Modeling Space Systems with the Data Systems Dynamic Simulator Plus

The Data Systems Dynamic Simulator Plus (DSDS+) is a discrete-event-based simulator used to simulate complex, high-data-rate, end-to-end systems. It was developed for the specific purpose of evaluating candidate data systems for spacecraft. DSDS+ features a graphical user interface and hierarchical modeling. A data system is modeled in DSDS+ by selecting preprogrammed elements from the simulation library, placing them in a work area, and connecting them together using direct manipulation to form a model of an end-to-end system. When using DSDS+ the user has access to a library of standard pre-programmed elements. These elements represent tailorable components of NASA data systems and can be connected in any logical manner. Additional elements can also be developed which allows the more sophisticated user the option of extending the standard element set. Next, DSDS+ supports the use of data streams simulation. Data streams is the name given to a technique that ignores packet boundaries, but is sensitive to rate changes. Because rate changes are rare compared to packet arrivals in a typical NASA data system, data stream simulations require a fraction of the CPU run time.