A high grade (700 series) aluminum and zinc alloy will be employed for the frame of the surface vehicle. After tempering and anodizing, this alloy should provide a desirable mix of durability, light weight, and strength. Other benefits of using aluminum are the ease with which it can be machined and its respectively low cost. Other options that were discarded included titanium alloys (too expensive and not sufficiently better than the aluminum to justify the increase in cost) and carbon fiber (though it is strong and light is also exceedingly expensive and not sufficiently abrasion-resistant to withstand the necessary 401 days on the Martian surface).