MENELAOSᴺᵀ Midterm Summer School (MSS) 2021 is a mixed on-site and online event held by MENELAOSᴺᵀ in Santiago de Compostela (Spain) next September. The Summer School is organized by CiTIUS, the Research Center on Intelligent Technologies of the University of Santiago de Compostela. The language of the Summer School is English, and the program consists of on-site and online presentations and lectures about the newest achievements and developments in multimodal – multi sensor data fusion in the context of the MENELAOSᴺᵀ project. All sessions will be scheduled between 20 September, 2021 and 24 September, 2021 in Santiago de Compostela