From left: Roscosmos’ cosmonaut Nikolai Tikhonov, David Saint-Jacques from the Canadian Space Agency, NASA’s Drew Feustel, ESA astronaut Andreas Mogensen, JAXA’s Soichi Noguchi and Mike Fincke from USA.

An international crew of six astronauts are training for a caving adventure designed to prepare them for spaceflight. There are many similarities to spaceflight such as a lack of day–night cycle, sensory deprivation, minimal hygiene and the necessity to work as a team and solve problems together.

After a week of training they entered the caves to spend six days living and working underground.