ESA astronaut Jean-Francois Clervoy training for an underwater simulated mission, dubbed ‘Apollo 11 Under the Sea’, supported by French deep-diving specialists Comex. Lunar gravity can be simulated by adjusting the astronaut’s buoyancy – our Moon has a sixth of the gravity we feel on Earth.
A mockup spacesuit, based on Russia’s Orlan suit as used on the International Space Station, increases the fidelity of these simulations. The mockup restricts movements as a real pressure suit would and has exactly the right amount of buoyancy to let Jean-Francois feel partial gravity.