Animation showing the Orion spacecraft, powered by the European Service Module-5, as it separates from the SLS second stage and returns to collect the Gateway module Esprit, at the beginning of the Artemis V mission.

The mega Moon rocket SLS will propel four astronauts inside Orion to the Moon as well as deliver Esprit to the Gateway.

Once the exploration upper stage has finished its boost to the Moon, Orion will detach from the second stage and the European Service Module will use its 24 reaction control thruster engines to turn itself around and return to Esprit that flew to space under a separate compartment of the SLS rocket fairing. Orion will then attach itself to Esprit, pull it away from the second stage and tug it to the Gateway on its four-day journey to the lunar Gateway’s orbit.

Orion and the European Service Module will tug the module into position around the Moon and dock with the Gateway, pushing Esprit into position. The Esprit refuelling module is part of the Gateway’s core structure. The module is 4.6 m in diameter and 6.4 meter in length. It weighs around 10 tonnes on Earth filled with fuel.

The Esprit Refueling Module (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 (the white cylinder pictured above) and an unpressurised element surrounding part of the pressurised hull.

More on the Artemis V mission here.