They talk about high levels of radiation on a round trip to Mars which with present technology will take over 500 days round trip.
However, the article doesn't even mention work being done on much more advanced propulsion systems such as Vasimir which can get you to Mars in a month or less depending on how much power you can generate with either solar cells or atomic reactors, fission or fusion or antimatter, whatever.
The bottom line is not to forget going to mars but to develop truly advanced propulsion systems that can get us there in a week or so. For instance, the Vasimir with its month long trip to mars is a system that runs 24/7 but at a very low rate of acceleration, like 1/20th of a g, but continuously which ends up being 6 or 7 times faster than chemical rockets in spite of the very low accel, like so low that if you weigh 200 pounds on Earth, you would weigh 10 pounds on the space ship, barely enough to keep you in bed if you are asleep. But with this new data in mind, it is imperative to develop these newer propulsion systems.