In December 2010, the Japanese IKAROS mission flew past Venus and successfully demonstrated solar sail technology in the inner solar system. Solar sail spacecraft operate on the principle that sunlight reflecting off a large sail can provide propulsion in space without the need for propellant fuel. However, solar sails become less effective the farther they are from the Sun. To address this challenge, researchers have been exploring the use of large ground-based laser arrays to focus beams of light with an intensity millions of times greater than sunlight.

“Breakthrough Starshot” aims to send probes to the Alpha Centauri system. This ambitious initiative proposes using a massive ground-based array consisting of a 1-kilometre grid of millions of lasers to propel tiny, microchip-sized probes at one-fifth the speed of light, allowing them to reach Alpha Centauri in approximately 20 years. Even if it does not prove feasible, work on this mission concept will have been very useful in advancing light sail form and material technology for extreme high velocity spacecraft.