Astronauts squeeze through a tight spot during ESA's underground astronaut training course CAVES, June 2016.
CAVES stands for Cooperative Adventure for Valuing and Exercising human behaviour and performance Skills. The two-week course prepares astronauts to work safely and effectively in multicultural teams in an environment where safety is critical – in caves.
After a week of surface training, the astronauts descend into the caves to set up basecamp 800 m underground.
The similarities between caving and spaceflight are highlighted throughout the course. Speleologists and astronauts adopt the ‘buddy system’, and both astronaut trainers and CAVES instructors repeat the same mantras of “slow is fast,” “check your gear, and then trust it,” and “always be aware of where you are and where your buddy is.”