Integrated subsystem test on Fine Guidance Sensor (FGS) unit of ESA's EUCLID mission

EUCLID is an ESA mission intended to investigate dark energy by measuring the redshift of distant galaxies with an unprecedent accuracy. This will help physicists and astronomers to better understand the origin of our universe. One of the main characteristics of EUCLID spacecraft is its attitude control capabilities, as they need to be very precise to perform the scientific measurements. The units that give EUCLID this characteristic are part of the AOCS (Attitude and Orbital Control Systems), being one of them the Fine Guidance Sensor (FGS). FGS EU is intended to communicate with the spacecraft onboard computer (CDMU), execute procedures of image processing, manage the internal modes by use of the Application Software (ASW) and Startup Software (SUSW), manage the power supplies for PEMs (Proximity Electronics Modules) and compute attitude of the spacecraft given the data coming from detectors. As part of the final stage of development and construction of this satellite, a set of test campaigns need to be done in order to validate and guarantee the correct functioning of the units, subsystems and systems. The ISST (Integrated Sub System Test) is a test that allows a broad but deep verification of the functionalities offered by the unit. The main scope of the thesis is to develop and perform an entire ISST on FGS EU to verify that a set of representative functionalities fulfill the requirements set at the design stage of the EUCLID project. The required specifications are given by Engineering Department of Thales Alenia Space Italy and are the basis of the test procedure followed.