The environmental conditions on Mars do not allow human beings to live without technical equipment, not even for a minute. While people on Earth can live from the nature's air, water, etc. this is not an option on Mars. Instead, people are bound to an artificial environment inside of buildings, rovers and space suits. The life support equipment must run 100% reliably. This article describes principles for a fail-safe construction.
Every system is built twice or more, where each can work independent from the other. The capacity of each system is big enough to support the full service in case of failure of one system. In normal operation both systems are running in parallel with half load. This principle provides the best reliability for the whole function.
Example: The number and size of solar panels is at least twice as big as actually needed for vital system operation. In normal operation mode the surplus energy can be used for additional convenience.
Services must be available independent from the failure location.
Example: If building A and building B have their own air supply system then People in building A can get air from building B in case of a failure in the air supply system of their own building.
A standby system is automatically powered up, or can be manually brought into operation shortly. Advantage: The system is not subject to full maintenance effort during standby mode. Risk: If not checked in regular intervals the backup system may not be able to work if needed.