Here is some interesting information about the relationship between the amount of very high energy cosmic rays (really the nuclei of atoms) entering the solar system and the weakening of the sun's magnetic field. The sun's magnetic field has become much weaker over the last 2 years and the concentration of cosmic rays in the solar system has become much higher. When the sun's magnetic field is strong, it protects the solar system from many of the cosmic rays by turning them away from the solar system like a magnetic shield. When the sun's magnetic field is weak (like the last 2 years) much higher numbers of cosmic rays enter the solar system. The high-energy particles that make up the cosmic rays pose a danger to astronauts in interplanetary space and to the electronics in the spacecraft.
The weaker magnetic field of the sun also seems to occur when the sun is producing less energy as heat and light, and causing lower temperatures on Earth. Cosmic rays hitting the Earth react with the atoms of oxygen and nitrogen in the atmosphere to produce radioactive beryllium-10 atoms that are otherwise very rare on Earth. High concentrations of beryllium-10 atoms in dated ice cores from Greenland indicate periods of time with higher concentrations of cosmic rays, a weaker magnetic field from the sun, and lower temperatures on Earth.
These are some very interesting correlations. There is more to the increase of cosmic rays than just a greater danger of flying to Mars.
Cosmic Rays Hit a Space Age High