Our landing site occupies a large area. It contains many key areas of interest interspersed across relatively vast distances around our martian base. To effectively run a comprehensive search of life, our astronauts will need to have some form of access to these distant sites. They must have the ability to obtain both visual and scientific data of these sites. They must be capable of retrieving samples of the martian surface at these different sites.

There are two main limitations to the astronauts' capabilities of reaching these sites: range and coverage. Even with the human-controlled rover, the astronauts will not be capable of travelling out farther than 75 km. This is due to a variety of factors that come together under a conceptual heading of limited resources. Oxygen is limited. Food is limited, and the astronauts will not be capable of eating on the rover as it is not pressurized. Human comfort levels are a limiting factor. It is too much to ask the astronauts to stay out in the field in an uncomfortable suit for inordinate amounts of time. Safety is a crucial factor. NASA policy on the Moon was that the astronauts never drove further than they could walk. This would allow the astronauts to return in case of a malfunction with the rover.

All these elements limit the amount of time the astronauts can spend out in the field, and thereby limits the maximum travelling range of an astronaut from the base. Analyzing a sample of soil by an astronaut is time consuming, and therefore detailed coverage is inhibited. These factors greatly affect the astronauts' abilities to fulfill the primary goal of the mission: finding life on Mars.