The service module hosts most of the spacecraft subsystems that are needed to operate the payload, including telemetry, power, thermal control, and attitude and orbit control (AOCS). For Euclid, the service module provides X and K band communications, with a K band science data rate of ~55 Mbit/s during the daily telecommanding and communications period of 4 hours. To store the large data volume that will be accumulated during observations, Euclid will have a mass memory of at least 2.6 Tbit. To meet the high precision imaging requirements, the Euclid AOCS provides an extremely stable pointing with a dispersion of less than 35 milli-arcseconds per visual exposure. At those accuracies, a high thermal stability is also required to protect the telescope assembly from optical misalignments.