>How did they get through the Ionsphere?
https://www.popularmechanics.com/space/moon-mars/a24678/nasa-van-allen-belts-explainer/
It's always difficult being the first, especially when you're going into space. The Apollo program encountered many difficulties on its trip to the Moon, ranging from mechanical to astrophysics. The issue of the Van Allen belt and its radioactivity was a particularly serious concern while planning the mission.
Fortunately, it was a problem with a solution, one that involved skirting the most dangerous parts of the belt, and making sure the astronauts got through it as quickly as humanly possible.