re: re:The time problem about Mars
The Moon was much more a technical challenge than a medical one.
Spending 1 or 2 weeks on the Moon would not be different. Of course, solar activity would have to be predictable or at least well monitored.
When it's about Mars, it's not just a technical challlenge but much much more a medical challenge and we all know what astronauts think about them being under constant medical surveillance.
Even with scientists in shuttle flights, there are no available records of astronauts getting space sick, for privacy reasons.
More time in space means accumulating problems not just affecting their bodies but everything they take with them for survival.