The spacecraft will monitor each of its target objects about 70 times over the first five years of the mission to study the precise position and motion of each target, and will keep doing so. The spacecraft has enough micro-propulsion fuel to operate until about November 2024. As its detectors are not degrading as fast as initially expected, the mission could therefore be extended. "Gaia" targets objects brighter than magnitude 20 in a broad photometric band that covers most of the visual range; such objects represent approximately 1% of the Milky Way population. Additionally, "Gaia" is expected to detect thousands to tens of thousands of Jupiter-sized exoplanets beyond the Solar System, 500,000 quasars outside our galaxy and tens of thousands of new asteroids and comets within the Solar System.