The Mars habitat will be a modular environment made up of multiple inflatable units, and will comprise about 1000 m3 of total living space, which equates to 250 m3 per inhabitant for a team of four. The astronauts will be staying on Mars for a long time, and they will need as much comfort as possible there.
As the habitat will be modular, and constructed using fully redundant systems, even if one inflatable unit is damaged beyond repair, the habitat will still be secure and fully functional, and there will be enough remaining volume available for relatively comfortable living until a replacement unit can be delivered.
The flight will take between seven to eight month. The transit habitat will feature less than 20 m3 of living space per astronaut. Showering with water will not be an option, there will be constant noise, and freeze dried and canned food is the only food on the menu. The trip to Mars will be tough, as we also explain on the Mars One Astronauts page. Mars One is proposing a mission of exploration, not luxurious living in space. However, the astronauts are living their dream - they are going to Mars!
By comparison, the explorers that sailed with Columbus across the Atlantic in 1492 had living space on board of less than 10 m3 per person.