One thing Harry doesn't know...
The navigation and course change control system is just for looks. It's fake, like that thermostat you stuck up in the living room for your wife.
The real system is buried deep in the ship, running on automatic. Eventually, they may find it, if they can work their way past the other fifty decoys.
Not only did they not want the colonists changing their minds, they didn't particularly want the ship coming back filled with the sorts of people who would take over the ship with guns and turn it around.