Development of a Ground Data Messaging Infrastructure for the Mars Science Laboratory and Beyond

The Mission Data Processing and Control Subsystem (MPCS) under development for the Mars Science Laboratory (MSL) incorporates a messaging-based architecture to support event-driven flight operations. MPCS (otherwise known as "Chill") applications communicate over a Java Messaging Service (JMS) compliant messaging bus using messages defined by common Extensible Markup Language (XML) data schemas. This communications approach provides a system-wide "information bus" that functions as a "blackboard" of flight and ground activity information available to interested clients. While messaging over JMS offers important connectivity benefits such as ease-of-integration, significant questions and challenges lie ahead. Primary concerns include the ability of clients to keep up with high rates of published messages during system tests as well as real-time operations and how to best mitigate information bus traffic problems through file system data storage and database management. This paper will discuss the issues and lessons learned by the Chill team from the development, integration and early stages of deployment of a ground data system (GDS) architecture built on a messaging infrastructure.