re: Arctic astronauts return from frontier
A person doesn't necessarily simulate a whole mission each time they run a sim. They may want to focus on some aspect of a mission.
The flight time is usually not simulated at Devon or MDRS. Some Astronauts have proposed a full up sim which would include a year stay at MDRS or FMARS with two 6 month stays at ISS or some orbiting platform as bookends.
The trip can be as little as 3 months with nukes or some other advanced proplusion system (tethers, M2P2, etc...) But, usually is figured as 6 to 9 months.