Storm shelter
A storm shelter is a place where colonists can take refuge from a solar flare. The main settlement will be well shielded, so it in itself will be a storm shelter. However, manned rovers, railroad cars, airship and landers will need emergency shielding if a solar flare occurs. A good material for this is polyethylene, because it contains many hydrogen atoms, is light and can be made on Mars easily.
Open issues
- Is there any way of measuring high radiation levels on the surface of Mars? If such levels are detected, will it be too late?
- Even with space access, an autonomous colony will not be able to launch its own satellites to monitor the sun.