I.7 Interplanetary environments

The interplanetary environment is characterized by cosmic rays and occasional solar energetic particle events. For mission analysis, it is important to take into account the variations in particle intensities with heliocentric radius and solar cycle modulation as specified in 9.2.2.

Science missions also take place at the Lagrangian points of the SunEarth system or EarthMoon system, locations which are usually considered interplanetary from the point of view of the radiation environment.