In the framework of the ESA-NASA Joint Aeolus Tropical Atlantic Campaign (JATAC), theASKOS experiment was implemented during the summer and autumn of 2021 and 2022. ASKOScomprised roughly 9 weeks of measurements in the Saharan dust outflow towards the North Atlantic,with operations conducted from the Cabo Verde Islands. Through its unprecedented dataset ofsynergistic measurements in the region, ASKOS will allow for the calibration and validation ofthe aerosol/cloud product from Aeolus and the preparation of the terrain for EarthCARE cal/valactivities. Moreover, ASKOS marks a turning point in our ability to study Saharan dust properties andthe processes affecting its atmospheric transport, as well as the link to other components of the Earth’ssystem, such as the effect of dust particles on cloud formation over the Eastern Atlantic and the effectof large and giant particles on radiation. This is possible through the synergy of diverse observationsacquired during the experiment, which include intense 24/7 ground-based aerosol, cloud, wind,and radiation remote sensing measurements, and UAV-based aerosol in situ measurements withinthe Saharan air layer, up to 5.3 km altitude, offering particle size-distributions up to 40 μm as wellas sample collection for mineralogical analysis. We provide an outline of the novel measurementsalong with the main scientific objectives of ASKOS. The campaign data will be publicly available bySeptember of 2023 through the EVDC portal (ESA Validation Data Center).