The primary function of ArcGIS Mission Server is to facilitate communication between ArcGIS Mission Manager users and ArcGIS Mission Responder users. This includes, but is not limited to, the following:
Organizing the presence and availability of mission members and their teams
Populating the location data from Responder onto mission maps
Routing near real-time data between Manager and Responder over WebSocket communication protocol
Transferring data to long-term storage in hosted feature layers
ArcGIS Mission Server is licensed through ArcGIS Enterprise and is federated with an ArcGIS Enterprise portal. Portal administrators assign and manage users for both Manager and Responder.
For more information see, Introduction to ArcGIS Mission Server.