Space may be the final frontier but the road to the future sometimes requires astronauts to take very terrestrial detours.
For instance, an international team participating in a European Space Agency training program recently spent six days in a dark cave on the island of Sardinia to simulate real exploration conditions. Why Sardinia? According to ESA, the island is chockablock with "isolated mountains and forest areas, rugged and savage."
For six days they lived and worked in the island's complex cave systems - some of them unmapped or unexplored.
"Even for astronauts, life in the dark, cool, humid underground environment can be a completely new situation with interesting psychological and logistical problems," according to Loredana Bessone, an astronaut trainer at the European Astronaut Centre in Cologne, Germany.
The caving team after return to the surface September 21: (clockwise from left) Randolph Bresnik from NASA, Sergey Ryzhikov from Russia, ESA astronauts Thomas Pesquet and Tim Peake, and Norishige Kanai from Japan in front.