Today, an international team of six astronauts from China, Japan, USA, Spain and Russia will descend into the caves of Sardinia, Italy, to explore the depths and train for life in outer space.

One of the last unexplored environments on our planet, caves offer parallels to exploring space. ESA’s underground training course “Cooperative Adventure for Valuing and Exercising human behaviour and performance Skills” – CAVES – prepares astronauts over two weeks to work safely and effectively in multicultural teams.

After a week of training, the astronauts are now descending 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.”

In every expedition, the astronauts work with seasoned instructors and explorers. “A mutual trust builds as stories and anecdotes are shared,” says mission director Loredana Bessone. “The atmosphere is always one of respect.”

CAVES focuses on multicultural approaches to leadership, following orders, teamwork and decision-making. At the end of the course the astronauts will have a better understanding of how they function in a multicultural team and what they are skilled at, as well as areas for self-improvement.