For more than ten years, a collaboration of European scientists has been producing
simulations of the Gaia mission. These simulations range from detailed realistic simulated
CCD images to large volume simulations of the Gaia telemetry.
The data of this decade of simulations has been used for many purposes: instrument
design, data processing software testing and validation, prediction of mission
performances, etc. Today the launch date is getting closer and the task of the simulator
in the mission preparation will be wrapped up in a couple of years.
However, this is not the end of the story since the Gaia simulator can also be used for
the preparation of the scientific exploitation of the Gaia data. In this talk we will
present the simulator and its components, the data it can produce and the perspectives for
the utilisation of this data during the mission, both for data evaluation and scientific