Concurrent Design Facility (CDF)

Simulation Role
The Modelling and Simulation section is actively supporting the Concurrent Design Facility (CDF) at Estec in the area of system level simulation. For a typical study, a simulator is created with models of the spacecraft and its environment. The information to create the simulator is based on what is provided by other disciplines in the CDF, such as mission analysis, ground stations, system, power, thermal, structures (CAD model), antennas, etc. With the simulator, a dynamic analysis of the spacecraft design in relation to the foreseen mission concept can be exercised. The results of the simulation can be used to highlight inconsistencies in the design or to support design trade-offs at system level.
CDF MeSE study
Simulator Implementation
In the earlier CDF studies, the simulator has been based on a Project Test Bed (PTB) prototype simulator, which is modelling a spacecraft in a generic way. Originally, the PTB software was focussing on the later phases of a spacecraft mission, but it has been adopted to support the very early phases of a project. The PTR simulation kernel runs in the EuroSim real-time simulation tool, in which all mathematical models are being integrated. The PTB simulator has a 3D visualisation front-end available in the form of the Image Generation System (IGS) software. With this software, it is easy to provide an intuitive 3D view of the mission concept and the initial spacecraft design. This visualisation has proven to be very powerful in a concurrent environment, as it allows all participants in a study to quickly understand the overall mission concept and the role of their subsystems in the spacecraft system design.
SIMVIS Designer
Recently, the PTB software has been replaced with the SIMVIS tool, which provides similar capabilities but with a more modern software engineering approach, which makes the simulator more flexible and easier to maintain. SIMVIS provides an automated interface to the CDF workbook model, where engineers from the various domain disciplines enter their part of the spacecraft design. This way the spacecraft as modelled in the simulation can be kept coherent with the actual spacecraft design. SIMVIS uses a further evolution of the IGS 3D graphics software, which is called the OpenIGS. The OpenIGS application provides standard interfaces to both EuroSim and SIMSAT, the latter being the simulation kernel of SIMVIS.
CDF SOLO study
Simulation Results
At this point in time, more than 50 studies have been performed in the CDF. Not all studies are big enough (in team size or duration) to justify the extensive use of simulation, but for a half of all CDF studies simulation have been applied. In various studies, simulation has contributed to the spacecraft design by providing the relevant trade-offs or to provide other auxiliary data. The 3D visualisation and also other displays like the 2D maps have been highly appreciated in various CDF studies, as it has increased awareness amongst engineers of the functioning of their subsystems in relation to the total spacecraft system. Also towards the customer some of the mission concepts and design choices could be communicated more clearly. The final simulation result is usually a short movie on CD-ROM, which can be shown as part of the promotion exercise of a particular study.
Last update: 20 September 2006

Related links

 •  CDF website (

Related articles

 •  GPTB (
 •  SIMVIS (
 •  OpenIGS (