The need to schedule and execute activities within mission operations is not a new concept and recently has gained new and stronger value within the ESOC general approach to provide missions with a required level of automation. The overall approach goes towards two directions: adoption as much as possible of standards and definition of reference models of the ground systems including modelling of the interfaces existing among the systems at data and interaction mechanisms level. In the automation concept the scheduling and execution functionality is modelled as a layer providing activities schedule and execution services to users required to plan mission resources usage (as result of the mission planning process) and to users required to automate repetitive operations. The scheduling and execution layer makes use of systems (e.g. mission control systems, ground segment interfaces, etc.) in charge to ensure low-level mission resources interfaces (e.g. resources monitoring and control). This paper describes an activities schedule and execution reference model together with the related interfaces as defined within the ESOC ATIS (Automatic Tool Interface Study) study. The main objective of the study is the definition of data specifications interfaces used by the user of the scheduling and execution layer to define activities and the functional reference model of such system. ATIS makes use of ESA and industry standards (such as ECSS-E-70-31/32 and W3C XSD for schema definition) and the paper provides a brief overview of the utilisation of such standards and the benefits derived from their adoption