ARINC-664 Part 7 specification (AFDX) provides the enabling technology for network I/O in Integrated Modular Avionics (IMA) architectures, since it is designed based on the IMA concepts and requirements (ARINC 653 specification), already an ESA roadmap (i.e. IMA4Space project). In order to avoid the lack of flexibility, scalability, reliability and to improve security and qualification process in spacecraft on-board data networks, ARINC-664 (AFDX) could be the solution by offering hardware assisted service, determinism and standardisation as a minimum. Additionally AFDX has been validated and is in use today in the European avionics industry, which has in some areas quite similar requirements with the space domain, in which could be more easily adopted (over SpW, or directly Ethernet for space).MISSION aims (1) to define the methodology for applying ARINC-664 (AFDX) in on-board spacecraft/satellite communication networks, (2) to define the interfaces/modifications to existing on-board I/O subsystems and (3) to implement and validate an experimental prototype ARINC-664 (AFDX) network for spacecraft on-board communications.The MISSION project aims to apply the IMA avionics concept on spacecraft, together with highly deterministic interconnected on-board network (ARINC-664, AFDX). It will constitute an enabling technology harmonization and standardization action. Together with an intrinsic improvement of systems performance, product assurance and reliability, it is expected to provide multiple benefits at all industrial level such as standardized and configurable systems, products and technology elements, easier and faster integration of complex systems, larger procurement basis, easier sub-contracting scheme.