A trip to Mars using current propulsion technology takes several months. During that time, astronauts will be exposed to solar and cosmic radiation. In Iowa, a group of undergrads is working the problem.
Here’s the most thorough evaluation of the the latest push for the Moon that I’ve found. The TL;DR is that the winds are all over the place. This push is likely to fail. But we should root for it anyway because it’s shaking things up.