I don't see how any morphological changes to an individual organism can possibly get reverse-translated into a corresponding change in the DNA of a sperm or egg.
I dont understand it either but Im watching with interest.
After 100 generations, the GA spawned a geometry/voltage set that boosted the ion engine grid's lifetime to 5.1 years - at least in the simulator (Journal of Propulsion and Power, DOI: 10.2514/1.44358). Factors optimised included grid hole diameter, hole spacing and the thickness of the grids. The engine could be improved further, says Farnell, by evolving the other parts too.