Mechanical architecture and loads definition for the design and testing of the Euclid spacecraft

Euclid is an astronomy and astrophysics space mission of the European Space Agency. The mission aims to understand why the expansion of the Universe is accelerating and what is the nature of the source responsible for this acceleration which physicists refer to as dark energy. This paper provides both an overview of the spacecraft mechanical architecture and a synthesis of the process applied to establish adequate mechanical loads for design and testing. Basic methodologies and procedures, logics and criteria which have been used with the target to meet a compliant, \"optimised\" design are illustrated. The strategy implemented to limit the risk for overdesign and over-testing without jeopardizing the design margins is also addressed.