and that's really just the cost the actual mission. Consider the impact of having to prepare a program that meets acceptable risk levels for humans vs. machines

and that's really just the cost the actual mission. Consider the impact of having to prepare a program that meets acceptable risk levels for humans vs. machines. This is a huge consideration. I'm not suggesting unmanned exploration can take a trial and error approach, but losing a robot is sad & expensive while losing a human astronaut can terminate the entire program.