Gateway Review And Virtual Interior Tools for Astronaut Systems (GRAVITAS) uses the latest computer graphics engine associated to the next generation XR-PC to render​ non-degraded CAD models of the lunar Gateway. This powerful tool enables ESA, in collaboration with European industrial companies, to assess habitability, make design choices, and validate numerous requirements using Mixed Reality. Experienced astronauts actively participate in VR reviews, ensuring that the upcoming lunar outpost is optimised for their living and working conditions around the Moon.