Evaluating the benefits of virtual satellite integration with SpaceWire

Virtual satellite integration refers to the use of a network such as the Internet to integrate the components of a satellite virtually. This concept has been successfully demonstrated by the SpaceWire Internet Tunnel, a combination of software and hardware which can be used to transparently replace one SpaceWire link with an Internet Tunnel: a virtual connection over which all traffic is sent. To determine the potential benefits of virtual satellite integration further research is necessary. The TopNet Pilot Project is an ESA funded project involving three separate consortia, with each consortium comprising geographically separated partners based across Europe. Each consortium performed experiments involving SpaceWire-based equipment connected virtually using the SpaceWire Internet Tunnel. On completion of these experiments, an evaluation of the benefits of virtual satellite integration and of the SpaceWire Internet Tunnel was performed by each consortium. This paper introduces the SpaceWire Internet Tunnel developed by the University of Dundee, and describes work recently undertaken to improve the Tunnel. Limitations of the virtual satellite integration concept are identified and the ways in which the SpaceWire Internet Tunnel addresses these are explained. The paper then describes the TopNet Pilot project and the use of the Tunnel in that project. A summary of the benefits of the SpaceWire Internet Tunnel is included at the end of the paper.