Artist's impression of a Soyuz launcher carrying Gaia into orbit, showing the moment the aerodynamic fairing is jettisoned. The ESA's Gaia space probe launched on December 19, 2013. The Gaia mission will yield the most detailed three-dimensional map ever made of the Milky Way galaxy. Gaia will chart a billion stars (about 1% of the stars in our galaxy) using two telescopes and three scientific instruments. On September 14, 2016, the mission released its first set of data from a year of scanning the sky.