[[File:Structure_of_the_magnetosphere-en.svg|thumb|upright=1.5|Schematic of Earth's magnetosphere. The [[solar wind]] flows from left to right.]]
The risk of [[Proton#Human_exposure|proton exposure]] from the [[solar wind]] as well as the [[health threat from cosmic rays]] iswould be significant. The Earth's [[magnetosphere]] protects against solar storms but provides little protection from the more energetic cosmic radiation - the Earth's atmosphere protects us from that{{cn|date=February 2018}}.
In the Earth–Moon system, the orbit of colonies at L3–L5 willwould take them outside the protection of Earth's [[magnetosphere]] for approximately two-thirds of the time (as occurs with the Moon). Colonies at L1 (located between Earth and the Moon) willwould experience this to a lesser degree, whereas L2 (located beyond the Moon) willwould experience this to a greater degree and all of them willwould be exposed to the little-understood [[plasma sheet]] of the [[Magnetosphere#Magnetic tails|magnetotail]].<ref>[http://www.nasa.gov/topics/moonmars/features/magnetotail_080416.html The Moon and the Magnetotail - Tony Phillips (2008)]</ref>
In the Sun–Earth system, L1 and L3–L5 are all outside the protection of Earth's magnetosphere. L2 periodically transfers from within the magnetotail, plasma sheet, and solar wind, depending on the intensity and direction of the solar wind.
Solar storm shielding iswould only be needed occasionally and it iswould also be easier to protect against in a shelter settlers could retreat to during a major storm. Cosmic radiation doses build up more slowly over years of exposure, and needswould need a couple of meters or more of shielding. Designs for space habitats usually supply this with an external shield of regolith or other materials.{{cn|date=February 2018}}
