Diagram of the basic geometry used in the simulation explained in Sect. 4.3. The lander Philae is surrounded by a barrier curved as a sinusoid. The front (bottom of the image) and the space above the lander are open. The illumination of the Sun mainly comes from the front because the Sun moves on a plane that forms <22° with the floor of this box. The ≈90° angle indicates the width of the field of view of the lander towards the Sun.