The StraVARIA project studies the autonomy of completely solar-powered unmanned flying platform. The aircraft is referred to as "High-Altitude Pseudo-Satellite (HAPS)" and is capable of providing communications and earth observation services over long periods of time. A multilateral mission planner is used which considers the following parameters: mission, weather and energy balance. The aim of the research/development is to increase mission efficiency and flight safety in order to enable future operation of the platform in commercial applications. Within the framework of this project, a man-machine interface for operating the mission planner was developed.