You've made a lot of arguments along the line of "it's difficult difficult difficult" but haven't given a specific example of why it can't be done. What do you think of self-driving cars? That was difficult too, and basically the same kind of problem (autonomous navigation). In fact, it's probably easier than robocars since it's much emptier up there.

The hardest part is building satellites in space, which they haven't said they will do (but I think is possible, as described in the 1980 study).