close to the sun—closer than Mercury. On each close pass, the spacecraft would fire its engine to capture more solar energy, allowing for more efficient propulsion. Because the engine only runs near the sun, the solar panels can remain small, keeping the spacecraft lightweight. The AI conducted most of the research independently, running on a billion tokens over three days, according to Matt Pines, cofounder and CEO of PSI. An astrophysicist on PSI’s team guided the AI to align with the mission’s requirements and checked the results for errors. Even if the Fermi probe launches, Johnston acknowledges that it may not be the first to reach Alpha Centauri. If a spacecraft were launched a thousand years from now and traveled 20% faster than today’s technology, it would still arrive more than 10,000 years before the Fermi probe. The Fermi project is not only an engineering challenge but also a scientific quest. It seeks to answer a long-standing question in physics posed by Enrico Fermi in 1950: If intelligent life exists, why haven’t we found evidence of it? The mission aims to explore whether the lack of evidence is due to the difficulty of interstellar travel or the rarity of intelligent life. If the Fermi probe successfully launches, it will mark the first time humanity has actively attempted to reach another star, potentially reshaping our understanding of life in the universe.