R&D projects in space robotics are characterized by the profound integration of various disciplines and the associated complexity of the systems to be designed. To support this multidisciplinary collaboration, the paradigm of Model-Based Systems Engineering (MBSE) is a suitable approach. Another essential challenge of space projects is the early verification and validation of the model-based design. Tests with physical prototypes give rise to considerable costs and can reproduce the real conditions only to a certain extent.In this paper, we present an approach to integrate the cross-domain system specification with the cross-domain test design with Virtual Testbeds to a comprehensive system model. This enables a continuous simulation-based engineering in the design of space applications. Requirements from the early design phase can be used systematically to test and integrate detailed models from the various disciplines.The presented system model offers the potential to efficiently integrate national and international know-how to support the development phases of a mission from the requirements analysis to design, visualization, control, operation, training up to marketing and technology transfer. Future projects can be realized faster, less expensive and more robust.Copyright © 2015 by ASME