The idea of light powered sails soaring across the cosmos is not a new idea in the slightest. The theory of quantum mechanics was largely developed by Albert Einstein furthering the concepts of Max Planck and James Clerk Maxwell. With this theory it was able to describe that a photon can behave like a wave as well as a particle that can exert a force on an object. With this discovery the idea of a sail that can use the power of the sun to propel itself through space
This idea did not really come to fruition until the late 1900s when the Russian Space Agency created the Znamya 2. The Znamya 2’s primary purpose was to reflect the sunlight back to Earth to use its energy on the ground, but it was still a significant milestone in the development of practical light sails, being really the first of its kind. This feat only lasted a few days and soon burned up in the Earth’s atmosphere.
Solar sails would continue to progress as the years went on leading to a Japanese sail by the name of Ikaros, launched in 2004, that was the first solar sail to use only light provided by the sun to travel to different planets. The Ikaros was able to fly past Venus on its mission and is currently still traveling through space.
There are other future projects such as the Lightsail 2 that will be launched this year (2019) but these were the major breakthroughs.