A Tiny Probe Launching in 2029 Will Spend 80,000 Years Reaching the Nearest Star

The Most Ambitious Journey Ever Planned—With No Expectation of Return

Sometime before the end of 2029, a small spacecraft will slip away from Earth and begin the longest journey in human history. It won't carry astronauts. It won't send back photos of alien worlds. And no one alive today—or anyone born for tens of thousands of years—will ever know if it truly succeeds. That is entirely the point.

A nonprofit organization called the Fermi Explorer Mission announced on September 1 that it intends to launch a spacecraft to our nearest star system by the end of 2029. 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. And the team behind it couldn't be more at peace with that reality. "We hope to be both the first to leave and the last to arrive at Alpha Centauri," said Philip Johnston, co-founder and president of the Fermi Explorer Mission. "None of us will be here when this journey ends, and that is the point. It's about taking the first achievable step and inspiring future generations to keep pushing beyond the limits we inherited."

Cheap, Proven, and Deliberately Slow

What makes this mission genuinely different from previous interstellar dreams is its radical embrace of what already exists. Instead of needing billions of dollars or propulsion breakthroughs that may take generations to develop, the nonprofit is designing around flight-proven electric propulsion and the constraints of what can be built today. The spacecraft must be aimed at Alpha Centauri, carry at least one kilogram of payload, launch before the end of 2029, and cost less than $15 million to design, build, launch, and operate.

The proposed vehicle would spend about 13 years using solar-electric propulsion near the Sun, escape into interstellar space around 2043, and then coast for almost 80,000 years. For Johnston, mission success means leaving the solar system on the right trajectory—which will take a more palatable 12 years, and will be faster than either the Voyager 1 or Voyager 2 missions that reached interstellar space in about 35 and 40 years, respectively. Crucially, this directed trajectory will be a first. Though NASA's Voyager probes have entered interstellar space, they're not headed toward any particular star; rather, they're journeying outward on the path they took to complete their "grand tour" of Jupiter, Saturn, Uranus, and Neptune.

There's another unexpected twist: the mission's flight path was discovered not by human engineers, but by an artificial intelligence. After the Fermi team struggled to find a workable route, Johnston mentioned the problem on a podcast, and the host offered to run it through an AI system called Get Physics Done—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 and OpenAI's GPT. A week later, the AI system turned up a novel trajectory, to Johnston's surprise. PSI's feasibility study ultimately devised the final "perihelion pump" maneuver that made the mission viable.

What It Will Carry Into the Dark

The Fermi Explorer envisions a spacecraft weighing between 220 and 440 pounds, carrying at least 2.2 pounds of useful payload and using electric propulsion to minimize fuel and cost. The payloads could include artistic works or scientific experiments—for example, a cosmic-ray ion detector or an interstellar dust catcher. Fermi also plans to carry a replica of the Voyager Golden Record and 300-character messages from children in every country, solicited through national education ministries. For donors who want a more personal connection to eternity, for $100, donors can have their names etched onto the spacecraft.

Fermi Explorer also plans to open-source its research, analysis, data, and simulation tools so scientists, engineers, educators, students, and curious contributors can test assumptions, improve the mission, and propose useful science for the journey. The organization is currently funded by private donations, and the openness is deliberate—this is meant to be humanity's mission, not a corporate one.

A Symbolic First Step With a Long Shadow

The organization believes humans will eventually develop much faster spacecraft and overtake the original probe during its 80,000-year journey. By the time the tiny spacecraft reaches Alpha Centauri, humanity could already have arrived there. That self-aware paradox is baked into the mission's DNA. Johnston has said the team is "not constraining ourselves to doing it in a human lifetime" and that they are "pretty confident that we will not be the first to arrive."

And if Johnston's even grander ambitions hold, this is just the opening move. "For $100 million, the next