Near-Earth space is a complex, dynamic environment that affects not just objects in space, but our everyday lives as well. It exists as the interaction of energy and mass from a variety of sources. Earth, with its magnetic field and its atmosphere, interacts with the Sun to form the solar-terrestrial system, which accounts for most of the effects of the near-Earth space environment. Deep space sources (e.g., other stars and galaxies) contribute particle and electromagnetic radiation that also interacts with Earth. Finally, there are solid bodies within and passing through the solar system that can and do interact with Earth. All of these systems affect orbiting artificial satellites and also have more direct effects on life on Earth, right down to the planet's surface.

This illustration of the space environment shows the Earth, surrounded by Van Allen Radiation Belts...