This is the first spacecraft to raise its orbit around the Earth using sunlight.

Weighing just 5 kilograms, this cubeSat (small, standardized spacecraft that have made space flight more affordable), the size of a loaf of bread called LightSail 2 from the Planetary Society, is set to become the first spacecraft to raise its orbit around the Earth using sunlight: it will take off on June 22 aboard a Falcon Heavy Space X rocket from Kennedy Space Center in Florida.

LightSail 2, arrived in space, will deploy a solar sail and attempt to raise its orbit with the gentle thrust of the solar photons. While light has no mass, it has an impulse that can be transferred to other objects. A solar candle takes advantage of this impulse for propulsion.

LightSail 2
The sails, which have a combined area of 32 square metres, will turn towards the Sun during half of each orbit, which will give the spacecraft a small push which in microgravity conditions will be more than sufficient. For about a month after the deployment of the sail, this continuous impulse should increase the orbit of LightSail 2 by a measurable amount.

LightSail 2 will travel into space aboard the Department of Defense Space Test Program (STP-2) mission scheduled for launch on June 22, 2019. This is an unprecedented milestone, according to Planetary Society CEO Bill Nye:

Forty years ago, my professor Carl Sagan shared his dream of using a solar-sailed spacecraft to explore the cosmos. The Planetary Society is realizing the dream. Thousands of people from all over the world came together and supported this mission. We couldn’t have done it without them. Carl Sagan, and his colleagues Bruce Murray and Louis Friedman, created our organization to empower people everywhere to advance space science and exploration.