Europa Clipper Tour Trajectory Navigation Analysis - Mitigating the Effects of Unintended ΔV Due to Safe Mode

The Europa Clipper mission will perform over 50 low-altitude flybys of Jupiter’s moon Europa. The overall mission plan must be robust to safing events at all points along the trajectory. Depending on the fault type, the spacecraft may demote to using RCS thrusters for attitude control, which can impart several hundred mm/s of unintended ΔV over the course of the safe mode response. If one were to occur at the wrong time in tour it could place the spacecraft on a direct impact trajectory with Europa or other flyby body. It could also be costly in terms of clean up ΔV. This paper describes the steps taken by the Mission System to mitigate the effects of RCS safing events, with a particular focus on the time between the approach maneuvers and their associated encounters.