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Quote: The thought that radiation would kill the astronauts on their way to the moon rests on a misunderstanding of radiation in space. It is true that the sun can release intense bursts of radiation, but not all radiation is harmful. Radiation from the sun can be measured in terms of solar particle energies. These range in intensity. The low energy particles, which measure in the thousands of electron volts, can easily be stopped by a space-craft's hull or a space suit. At the other end of the scale, the very high energy particles (over 1000 million electron volts) can pass right through a space-craft and the people on board without actually interacting with their body cells. The most dangerous particle energy level sits somewhere in the middle (in the millions of electron volts). During a solar flare, particles at all energy levels are produced and this can be very dangerous for astronauts. Fortunately, solar flares do not occur everyday and they do not send particles out in all directions. An understanding of radiation in space shows us that an astronaut on a trip to the moon will not necessarily be exposed to dangerous levels of radiation. Of course, this is not to say that there are no risks. A solar flare in the wrong direction could do serious harm to an astronaut. But such flares are not everyday occurrences. Furthermore, being exposed to a high dose of radiation does not guarantee illness, cancer, or death. It merely raises the probability. It is possible for an astronaut to live a long healthy life after being exposed to radiation levels produced during a solar flare. For the Apollo missions specifically: •The trajectory of the spacecraft was not a straight line between the earth and the moon. It was arced. They did this in order to avoid the densest area of radiation in the van Allen belts. •At the speed the capsule was travelling, the crew spent far less time inside the belts than the amount of time needed to give them a lethal dose. •There are different types of radiation, wave and particle. Wave radiation requires the most shielding, sometimes very thick shielding depending on the wavelength (for example, UV radiation is wave radiation, but can be blocked by a thin sheet of plastic like sunglasses, whereas gamma radiation requires several inches of lead). Particle radiation, in comparison, is much easier to shield against. Alpha particles can't even penetrate the top layer of dead skin cells on the human body. Proton and Beta particles can both be shielded against using a centimeter or so High Density Polyethylene (HDPE). Plastic. •The Van Allen belts consist primarily of Proton Particle radiation, which, as noted above, can be effectively shielded against using HDPE plastic. •The Command Module was built using materials that could shield particle radiation •Summary: The mission was planned to go through the weakest, least dense section of radiation, in the shortest amount of time, with shielding built into the module. NASA spent a lot of time and money mitigating the problems presented by the radiation belts. The money was well spent.