ESPRIT Refuelling Module

The ESPRIT Refuelling Module (ERM) is part of the Gateway’s core structure. The module is 4.6 m in diameter and 6.4 m in length. It weighs around 10 tonnes on Earth filled with fuel.

The ERM has four main functions: transport cargo to the station, provide storage space once docked at Gateway, provide fuel to propulsion system of Gateway (NASA’s Gateway Power and Propulsion Element), and provide a view of space and the Moon through its windows.

The ERM has two main structural elements: the pressurised tunnel where astronauts can float inside and an unpressurised element surrounding part of the pressurised hull.

The pressurised tunnel is a habitable environment used for storage and offering passage between the two docking ports at each end of the tunnel. At launch the ESPRIT module is designed to hold cargo of up to 1.5 tonnes.

The pressurised tunnel has six windows and one workstation position, where astronauts can dock their laptops, cameras and other tools to work especially when an outside view is required, such as docking spacecraft or operating robotic arms.

The unpressurised system is a set of external volumes in which the module’s computer and refueling systems are hosted. The unpressurised system is clearly visible as octagonal gold ring around the white tunnel. Batteries are also mounted outside on the surface of the pressurised tunnel, providing power to keep ESPRIT operating at the right temperature on its voyage to the Gateway orbit.