> By the nature of the beast, a spacecraft with humans is going to have absolutely thunderous mass and energy budgets compared to robotic ones, so any instrument you can put on a robot you can put on a manned mission.
By the nature of the beast, for the cost of a single manned mission, you can launch dozens of expendable, unmanned missions, that can go on for more than a few days. Robots don't need to eat, or breathe, and they don't grouse when you abandon them on an alien surface.
