The Griffiths Free-Flying EVA Logistics Sled (NGLS)

Abstract

As deep-space habitats, propulsion modules, and distributed construction platforms grow in scale and operational complexity, existing EVA mobility systems are no longer adequate to meet the increasing logistical demands on human crews. Conventional astronaut maneuvering units, such as SAFER and the historical MMU, were primarily designed for personal mobility and emergency self-rescue, rather than for transporting heavy equipment, structural components, or modular payloads across expansive spacecraft and habitat exteriors. The Griffiths Free-Flying EVA Logistics Sled (NGLS) addresses this critical gap by introducing a dedicated logistics-focused EVA architecture. It features dual high-pressure cold-gas propellant tanks, vectorable thruster assemblies, full six-degree-of-freedom control, autonomous stabilization, and modular cargo interfaces integrated into a lightweight composite frame. Designed for both piloted and autonomous operation, the system incorporates multiple redundant safety mechanisms, including fail-closed valves, dead-man stabilization, collision-avoidance sensors, and autonomous return-to-base capability, ensuring safe operation in proximity to complex, rotating, or thermally active structures. Performance modelling indicates that the NGLS can achieve an operational Δv of 50–150 m/s, transport payloads of 50–200 kg, and sustain sortie durations of 10–45 minutes, enabling logistics operations that extend well beyond the physiological limits of a suited astronaut. Furthermore, the architecture integrates seamlessly within the broader Griffiths ecosystem, supporting external maintenance of the Dual-Ring Habitat, inspection of propulsion modules such as the GNMT-Drive and MSH-Drive, and last-mile delivery of DIMDCP-fabricated components. Overall, the NGLS represents a practical, manufacturable, near-term solution that formalizes EVA logistics as a distinct and essential operational domain.