The European Space Agency (ESA) challenged cybersecurity experts in the space industry ecosystem to disrupt the operation of the agency's OPS-SAT demonstration nanosatellite. Participants used a variety of ethical hacking techniques to take control of the system used to manage the payload's global positioning system, attitude control system1 and onboard camera. Unauthorised access to these systems can cause serious damage to the satellite or lead to a loss of control over its mission. Thales's offensive cybersecurity team worked with the Group's Information Technology Security Evaluation Facility (ITSEF2) for this unique exercise, which demonstrates the need for a high level of cyber resilience in the very specific operating environment of space.