Breakthrough Starshot

Breakthrough Starshot was a research and engineering project by the Breakthrough Initiatives program to develop a proof-of-concept fleet of light sail interstellar probes named Starchip, to be capable of making the journey to the Alpha Centauri star system 4.34 light-years away. It was founded in 2016 by Yuri Milner, Stephen Hawking, and Mark Zuckerberg. A flyby mission was proposed to Proxima Centauri b, an Earth-sized exoplanet in the habitable zone of its host star, Proxima Centauri, in the Alpha Centauri system. At a speed between 15% and 20% of the speed of light, it would take between 20 and 30 years to complete the journey, and approximately 4 years for a return message from the starship to Earth. The conceptual principles to enable this interstellar travel project were described in "A Roadmap to Interstellar Flight", by Philip Lubin of UC Santa Barbara. Sending the lightweight spacecraft involves a multi-kilometer phased array of beam-steerable lasers with a combined coherent power output of up to 100 GW. In September 2025, Scientific American reported that the project was on hold indefinitely. Philip Lubin estimates that the project had spent about $4.5 million of the proposed $100 million by this point.