Proposed Retractable Pressurized Tunnels for Crewed Mars Missions

• NASA and university partners are developing retractable, pressurized tunnel concepts for future crewed Mars missions to eliminate the need for cumbersome EVA (Extravehicular Activity) suits for short surface transits.
• Current EVA procedures for moving between habitats and vehicles are time-consuming and pose risks related to decompression and radiation exposure.
• Eliminating EVA suits for routine surface transit could save approximately 560 kilograms of propellant per Mars Ascent Vehicle (MAV) trip.

BLiSS Tunnel Concept

• Developed by the University of Michigan's Bioastronautics and Life Support Systems (BLiSS) team, the LATCH (Lightweight Actuated Tunnels for Crewed Habitation) system was submitted for the NASA 2026 M2M X-Hab challenge.
• The design features an inflatable, motorized shell with structural rings, track units, and an automated interface for alignment and connection.
• Tunnels are pressurized with oxygen and nitrogen after docking, allowing up to two crew members to transit without suits.
• Retractable design reduces structural wear, radiation exposure, and dust accumulation when not in use.

Risk Mitigation and Alternative Approaches

• The BLiSS team conducted a full risk analysis, incorporating floor reinforcement to support heavy loads and multi-sensor fusion (LiDAR and computer vision) for precise docking.
• Baldwin Wallace University also proposed a competing concept, T.R.E.A.D (Tunnel Ready Elements for Active Deployment), which utilizes a double-tendon, winch-driven actuation system for flexibility over uneven terrain.
• Both projects emphasize reusability and operational efficiency to support long-term Martian exploration.