How far underground do you need to be on Mars to be protected from the radiation of the Sun?
Could a future Martian colony become self sufficient ? I am thinking mainly of power generation, ability to make air to breath, water , growing food, mining metals and chemicals from the surface.
Since the Hellas impact site and the Mariner Valley both are roughly as deep as Mt. Everest is tall, would it be possible to have a "shirt-sleeve" (non-pressure suit) environment at the bottom?
