In terms of "understanding the environment around you such that you can land a booster stage," it's not a particularly hard problem. The challenges are about d

In terms of "understanding the environment around you such that you can land a booster stage," it's not a particularly hard problem. The challenges are about designing a booster stage that can handle the flipping and reentry, then figuring out the details of how to stick the landing with several times your empty weight as your minimum thrust. "Where am I, and what's between me and my destination?" isn't the hard part, as it is with surface driving.