Gram-scale lightsail eyes 20-year voyage to Alpha Centauri

A Space Daily piece outlines Breakthrough Starshot's concept: a gram‑scale payload on an ultrathin lightsail accelerated by a ground‑based laser array to about 0.2c, enabling a flight to Alpha Centauri in a little over 20 years. The plan hinges on building the laser, sail, and communications systems, plus solving beam stability, navigation, and decades‑long durability challenges. Even if launched, data would take years to return—about 26 years after launch—since a transmission from Proxima Centauri to Earth adds another 4.2 years. No launch date is set; the concept remains a physics‑proof, research program rather than an imminent mission.