during the 1173 sol-stay on the martian surface the crew would carry out a number of expeditions across the polar ice cap. expeditions to the chasma boreale and along the polar spiral valleys were considered in detail. the study also considered the possibility of exploratory mid-winter expeditions across the polar ice cap. these expeditions would be supported by pressurised and unpressurised rovers. trafficability issues of trans-polar expeditions were considered.