Immediately after Nicholas moves his fleet into the "Mecatol Rex" system, for completeness sake, we should review PDS fire. If a player in an adjacent system has PDS units there is a possibility that they can fire at the arriving fleet.
Melissa has a Planetay Defense System on the planet "Wellon". This would be a cause for concern for Nicholas if Melissa has the "Deep Space Cannon" Technology.
Melissa does not have this Technology advance. She could not choose to fire at Nicholas' arriving fleet.