Mission Planning and Operational Constraints and Their Resolution for EO Missions Like EnMAP

Kurzfassung

Earth observation missions are generally operated by execution of predefined time-tagged commands. However, depending on the type of mission, issues relevant to different types of mission may occur. These issues are drivers for the design of the operations system of EnMAP (Environmental Mapping and Analysis Program). The main challenges are limited transfer of telecommands and limited downlink capabilities; also the cloud coverage in the target area - for optical sensors - plays a huge role. There are certain constraints, concerning this satellite bus in particular. For example a limited time tagged list which allows no more than 120 time tagged commands on board. Further the fact that every dumped house keeping packet has to be requested from the space craft which leads to a delay in the reception of telemetry can be a bottle neck. In addition to these S-band related issues it is a real challenge to coordinate the amount of payload data which will be down-linked via X-band. In this paper the strategy of managing all these difficulties and optimally operating the satellite under these conditions, will be described. For handling of cloud coverage a database with weather statistics will be implemented. These statistics are compared with global forecast models as provided by e.g. the German weather service (DWD). With the calculated forecast values, planning priority of datatakes is increased or decreased.