Six international crew members emerged from a Moscow space research facility on Friday, after spending 520 days in isolation as part of a real-time virtual mission to Mars.

Since June of last year, the crew was confined to four hermetically sealed habitat modules that simulated the psychological and physiological effects of interplanetary travel – minus the weightlessness.

The crew members appeared to be pale, but were reported to be in good health after emerging from the mock spacecraft.

They will undergo several days of medical check-ups as they re-adjust to life outside the facility.

The crew consumed only canned food and was only permitted to communicate with the outside world via email, which was delayed and periodically interrupted to imitate an actual space mission.

Researchers hope the experiment will provide valuable insight into how to conduct a real mission to Mars.

The program was a joint mission between the European Space Agency and the Russian Institute for Biomedical Problems.