The doors of the Extreme-UV Imager onboard Solar Orbiter: from design to flight

The EUI instrument on board ESA’s Solar Orbiter carries three doors designed to protect the instrument’s delicate entrance filters from contamination throughout the mission. These mechanisms must withstand harsh launch and in-orbit thermal loads, ensure precise repositioning. They rely on passive end-stops, launch locks, and a single stepper motor per door. One door includes an additional intermediate occulter position for coronal imaging. Extensive modelling, including thermal, structural, contamination, and magnetic analyses, validated the mechanisms' performance. In-flight results confirm reliable operation, minimal degradation, and compliance with all mission requirements.