JUICE time distribution protocol: SpaceWire networks and protocols, short paper

JUpiter ICy moons Explorer (JUICE) is the first ESA large-class mission aiming at the exploration of Jupiter and three of its largest moons, Ganymede, Callisto and Europa. The JUICE payload suite counts 10 instruments, 9 of which are interfaced with the On-Board Computer (OBC) and Solid State Mass Memory (SSMM) using a SpaceWire (SpW) network both for science data and command & control traffic. JUICE requirements favor the adoption of SpaceWire ECSS protocol standards in a layered architecture fashion. With regards to the time synchronization and distribution, the “High Accuracy Time Synchronization over SpaceWire Networks” draft protocol specification (developed within the SpaceWire Working Group) has been analyzed and tailored to meet JUICE needs. The paper presents the rationale behind the use of the SpW TDP, it's tailoring and concludes with lessons learned and recommendations towards an ECSS standard document.