Getting to Mars is a big jump compared with going to the moon, since you’re traveling 500-1000x farther on any efficient route, and have to do much more to keep the astronauts from getting irradiated, or hopelessly weakened by the lack of gravity. Getting to Pluto is 100x farther than that, so you would need to do some special things to, e.g., not have your astronauts die of old age on the trip.
This is all true, but these jumps in difficulty are nothing compared with the jump in difficulty of getting to the moon (or even LEO), versus getting between any two points on Earth.
Getting to Mars is a big jump compared with going to the moon, since you’re traveling 500-1000x farther on any efficient route, and have to do much more to keep the astronauts from getting irradiated, or hopelessly weakened by the lack of gravity. Getting to Pluto is 100x farther than that, so you would need to do some special things to, e.g., not have your astronauts die of old age on the trip.
This is all true, but these jumps in difficulty are nothing compared with the jump in difficulty of getting to the moon (or even LEO), versus getting between any two points on Earth.