Integrating Systems Modeling With Simulation Helps Ensure Robust Space Debris Removal Mission Success

The European Space Agency (ESA) is studying an active debris removal mission called e.Deorbit, which is intended to capture an ESA-owned derelict satellite in low orbit and safely crash it into the ocean in a controlled atmospheric reentry. The proposal from a global defense and space manufacturer for this project used model-based systems engineering (MBSE) to simultaneously define the mission requirements and the architecture.

In a parallel internal study, engineers from the company used Ansys ModelCenter™ MBSE software to integrate the simulation tools used to evaluate the performance of the architecture with the system model. This integration demonstrated that it is possible to greatly reduce the time required to verify the requirements and architecture by making it possible to run all the major simulation tools as part of an automated workflow driven by the systems model. This streamlined process increased the number of cases against which the entire system could be simulated by several orders of magnitude. It also makes it possible to cycle through the simulation one time step at a time while simultaneously viewing simulation results for the entire mission. The result is that engineers can have much more confidence in the proposal and managers and customers can receive a much better understanding of the details.

Challenges

On the e.Deorbit proposal, the manufacturer’s engineers addressed these concerns by using system modeling to simultaneously develop the mission requirements and architecture. They developed a SysML model that integrates the safety and architecture requirements, system capabilities, functional architecture, and concept of operations (CONOPS). Developing the architecture and requirements in parallel helped in validating the requirements at an earlier stage in the project, saving considerable time and money.

While this approach was a major step forward, engineers recognized that its benefits were limited by the fact that the domain simulations required to support the development of the architecture were each run manually and separately by engineers responsible for a particular domain. The results from these simulations were later uploaded to a database and used as input parameters for the system model and other simulations. This meant that the performance of the entire system for a particular use case was not clear until each of the simulations involved is completed, which could take days or weeks. Considerable time and effort are required to simulate the performance of the entire system for even a single case, limiting the number of cases that can be run in the architecture definition phase. This creates the potential for errors and unexpected interactions that cost considerable time and money to correct when they are discovered later during the detailed design stage.