the whole of humanity is minified to small then milli then micro level
every time they achieve a minification of 10 times they achieve a reduction in energy consumption and the population increase can continue
As a gesture of good will the cowboy has over delivered and estimated the journey time from the specs and tree growth simulations. We have no return route for the journey. It is possible that the navigation is sourced to another corporation or perhaps it is following a desire or a calling to join another of its kind, on another star system.