Zuckerberg co-founded the Breakthrough Starshot project

Person: Mark Zuckerberg
Lived: b. 1984
Field: Technology
From: American

The story

The nearest star system to the Sun, Alpha Centauri, lies about 4.37 light-years away. In 2016 a group of scientists and backers set out to find a way to reach it within a single human lifetime.

On 12 April 2016 the physicist and investor Yuri Milner announced Breakthrough Starshot at an event in New York, together with the cosmologist Stephen Hawking. Mark Zuckerberg co-founded the project with them and joined its board. Part of the Breakthrough Initiatives research programme, it began with $100 million in funding, with Pete Worden as executive director and the Harvard astronomer Avi Loeb chairing its advisory board.

The plan built on ideas set out by the physicist Philip Lubin of UC Santa Barbara in A Roadmap to Interstellar Flight. Instead of a large rocket, Starshot envisaged a fleet of about a thousand tiny probes called StarChips, each weighing only a few grams and carrying miniature cameras, processors and communications equipment, attached to an ultra-thin light sail a few metres across. A huge array of ground-based lasers, with a combined power of up to 100 gigawatts, would push the sails to 15 to 20 percent of the speed of light within minutes. At that speed the probes could reach Alpha Centauri in 20 to 30 years, and their signals would take about four more years to return to Earth.

A natural target soon emerged. In August 2016 astronomers announced Proxima Centauri b, an Earth-sized planet in the habitable zone of the nearest star, and Starshot proposed a flyby that might photograph it. In 2017 Breakthrough Initiatives began working with the European Southern Observatory, funding an upgrade to an instrument on the Very Large Telescope in Chile to search for planets around Alpha Centauri. Test precursors of StarChips, called Sprites, were flown in orbit in 2017 and 2019.

Starshot was always a long-range bet: it required major advances in lasers, materials and spacecraft design. By 2025 the project was reported to be on hold. Its studies nonetheless set out in engineering detail what humanity's first interstellar mission might require, from gram-scale spacecraft to sails that can survive intense laser light.