The following is Science The Wire’s attempt at explaining how Apollo 11 was able to get through the Van Allen belts. “ When NASA commenced its lunar spaceflight program, its scientists already knew about the belts and their spatial and energy distribution. Apropos the energies: electrons below about 1 MeV were unlikely to be dangerous, as were protons below 10 MeV. For example, a proton with an energy of 3 MeV could penetrate about 6 mm of aluminium (a typical spacecraft material) whereas one of 100 MeV could penetrate up to 40 mm. So engineers fashioned shielding that consisted of a spacecraft hull and all the instrumentation lining the walls. Further, knowing the belts’ absence above the poles, the altitude of the lower edge of the inner belt being ~600 km (well above the LEO) and the location of the South Atlantic anomaly, where doses are at a high 40 mrads/day at an altitude of 210 km allowed NASA to design the Apollo translunar injection (TLI) orbit in a way that the spacecraft would avoid the belts’ most dangerous parts. Apollo 11 bypassed the inner belt and only passed through the weaker part of the outer belt (Fig. 4). According to NASA’s ‘The Apollo Spacecraft: A Chronology’, the high-altitude nuclear tests would have had a significant impact on Apollo orbits but NASA scientists had accounted for this possibility in radiation-protection planning.” https://science.thewire.in/the-sciences/apollo-11-van-allen-radiation-belts-translunar-injection/