Request-Driven Scheduling for NASA's Deep Space Network

Abstract

This paper describes recent work undertaken to increase the level of automated scheduling support available to users of NASA’s Deep Space Network (DSN). We have adopted a request-driven approach to DSN scheduling, in contrast to the activity-oriented approach used up to now. We describe some of the key constraints and preferences of the DSN scheduling domain and how we have modeled these as scheduling requests. Algorithms to expand requests into valid resource allocations, and to resolve schedule conflicts and unsatisfied requests, have been developed and incorporated into a distributed system of servers called the DSN Scheduling Engine (DSE). To explore the usability aspects of our approach we have developed a pathfinder graphical user interface that utilizes the DSE. This GUI incorporates several key features to make it easier to work with complex scheduling requests, including progressive revelation of detail, immediate propagation and feedback of implications, and a “meeting calendar” metaphor for repeated patterns of requests. This pathfinder system has been deployed and adopted by one of the JPL DSN scheduling teams, representing an initial validation of our overall approach. The DSE is planned to be a central element of the Service Scheduling Software (S 3 ) web-based scheduling system now under development for deployment to all DSN users.