The incoming transit gallery connecting the canyon airlocks with the habitat vehicle maintenance hangars. Excavated in the canyon wall massif using 'Room and Pillar' cutting techniques to provide large usable spaces with substantial roof support and stability. This works well with a relatively soft medium such as in the coal-mining industry on Earth, and is particularly applicable in the case of harder Mars regoliths with the lower gravity allowing more scope for spacious yet stable excavated galleries. Cross-members support roof rock-debris screen, power cabling, and environmental atmosphere conduits, as well as signal lights controlling the direction of transit. Overhead lighting is of the low-wattage, thin-film, cold-running, electroluminescent-panel type. The transit tunnel travels deep into the canyon massif to maximise the benefits of thermal and radiation protection, as well as from any large meteoric impacts that might descend into the canyon itself.