Elon Musk wants to go to Mars. More precisely, he wants you or me to go. It’s a bad idea.
Apart from provisioning and energy problems that are potentially solvable, there are three big problems with a Mars mission: Getting there, getting back and being there. All three problems center around an insolvable radiation problem.
On Earth, molten material under the mantle slowly circles a solid iron core. This produces a dynamo effect generating an electrical current and a corresponding magnetic field. This magnetic field is well known, and is the basis for the simple magnetic compass that has been used for centuries.
This magnetic field also serves to divert away from the earth 99.9% of the radiation and cosmic rays that bathe the universe. The remaining tiny amount that is not diverted is largely blocked by the earth’s atmosphere. Our atmosphere blocks radiation as effectively as a slab of steel three feet thick.