I'm confident that if they tried to launch a Mars mission with current-day technology now, the crew wouldn't make it. Nobody's ever been in space for that long, to start - yet Musk wants to deorbit the ISS, the only viable platform at the moment to even try and simulate a two year space trip.
The annoying thing is that we could’ve been simulating long duration partial gravity using artificial gravity for decades, but NASA has refused to do so. For inexplicable reasons. If I had to guess, it’s due to the microgravity research community fiefdoms who have made a career of microgravity health effects and so don’t like the idea of directly addressing them using artificial gravity as it makes a whole career’s worth of work largely obsolete.
Not if you want it dependable enough to entrust a multi billion dollar project and several people’s lives to it.
People talk about the moon mission like some massive conquest of space, but we needed to get the fuck off the moon much past sunrise or astronauts would have cooked. It was based on extremely limited oxygen supplies and involved significant radiation exposure that was only ok because again we ran away from an extremely inhospitable environment before things went wrong.
Even today the ISS benefits from earths magnetic field, its space light not a true replica of a mars mission.