Just before this BBC podcast gets underway, here's something you may not know.

My name's Linda Davies and I Commission Podcasts for BBC Sounds.

As you'd expect, at the BBC we make podcasts of the very highest quality featuring the most knowledgeable experts and genuinely engaging voices.

What you may not know is that the BBC makes podcasts about all kinds of things like pop stars,

poltergeist, cricket, and conspiracy theories and that's just a few examples.

If you'd like to discover something a little bit unexpected, find your next podcast over at BBC Sounds.

Hello and welcome to the Witness History Podcast from the BBC World Service with me Alex Last

and today a story about isolation

as we go back to 2010 and the Mars 500 experiment in Moscow when for almost 18 months six men were

locked inside a simulated spaceship to test human endurance for a possible trip to Mars.

We knew that no human had done this before.

You don't know exactly how you're going to react. It was very uncertain what

could happen psychologically, physically.

Diego Obina is a space systems engineer, but back in the late 2000s he just completed an internship

at the European Astronaut Center when he saw an advert for a very unusual opportunity.

It was a call for volunteers to be locked inside a fake

spaceship on Earth for 520 days. It was the final stage of the Mars 500 experiment set up by Russia, China and the European Space Agency

to see how people would cope if they were cooped up for the duration of a potential trip

to Mars. The purpose of the mission was to study the isolation and confinement of a trip to Mars

with a duration that is representative of the real trips, a full round trip trip that's about one year and a half

and studying to human psychology and human physiology during such a trip. I was very

interested in learning what it would be like because my intention was to

...