Euclid is a mission selected by the European Space Agency (ESA) at the end of 2011 to understand the nature of the dark Universe. It will investigate the distance-redshift relationship and the evolution of cosmic structures by means of two instruments: the Visual Imager (VIS) and the Near-Infrared Spectrometer and Photometer (NISP). Euclid Instruments are maintened and operated by the Instrument Operation Teams (IOTs), as a connection point between the EC Science Ground Segment (SGS), to whom it belongs, and the Science Operation Centre (SOC), run by ESA. The IOTs shall play a crucial role in the successful execution of the Euclid mission; they are in charge of the monitoring, control and maintenance of the Euclid payload, from initial diagnostics of field quality to detailed trend analysis of instrument characteristics and calibration. The simulation of synthetic data is commonly used by scientist and engineers to consolidate the instrument configuration and to define retrieval strategies on such complex missions. The IOTs will be equipped with dedicated software tools to allow a quasi-automatic monitoring and manage operational
activities. Such simulator enables the generation of simulated output data for selected test scenarios to support the assessment of instrument configuration changes on the mission performance and allow to analyse the impact of individual error sources on the output of an ideal system, both separately and simultaneously. This paper describes the Euclid End-to-End Mission Performance Simulator (Euclid E2ES) which includes both the NISP and VIS instruments, to be run separately, to assess the synergy between the two instruments embarked on the mission, the impact on the observation strategy and the operations. An overview of Euclid E2ES design and current status is given, with a demonstration of some preliminary results. It is expected that Euclid E2ES will serve to consolidate the mission concept and instrument design as well as it will support IOTs during satellite operations and the first space mission phases (Performance Verification).
