Historically, civilian space missions have employed limited security mechanisms. Telecommands, telemetry, and scientific payload data have often been transmitted over unencrypted and unauthenticated Radio Frequency (RF) channels. While this operational model was once considered acceptable, the growing threat landscape makes such an approach increasingly dangerous. In response to these evolving needs, this thesis focuses on the design and implementation of a secure software patching mechanism for the Avum Orbital Module (AOM), part of Space Rider, the European Space Agency’s reusable space transportation system. The project aims to enhance the spacecraft’s ability to safely receive and apply software updates, reinforcing both its resilience and mission reliability.