With our current level of technology, at the time of this writing, a manned mission to Mars would take only eight months to arrive at the famed red planet. While this is certainly a lengthy space of time it’s not as unheard of as it may at first sound. In the early days of ocean exploration, some crews would be at sea for months or years at a time.
The difference is those ancient sea ships would occasionally come into port or weigh anchor at an island where the crew could get out and relax on land. And although the ships themselves weren’t huge, especially when you factor in the number of crew on them, there was still space for the crew to walk around and stretch their legs.
The available space on a current spacecraft would be tiny. The crew wouldn’t be able to move around much during the entire eight-month voyage and there’s no way they could stop in at an island if they wanted to rest for a few days. So while the length of such a trip might not be beyond the realm of possibility, real attention would need to be paid to how much space those voyagers are afforded.
The one thing that would really spur the attempt to get to Mars would be if one of the Martian rovers found some verifiable ancient alien artifacts, however unlikely that would be. If that were to happen, all resources would pivot full-tilt to get people to Mars and begin the real exploration.