Currently, the high increase of space systems capacity requires investigating a new generation of satellites capable of assuring a high data rate in the link between satellite and ground. In particular, in the Earth Observation domain, Optical Communications are being studied to ensure high throughput communication systems for the download of images taken by the satellite: they will play an important role in the near future as they offer potential advantages over microwaves. However, the impact of clouds delays its implementation for the time being. These atmospheric events vary as a function of the ground station location. Hence, this report describes a research study with a system engineering point of view on the feasibility of optical links.