Musk is no genius when it comes to launching a Mars mission from Earth. It is far more wise to stage and build the spacecraft from lunar orbit and shield the craft with water from lunar polar ice.

Its only a couple days journey to lunar orbit that limits exposure to solar and cosmic radiation. Spending a year or more in an unshielded craft all the way to Mars is a good way to kill astronauts if you give a damn.

Yes we have had astronauts in lower Earth orbits for a year but that still limits radiation poisoning with the Earth's magnetic shield.