The mission's primary aim is to build a three-dimensional map of our galaxy. It will help in measuring precise distances to a billion stars. Scientists estimate that there are at least 100 billion stars in our galaxy. In addition, Gaia is expected to discover up to ten thousand planets beyond our Solar System, as well as hundreds of thousands of asteroids and comets within it.
Gaia's twin telescopes will see an average of 40 million stars every day over its five-year mission, with a launch atop a Europeanized version of the Russian Soyuz rocket from the Guiana Space Center on the northern coast of South America.
