Space radiation is one of the primary environmental hazards associated with space flight.
Crew members are subjected to greater amounts of natural radiation in space than they receive on Earth, exposing them to immediate and long-term risks. Trapped belts of energetic particles, found in the Earth's magnetic field, consist predominantly of protons and electrons. A solar particle event, which sometimes accompanies CMEs, may be the most potent space radiation hazard. High-dose radiation exposure can lead to acute radiation sickness. It has the potential to cause late effects, such as cancer and cataracts in humans.