One of NASA’s many projects running concurrently to its space missions is NEEMO. It stands for NASA Extreme Environment Mission Operations and it prepares a crew for the conditions of space by putting them through ‘analog’ test missions: in other words, terrestrial missions which are analogous, or comparable, to those they will encounter on leaving this world.
An analog mission might require an astronaut to sit in a giant centrifuge and be spun at dizzying g-forces and various pressures in a specialised chamber or, in the case of NEEMO, it might focus on underwater activities that simulate low gravity.
The base is a habitat located 19 metres (62 feet) underwater that weighs around 85 tons.
The astronauts-in-training can stay in the habitat for several weeks, with training simulations like moving from one workstation to the next, using tools and working in an asteroid space environment.