Launching from the surface of Mars takes a lot less fuel, too. Martian gravity also happens to be high enough for earth manufacturing machinery to mostly work a

Launching from the surface of Mars takes a lot less fuel, too. Martian gravity also happens to be high enough for earth manufacturing machinery to mostly work as it does here on earth, meaning that we can mostly reuse the systems we're using today. These two factors combine to make Mars quite ideal for building and launching staggeringly huge space vehicles, habitats, and mining machinery which in turn makes bootstrapping a human presence in the asteroid belt and other locations in the solar system a lot easier than if we were to just start at those destinations.