The Jupiter Icy moons Explorer (JUICE) will generate ephemerides of the Galilean moons to assess their ability to sustain live. However, determining the ephemerides only using radiometric tracking (acquired using PRIDE and 3GM) results in an unstable solution which is related to the absence of flybys of especially Io, such that its dynamics can only be estimated indirectly (through the Laplace resonance). This problem is partially mitigated in this thesis by optimizing the observation schedule for optical astrometry of Io (provided by JANUS) using the NSGA-II algorithm. The optimal epochs for space-based astrometry are found to be preferentially distributed around the closest approaches of JUICE with respect to Io. During these events, the observations show a high sensitivity with respect to the dynamics of Io and have a low positional uncertainty. Using the optimized astrometry, both the condition number and formal errors can be substantially reduced.