A band of make-believe space travelers locked in a steel capsule in Moscow is about to “land” on Mars, mission managers said Friday, nearly halfway through their 520-day mission.

The tenacious Mars500 crew has been locked together for 233 days (as of Jan. 21) and are preparing for their mock arrival on Mars as soon as Feb. 12, the AP reports. The six-man crew, including three Russians, a Chinese, a Frenchman and an Italian-Colombian, are free to walk out on the experiment at any time, but as of now, they’re all in for the long haul, mission managers said.