Why Breakthrough Starshot May Never Happen

Breakthrough Starshot is a research and engineering project by the Breakthrough Initiatives to develop a proof-of-concept fleet of light sail spacecraft named StarChip, to be capable of making the journey to the Alpha Centauri star system 4.37 light-years away.

It was founded in 2016 by Yuri Milner, Stephen Hawking, and Mark Zuckerberg.

A flyby mission has been 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 twenty to thirty years to complete the journey, and approximately four 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.

It is estimated that a 100 GW laser array will be needed. But 100 GW is a lot of power, or more like all U.S. nuclear power plants combined for 20 minutes for each Solar Sail multiplied by 1000.

There are powerful lasers that could do the job, but they are massive and can only fire for extremely short periods of time.

Now there is a technology currently being used by the U.S. military that could be the answer.